52911 November 2009 Water and Climate Change: Understanding the risks and making Climate-smart investment deCisions Vahid Alavian Halla Maher Qaddumi Eric Dickson Sylvia Michele Diez Alexander V. Danilenko Rafik Fatehali Hirji Gabrielle Puz Carolina Pizarro Michael Jacobsen Brian Blankespoor November 2009 Water and Climate Change: Understanding the risks and making Climate-smart investment deCisions Table of ConTenTs . Foreword. ...................................................................................................................... ix Acknowledgements...................................................................................................... xi . AbbreviAtions.And.Acronyms. ................................................................................... xiii executive.summAry........................................................................................................ xv introduction................................................................................................................ xv the.context................................................................................................................. xv . climate.change,.hydrologic.cycle,.and.water...............................................................xvii water.sector.is.highly.exposed.to.climate.change.with.implication.. beyond.the.sector........................................................................................................xix world.bank.water.investments.and.climate.change........................................................ xx Projections.of.key.hydrologic.indicators.for.water.planning............................................xxii . exposure.of.the.bank.investment.to.climate.change..................................................... xxvi climate-smart.investments.must.explicitly.consider.risk................................................ xxvii way.forward............................................................................................................. xxix . cHAPter.1:.context.And.overview. ............................................................................. 1 introduction................................................................................................................. 1 climate.change.and.the.world.bank............................................................................. 2 climate.change.and.the.water.sector............................................................................. 3 value.added.and.content.of.this.report.......................................................................... 5 cHAPter.2:.imPAct.oF.climAte.cHAnge.on.tHe.Hydrologic.cycle.And.tHe.. . wAter.resource.bAse. .................................................................................................... 9 . the.climate.system.and.the.hydrologic.cycle.are.intimately.linked.................................... 9 evidence.is.mounting.that.climate.change.is.occurring.and.that.it.is.altering.. the.hydrologic.cycle.................................................................................................... 10 Future.changes.in.climate.are.projected.to.lead.to.a.further.acceleration.. and.intensification.of.the.hydrologic.cycle.................................................................... 11 Hydrologic.change.and.increased.variability.will.have.a.significant.impact.. on.the.water.resource.base......................................................................................... 14 uncertainties.in.projected.climate.change.impacts................................................ 14 . runoff.and.river.discharge.................................................................................. 14 . groundwater..................................................................................................... 15 . water.quality. .................................................................................................... 17 . Floods.and.droughts. ......................................................................................... 18 Freshwater.ecosystems........................................................................................ 19 cHAPter.3:.imPAct.oF.climAte.cHAnge.on.wAter.AvAilAbility.And.use................. 21 . climate.change.is.expected.to.increase.global.water.stress.and.insecurity. ..................... 21 surface.water.stress.assessments.......................................................................... 21 groundwater.stress.assessments.......................................................................... 22 . water.security.................................................................................................... 22 transboundary.basins......................................................................................... 23 . water.dependent.sectors.and.climate-induced.hydrologic.changes................................ 24 iii Health............................................................................................................... 24 Agriculture......................................................................................................... 26 . industry.and.transport.sector............................................................................... 27 energy/Hydropower............................................................................................ 27 . natural.ecosystems. ........................................................................................... 28 impact.of.non-climatic.drivers.on.water.availability.and.use.patterns.............................. 29 cHAPter.4:.tHe.cost.oF.vulnerAbility.to.Hydrologic.cHAnge.And.. . increAsed.vAriAbility.................................................................................................... 31 . the.developing.world.is.particularly.vulnerable.to.climate.change. ................................ 31 vulnerability.to.surface.water.stress...................................................................... 32 vulnerability.to.groundwater.stress....................................................................... 32 costs.to.the.most.vulnerable....................................................................................... 34 implications.for.sustainable.development.and.the.bank's.mission.for.. . poverty.reduction. ...................................................................................................... 35 cHAPter.5:.climAte.And.Hydrology.Projections.For.investment.decisions.... 37 introduction............................................................................................................... 37 key.issues.in.climate.change.impact.assessments.......................................................... 37 resolution.and.scale.in.impact.assessments.......................................................... 37 generating.and.capturing.climate.change.projections........................................... 40 Analytical.framework.................................................................................................. 41 key.hydrologic.variables.for.water.planning.and.management............................... 41 . sres.scenarios.and.gcms. ................................................................................ 42 timeframe.of.analysis......................................................................................... 42 Application.of.tools.to.dialogues.at.national,.river.basin.and.. Project.level.Analysis.......................................................................................... 43 Hydrologic.drivers.and.data........................................................................................ 44 . Historical.climate. .............................................................................................. 44 . Historical.observed.runoff................................................................................... 44 Historical.indicators.as.baseline.for.future.water.investment.assessment.................. 44 . Projections.using.climate.moisture.index. .................................................................... 47 . runoff.projections. ..................................................................................................... 49 basin.yield.projections................................................................................................ 49 extreme.events.projections.......................................................................................... 52 base.flow.projections.................................................................................................. 57 . net.irrigation.demand.projections............................................................................... 59 cHAPter.6:.climAte.cHAnge.And.tHe.world.bAnk.wAter.PortFolio.................... 63 introduction............................................................................................................... 63 Framework.for.analysis............................................................................................... 63 . content.of.the.water.portfolio..................................................................................... 64 climate.change.content.of.the.portfolio....................................................................... 67 Adaptation.to.climate.change.in.the.portfolio....................................................... 67 types.of.Adaptation.interventions.as.identified.in.the.Portfolio................................ 69 cHAPter.7:.exPosure.oF.tHe.wAter.PortFolio.to.current.Hydrologic.. . vAriAbility.And.Future.climAte.cHAnge.................................................................... 75 introduction............................................................................................................... 75 iv exposure.criteria.and.investment.exposure.................................................................... 75 exposure.to.current.hydrologic.variability.and.future.climate.change.............................. 76 irrigation.and.drainage....................................................................................... 76 urban.water.supply.and.sanitation....................................................................... 77 . rural.water.supply.and.sanitation........................................................................ 77 Flood.control.................................................................................................... 78 river.basin.management.and.multi-purpose.infrastructure..................................... 78 . Potential.exposure.of.the.investment.portfolio............................................................... 84 cHAPter.8:.risk-bAsed.decision.mAking.For.`climAte.smArt'.investments........... 87 introduction............................................................................................................... 87 sector.investment.decisions.must.be.made.under.increased.risk.and.. uncertainty................................................................................................................. 88 A.framework.for.risk-based.decision.making.for.water.investments................................. 90 definitions.and.terminology................................................................................. 90 risk-based.decision.framework............................................................................ 93 stage.1.­.identify.problem,.objectives,.performance.criteria.and.rules.. for.decision-making............................................................................................ 93 stage.2.­.Assess.risks......................................................................................... 94 stage.3.­.identify.and.evaluate.options.to.manage.risk......................................... 95 considerations.for.the.water.sector.............................................................................. 96 . susceptibility.of.water.systems.to.climate.change. ................................................. 96 Adaptation.options.for.water.systems................................................................. 96 . categories.of.adaptation.options. ....................................................................... 98 class.of.projects.for.which.risk-based.analysis.would.be.particularly.essential....... 100 . Assessing.risk:.application.to.multi-purpose.infrastructure.projects................................ 101 . Hydrologic.drivers.for.multi-purpose.hydraulic.infrastructure................................ 101 Project.components.......................................................................................... 101 . mapping.the.climate.change.impact.onto.project.components. ........................... 103 . scoring.of.component.risk. ............................................................................... 103 Assessment.of.project.components.most.at.risk................................................... 105 cHAPter.9:.next.stePs:.An.AgendA.on.climAte.cHAnge.. For.tHe.wAter.PrActice............................................................................................. 107 continue.to.strengthen.the.analytical.foundation........................................................ 107 incorporate.hydrologic.variability.and.climate.resiliency.considerations.. in.bank.operations................................................................................................... 108 . strengthen.bank.expertise.on.water.and.climate.change. ............................................ 109 cHAPter.10:.reFerences.............................................................................................. 111 Annexes Annex.A:.summAry.oF.wAter.PortFolio.by.region............................................... 115 Africa.region........................................................................................................... 115 . east.Asia.and.Pacific.region. .................................................................................... 116 . europe.and.central.Asia.region. .............................................................................. 117 . latin.America.and.caribbean.region. ....................................................................... 119 middle.east.and.north.Africa.region......................................................................... 120 south.Asia.region.................................................................................................... 121 v Annex.b:.risk-bAsed.decision.mAking.FrAmeworks............................................... 123 . united.kingdom.climate.impacts.Programme. ........................................................... 123 Australian.greenhouse.office................................................................................... 125 Annex.c:.AdAPtAtion.oPtions.For.multi-PurPose.inFrAstructure..................... 129 . Annex.d:.glossAry.oF.terms. ................................................................................... 133 Figures distribution.of.world.bank.water.projects.for.Fy06­08.(active).and.Fy09­10.(pipeline)...........xxi . water.investments.by.volume.and.category.(services/resource.management)..........................xxii climate.moisture.index:.range.of.cgms.for.three.emission.scenarios.for.various.regions...... xxiii Projected.percent.change.in.hydrologic.indicators.for.2030.from.1961­1990.baseline.......... xxiv . Projected.exposure.map.by.hydrologic.drivers.(2030). .......................................................... xxv Potential.exposure.of.water.projects.to.climate.change.in.2030.and.2050............................ xxvi Potential.exposure.of.water.investments.to.climate.change.in.2030.and.2050...................... xxvii Figure.2.1:. the.Hydrologic.cycle...................................................................................... 10 Figure.2.2:. large-scale.relative.changes.in.annual.runoff.(water.availability,.in.percent).. . for.the.period.2090­2099,.relative.to.1980­1999........................................... 16 Figure.2.3:. global.estimates.of.climate.change.impact.on.groundwater.recharge................. 17 . Figure.3.1:. reported.countries.with.groundwater.depletion... .............................................. 23 Figure.4.1:. some.preliminary.results.for.applying.the.climate.vulnerability.index.(cvi).. for.comparison.of.vulnerability.by.region.at.present.and.in.30.years................... 32 Figure.4.2:. illustrative.map.of.future.climate.change.impacts.related.to.freshwater.. which.threaten.the.sustainable.development.of.the.affected.regions.................... 36 . Figure.5.1:. the.cone.of.uncertainty.in.scale.and.resolution.of.modeling. ............................. 39 Figure.5.2:. section.of.the.sAr.region.showing.0.5°.by.0.5°.grid.scale,.2.5°.by.2.5°.. (gcm).grid.scale.(dark.larger.grids),.and.catchment.boundaries.in.color............ 40 Figure.5.3:. range.of.relative.change.from.historical.climate.for.different.gcms... mean.is.shown.in.heavy.line............................................................................ 41 Figure.5.4:. multi-model.averages.and.assessed.ranges.for.surface.warming. ....................... 42 . Figure.5.5:. modeled.historical.baseline.indicators.at.catchment.scale.for.bank.regions.. (1961­1990)..units.are.in.mm/yr..................................................................... 45 Figure.5.6:. modeled.historical.baseline.indicators.at.catchment.scale.for.Africa.. (1961­1990)..lines.on.the.map.delineate.catchment.boundaries..units.are.. in.mm/yr........................................................................................................ 46 Figure.5.7:. climate.moisture.index.range.for.each.climate.scenario.and.. . each.bank.region. .......................................................................................... 48 Figure.5.8:. climate.moisture.index.range.comparison.of.bank.and.non-bank.regions. ......... 49 . Figure.5.9:. Projected.percent.change.in.runoff.for.2030..................................................... 50 Figure.5.10:.Projected.percent.change.in.runoff.for.2030.at.catchment.level.­.Africa.region.. . catchment.boundaries.are.not.delineated. ....................................................... 51 . Figure.5.11:.impact.of.climate.change.on.reservoir.yield.and.Adaptations. ......................... 52 Figure.5.12:.Projected.percent.change.in.basin.yield.for.2030.............................................. 53 Figure.5.13:.Projected.percent.change.in.basin.yield.for.2030.at.catchment..level.­.. Africa.region..catchment.boundaries.are.not.delineated................................... 53 Figure.5.14:.Projected.percent.change.in.low.flows.(drought).for.2030.................................. 55 Figure.5.15:.Projected.percent.change.in.high.flows.(floods).for.2030................................... 56 vi Figure.5.16:.Projected.percent.change.in.low.flows.(drought).for.2030.at.catchment.level.­.. Africa.region..catchment.boundaries.are.not.delineated................................... 56 Figure.5.17:.Projected.percent.change.in.high.flows.(floods).for.2030.at.catchment.level.­.. Africa.region..catchment.boundaries.are.not.delineated................................... 57 Figure.5.18:.Projected.percent.change.in.base.flow.for.2030................................................ 58 Figure.5.19:.Projected.percent.change.in.base.flow.for.2030.at.catchment.level.­.. Africa.region..catchment.boundaries.are.not.delineated................................... 59 . Figure.5.20:.Projected.percent.change.in.water.deficit.index.for.2030................................... 61 Figure.5.21:.Projected.percent.change.in.water.deficit.index.for.2030.at.catchment.level.­.. Africa.region..catchment.boundaries.are.not.delineated................................... 61 Figure.6.1:. classification.of.water.systems........................................................................ 64 Figure.6.2:. location.of.world.bank.water.projects.for.Fy06­08.(active).and.. . Fy09­10.(pipeline).. ....................................................................................... 65 Figure.6.3:. world.bank.water.lending.volume.(shading).and.class.(bar).for.Fy06­08.. ......... 65 . Figure.6.4:. water.lending.as.a.share.of.overall.regional.lending.in.the.Fy06­08. ................ 66 . Figure.6.5:. world.bank's.water.lending.and.number.of.projects.for.Fy06­08.. and.Fy09­10................................................................................................. 66 Figure.6.6:. regional.distribution.of.the.world.bank.water.lending.for.the.Fy06­08.. ............ 67 . Figure.6.7:. lending.distribution.in.water.services.and.water.resources.for.the.Fy06­08......... 67 Figure.6.8:. Projects.with.potential.adaptation.measures.(%)................................................. 68 Figure.6.9:. types.of.climate.change.interventions............................................................... 70 . Figure.6.10:.type.of.intervention.for.projects.in.Fy06­08.and.Fy09­10.. .............................. 73 Figure.7.1:. Projected.2030.exposure.map.to.change.in.water.deficit.index........................... 79 Figure.7.2:. Projected.2030.and.2050.exposure.maps.to.change.in.water.deficit.index.­.. Africa.region.................................................................................................. 79 Figure.7.3:. Projected.2030.exposure.map.to.change.in.low.flows.(drought)......................... 80 Figure.7.4:. Projected.2030.and.2050.exposure.maps.to.change.in.low.flows.(drought).­.. Africa.region.................................................................................................. 80 Figure.7.5:. Projected.2030.exposure.map.to.change.in.base.flow....................................... 81 Figure.7.6:. Projected.2030.and.2050.exposure.maps.to.change.in.base.flow.­.. Africa.region.................................................................................................. 81 . Figure.7.7:. Projected.2030.exposure.map.to.change.in.high.flows.(floods). ......................... 82 Figure.7.8:. Projected.2030.and.2050.exposure.maps.to.change.in.high.flows.(floods).­.. Africa.region.................................................................................................. 82 . Figure.7.9:. Projected.2030.exposure.map.to.change.in.basin.yield. .................................... 83 Figure.7.10:.Projected.2030.and.2050.exposure.maps.to.change.in.basin.yield.­.. Africa.region.................................................................................................. 83 Figure.7.11:.exposure.of.water.projects.to.climate.change.in.2030.and.2050....................... 84 . Figure.7.12:.exposure.of.water.investments.to.climate.change.in.2030.and.2050.................. 85 Figure.8.1:. consequence.and.probability.components.of.risk.............................................. 91 Figure.8.2:. stages.in.risk-based.decision.making................................................................ 93 Figure.8.3:. stage.1.­.objectives.identification.and.system.characterization.......................... 94 Figure.8.4:. stage.2.­.Assessment.of.risks........................................................................... 95 . Figure.8.5:. stage.3.­.options.identification.and.assessment.to.reduce.risk.......................... 95 Figure.A1:. Africa.region.water.investment.for.the.Fy06­08.period.................................... 115 Figure.A2:. east.Asia.and.Pacific.region.water.investment.for.the.Fy06­08.period. ............. 116 . Figure.A3:. europe.and.central.Asia.region.water.investment.for.the.Fy06­08.period. ....... 118 . Figure.A4:. latin.America.and.caribbean.region.water.investment.for.the.. . Fy06­08.period. .......................................................................................... 119 vii Figure.A5:. middle.east.and.north.Africa.region.water.investment.for.the.. . Fy06­08.period. .......................................................................................... 120 Figure.A6:. south.Asia.region.water.investment.for.the.Fy06­08.period............................. 122 Figure.b1:. the.ukciP.framework................................................................................... 124 Figure.b2:. the.Australian.framework.............................................................................. 125 tAbles table.2.1:. changes.in.key.Hydrologic.variable................................................................. 13 table.3.1:. mediating.processes.and.potential.effects.on.health.of.changes.. . in.temperature.and.weather............................................................................. 25 table.4.1:. Preliminary.assessment.of.vulnerability.of.groundwater.in.world.bank.. . regions.to.climate.change. .............................................................................. 33 . table.5.1:. spatial.resolution.of.Ar4.iPcc.Archived.gcms............................................... 38 table.5.2:. coverage.area.of.1-degree.latitude.by.1-degree.longitude................................ 38 table.5.3:. Available.Ar4.models,.scenarios,.and.variables.via.iPcc.................................. 43 table.5.4:. gcm.and.associated.base.cmis.used.for.each.scenario.and.regions.. eAP . ,.ecA,.and.lcr. ........................................................................................ 47 table.5.5:. gcm.and.associated.base.cmis.used.for.each.scenario.and.regions.mnA,.. sAr,.and.AFr................................................................................................. 47 . table.5.6:. summary.changes.in.runoff.projections.for.bank.regions. .................................. 50 table.5.7:. summary.changes.in.basin.yield.projections.for.bank.regions............................. 52 table.5.8:. summary.changes.in.low.flow.projections.for.bank.regions................................ 54 table.5.9:. summary.changes.in.high.flow.projections.for.bank.regions............................... 55 table.5.10:. summary.changes.in.base.flow.projections.for.bank.regions.............................. 58 table.5.11:. summary.changes.in.water.deficit.index.projections.for.bank.regions.................. 60 table.7.1:. list.of.water.systems.and.indicators................................................................. 75 table.7.2:. irrigation.and.drainage.exposure.level.descriptions............................................ 77 table.7.3:. urban.water.supply.and.sanitation.exposure.level.description............................. 77 . table.7.4:. rural.water.supply.and.sanitation.exposure.level.description. ............................. 77 . table.7.5:. Flood.control.exposure.level.description........................................................... 78 table.7.6:. river.basin.management.exposure.level.description........................................... 78 . table.8.1:. matrix.of.hydrologic.drivers.and.infrastructure.components.. ............................ 104 table.8.2:. scoring.by.category.for.each.component........................................................ 104 table.8.3:. scoring.matrix.template................................................................................. 105 boxes box.2.1:. weather,.climate,.and.climate.variability............................................................. 9 box.2.2:. mass.loss.of.glaciers....................................................................................... 12 box.2.3:. Primary.sources.of.uncertainty.in.projections.of.hydro-climatic.change................ 14 box.3.1:. malaria.in.Africa.under.climate.change............................................................ 25 box.3.2:. Hydropower.in.Zambezi.basin.under.climate.change......................................... 28 box.3.3:. . Fate.of.ecosystems.in.southern.Africa.under.climate.change.............................. 29 box.3.4:. non-climatic.drivers.of.change.in.freshwater.systems......................................... 30 box.8.1:. risk.and.uncertainty........................................................................................ 91 box.8.2:. standardized.indicators.to.assess.the.vulnerability.of.regions.and.. . systems.to.climate.change............................................................................... 97 box.8.3:. Potential.impact.some.of.key.hydrologic.drivers............................................... 102 viii foreword the.iPcc's.Fourth.Assessment.report.(2007).and.other.technical.studies.have.concluded.that. observational.records.and.climate.projections.provide.abundant.evidence.that.freshwater.resources. are.vulnerable.and.have.the.potential.to.be.strongly.impacted.by.climate.change,.with.wide. ranging.consequences.on.human.societies.and.ecosystems..each.bank.region.is.likely.to.face.a. unique.set.of.water-related.climate.change.challenges,.deriving.from.such.impacts.as.accelerated. glacier.melt;.altered.precipitation,.runoff.and.recharge.patterns.and.rates;.extreme.floods.and. droughts;.water.quality.changes;.saltwater.intrusion.in.coastal.aquifers;.and.changes.in.water. uses..in.this.context,.the.2010.world.development.report.emphasizes.that.water.will.have.to.be. used.more.efficiently,.that.climate-smart.practices.will.have.to.be.adopted.and.that.countries.will. need.to.co-operate.to.manage.shared.water.resources. Potential.adaptation.strategies.to.the.impacts.of.climate.change.on.water.resources.have.become. central.to.the.dialogue.on.water.policy.reforms.and.investment.programs.with.client.countries..in. order.to.complement.regional.efforts.already.underway,.and.to.support.future.regional.initiatives,. the.water.Anchor.in.the.energy,.transport.and.water.department.(etw).in.the.sustainable. development.vice.Presidency.has.undertaken.a.two-year.analytical.work.on.climate.change.and. water. the.main.objective.is.to.provide.analytical,.intellectual.and.strategic.assistance.to.the.regions. for.incorporating.adaptation.to.climate.variability.and.change.in.their.work.programs..the. report.focuses.on.water.and.water-related.issues.and.investments..A.particular.focus.of.the.work. is.on.reducing.the.vulnerability.of.water.sector.investments.to.the.impacts.of.climate.change.. Furthermore,.the.report.provides.a.first.version.of.a.tool.that.can.be.used.to.assess.exposure.and. screen.the.investment.portfolio.on.a.regional.basis. this.etw.Anchor.Flagship.consists.of.this.main.report.and.a.series.of.supporting.technical.reports. and.papers.reflecting.the.output.of.a.two.year.effort..the.series.includes.a.synthesis.of.the.state- of-the-art.of.the.science.as.related.to.climate.and.hydrologic.cycle;.an.analysis.of.climate.change. impacts.on.groundwater.resources.and.adaptation.options;.a.review.of.the.bank's.current.water. investment.portfolio.with.regards.to.the.extent.to.which.climate.change.is.considered.at.the.project. design.level;.and.an.evaluation.of.the.exposure.of.the.world.bank.water.sector.investments.. Also.included.in.this.Flagship.product.is.a.menu.of.adaptation.options.for.increased.robustness. and.resiliency.of.water.systems.to.climate.variability/change,.and.a.framework.for.risk-based. analysis.for.water.investment.planning..it.is.hoped.that.this.work.will.help.enhance.knowledge. and.understanding.of.both.bank.staff.and.client.country.professionals.for.making.better-informed. decisions.regarding.water.investments.. Jamal Saghir director,.energy,.transport.and.water. chair,.water.sector.board ix aCknowledgemenTs this.report.provides.an.overview.of.the.series.of.reports.and.documents.prepared.as.part.of.the. Flagship.product.of.the.water.Anchor.of.the.energy,.transport,.and.water.department..the.effort.was. led.by.vahid.Alavian.under.the.overall.guidance.of.Abel.mejia.and.jamal.saghir..the.core.water.and. climate.change.team.responsible.for.this.work.includes.Halla.maher.Qaddumi,.eric.dickson,.sylvia. michele.diez,.Alexander.v..danilenko,.rafik.Fatehali.Hirji,.gabrielle.Puz,.carolina.Pizarro,.michael. jacobsen,.all.from.the.water.Anchor.and.brian.blankespoor.from.dec.research.group. significant.contributions.were.made--through.preparation.of.technical.reports,.background.notes,. thematic.inputs,.and.model.simulation--by.Professor.kenneth.strzepek.and.his.climate.change. team.at.the.university.of.colorado.and.massachusetts.institute.of.technology.(mit);.by.stratus. consulting,.particularly.joel.smith.and.his.team;.by.nick.Pansic.and.his.team.at.montgomery. watson.Harza.(mwH);.and.by.sinclair.knight.merz.(skm),.particularly.rick.evans.and.his.team.. these.consultants.effectively.served.as.partners.and.members.of.the.water.and.climate.change. team.at.the.water.Anchor.during.the.course.of.this.work. the.water.Anchor.team.is.grateful.to.the.peer.reviewers.and.other.bank.staff.who.provided. valuable.insight.and.guidance.from.the.concept.note.stage.through.to.the.completion.of.this. Flagship.product..they.are.doug.olson,.ronald.Hoffer,.Ashok.subramanian.and.the.Africa.water. group,.dean.cira,.ian.noble,.kseniya.lvovsky.and.the.env.climate.change.team,.nagaraja.rao. Harshadeep,.john.briscoe,.winston.yu,.walter.vergara,.guy.Alaerts,.Aziz.bouzaher,.raffaello. cervigni,.julia.bucknall,.marianne.Fay,.and.Ariel.dinar..external.experts,.including.eugene.stakhiv,. us.Army.corps.of.engineers.water.resource.institute.and.stephen.Foster,.gw-mAte/dFid. provided.valuable.input.and.guidance.to.this.work. editing.of.this.report.was.completed.on.june.1,.2009. Disclaimer this.volume.is.a.product.of.the.staff.of.the.international.bank.for.reconstruction.and.development/ the.world.bank..the.findings,.interpretations,.and.conclusions.expressed.in.this.paper.do.not. necessarily.reflect.the.views.of.the.executive.directors.of.the.world.bank.or.the.governments.they. represent..the.world.bank.does.not.guarantee.the.accuracy.of.the.data.included.in.this.work..the. boundaries,.colors,.denominations,.and.other.information.shown.on.any.map.in.this.work.do.not. imply.any.judgment.on.the.part.of.the.world.bank.concerning.the.legal.status.of.any.territory.or. the.endorsement.or.acceptance.of.such.boundaries. the.material.in.this.publication.is.copyrighted..copying.and/or.transmitting.portions.or.all.of. this.work.without.permission.may.be.a.violation.of.applicable.law..the.international.bank.for. reconstruction.and.development/.the.world.bank.encourages.dissemination.of.its.work.and.will. normally.grant.permission.to.reproduce.portions.of.the.work.promptly. 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Atmospheric-ocean.general.circulation.model cAs. country.Assistance.strategy cc. climate.change cdm. clean.development.mechanism ceiF. clean.energy.for.development.investment.Framework cF. carbon.Finance coP. conference.of.the.Parties co2. carbon.dioxide cPiA. country.Policy.and.institutional.Assessment dec. development.economics.department dPl. development.policy.lending eAP. east.Asia.and.the.Pacific ecA. europe.and.central.Asia enso. el.niño-southern.oscillation esmAP. energy.sector.management.Assistance.Program 4Ar. Fourth.Assessment.report.(iPcc) FAr. First.Assessment.report.(iPcc) gcm. general.circulation.model gdP. gross.domestic.product geF. global.environment.Facility gHg. greenhouse.gases gPg. global.public.good ibrd. international.bank.for.reconstruction.and.development idA. international.development.Association iFc. international.Finance.corporation iPcc. intergovernmental.Panel.on.climate.change km. kilometer lcr. latin.America.and.the.caribbean mdg. millennium.development.goals migA. multilateral.investment.guarantee.Agency mnA. middle.east.and.north.Africa moses. met.office.surface.exchange.scheme nAo. north.Atlantic.oscillation nAPA. national.Adaptation.Programme.of.Action odA. official.development.assistance Pcmdi. Program.for.climate.model.diagnostics.and.intercomparison PPiAF. Public-Private.infrastructure.Advisory.Facility ppm. parts.per.million PPP. Public-Private.Partnership PrsP. Poverty.reduction.strategy.Paper Psdi. Palmer.drought.severity.index rcm. regional.climate.model sAr. second.Assessment.report.(iPcc) sAr. south.Asia.reigon xiii sccF. special.climate.change.Fund sd. statistical.downscaling seA. strategic.environmental.Assessment skm. sinclair.knight.merz sres. special.report.on.emissions.scenarios ssA. sub-saharan.Africa swAp. sectorwide.approach tA. technical.assistance tAr. third.Assessment.report.(iPcc) undP. united.nations.development.Programme uneP. united.nations.environment.Programme unFccc. united.nations.Framework.convention.on.climate.change wbg. world.bank.group wdr. world.development.report wwF. world.wildlife.Fund xiv exeCuTive summary introduction Climate change is real, and taking prudent measures to plan for and adapt to climate change must become an integral part of the Bank's water practice..there.is.now.ample. evidence.that.increased.hydrologic.variability.and.change.in.climate.has.and.will.continue.have.a. profound.impact.on.the.water.sector.through.the.hydrologic.cycle,.water.availability,.water.demand,. and.water.allocation.at.the.global,.regional,.basin,.and.local.levels..many.economies.are.at.risk.of. significant.episodic.shocks.and.worsened.chronic.water.scarcity.and.security..this.can.have.direct. and.severe.ramifications.on.the.economy,.poverty,.public.health.and.ecosystem.viability..this.report. documents.the.results.of.the.first.two.years.of.a.sustained.effort.at.the.energy,.transport,.and.water. department.of.the.world.bank.to.understand.the.risks.of.climate.change.to.the.water.sector.and.to. identify.ways.to.manage.these.risks.for.better.and.climate-smart.investment.decisions. This report and the analytical work leading to it are focused on key topics related to the impact of climate change on the water cycle and water investments. specifically,.the. topics.addressed.are:.a.better.understanding.of.the.science.and.uncertainties.of.climate.change. projections.as.related.to.the.hydrologic.cycle;.translating.the.climate.projections.to.projection.of. hydrologic.indicators.useful.in.policy.and.planning.of.water.investments;.a.review.of.the.world. bank.water.portfolio.for.climate.change.content.and.adaptation.options.considered;.and.finally. an.examination.of.the.exposure.of.the.portfolio.to.climate-induced.changes.in.hydrologic.drivers. if.the.active.portfolio.were.placed.in.2030.and.2050..special.care.has.been.taken.to.provide.the. reader.with.an.understanding.of.the.critical.assumptions.behind.the.climate.change.projections,. hydrologic.models,.and.application.of.the.science.in.practice..cautionary.notes.are.also.provided. where.common.misunderstandings,.misconceptions,.or.pitfalls.may.occur.in.making.use.of.the. climate.change.information.in.making.investment.decisions..the.results.reported.herein.focus.on. the.impact.of.climate.change.on.the.water.cycle.as.the.primary.driver.of.the.water.sector.and. are.meant.for.use.at.the.policy.and.planning.level.in.making.investment.decisions..the.findings. here.are.not.intended.for.detailed.project.design.applications..with.the.best.available.knowledge. on.climate.change.and.water.as.the.foundation,.economics.of.adaptation,.social,.poverty,.and. environmental.aspects.can.now.be.addressed.and.are.on.the.agenda.for.the.follow.up.work. The context Climate change is a development issue for the Bank and its clients with significant implications in the water sector. wbg.clients,.by.virtue.of.their.geographic.location.and. often.low.coping.capacity,.are.among.the.most.affected..the.bank's.2007.report.IDA and Climate Change: Making Climate Action Work for Development provides.compelling.evidence. that.the.distribution.of.major.climate-related.risks.around.the.world.is.skewed.against.poor. countries..the.bank's.2009.development.and.climate.change.strategic.Framework.(dccsF). (world.bank,.2008a).asserts.that.climate.change.is.a.development.issue,.among.others,.and. recognizes.the.water.sector.as.one.that.will.be.heavily.impacted.by.climate.change..the.2010. world.development.report.focuses,.among.other.factors,.on.the.land.and.water.interface.for. managing.competing.demands.and.creating.new.opportunities.for.climate-smart.development.. many.client.countries.in.partnership.with.the.world.bank.group.have.begun.to.take.action.to. adapt.their.water.sector.to.implications.of.climate.change.and.resulting.hydrologic.impacts..this. process.is.supported.by.analytical.and.advisory.assistance.on.water.and.climate.change.carried. out.by.regional.units,.as.well.as.the.water.Anchor..incorporating.climate.change.in.the.portfolio. xv has.been.steadily.increasing.in.response.to.client.demands..A.number.of.stand-alone.climate. change.projects.have.also.been.financed.through.various.grant.and.lending.instruments.and.they. are.increasing..the.recent.financial.crisis,.as.well.as.the.food.and.fuel.price.crises.put.stress.on. many.economies.and.sectors,.including.water..However,.this.provides.a.unique.opportunity.to.use. the.bank's.increased.engagement.to.close.the.financial.gap.for.thinking.and.investing.smartly.by. taking.into.account.the.wider.climate.change.issues. Each World Bank region, even each country and each river basin face a unique set of climate change-related water challenges..depending.on.the.hydrologic.regime,.regional.and. sub-regional.hydrology.and.climate.variability.have.a.direct,.but.differential,.impact.on.the.various. water.use.areas..Floods/droughts,.water.availability/allocation.and.water.quality.management. are.affected.by.climate.change.and.have.an.upward.linkage.to.the.economy..indirect.and. second.order.impacts.can.also.be.significant.in.water.storage.lakes.and.reservoirs;.agricultural. production;.navigation;.and.the.increased.vulnerability.of.ecosystems..many.client.countries.are. particularly.vulnerable.to.the.impacts.of.hydrologic.variability.and.climate.change.given.weak. institutions.and.institutional.capacity,.high.levels.of.poverty,.insufficient.stock.of.water.management. and.services.infrastructure.and.dependence.of.the.rural.economy.on.agriculture..the.gap.between. availability.of.water.storage.infrastructure.in.developed.and.developing.countries.is.wide..climate. change.may.increase.or.reduce.the.need.for.water.storage.infrastructure.depending.on.its.impact. on.the.hydrologic.cycle..one.key.question.concerns.the.strategies.that.need.to.be.put.in.place.to. mitigate.the.negative.impacts.of.climate.change..Potential.adaptation.strategies.to.the.impacts.of. climate.change.on.water.resources.have.become.central.to.the.dialogue.on.water.policy.reforms. and.investment.programs.with.client.countries. Conventional interventions are necessary but not sufficient..water.practitioners.have.long. coped.with.and.designed.for.variability.in.hydrology..consequently,.numerous.examples.of. adaptation.to.hydrological.variability.and.extreme.events.exist.in.the.water.sector..implementing. the."good.practices".more.widely.(e.g.,.efficient.irrigation.technologies,.water.harvesting,. increased.sub-surface.storage,.etc.).would.go.a.long.way.in.confronting.the.climate.change. challenge..Adapting.to.climate.change.must.continue.to.build.on.conventional.interventions. while.addressing.the.immediate.challenges,.but.must.make.a.major.shift.in.thinking,.planning. and.designing.water.investments.of.the.future..new.approaches.in.technology.and.management,. as.well.as.the.development.of.flexible.and."smart".systems.that.can.be.operated.to.anticipate. and.react.to.changing.circumstances.must.be.developed,.particularly.in.light.of.uncertainties. in.projected.impacts..new.design.standards.and.criteria.will.also.need.to.be.developed.for. a.changed.hydrology.characterized.by.increased.variability.and.uncertainty..guidelines.for. mainstreaming.adaptation.into.project.design.must.take.all.of.these.aspects.into.account.if.they. are.to.be.effective. This report contributes to the World Bank agenda on climate change and more specifically, informs the water sector investments on climate issues and climate-smart adaptation options. using.the.existing.knowledge.and.additional.analysis.commissioned.by.the. world.bank.water.Anchor,.the.report.illustrates.that.climate.change.is.affecting.the.hydrologic. cycle.and.the.projected.future.hydrology.will.have.a.direct.impact.on.the.water.resources.base-- availability,.usage,.and.management..depending.on.the.type.of.the.water.investment,.this.impact. can.be.positive,.negative,.or.neutral..the.report.addresses.the.stress.on.and.vulnerability.of.the. water.systems.through.use.of.reliability,.resilience,.and.robustness.as.the.key.indicators.of.sensitivity. of.water.systems.for.climate.induced.failure..current.practices.in.the.sector.are.examined.in.order. to.better.understand.the.state-of-the-science.for.incorporating.current.and.future.variability.and. xvi change.in.hydrology.and.climate.in.the.bank's.portfolio.for.project.planning.and.design..new. and.innovative.practices.taking.into.account.adaptation.options.for.water.systems.and.risk-based. decision.making.in.water.investments.are.reviewed.and.assessed.for.application.to.investments.in. infrastructure..the.climate.change.dimension.is.placed.within.the.context.of.the.impact.of.other. factors.(within.and.outside.the.sector).such.as.population.growth.(and.associated.increase.in. demand).and.land.management.(particularly.as.related.to.water),.which.in.some.cases.may.be. far.more.significant.and.critical.than.that.of.climate.change.in.some.parts.of.the.world..Finally,. recommendations.for.a.progressive.agenda.on.water.and.climate.change.are.made. Climate change, hydrologic cycle, and water Hydrologic cycle as the key external driver of the water cycle is accelerating due to climate change..Projected.increases.in.global.temperatures.are.associated.with.changes.in.the. hydrologic.cycle,.including.increased.atmospheric.water.vapor,.changes.in.precipitation.patterns. (frequency.and.intensity),.as.well.as.changes.in.groundwater.and.soil.moisture..these.changes. Key Variables Observed Trends Projections for 21st Century Precipitation trend.is.unclear..general.increases.in. increase.(about.2%/oc).in.total. precipitation.over.land.from.30 n.to.85 n.. o o precipitation..High.latitude.areas.generally. notable.decreases.from.10os.to.30on. projected.to.increase..many.low.to.mid- latitude.areas.projected.to.decrease.. changes.at.the.regional.scale.vary. Atmospheric increasing.in.lower.atmosphere.(lower. increasing water vapor troposphere;.about.1%/decade).in.specific. content humidity;.little.change.in.relative.humidity Intensity of disproportionate.increase.in.volume.of. increasing.(about.7%/oc) precipitation precipitation.in.heavy.or.extreme.precipitation. events Droughts drought,.as.measured.by.the.Palmer.drought. increasing.in.many.areas,.particularly. severity.index,.increased.in.the.20 .century,. th lower.latitudes..decreasing.in.many.high. although.some.areas.became.wetter latitude.areas..Patterns.are.complex. Tropical cyclones increases.in.intensity,.particularly.in.north. increase.in.intensity..changes.in.frequency. Pacific,.indian.ocean,.and.southwest.Pacific and.track.are.uncertain Glaciers and decrease.in.mass.of.glaciers,.but.not.in.all. continued.decrease.in.glacial.mass.and. snow cover regions..decrease.in.snow.cover.in.regions.in. snow.cover the.northern.Hemisphere..earlier.peak.runoff. from.glacier.and.snowmelt. Sea level increased.about.0.2.meters.over.the.20th. iPcc.projects.0.2.to.0.6.meters.by.2100,. century..A.rise.equivalent.to.0.3.meters.per. but.upper.end.could.be.much.higher. century.was.recorded.since.the.early.1990s,. but.it.is.not.clear.if.this.is.an.acceleration.of. long.term.sea.level.rise Source: derived.from.iPcc,.2007a;.kevin.trenberth,.national.center.for.Atmospheric.research..Personal.communication..may.19,. 2008;.trenberth.et.al.,.2003. xvii are.often.referred.to.as.an.intensification and acceleration of the hydrologic cycle..the.result.of. hydrologic.change.and.increased.variability.is.shorter.periods.of.more.intense.rainfall,.and.longer. warmer.dryer.periods..the.table.below.summarizes.the.observed.trends.and.projections.for.the. 21st.century.of.key.hydrologic.variables..increase.in.variability.and.intensification.of.hydrologic. processes.is.evident. The impact of climate change varies with hydrology/climate regime and water use sectors..in.some.climatic.regions.(such.as.parts.of.lcr.and.ecA),.glacier.and.snowmelt.define. hydrology.while.in.other.parts.of.the.world,.precipitation.is.the.driving.factor.(for.example. much.of.AFr)..the.impact.of.climate.change.on.snow-driven.hydrology.is.quite.different.from. rainfall-driven.hydrology..in.snow-driven hydrology,.changes.in.the.pattern.of.precipitation.and. the.associated.acceleration.of.snow.and.glacier.melt.from.rising.temperatures.are.projected.to. significantly.affect.runoff.and,.consequently,.water.available.for.human.consumption,.agriculture. and.energy.generation..changes.in.the.timing.of.runoff.can.cause.increased.flooding,.failure.of. storage.infrastructure,.landslides,.and.loss.of.surface.soil..in.systems.fed.by.snowmelt.it.is.generally. the.shape.(volume).and.timing.of.the.runoff.that.matters..Hydrologic.variability--while.always. present--is.more.predictable.and.so.less.significant..in.contrast,.in.rainfall-driven hydrology,.flood. and.drought.cycles.are.much.less.predictable.and.their.magnitude.(severity).has.a.significant. impact.on.water.availability.(quantity,.quality,.and.timing).for.water.supply.and.sanitation,. agricultural.production.(yield,.growing.season),.energy.(hydropower),.and.environmental. sustainability..climate.change.will.exacerbate.the.uncertainty.and.severity.of.hydrologic.variability.. regardless.of.the.hydrologic.regime,.the.impact.of.hydrologic.variability.and.climate.change.on. coastal.regions.(particularly.in.eAP,.sAr.and.the.caribbean).is.expected.to.be.significant.through. sea.level.rise.on.the.sea-side.and.increased.flooding.from.the.land-side. Climate change could profoundly alter future patterns of both water availability and use, thereby increasing global levels of water stress. direct.effects.of.climate.change.on. water.resources.and.availability.as.a.result.of.changes.in.hydrology.is.shown.above..less.is. known.about.the.impacts.of.climate.change.on.groundwater.availability,.including.interactions. with.surface.water..there.is.also.relatively.little.information.on.the.impact.on.water.quality.and. aquatic.systems..the.potential.changes.in.water.availability.and.use.may.aggravate.global. `water.stress'..most.studies.have.found.that.levels.of.water.stress.will.increase,.although.there.are. significant.differences.in.estimates..Arnell.(2004)--who.accounts.for.population.growth.and.the. impact.of.climate.change--found.that.the.number.of.people.projected.to.experience.an.increase. in.water.stress.is.between.0.4.to.1.7.billion.in.the.2020s.and.between.1.and.2.7.billion.in.the. 2050s.(using.the.A2.population.scenario.for.the.2050s)..when.environmental.flow.needs.are. incorporated--that.is,.the.amount.of.water.required.to.sustain.a.functioning.ecosystem--the. degree.of.water.stress.is.projected.to.increase.even.further.(smakhtin.et.al,.2003). Future water availability and use will also depend on non-climatic factors..climate.change. is.only.one.of.many.factors.that.will.determine.future.patterns.of.water.availability.and.use..in.the. absence.of.policy.changes,.non-climatic.factors.are.likely.to.aggravate.or.attenuate.the.adverse. effects.of.climate.change.on.water.availability.and.quality,.as.well.as.have.a.significant.influence. on.water.demand..Population.growth.and.economic.development.will.play.a.dominant.role..non- climatic.impacts.could.be.generated.through.many.realms--from.population.growth,.migration. and.income.to.technologies.and.infrastructure.to.land-use.patterns.and.agricultural.activities/ irrigation..such.non-climatic.drivers.could.dwarf.the.impacts.attributed.to.climate.change.alone.. changes.in.policies,.legislation.and.management.could.induce.additional.and.substantial.effects. on.water.demand.and.water.availability.(quantity.and.quality),.in.a.positive.or.negative.direction. xviii water sector is highly exposed to climate change with implication beyond the sector The impacts of a changing climate will be felt in developed and developing countries alike. However, many parts of the developing world are particularly vulnerable.. vulnerability.to.climate.change.has.been.defined.by.iPcc.as.the.degree.to.which.geophysical,. biological.and.socioeconomic.systems.are.susceptible.to,.or.unable.to.cope.with,.adverse.effects. of.climate.change,.including.climate.variability.and.extremes..it.is.a.function.of,.amongst.others,. the.character,.magnitude.and.rate.of.climate.variation.to.which.a.system.is.exposed,.its.sensitivity. and.its.adaptive.capacity..within.the.water.sector,.a.number.of.additional.factors.make.many. developing.countries--and.the.poorest.within.them--particularly.vulnerable.to.the.potentially. adverse.impacts.of.climate.change. these.include.weak.institutions.and.limited.institutional. capacity,.high.levels.of.poverty,.insufficient.stock.of.water.management.and.services.infrastructure,. lack.of.access.to.technology.and.capital.to.invest.in.risk.reduction,.and.dependence.on.climate- sensitive.sectors.such.as.agriculture,.forestry.and.fisheries. Water investments are particularly vulnerable to impacts of climate change through the hydrologic drivers. climatic.impacts.will.have.significant.consequences.on.investments.in.water. systems.(or.infrastructure).associated.both.with.delivering.water.services.and.with.managing. water..water.systems.for.delivering.water.services.include.irrigation;.urban.water,.sanitation.and. drainage;.rural.water.and.sanitation;.and.ports.and.navigation..systems.for.managing.water. resources.include.those.for.delivery.of.bulk.irrigation,.watersheds,.and.water.resources.broadly,. as.well.as.multi-purpose.systems.(including.hydropower).and.flood.control..For.example,.in.urban. environments,.more.heavy.rainfall.events.could.overload.the.capacity.of.storm.drain.systems.and. water.and.wastewater.treatment.facilities;.sea.level.rise.could.lead.to.salinisation.of.water.supplies. from.coastal.aquifers..climate.change.could.increase.irrigation.demand.due.to.the.combination. of.decreased.rainfall.and.increased.evapotranspiration,.placing.additional.pressure.on.irrigation. systems.that.are.in.many.cases.already.under.performing..changes.in.river.flows.have.a.direct. impact.on.hydropower.generation..soil.erosion.from.increased.rainfall.intensity.could.affect. watershed.sustainability.and.lead.to.sedimentation.in.reservoirs,.impacting.on.the.operation.of. multi-purpose.facilities..extreme.variability.and/or.reduced.supplies.could.stretch.the.infrastructural. and.institutional.limits.of.systems.that.manage.water.across.sectors.and.even.national.boundaries.. the.term.`system'.and.`infrastructure'.are.used.interchangeably.in.this.report.to.capture.all. elements--physical.infrastructure,.management.institutions,.and.financial.aspects--that.contribute. to.the.performance.of.the.intended.function.of.water.investments. The extent to which each water system will be impacted by climate change will depend on its degree of vulnerability, including internal capacity to adapt..However,.the.potential. impacts.of.climate.change.are.real,.and.may.extend.far.beyond.the.water.sector..For.example,. pressure.on.water.supply.and.sanitation.facilities.could.have.a.wide.range.of.adverse.effects. on.human.health..reduced.availability.of.water.for.irrigation.could.threaten.food.security,.rural. development,.and.the.economies.of.countries.that.are.largely.dependent.on.the.agricultural. sector..reduced.water.for.hydropower.generation.(or.increased.fluctuations.in.river.flows).could. decrease.electricity.grid.stability.and.reliability,.with.consequent.effects.on.the.economy..managing. sedimentation.(e.g.,.through.flushing).could.affect.the.timing,.supply.and.quality.of.water.to.the. various.sectors.served.by.a.multi-purpose.system,.with.impacts.felt.in.the.larger.economy..in.the. worst.case,.competition.over.limited.water.resources.across.sectors.and.nations.could.worsen. hostility.and.mistrust,.and.increase.conflicts.over.water. xix Water-dependent sectors are affected by the impact of climate change on the water sector. in.most.countries,.water.use.has.increased.in.recent.decades..sectoral.water.use.patterns. can.be.expected.to.continue.to.change.over.time.in.response.to.non-climatic.drivers,.in.addition. to.water.resource.management.and.delivery.systems..this.includes.not.only.infrastructure.and. technology,.but.also.institutions.that.govern.water.use.within.sectors.(e.g.,.water.pricing),.amongst. sectors.(e.g.,.water.trading),.and.even.across.national.boundaries.(e.g.,.transboundary.river.basin. agreements)..in.the.future,.climate.change.could.also.impact.water.using.sectors,.affecting.both. the.amount.and/or.quality.desired.(on.the.demand.side).and/or.the.extent.to.which.demands.are. met.(on.the.supply/availability.side)..it.is.important.to.emphasize.that.changes.in.variability.could. be.as.important.as.changes.in.long-term.averages,.particularly.if.water.is.not.withdrawn.from. groundwater.bodies.or.reservoirs. International basins can be at risk due to climate change..over.270.international.rivers. are.shared.by.some.90%.of.the.world's.nations.and.territories..transboundary.river.basins.and. shared.rivers.present.both.challenges.and.opportunities.for.cooperation.and.growth..developed. economies,.in.europe.and.north.America,.have.in.most.cases.achieved.a.relative.equilibrium.in. managing.transboundary.basins.for.best.return.on.hydrology.through.transboundary.institutional. arrangements,.including.treaty.regimes.dealing.with.issues.of.river.infrastructure.and.the.quantity. and.quality.of.water.flows,.as.well.as.infrastructure.to.manage.variability.and.extreme.events.. increasingly,.cooperative.efforts.are.focusing.on.the.sharing.of.benefits,.rather.than.water..the. developing.economies.sharing.river.basins.remain.challenged.by.lack.of.weak.institutional. arrangements.and.inadequate.infrastructure.for.optimum.benefit..regardless.of.the.level.of. economic.development,.climate.change.poses.a.threat.to.transboundary.basins..evidence. suggests.that.the.challenges.and.conflicts.among.the.riparian.states.depend.on.the.degree.of. variability.and.uncertainty.associated.with.the.resource.availability..Projected.changes.in.water. resources.variability.due.to.climate.change.can.impact.the.water.balance.and.consequently.the. hydropolitical.balance.in.transboundary.basins..Administrative.instruments.for.transboundary. basins,.such.as.treaties.and.agreements.should.be.reviewed.for.impact.of.climate.change.with. adaptation.measures.explored.and.negotiated.in.advance. The current financial crisis and various sector crises have and will continue to impact financing of adaptation to climate change..A.theme.that.has.been.emphasized.throughout.this. report.is.that.climate.change.is.not.the.only--or.even.the.primary--factor.exerting.stress.on.the. water.sector,.and.by.extension.societies,.economies,.and.the.environment..the.current.financial. crisis.and.the.sector.crises.(e.g.,.rising.food.prices,.energy.cost).have.forced.many.governments. in.developing.countries.to.defer.urgent.operation.and.maintenance,.as.well.as.water.investment. needs..in.the.near-.to.medium-term,.the.situation.is.expected.to.worsen.unless.investment.funds. are.channeled.to.the.water.sector..Here,.a.combination.of.the.new.financial.and.climate.change. architectures.such.as.the.vulnerability.Fund,.the.climate.investment.Fund,.and.other.mechanisms. to.alleviate.the.investment.bottle.neck.should.be.made.available.to.the.client.bank.countries.. viewed.in.the.long.term,.the.current.financial.crisis.and.the.stimulus.packages.to.respond.to.this. crisis.can.be.designed.to.take.into.account.the.wider.risk.of.climate.change.in.the.recovery.and. rebuilding.process. world bank water investments and climate change Climate change poses risk to World Bank investments in the water sector..A.review.of.the. water.portfolio.was.undertaken.to.understand.the.composition.of.the.bank.water.investments.and. their.exposure.to.climate.change..bank's.investments.in.the.water.sector.over.the.period.fiscal. xx years.2006­2010.are.reviewed.for.class.of.investment--water.services.delivery.or.water.resources. management--and.climate.change.content.of.the.project..this.particular.period.offers.sufficient. number.of.approved.and.pipeline.projects.for.review.during.a.time.frame.that.climate.change.is. high.in.the.bank's.agenda..Additionally,.exposure.of.bank's.water.investment.to.current.hydrologic. variability.and.future.climate.change.were.assessed.using.hydrology.projections.at.a.scale.and. resolution.useful.in.water.planning.and.design. The water portfolio reviewed consists of 191 projects approved in 83 countries during FY06­08 for net commitments of $8.8 billion. the.regions.that.invested.the.most.in.water. relative.to.their.total.regional.investment.are.mnA.(14%).and.sAr.(14%).and.the.region.that. invested.the.least.is.lcr.(8%)..the.share.of.water.lending.relative.to.the.overall.world.bank's. investments.increased.from.8%.in.Fy06.to.12%.in.Fy08..the.pipeline.of.projects.for.Fy09­10. consists.of.220.projects.corresponding.to.a.volume.of.us$11.3.billion..it.should.be.noted.that.not. all.the.projects.in.the.pipeline.will.be.approved.by.end.of.Fy10..the.two.figures.below.show.these. investments.by.geographic.location,.volume,.and.type--services/resource.management. The water portfolio is dominated by projects that primarily deliver water services..For. the.Fy06­08.period.lending.for.water.services.consist.of.70%.of.the.lending.volume.for.63%. of.the.projects..the.largest.investment.in.water.services.systems.is.in.eAP.($1,327.million),.sAr. ($1,241.million).and.AFr.($1,128.million).regions..For.this.period,.highest.lending.in.water. resources.is.in.AFr.($926.million),.followed.by.sAr.($703.million).and.eAP.($364.million).. implication.of.climate.change.on.these.investments.would.be.different.as.the.driving.hydrologic. conditions.are.different. Review of the content of the portfolio suggests an increasing level of attention to climate change..the.review.of.water.projects.for.inclusion.of.mitigation.and.adaptation.measures.shows. that.out.of.191.active.projects.approved.in.Fy06­08,.35%.(67.projects).considered.strategies. Distribution of World Bank water projects for FY06­08 (active) and FY09­10 (pipeline) Source: world.bank,.2009. xxi Water investments by volume and category (services/resource management) Source: world.bank,.2009. to.reduce.the.impacts.of.climate.variability.and.change,.including.adaptation.and/or.mitigation. measures..of.the.67.projects.with.some.strategy,.58%.are.related.to.adaptation,.31%.related.to. mitigation.and.10%.related.to.both..the.water.sector.projects.are.primarily.focused.on.adaptation.. For.the.active.portfolio,.20%.of.the.projects.addressed.climate.variability.and.change.through. adaptation.measures..of.the.20%.of.projects.taking.adaptation.measures,.it.is.important.to. note.that.these.measures.address,.for.the.most.part,.strategies.to.reduce.vulnerability.to.climate. variability.rather.than.considering.the.long-term.effects.of.climate.change..of.the.total.number. of.projects.at.the.regional.level,.lcr.had.the.largest.portfolio.with.possible.adaptation.measures. (28%).followed.by.sAr.(25%).and.mnA.(25%)..Pipeline.shows.an.increased.attention.to.the. adaptation.agenda.for.most.regions..overall,.there.is.clearly.a.higher.level.of.awareness.among. the.bank.and.client.countries.towards.climate.change.and.climate.variability.issues. Projections of key hydrologic indicators for water planning A common set of hydrologic indicators are projected for 2030 and 2050 for Bank regions. these.are:.runoff,.basin.yield,.high.and.low.flows.(floods.and.droughts),.minimum.base. flow.(a.proxy.for.shallow.groundwater.movement),.and.net.irrigation.demand..these.indicators. are.projected.at.the.catchment.level,.most.appropriate.scale.for.water.planning.and.investment.. the.methodological.approach.used.for.this.analysis.was.designed.to.capture.the.full.spectrum.of. gcm.climate.projections..twenty-two.gcms.along.with.three.emissions.scenarios.(b1,.A1b,.A2). are.used.to.analyze.changes.in.the.key.hydrologic.variables.in.the.years.2030.and.2050.from. historical.values.in.1961­1990..in.this.analysis,.gcm.output.is.used.as.input.to.the.hydrologic. model.clirun-ii.(strzepek,.et.al,.2008),.developed.specifically.to.assess.the.impact.of.climate. change.on.runoff.and.to.address.extreme.events.at.the.annual.level.by.modeling.low.and. high.flows..this.analysis.advances.an.earlier.and.much.referenced.effort.by.milly,.et.al.(2005).. clirun-ii.is.stand-alone.hydrologic.model.designed.for.application.in.water.resource.projects. and.generates.output.at.a.0.5.x.0.5.degree.grid.scale,.aggregated.to.approximately.2.x.2.degree. xxii resolution..the.entire.projection.set.reflecting.the.historical.baseline.conditions.and.projections.for. 2030.and.2050.is.now.available.for.all.bank.regions. In the context of downscaling, relying on results from a single or even just a few GCMs is not advisable..care.needs.to.be.taken.in.selecting.a.method..beyond.reproducing.the.underlying. uncertainties.of.gcms,.many.introduce.additional.uncertainty.and.biases..this.is.because.there. Climate Moisture Index: Range of CGMs for three emission scenarios for various regions CMI Historic and Range of 2050 Climate Change Impacts 0 ­0.1 ­0.2 EAP ­0.3 LCR ECA ­0.4 ­0.5 SAR ­0.6 AFR ­0.7 MNA ­0.8 ­0.9 A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1 ­0.18 ­0.2 ­0.22 Globe ­0.24 WB Regions ­0.26 Non WB ­0.28 ­0.3 ­0.32 ­0.34 A2 A1b B1 A2 A1b B1 A2 A1b B1 Legend Top of box: 25th percentile Red line: median CMI Bottom of box: 75th percentile Dashed line: historical CMI (1960­1990) Whiskers: extreme CMI values Cross hairs: model outliers xxiii Projected percent change in hydrologic indicators for 2030 from 1961­1990 baseline < ­50 ­20 to ­10 0 to +10 20 to 50 Basin < ­50 ­20 to ­10 0 to +10 20 to 50 Runoff ­50 to ­20 ­10 to 0 10 to 20 > +50 Yield ­50 to ­20 ­10 to 0 10 to 20 > +50 Low < ­50 ­20 to ­10 0 to +10 20 to 50 High < ­50 ­20 to ­10 0 to +10 20 to 50 Flow ­50 to ­20 ­10 to 0 10 to 20 > +50 Flow ­50 to ­20 ­10 to 0 10 to 20 > +50 Irrigation < ­50 ­20 to ­10 0 to +10 20 to 50 Base < ­50 ­20 to ­10 0 to +10 20 to 50 Deficit ­50 to ­20 ­10 to 0 10 to 20 > +50 Flow ­50 to ­20 ­10 to 0 10 to 20 > +50 are.model.errors.in.any.one.model.and.natural.variability.(randomness).in.any.particular.run..A. single.model,.if.run.multiple.times.with.differing.initial.conditions,.can.provide.an.estimate.of.the. uncertainty.due.to.natural.variability..However,.for.any.given.model,.there.are.also.uncertainties. associated.with.the.assumptions.made.about.model.physics.and.parameterizations,.as.well.as. with.the.structural.aspects.of.the.model.itself..using.a.group.of.gcms.(multi-model.ensembles),. as.opposed.to.one.individual.gcm,.can.account.for.biases.and.errors..the.use.of.multi-model. ensembles.raises.the.question.of.how.to.capture.the.full.range.of.results.from.model.runs. Climate Moisture Index characterizes the projected climate conditions. the.calibrated. historical.model.simulations.and.all.of.the.22.gcm.projections.for.the.three.emissions.scenarios. for.2030.and.2050.are.analyzed..the.climate.condition.was.categorized.by.the.projected.level. of.moisture.(or.aridity).using.the.climate.moisture.index.(cmi)..the.box.and.whiskers.plots.on. the.previous.page.show.the.climate.moisture.index.projection.for.2050.for.bank.regions,.as.well. as.other.regions..the.height.of.the.box.indicates.the.degree.of.variability.which.results.from.the. xxiv Projected exposure map by hydrologic drivers (2030) Basin Runoff Low Medium High Yield Low Medium High Low High Flow Low Medium High Flow Low Medium High Irrigation Base Deficit Low Medium High Flow Low Medium High differences.in.means.between.different.climate.models..For.example,.in.the.lcr,.75%.of.the. gcms.indicate.drying.with.all.3.scenarios..the.cmi.for.the.sAr.has.the.largest.spread.because. of.the.way.the.different.gcms.model.the.monsoons..in.mnA,.there.is.little.variation.because.the. area.is.so.dry..note.that.the.land-based.cmi.projections.for.the.bank.regions.are.more.negative. than.non-bank.regions.(e.g.,.oecd)..However,.the.relative.aridity.(compared.with.the.historical). for.both.bank.and.non-bank.regions.remains.the.same. Projections at the catchment level allow for analysis of inter-regional variation at the project planning scale. Hydrologic.indicators.mapped.for.the.bank.regions.for.the.middle. climate.condition.are.shown.in.the.figure.on.page.xxiv..the.general.pattern.is.consistent.with. projections.of.runoff.made.directly.from.climate.model.runs..Here,.specific.indicators.provide.a. deeper.and.more.water-specific.insight.regarding.potential.changes.in.the.water.availability.and. distribution.for.various.uses.and.by.various.water.infrastructure.interventions..For.each.region,. detailed.information.for.each.of.these.indicators.is.available.at.the.0.5.x.0.5.degree.resolution,.as. xxv well.as.aggregated.at.the.catchment.level..it.is.planned.that.this.information.will.be.available.via.a. web-based.interface. exposure of the bank investment to climate change The World Bank's investments in the water sector are highly exposed, both to current variability and future climate change..the.purpose.of.this.assessment.is.to.provide. some.sense.of.magnitude.of.the.exposure.of.the.projects.and.the.financial.investments.they. represent..using.threshold.criteria.for.changes.in.each.indicator,.maps.were.created.for.high,. medium,.and.low.exposure.categories.for.each.indicator.(see.figure.page.xxv)..water.projects,. classified.by.water.systems,.are.superimposed.on.the.appropriate.exposure.map..the.outcome. is.an.exposure.categorization.of.each.water.system.according.to.its.respective.indicator..in.this. analysis,.exposure.to.the.impact.of.climate.change.for.the.following.water.systems.on.the.bank. portfolio.is.assessed:.irrigation.and.drainage,.urban.water.supply.and.sanitation,.rural.water. supply.and.sanitation,.flood.control,.river.basin.management,.and.multi-purpose.(supply.water. for.multiple.purposes)..results.of.the.potential.exposure.of.the.active.bank.water.investments. were.they.to.operate.in.2030.and.2050.are.available. The following bar charts show the level of exposure of the Bank water investments to climate change by volume of investment and number of projects by region and Bank-wide.. similar.charts,.categorized.by.water.systems,.are.available.for.each.region.and.bank-wide. Projections indicate that about half of the Bank water projects reviewed would potentially be at high to medium level of exposure to climate change impacts in 2030.. within.each.regional.portfolio,.eAP.shows.close.to.two-third.of.projects.with.potential.exposure. to.high/medium.risk,.possibly.due.to.increased.flooding..AFr.and.lcr.show.about.half.of. the.projects.and.mnA.some.40%.at.potential.high.to.medium.risk.of.exposure..ecA.and. sAr.show.about.one-third.of.the.projects.at.potential.risk.of.exposure.to.hydrologic.changes.. Projections.for.2050.show.exposure.increasing.for.all.regions.except.eAP ..obviously,.the.level.of. Potential exposure of water projects to climate change in 2030 and 2050 2030 2050 100 100 80 80 % of water projects % of water projects 60 60 40 40 20 20 0 0 EAP ECA LCR MNA SAR AFR Bankwide EAP ECA LCR MNA SAR AFR Bankwide Low Med High xxvi Potential exposure of water investments to climate change in 2030 and 2050 2030 2050 100 100 % of water projects 80 80 % of water projects 60 60 40 40 20 20 0 0 EAP ECA LCR MNA SAR AFR Bankwide EAP ECA LCR MNA SAR AFR Bankwide Low Med High uncertainty.related.to.projecting.climate.change.so.far.in.time.would.be.too.high.to.make.much. of.this.difference. In terms of investments, about half of the total water investments (including the pipeline) are projected at high/medium exposure level to climate change impacts in 2030..this. translates.to.approximately.$10.billion.on.the.Fy06­10.water.projects.reviewed.here,.risk. associated.with.approval,.delay,.or.drop.of.pipeline.projects.notwithstanding..the.pattern.of. risk.of.exposure.of.investment.roughly.follows.that.of.the.projects..For.2050,.climate.change. projections.show.an.increase.in.mnA,.AFr,.lcr,.and.ecA,.while.expected.to.decrease.in.eAP ,. and.sAr..Again,.the.uncertainty.associated.with.the.climate.change.projections.in.2050.is. considered.quite.high.and.therefore.this.conclusion.should.be.viewed.with.caution. Climate-smart investments must explicitly consider risk Climate change projections contain a great deal of uncertainty and their use requires special care..the.best.available.science.is.used.here.to.assess.the.exposure.of.the.bank's. water.investments.to.the.potential.impact.of.hydrologic.variability.and.climate.change..none- the-less,.substantial.uncertainty.remains.regarding.the.real.effects.of.climate.change..there. have.been.major.advances.in.projecting.the.impacts--both.from.general.circulation.models. and.downscaling/statistical.methods--which.allows.reporting.general.trends.with.some.degree. of.confidence.(including.in.temperature,.precipitation,.and.extreme.events)..However,.there.are. still.significant.unknowns,.and.even.more.challenging."unknown.unknowns"..there.is.no.way. around.these.uncertainties.given.the.current.state.of.the.science--even.agreement.on.a.particular. phenomenon.across.multiple.models.does.not.`prove'.that.a.given.climate.projection.will.indeed. come.to.pass. Reducing water sector's vulnerability to climate change means managing water under conditions of uncertainty. water.professionals.have.always.dealt.with.and.accounted.for.risk. xxvii and.uncertainty,.but.climate-change.related.uncertainties.will.require.water.to.be.managed. fundamentally.different.than.in.the.past..Historically,.water.planning.was.carried.out.under.the. key.assumption.of.a.stationary.hydrologic.pattern:.the.mean,.variance.and.standard.deviation. of.hydrologic.time.series.fixed.over.time--commonly.known.as.stationarity.of.hydrology..this. assumption.is.no.longer.considered.valid,.forcing.decision-makers.to.estimate.hydrologic.risks. to.water.systems.under.even.more.uncertain.conditions..the.only.viable.approach.in.most. investment.cases.is.explicit.consideration.of.risk.and.probability.of.occurrence.of.extreme. events. Water investments require a formal risk-based analysis in all aspects of the project/ program cycle..water.systems.are.subject.to.both.climate.and.non-climate.related.stresses,. but.there.are.certain.types.of.water.investments.where.uncertainties.related.to.climate.change. could.have.a.significant.impact,.and.so.particular.care.needs.to.be.taken.in.undertaking.a. detailed,.rigorous.risk.assessment..these.include.highly.capitalized.or.unique.projects,.irreversible. investments,.engineering.structures.with.long.lifetimes,.long-lived.benefits.and.costs,.etc..examples. include:.multi-purpose.hydraulic.infrastructure,.interbasin.water.transfer.schemes,.water.conveyer. systems.for.irrigated.agriculture,.regional/transboundary.investments..yet,.there.are.water.systems. that.are.inherently.resilient.to.some.degree.of.hydrologic.variability.and.climate.change,.are.not. significantly.impacted,.or.the.consequents.of.impact.can.be.readily.remedied..in.these.cases,.a. less.rigorous.risk.assessment.(screening.level).may.be.sufficient. Given the policy and financial implications of making water investment decisions, a more systematic approach is needed..risk-based.decision.making.is.the.systematic.consideration. of.the.probabilities,.consequences,.and.values.associated.with.different.decision.alternatives..in. general,.risk-based.approach.involves.the.following.general.stages:.project.objectives.definition. and.characterization.of.the.system.components;.knowledge.of.the.likelihood.and.consequences.of. adverse.events.that.could.compromise.those.objectives;.identification.of.the.options.for.adapting. the.system.or.project.to.render.it.less.vulnerable.in.the.face.of.the.identified.risks;.and.assessment. (either.quantitatively.or.qualitatively).of.adaptation.options. A special class of diagnostic indicators is used for the analysis of specific water resource systems or system design configurations and performance..several.measures.of.system. performance.have.been.proposed.that.permit.the.evaluation.of.a.specific.design.configuration. over.a.range.of.system.inputs.and.service.levels..each.indicator.is.based.on.the.probability. that.a.system,.characterized.by.a.given.set.of.design.parameters,.will.provide.the.intended. level.of.services.under.a.range.of.dynamic.inputs.and/or.demand.conditions..the.measures.of. system.performance.are.defined.over.a.sequence.of.discrete.time.periods..within.each.period,. the.system.either.performs.(provides.an.acceptable.level.of.services).or.fails.to.do.so..these. indicators.are:.reliability;.resiliency;.vulnerability;.and.robustness. Potential adaptation options can be categorized into those that carry `no regrets' and those that are `climate justified'. many.of.the.options.to.reduce.vulnerability.to.climate. variability.are.no.different.in.a.world.with.climate.change.than.they.are.in.a.world.without..these. include.demand.management.measures.to.increase.water.use.efficiency.and.productivity,.such. as.water-conserving.irrigation.technologies;.wastewater.recycling;.economic.incentives,.including. water.pricing;.and.the.encouragement.of.water.markets.that.move.water.to.high-valued.uses..they. also.include,.for.example,.measures.to.improve.early.warning.systems.and.risk-spreading.(e.g.,. disaster.insurance)..these.options.carry.`no regrets'.in.that.they.would.generate.net.social.and/ or.economic.benefits.irrespective.of.whether.or.not.anthropogenic.climate.change.occurs..on.the. xxviii other.hand,.other.actions.might.only.be.justifiable.under.man-made.change.in.climatic.variability.. `Climate justified'.measures.may.include,.for.example,.constructing.new.infrastructure.(dams,. water.conveyance.systems,.irrigation.systems),.retro-fitting.existing.infrastructure,.changing.rules.of. operation,.tapping.new.sources.of.water.(e.g.,.desalinization),.water.transfers,.conjunctive.use.of. surface.and.groundwater,.innovative.demand.management,.etc..However,.many.of.these.measures. may.be.of.the.`no-regrets'.type.depending.on.the.specific.circumstances..whether.they.belong.to. one.or.the.other.category.will.have.to.be.determined.on.a.case.by.case.basis. The distinction between `no regrets' and `climate-justified' options is important in near- term and long-term decision making..For."no.regrets".options,.uncertainties.in.projections.are. to.a.large.extent.immaterial..by.definition,.these.actions.should.be.taken.in.order.to.meet.current. economic,.social.and.environmental.objectives,.but.they.also.serve.the.dual.purpose.of.reducing. vulnerabilities.to.future.climatic.conditions..it.is.in.the.realm.of.the.`climate-justified'.that.water. managers.will.have.to.make.difficult.decisions.about.how.to.balance.the.political,.economic,. social.and.environmental.costs.of.action.versus.of.non-action,.given.an.uncertain.future..it.is.in. this.context.that.the.indicators.of.performance.listed.above.are.used..the.options.selected.should. include.plan.and.design.for.more.resilient.water.interventions..the.systems.designed.must.be. `intelligent'.and.robust.in.the.sense.that.they.are.able.to.deliver.(near).optimal.levels.of.service.or. management.over.a.range.of.conditions,.including.through.relatively.modest.re-design,.retrofitting. or.re-operation..implicit.in.robustness.is.also.flexibility,.that.is,.the.ability.to.anticipate.and.react.to. a.wider.and.largely.unknown.range.of.future.climatic.conditions. There is a certain class of projects for which risk-based analysis would be particularly essential..climate.change.will.affect.most.water.systems.to.some.degree..However,.some.water. services.or.resources.by.their.very.nature.are.more.vulnerable.to.climate.change.than.others..For. example,.small.or.distributed.water.supply.systems.that.can.easily.make.incremental.changes.at. low.cost.are.vulnerable.to.climate.change,.but.may.face.less.exposure.to.changes.in.climate,.may. be.less.sensitive.to.climate.changes,.or.may.have.sufficient.adaptive.capacity.to.manage.those. changes..the.systems.listed.below,.however,.are.particularly.vulnerable.and.special.care.should. be.taken.to.flag.such.water.investments.for.risk-based.analysis..these.systems.would.likely.be. designed.differently.if.climate.change.were.taken.into.account,.and.failing.to.take.climate.change. into.account.likely.would.cause.significant.economic.loss.(Hobbs,.et.al.1997). ·.Highly.capitalized.or.unique.projects ·.engineering.structures.with.long.lifetimes ·.multi-purpose.infrastructure.systems ·.long-lived.benefits.and.costs ·.systems.susceptible.to.climate.anomalies.or.extreme.events ·.urban.water.supply way forward Insight into the various dimensions of water and climate change has identified the gaps and guides the next steps. As.the.world.bank.water.agenda.mainstreams.adaptation.to.the. impact.of.climate.change,.the.questions.raised.in.this.report.will.continue.to.be.an.integral.part.of. the.ongoing.work..these.questions.are:.(i).what.are.the.impacts.of.climate.variability.and.change. on.water.systems,.both.natural.and.engineered;.(ii).what.are.adaptation.strategies.to.reduce. vulnerability.of.water.systems.to.these.impacts;.and.(iii).how.can.the.bank.assist.client.countries.in. making.informed.decisions.regarding.adaptation.options.in.their.water.investments? xxix in.order.to.address.these.questions.the.following.actions.will.guide.the.bank's.water.practice:. (i).continued.strengthening.of.the.analytical.foundation,.(ii).explicit.incorporation.of.hydrologic. variability.and.climate.resiliency.in.project.preparation.and.other.bank.operations.(iii).a. strengthening.of.bank.expertise.on.water.and.climate.change. in.particular.it.is.foreseen.that:.(i).the.water.Anchor.will.up-date.the.projections.of.the.hydrologic. drivers.for.water.investment.presented.in.this.report.on.a.regular.basis.and.make.them.more. readily.available.for.the.regional.staff.for.use.through.guidelines,.notes,.web-page.etc..(ii).jointly. with.the.regions.there.will.be.a.further.expansion.and.formalization.of.a.risk-based.approach. to.adaptation.related.investments.(iii).guidelines.will.be.provided.for.improved.decision.making. by.explicit.incorporation.of.climate.change.effects.in.project.economic.analysis.and.through.the. preparation.of.assessments.of.the.cost.of.adaptation.and.measures.to.reduce.vulnerability.at.the. river.basin.level. Finally,.in.the.future.more.work.is.needed.on.the.impact.of.climate.change.on.social.and. economic.development. xxx CHaPTer 1: ConTexT and overview introduction Evidence of increased hydrologic variability and climate change is solid..the. intergovernmental.Panel.on.climate.change.has.concluded.that.there.is.increasing.evidence.that. the.earth's.climate.is.changing.and.at.an.unprecedented.rate.(iPcc,.2007a)1..this.is.contributing. to.increased.frequency.and.magnitudes.of.extreme.events,.including.both.floods.and.droughts. (e.g.,.2007­8.floods.in.south.and.east.Asia,.2006­7.droughts.in.parts.of.Africa.and.middle.east,. 200­009.drought.in.Australia)..Accelerated.glacial.melt.has.been.documented.in.the.Andes.in. south.America,.the.Himalayas.in.Asia,.and.even.on.mt..kilimanjaro.in.east.Africa..sea.level.rise.is. already.threatening.many.major.coastal.cities.and.small.islands. Warming of the climate system in recent decades is `unequivocal' (IPCC, 2007a)..the. earth's.temperature.is.highly.variable,.with.year.to.year.changes.often.masking.the.overall.rise.of. approximately.0.74°c.that.has.occurred.from.1906­2005..nevertheless,.there.is.a.clear.twentieth. century.upward.trend,.and.in.particular.a.rapid.rise.over.the.past.50.years..indeed,.the.period. from.the.1980s.onwards.has.been.the.warmest.period.in.the.last.2000.years..the.iPcc.has. projected.that.by.the.end.of.the.21st.century,.the.earth's.average.temperature.is.likely.to.rise.by. between.1.1.and.6.4°c.from.the.mean.in.1990,.depending.on.the.emission.path. And human activities are in part responsible. greenhouse.gases.that.trap.heat.(water.vapor,. carbon.dioxide,.and.methane).exist.naturally.in.the.atmosphere..However,.there.is.increasingly. strong.evidence.that.`anthropogenic.forcings'--and.in.particular.increasing.concentrations.of.co2. from.the.burning.of.fossil.fuels--have.contributed.to.global.warming..According.to.the.iPcc,.most. of.the.observed.increase.in.global.temperatures.since.the.mid-20th.century.is.very.likely.due.to. the.observed.increase.in.anthropogenic.greenhouse.gas.concentrations.(iPcc,.2007a)..this.also. holds.at.the.continental.scale.for.all.regions.except.Antarctica. Responses to climate change take two linked tracks--mitigation and adaptation. mitigation. seeks.to.minimize.the.human.footprint.through.efforts.to.control,.reduce.or.even.eliminate. greenhouse.gas.emissions..this.is.generally.referred.to.as.a.transition.to.low.or.constrained.carbon. growth..examples.include.the.introduction.of.low-carbon.technologies.for.electricity.generation.and. transport,.reforestation,.and.capturing.and.sequestering.emissions..because.the.effects.of.historical. greenhouse.gas.emissions.cannot.be.reversed,.attention.is.increasingly.being.given.to.the.need. for.adapting.to.a.changing.climate..Adaptation.attempts.to.reduce.the.vulnerability.of.human. livelihoods,.economies,.and.natural.systems.to.the.impact.of.climate.induced.changes..examples. include.(a).increasing.the.resiliency.of.the.agricultural.sector.to.droughts.and.reducing.the.risk.of. floods.through.improved.storage.and.infrastructure.management.and.(b).protecting.freshwater. ecosystem.functions.by.integrating.environmental.flow.requirements.in.infrastructure.planning,. design.and.operations..in.some.cases.(e.g.,.hydropower,.wetlands.management).mitigation.and. adaptation.strategies.may.be.closely.linked.and.complimentary. This report contributes to the World Bank agenda on climate change and more specifically, informs the water sector investments on climate issues, risks and climate- 1 AllreferencestoIPCCliteraturecomplywiththespecificcitationformatindicatedbyIPCC. 1 smart adaptation options. using.the.existing.knowledge.and.additional.analysis.commissioned. by.the.world.bank,.the.report.intends.to.illustrate.that.climate.change.is.affecting.the.hydrologic. cycle.and.projections.show.direct.impact.on.the.water.resources.base..depending.on.the.water. investment,.this.impact.can.be.positive,.negative,.or.neutral..the.report.distinguishes.between. stress.on.and.vulnerability.of.the.water.systems.through.use.of.reliability,.resilience,.and.robustness. as.the.key.indicators.of.performance..current.practices.in.the.sector.are.examined.in.order.to. better.understand.the.state-of-the-science.for.incorporating.current.and.future.variability.and. change.in.hydrology.and.climate.in.the.bank's.portfolio..new.and.innovative.practices.taking. into.account.adaptation.options.for.water.systems.and.risk-based.decision.making.in.water. investments.are.reviewed.and.assessed.for.application.to.major.bank.investments.in.infrastructure.. the.climate.change.dimension.is.placed.within.the.context.of.the.impact.of.other.factors.(within. and.outside.the.sector).such.as.population.growth.(and.associated.increase.in.demand).and.land. management,.which.may.be.far.more.significant.and.critical.than.that.of.climate.change.in.some. cases.and.in.some.parts.of.the.world. Climate Change and the world bank Climate change is a development issue for the Bank and its clients. wbg.clients,.by.virtue. of.their.geographic.location.and.often.low.coping.capacity,.are.among.the.most.affected..the. bank's.2007.report.IDA and Climate Change: Making Climate Action Work for Development provides.compelling.evidence.that.the.distribution.of.major.climate-related.risks.around.the.world. is.skewed.against.poor.countries..the.bank's.2009.development.and.climate.change.strategic. Framework.(dccsF).(world.bank,.2008a).asserts.that.climate.change.is.a.development.issue,. among.others..dccsF.states:.the.anticipated.impacts.of.climate.change,.which.could.begin. to.occur.within.the.next.two.to.three.decades,.include:.dangerous.floods.and.storms.and.more. frequent.and.longer.droughts;.exacerbated.water.stress;.decline.in.agricultural.productivity.and. food.security;.increased.saltwater.intrusion.in.coastal.aquifers.and.estuaries;.increased.stress.on. freshwater.ecosystems;.and.further.spread.of.water-related.diseases,.particularly.in.tropical.areas.. this.could.lead.to.population.displacement,.migration,.and.potential.conflicts..in.the.longer. term,.sea.level.rise.and.glacier.melting.threaten.the.existence.of.nations.and.the.development. foundation.of.subcontinents. Sub-Saharan African countries dominate the list of most climate-affected client countries. other.regions.are.also.affected.by.extreme.events.(e.g.,.south.and.southeast.Asia.flooding,. latin.America.and.south.Asia.rapid.glacial.melt)..climate.change.poses.a.risk.to.world. bank.investments.in.a.wide.range.of.sectors,.including.potentially.undermining.performance,. sustainability.and.contributing.to.water.scarcity.and.water.security.in.certain.cases..this.makes.it. imperative.that.climate.change.adaptation.is.not.separated.from.other.priorities,.but,.rather,.is. integrated.into.development.planning,.programs.and.projects.in.the.client.countries. Climate change has direct implications for the World Bank's mission of poverty reduction. the.bank's.2009.development.and.climate.change.strategic.Framework.(dccsF).states:. "climate.change.threatens.to.reverse.hard-earned.development.gains..the.poorest.countries.and. communities.will.suffer.the.earliest.and.the.most..yet.they.depend.on.actions.by.other.nations.. while.climate.change.is.an.added.cost.and.risk.to.development,.a.well-designed.and.well- implemented.global.climate.policy.can.also.open.new.economic.opportunities.to.developing. countries.".indeed,.developing.countries,.and.particularly.the.poorest.people.in.these.countries,. are.the.most.vulnerable.to.the.adverse.impacts.of.climate.variability.and.projected.climate.change.. their.economies.depend.heavily.on.climate-sensitive.sectors.such.as.agriculture,.livestock,.forestry,. 2 fisheries,.water.supply,.and.other.natural.resources..they.are.generally.hindered.by.limited. institutional.capacity.and.access.to.technology.and.capital.to.invest.in.risk.reduction..world. bank.analysis.of.ethiopia,.mozambique.and.kenya.shows.huge.impacts.of.climate.variability.on. the.performance.of.key.economic.sectors.such.as.agriculture,.transport,.energy,.manufacturing,. livestock.and.tourism..estimates.of.the.economic.impacts.of.climate.change.are.likely.to.be. significant,.especially.in.developing.countries.(stern,.2006)..However,.these.can.be.minimized.and. reduced.with.appropriate.adaptation.strategies. Addressing climate variability through both mitigation and adaptation has been, and continues to be a key priority for the Bank..For.decades,.the.world.bank.has.been.actively. engaged.in.efforts.to.mitigate.climate.variability..the.world.bank.has.provided.countries.with. incentives.to.develop.and.implement.clean.energy.technologies.and.sustainable.transport. systems,.as.well.as.to.improve.practices.in.agriculture,.forestry.and.land.management..this. has.allowed.many.countries.to.achieve.increased.energy.access.for.the.poor.and.improved. livelihoods.for.the.vulnerable,.while.at.the.same.time.moving.towards.a.sustainable,.low-carbon. path.of.development..more.recently.the.focus.has.also.turned.to.adaptation..dccsF.articulates. the.wbg's.vision.on.how.to.integrate.climate.change.and.development.challenges,.without. compromising.growth.and.poverty.reduction.efforts.through.its.country.operations,.including. policy.dialogue,.lending,.and.analytical.work.in.client.countries,.and.through.its.regional.and. global.operations..A.coordinated.way.to.finance.the.mitigation.and.adaptation.efforts.is.through. the.climate.investment.Funds.(ciFs)..these.funds.are.established.to.serve.as.interim.financing.to. developing.countries.in.addressing.climate.change.issues..the.wbg.is.among.the.multilateral. development.banks.(mdbs).that.will.engage.in.partnership.with.developing.countries.in.their. transition.to.a.carbon-constrained.and.climate.resilient.economies. Climate change and the water sector The World Bank is responding by first understanding the risks and impacts, then managing them through climate-smart investments. the.world.bank.recognizes.water.as. a.key.affected.sector..consequently,.the.impact.of.climate.change.and.potential.adaptation. strategies.has.become.central.to.the.dialogue.on.water.policy.reforms.and.investment.programs. with.client.countries..this.has.been.guided.by.climate.change.strategies.prepared.by.each. region.of.the.world.bank.within.the.context.of.the.dccsF ..the.2010.world.development. report.focuses,.among.other.factors,.on.the.land.and.water.interface.for.managing.competing. demands.and.creating.new.opportunities.for.climate-smart.development..many.client.countries. in.partnership.with.the.world.bank.group.have.begun.to.take.action.to.adapt.their.water.sector. to.implications.of.climate.change.and.resulting.hydrologic.impacts..this.process.is.supported. by.analytical.and.advisory.assistance.on.water.and.climate.change.carried.out.by.regional. units,.as.well.as.the.water.Anchor..incorporating.climate.change.in.the.portfolio.has.been. steadily.increasing.in.response.to.client.demands..A.number.of.stand-alone.climate.change. projects.have.also.been.financed.through.various.grant.and.lending.instruments.and.they.are. increasing. There is strong link between changes in climate and the hydrologic cycle..According.to. the.iPcc's.most.recent.report,."Observational records and climate projections provide abundant evidence that freshwater resources are vulnerable and have the potential to be strongly impacted by climate change, with wide ranging consequences on human societies and ecosystems. (bates,.et.al,.2008,.p.4)..long-term.trends.in.hydrologic.variables.are.difficult.to.detect.due. to.significant.natural.variability.in.all.components.of.the.hydrologic.cycle.over.both.time.and. 3 space.2.However,.observed.changes.in.the.hydrologic.cycle.at.the.sub-continental.scale.have. consistently.been.associated.with.climate.warming.over.the.past.several.decades..these.changes. are.often.referred.to.as.intensification.and.acceleration.of.the.hydrologic.cycle..these.changes. include.increasing.atmospheric.water.vapor.content;.changing.precipitation.patterns,.intensity. and.extreme.events;.reduced.snow.cover.and.faster.and.widespread.melting.of.ice;.and.changes. in.soil.moisture.and.runoff..it.is.projected.that.many.of.these.phenomena.will.become.more. pronounced.with.climate.change. Climate change could profoundly alter future patterns of both water availability and use, thereby increasing water stress globally. many.of.the.direct.effects.of.climate.change. on.water.availability.have.been.presented.above..However,.less.is.known.about.the.impacts.of. climate.change.on.groundwater.availability.and.use,.including.interactions.with.surface.water.. there.is.also.relatively.little.information.on.freshwater.ecosystems.and.water.quality,.although. according.to.iPcc.(and.other.studies).higher.water.temperatures.and.changes.in.extreme. events,.including.floods.and.droughts,.are.projected.to.affect.water.quality.and.exacerbate.many. forms.of.water.pollution..in.addition,.sea-level.rise.is.projected.to.extend.zones.of.salinisation. of.groundwater.and.estuaries..taken.together,.the.potential.changes.in.water.availability.and. use.may.aggravate.global.`water.stress'..most.studies.have.found.that.levels.of.water.stress.will. increase,.although.there.are.significant.differences.in.estimates.across.studies..Arnell.(2004)-- who.accounts.for.population.growth.and.the.impact.of.climate.change--found.that.the.number. of.people.projected.to.experience.an.increase.in.water.stress.is.between.0.4.to.1.7.billion.in.the. 2020s.and.between.1.and.2.7.billion.in.the.2050s.(using.the.A2.population.scenario.for.the. 2050s)..when.environmental.flow.needs.are.incorporated--that.is,.the.amount.of.water.required. to.sustain.a.functioning.ecosystem--the.degree.of.water.stress.is.projected.by.some.to.increase. further.(smakhtin.et.al,.2003).3.based.on.these.and.other.studies,.the IPCC concluded with high confidence that, globally, the negative impacts of future climate change on freshwater systems and ecosystems are expected to outweigh the benefits. Future water availability, use, and investments will also depend on non-climatic drivers, including financial and sector conditions. climate.change.is.only.one.of.many.factors. that.will.determine.future.patterns.of.water.availability.and.use..non-climatic.factors.could. aggravate.or.attenuate.the.adverse.effects.of.climate.change.on.water.availability.and.quality,. as.well.as.have.a.significant.influence.on.water.demand..Population.growth.and.economic. development.(and,.by.extension,.changes.in.lifestyles.and.diets).will.play.a.dominant.role.. non-climatic.impacts.could.be.generated.through.many.realms--from.policies.and.legislation. to.technologies.and.infrastructure.to.land-use.patterns.and.agricultural.activities/irrigation.. Additionally,.water.infrastructure.investments.are.highly.sensitive.to.the.trends.of.the.official. development.Assistant.(odA),.availability.of.financing.through.multilateral.development.banks. (mdb),.and.the.private.sector.appetite.for.investment..recent.financial.crisis.and.sector.crises. (e.g.,.food,.energy).have.already.shown.their.impact.on.the.water.sector.and.will.continue. to.remain.a.major.challenge..such.non-climatic.drivers.could.dwarf.the.impacts.attributed.to. climate.change.alone,.in.a.positive.or.negative.direction..the.impact.of.the.financial.crisis. on.water.infrastructure.vis a vis.deferred.operation.and.maintenance.can.be.particularly. devastating. 2 Large-scaleatmosphericcirculationpatternsassociatedwithENSO(ElNiño-SouthernOscillation),NAO(NorthAtlanticOscillation)and othervariabilitysystemsthatoperateatwithin-decadalandmulti-decadaltime-scalesareaverystronginfluenceinsomeregions. 3 Notethatsuchindicesofwaterstressaretypicallydefinedintermsofannualaveragesanddonotincludevaryinglevelsofwater quality. 4 Water investments are particularly vulnerable to impacts of climate change. climatic. impacts.will.have.significant.consequences.on.investments.in.water.systems4.(or.infrastructure). associated.both.with.delivering.water.services.and.with.managing.water..water.systems.for. delivering.water.services.include.irrigation;.urban.water,.sanitation.and.drainage;.rural.water. and.sanitation;.and.ports.and.navigation..systems.for.managing.water.resources.include. those.for.delivery.of.bulk.irrigation,.watersheds,.and.water.resources.broadly,.as.well.as.multi- purpose.systems.(including.hydropower).and.flood.control..For.example,.in.urban.environments,. more.heavy.rainfall.events.could.overload.the.capacity.of.storm.drain.systems.and.water.and. wastewater.treatment.facilities;.sea.level.rise.could.lead.to.salinisation.of.water.supplies.from. coastal.aquifers..climate.change.could.increase.irrigation.demand.due.to.the.combination.of. decreased.rainfall.and.increased.evapotranspiration,.placing.additional.pressure.on.irrigation. systems.that.are.in.many.cases.already.under.performing..changes.in.river.flows.have.a.direct. impact.on.hydropower.generation..soil.erosion.from.increased.rainfall.intensity.could.affect. watershed.sustainability.and.lead.to.sedimentation.in.reservoirs,.impacting.on.the.operation. of.multi-purpose.facilities..extreme.variability.and/or.reduced.supplies.could.stretch.the. infrastructural.and.institutional.limits.of.systems.that.manage.water.across.sectors.and.even. national.boundaries. The extent to which water investments are impacted by climate change will have ramifications that could extend to the economy and society at large..this.depends.highly. on.the.degree.of.vulnerability.of.the.system.(or.project).design.and.operation,.including.its.internal. capacity.to.adapt..For.example,.pressure.on.water.supply.and.sanitation.facilities.could.have. a.wide.range.of.adverse.effects.on.human.health..reduced.availability.of.water.for.irrigation. could.threaten.food.security,.rural.development,.environmental.uses.of.water,.and.the.economies. of.countries.that.are.largely.dependent.on.the.agricultural.sector..reduced.freshwater.supplies. may.lead.to.a.shift.towards.increased.use.and.dependence.on.groundwater..reduced.water.for. hydropower.generation.(or.increased.fluctuations.in.river.flows).could.decrease.electricity.grid. stability.and.reliability,.with.consequent.effects.on.the.economy.as.well.as.livelihoods.dependent. on.downstream.uses.of.water..managing.sedimentation.(e.g.,.through.flushing).could.affect.the. timing,.supply.and.quality.of.water.to.the.various.sectors.served.by.a.multi-purpose.infrastructures,. with.impacts.felt.in.the.larger.economy..in.the.worst.case,.competition.over.limited.water.resources. across.sectors.and.nations.could.worsen.hostility.and.mistrust,.and.increase.conflicts.over.water. and.further.degrade.freshwater.ecosystems. value added and content of this report The primary objective of this report is to support Bank operations and the client countries in making informed and climate-smart water investment decisions. this.report.provides. an.overview.of.a.package.of.background.technical.reports,.papers,.and.analyses.commissioned. by.the.bank's.water.Anchor.in.an.attempt.to.understand.the.risks.of.the.impact.of.climate. change.on.the.bank's.water.investments.and.to.provide.ways.to.manage.them..this.package. of.information,.knowledge,.and.guidelines.is.intended.for.use.by.the.bank.water.staff.and.client. countries. 4 Theterm`system'incapturesallelements--frominfrastructuretoinstitutions--thatcontributetoperformanceoftheintendedfunction.In thisreport,systemandinfrastructureissometimesusedinterchangeablywithwatersystemswiththeimpliedbroadestdefinitionofthe term. 5 This report adds value to the Bank's work on climate change and water in the following areas: A compilation of the state-of-the-knowledge for the Bank's water practice..there.is.a.wealth.of. information.on.climate.change,.adaptation.and.the.water.sector,.which.is.held.within.the.bank. and.beyond,.and.which.includes.both.analytical.studies.and.on-the-ground.experiences..the.body. of.knowledge.on.this.subject.is.rapidly.expanding..A.significant.added.value.of.this.report.is.in. bringing.together.the.various.information,.references,.and.conclusions.from.this.vast.knowledge. base.in.a.condensed,.structured.and.coherent.manner.specifically.useful.to.the.bank's.water. practice..Another.value.of.this.report,.equally.important.to.the.water.professionals.is.provision.of. the.best.available.information.regarding.the.gaps.in.the.knowledge,.critical.assumptions.made.in. the.modeling.effort,.shortcomings.and.pitfalls.in.the.analysis,.and.potential.misuse.of.the.results. A consolidated package of historical data and projections of key hydrologic drivers useful for policy, planning, and investment decisions in the sector..one.potential.difficulty.with.using.climate. information.in.impact.assessments--including.in.the.water.sector--is.the.`mis-match'.between. the.low.spatial.(and.temporal).resolution.of.gcms,.on.the.one.hand,.and.the.scale.at.which. assessments.need.typically.to.be.conducted.for.investment.purposes,.on.the.other..to.facilitate. initial.dialogue.and.assessment.for.incorporation.of.climate.change.in.water.investments,.a.set.of. historical.and.projected.hydrologic.parameters.have.been.compiled.for.bank.use..the.historical. information.is.based.on.1960­1990.period.organized.to.serve.as.baseline..the.projections.are. based.on.projections.from.22.gcms,.scaled.to.basin.level.and.translated.to.hydrologic.drivers. and.indicators.for.planning.and.investment.decisions. An analysis of the exposure of Bank water investments to current hydrologic variability and future climate change. the.world.bank's.water.investments.are.exposed.to.current.hydrologic.variability. and.future.climate.change..the.historical.and.future.hydrologic.drivers.and.indicators.are.mapped. on.to.the.bank's.active.and.pipeline.projects.to.assess.the.potential.exposure.to.hydrologic. variability.and.climate.change..Assessment.of.the.exposure.of.the.water.services.investments.(.e.g.,. irrigation.and.drainage,.urban.water.supply.and.sanitation,.rural.water.supply.and.sanitation). and.water.management.systems.(e.g.,.flood.control,.river.basin.management,.and.multi-purpose. infrastructure).are.reported.here. Climate change implications on groundwater and groundwater management adaptation opportunities are highlighted. relative.to.surface.water,.aquifers.have.the.capacity.to.store.large. volumes.of.water.and.are.naturally.buffered.against.seasonal.changes.in.temperature.and.rainfall.. they.provide.a.significant.opportunity.(through.conjunctive.use.and.management.of.surface.and. groundwater.resources,.managed.aquifer.recharge.and.land.use.protection.and.management). to.optimize.use.of.water.resources,.to.store.excess.water.during.high.rainfall.periods,.to.reduce. evaporative.losses.and.to.protect.water.quality..However,.these.opportunities.have.received.little. attention,.in.part.because.groundwater.is.often.poorly.understood.and.managed. Freshwater ecosystem adaptation options..As.hydrology.and.water.use.changes.due.to.altered. precipitation.patterns.and.as.waters.become.warmer,.freshwater.ecosystems.will.be.stressed.further. and.the.aquatic.life.they.now.support.will.be.replaced.by.other.species.better.adapted.to.warmer. water.(i.e.,.cold.water.fish.will.be.replaced.with.warm.water.fish)..this.process,.however,.will.occur. at.an.uneven.pace.disrupting.ecosystem.health.and.allowing.non.indigenous.and/or.invasive. species.to.become.established..in.the.long.term,.warmer.water.and.changing.river.flows.may. 6 result.in.significant.deterioration.of.aquatic.ecosystem.health.in.some.areas.(usePA,.2008)..A.key. response.to.climate.adaptation.is.to.develop.both.adaptive.management.systems.that.can.enable. ecosystems.to.respond.to.changes.and.the.establishment.of.resilient.ecosystems. Guidance on inclusion of risk-based decision making in water investments..world.bank.water. investments.can.have.significant.exposure.and.vulnerability.to.climate.change..most.water. investments.can.no.longer.be.designed.based.on.average.conditions.and.simplified,.deterministic. assumptions..to.avoid.or.reduce.climate-induced.losses,.a.shift.in.decision.making.from. traditional.deterministic.approach.to.a.risk-based.approach.is.necessary..this.will.help.to.better. understand.(and.characterize).the.risks.and.develop.ways.to.manage.them..A.framework.for. systematic.and.pragmatic.incorporation.of.risk.and.uncertainty.in.the.bank's.water.investment. project.cycle.is.presented.in.this.report. The content of this report will help enhance sustainability of Bank investments in the water sector by providing staff and client countries..the.report.presents/summarizes. approaches,.methodologies.and.guidelines.for.incorporating.hydrologic.variability,.climate. change,.and.risk.management.in.project,.program.and.sector-wide.investments..it.will.contribute. to.preparation.of.future.country.water.resources.assistance.strategies.that.incorporate.adaptation. to.climate.change.in.investment.planning.and.inform.institutional.and.policy.reform.for.sustainable. management.of.water.resources..the.report.begins.with.illustrating.the.impact.of.climate.change. on.the.hydrologic.cycles.and.identifies.the.drivers.significant.to.investments..the.scientific.effort. to.understand.and.describe.climate.change.is.assessed.for.application.to.the.bank.operations.. the.impact.of.the.changing.hydrologic.cycle.on.water.availability,.demand,.and.management,. including.the.potential.vulnerability.of.various.water.systems.and.its.implication.in.the.sector.is. then.examined..A.package.of.climate.change.projections.at.a.scale.appropriate.for.planning.and. investment.decisions.had.been.developed..this.package.is.designed.to.serve.as.a.common.basis. for.analysis.of.the.impact.of.climate.change.in.any.sector..using.these.projections,.exposure.of.the. current.and.future.bank.portfolio.to.climate.change.is.evaluated..Finally,.an.agenda.for.continued. effort.in.the.water.practice.to.address.hydrologic.variability.and.climate.change.is.proposed. The primary audience for this report and its associated technical reports is World Bank staff and as appropriate the client countries. the.objective.is.to.equip.bank.staff.with.needed. knowledge.and.tools.to.effectively.incorporate.climate.variability.and.change.in.their.operational. work.in.the.water.sector..the.outcome.of.this.work.will.also.assist.client.countries.in.making. informed.decisions.on.incorporating.hydrologic.variability.and.adaptation.strategies.into.long-term. planning.and.investment.decisions..this.is.timely.and.relevant.as.both.the.bank.staff.and.client. country.professionals.are.becoming.increasingly.aware.of.the.risks.of.no.action..A.comprehensive. dissemination.strategy,.including.capacity.building.programs,.for.bank.staff.and.clients.countries. will.be.developed.by.the.water.Anchor.and.implemented.in.collaboration.with.the.regions.and.as. part.of.the.world.bank.institute.climate.change.activities. 7 CHaPTer 2: imPaCT of ClimaTe CHange on THe HydrologiC CyCle and THe waTer resourCe base The climate system and the hydrologic cycle are intimately linked Powered by solar radiation, the climate system is a complex, inter-active system consisting of the atmosphere, land surface, snow and ice, oceans and other bodies of water, and living things (IPCC, 2007a)..the.climate.system.evolves.over.time.under.the.influence.of.its.own. internal.dynamics.and.due.to.changes.in.external.factors.that.affect.climate.(called.`forcings').. external.forcings.include.natural.phenomena.(e.g.,.volcanic.eruptions.and.solar.variations),.as. well.as.anthropogenic.changes.that.alter.atmospheric.composition.and.land-use.change..changes. in.any.of.these.factors.can.alter.the.balance.between.incoming.(solar).short-wave.radiation.and. outgoing.long-wave.radiation..the.climate.system.responds.both.directly.and.indirectly.(through. feedback.mechanisms).to.such.changes..description.of.weather,.climate,.and.climate.variability. are.provided.in.box.2.1. Any variability in climate affects the hydrologic cycle.5.the.hydrologic.cycle.describes.the. continuous.movement.of.water.through.the.oceans,.atmosphere,.and.land.surface.(Figure.2.1).. driven.by.solar.energy,.the.hydrologic.cycle.begins.with.the.evaporation.of.water.from.the.surface. of.the.ocean..As.moist.air.is.lifted,.it.cools.and.water.vapor.condenses.to.form.clouds..moisture. is.transported.around.the.globe.and.returns.to.the.surface.as.precipitation.(in.its.multiple.forms. of.rain.and.snow,.sleet,.hail,.etc.)..once.the.water.reaches.the.ground,.one.of.two.processes. may.occur:.i).water.evaporates.or.transpires.back.into.the.atmosphere6.or.ii).the.remaining.water. penetrates.the.surface.and.becomes.groundwater..groundwater.seeps.into.oceans,.rivers,.and. streams..the.balance.of.water.that.remains.on.the.earth's.surface.is.runoff,.which.empties.into. lakes,.rivers.and.streams.and.is.carried.back.to.the.oceans,.where.the.cycle.begins.again.(bramer. et.al.,.2008). Box 2.1 Weather, climate, and climate variability Weather.is.a.measure.of.short-term.changes.in.atmospheric.conditions.(e.g.,.temperature,.precipitation. amount,.humidity)..Climate.describes.the.typical.weather.of.a.region..more.precisely,.it.is.a.statistical. description.of.long-term.(e.g.,.30.years).average,.variances,.and.extremes.derived.from.observed.weather.. Climate variability generally.refers.to.fluctuations.around.a.mean.climate.that.occur.on.seasonal,.inter- annual,.and.even.decadal.timescales..A.significant.component.of.climate.variability.can.be.linked.to.a.relatively. small.number.of.patterns.(or.modes).of.variability,.including.el.niño-southern.oscillation.(enso),.north. Atlantic.oscillation.(nAo),.and.Atlantic.multi-decadal.oscillation.(Amo)..these.events--which.may.occur. on.timescales.of.years.to.decades--lead.to.changes.in.atmospheric.circulation.and.rainfall.distribution.that. characterize.many.parts.of.the.world..A.key.point.is.that.these.patterns.are.not.long-term.changes.in.climate,. but.rather.deviations.from.mean.climate.conditions. 5 Theinfluencealsoworksinthereversedirection,i.e.,thechangesinthehydrologiccyclecanalsoaffecttheclimatesystem.Thefocus here,however,isontheimpactofclimaticchangeonhydrology. 6 Evaporationiswaterthatturnstowatervapordirectlyfromsurfacewaterbodies(e.g.,oceans,lakes,andreservoirs).Transpirationis waterthatistakenupbyplantsandthenreleasedtotheatmosphere. 9 Figure 2.1 The Hydrologic Cycle Source: iPcc.2007c,.pg..96,.FAQ1.2,.Fig..1. evidence is mounting that climate change is occurring and that it is altering the hydrologic cycle Climate change is "an altered state of the climate that can be identified by changes in the mean and/or variability of its properties, and that persists for an extended period, typically decades or longer" (Bates, et al., 2008)..definitions.of.climate.change.vary,.not.in. terms.of.what.it.is,.but.in.terms.of.what.is.responsible,.and.specifically.whether.it.is.attributable. to.natural.causes.and/or.anthropogenic.causes..the.united.nations.Framework.convention. on.climate.change.(unFccc).definition.of.climate.change.is.restrictive,.in.the.sense.that.it. includes.only.anthropogenic-induced.changes.and.not.those.associated.with.natural.causes.. the.intergovernmental.Panel.on.climate.change.(iPcc).definition,.which.includes.both,.is.more. widely.accepted,.so.it.is.adopted.here..According.to.the.iPcc.definition,.climate.change.can.be. attributed.to.natural.internal.processes.and.to.external.forcings,.both.natural.and.anthropogenic. While there is wide agreement on the potential causes of climate change, it is difficult to attribute observed (or detected) changes in climate to a specific cause, and, in particular to anthropogenic changes..the.difficulties.of.distinguishing.between.human.and.natural.causes. of.climate.change.increase.at.finer.spatial.and.temporal.scales..nonetheless,.the.iPcc.has.found,. based.on.a.number.of.observed.trends,.that.global.climate.is.changing,.and.that.it.is.very likely. that.human.activities.are.in.part.responsible..the.earth's.temperature.is.highly.variable,.with.year. to.year.changes.often.masking.the.overall.rise.of.approximately.0.74°c.that.has.occurred.from. 1906­2005.(iPcc,.2007a;.bates,.et.al.,.2008)..nevertheless,.there.is.a.clear.twentieth.century. upward.trend,.and.in.particular.a.rapid.rise.over.the.past.50.years..greenhouse.gases.that.trap. 10 heat.(water.vapor,.carbon.dioxide,.and.methane).exist.naturally.in.the.atmosphere..However,.there. is.increasingly.strong.evidence.that.anthropogenic.radiative.forcings--and.in.particular.those. deriving.from.increased.concentrations.of.co2.from.burning.of.fossil.fuels--have.contributed.to. global.warming. There is now strong evidence that global warming is changing hydrologic cycle..long- term.trends.in.hydrologic.variables.are.difficult.to.detect.due.to.significant.natural.variability.in. all.components.of.the.hydrologic.cycle.over.both.time.and.space..However,.observed.changes.in. the.hydrologic.cycle.at.the.sub-continental.scale.have.consistently.been.associated.with.climate. warming.over.the.past.several.decades.7.A.summary.of.the.evidence,.based.on.iPcc.findings.is. provided.below.(bates,.et.al.,.2008;.kundzewicz,.et.al.,.2007). Precipitation (including extreme events) and water vapor: ·.the.average.atmospheric.water vapor content.has.increased.since.at.least.the.1980s.over.land. and.ocean.as.well.as.in.the.upper.troposphere. ·.over.the.20th.century, mean precipitation.has.mostly.increased.over.land.in.high.northern. latitudes.over.the.period.1901.to.2005,.while.decreases.have.dominated.from.10°s.to.30°n. since.the.1970s. ·.widespread.increases.in.heavy precipitation events.(e.g.,.above.the.95th.percentile).have.been. observed,.particularly.in.mid-latitude.regions.and.even.where.total.precipitation.has.decreased. ·.globally,.soil moisture.has.decreased..Droughts.have.become.more.intense.and.longer,. especially.in.the.tropics.and.subtropics. ·.there.is.observational.evidence.that.intense.tropical cyclone.activity.has.increased.is.some. regions.(e.g.,.north.Atlantic.since.about.1970)..there.is.no.clear.trend.in.the.frequency.of. tropical.cyclones. Snow and land ice: ·.Snow cover.has.decreased.in.most.regions,.especially.in.spring.and.summer;.degradation.of. permafrost and seasonally frozen ground.has.occurred.in.many.areas;.freeze-up.and.break- up.dates.for.river and lake ice.have.been.delayed.and.taken.place.earlier,.respectively,.in.the. northern.hemisphere,.where.data.are.available. ·.considerable.mass.loss.has.occurred.on.the.majority.of.glaciers and ice caps.worldwide. (box.2.2). future changes in climate are projected to lead to a further acceleration and intensification of the hydrologic cycle Changes in the global climate system during the 21st century will very likely be larger than those observed during the 20th century. the.iPcc.has.projected.that.by.the.end.of.the.21st. century,.the.earth's.average.annual.mean.temperature.is.likely.to.rise.by.between.1.1.and.6.4°c. from.the.mean.in.1990..the.wide.range.in.projections.of.mean.surface.air.warming.result.from. two.factors:.the.sres.(special.report.on.emissions.scenarios).emissions.scenario.and.different. models.used. However,.the.iPcc.concluded.that.it.is.very likely.that.nearly.all.land.areas.will.warm. more.rapidly.than.the.global.average.and.particularly.those.at.northern.high.latitudes.in.the.cold. 7 Thereareseveralprocessesthroughwhichchangesinhydrologicalvariablescanproducefeedbackeffectsonclimate(e.g.,landsurface effects,feedbacksthroughchangesinoceancirculation,emissionsorsinksaffectedbyhydrologicalprocesses),butthefocushereisin thereversedirection,thatis,theimpactofclimatechangeonhydrology. 11 Box 2.2 Mass loss of glaciers tropical.glaciers.located.between.bolivia.and.venezuela.decreased.in.area.by.just.under.20%.between1970. and.2002..several.glaciers.in.south.America,.such.as.ecuador's.cotacachi,.have.already.disappeared.(eos,. 19.june.2007)..Peruvian.glaciers.declined.nearly.22.percent.between.1970.and.1997.as.a.result.of.warmer. temperatures..major.additional.reductions.in.surface.area.have.been.measures.since.then..the.largest.of.these. glaciers.in.the.cordillera.blanca.have.lost.15.percent.of.their.glacier.surface.area.in.a.period.of.30.years.. many.of.the.smaller.glaciers.in.Peru.have.already.been.heavily.affected.and.others.are.likely.to.completely. disappear.within.a.generation. evidence.suggests.that.the.rate.of.temperature.increase.in.nepal.and.the.tibetan.Plateau.is.greater.than.the. global.average,.and.a.pronounced.warming.in.winter.has.already.been.observed..retreating.glaciers.in.the. Himalayas.present.one.of.the.most.difficult.challenges.for.the.region,.because.glaciers.and.snow.provide.water. storage.that.helps.to.regulate.the.flow.of.perennial.rivers.and.to.enhance.low.season.flows..the.Himalayan. glaciers.are.reducing.at.a.rate.of.10­15.m.every.year.(tehelka,.3.may.2008)..the.region.is.also.at.risk.of.an. increase.in.the.frequency.and.magnitude.of.climate.change-related.natural.disasters,.including.glacier.and. snow.melt,.and.glacial.lake.outburst.floods. observed.and.anticipated.climate.change-related.impacts.include.deterioration.of.watersheds.and.depletion.of. water.recharge.capacities,.increased.likelihood.of.mountain.fires,.and.biotic.changes.in.ecosystem.thresholds. and.their.ability.to.store.water..the.effects.and.consequences.may.be.different.at.the.initial.and.final.stages.of. the.glacier.retreat.and.may.differ.depending.on.location. season..climate.variability.is.also.likely.to.change,.although.the.nature.of.this.change.is.uncertain.. Along.with.the.substantial.changes.in.average.climatic.conditions,.it.is.likely.that.there.will.also.be. changes.in.the.seasonal.cycle.of.the.climate.and.in.the.intensity.and.frequency.of.extreme.events. (refer.below). It is projected that many of the currently observed changes in the hydrologic cycle will become more pronounced with continuing climate change..Projected.increases.in. global.temperatures.are.associated.with.changes.in.the.hydrologic.cycle,.including.increasing. atmospheric.water.vapor,.changes.in.precipitation.patterns.(frequency.and.intensity),.leading.to. changes.in.soil.moisture..these.changes.are.often.referred.to.as.an.intensification and acceleration of the hydrologic cycle..the.result.of.hydrologic.change.and.increased.variability.is.shorter.periods. of.more.intense.rainfall,.and.longer.warmer.dryer.periods..iPcc.findings.on.the.projected.impacts. of.climate.change.on.the.hydrologic.cycle.are.summarized.below.(bates,.et.al.,.2008;.kundzewicz,. et.al.,.2007). ·.Annual average precipitation:.Precipitation.is.projected.to.increase.in.high.latitudes.(very.likely). and.parts.of.the.tropics,.and.decrease.in.some.subtropical.and.lower.mid-latitude.regions.(likely). ·.Precipitation Extremes:.increased.precipitation.intensity.and.variability.is.projected.to.increase. the.risk.of.flooding.and.drought.in.many.areas.(increased.rain-generated.floods.very.likely,. increased.extreme.drought.likely)..it.is.likely.that.future.tropical.cyclones.will.become.more. intense,.with.larger.peak.wind.speeds.and.heavier.precipitation. ·.Glaciers and snow:.water.stored.in.glaciers.and.snow.cover.is.projected.to.decline.(high. confidence). ·.Sea level:.in.all.but.one.sres.marker.scenario.(b1),.the.average.level.of.sea.level.rise.during. the.21st.century.will.very.likely.exceed.the.1961­2003.average.rates..thermal.expansion.is.the. 12 largest.component..it.has.been.suggested.that.melting.of.glaciers,.ice.caps.and.the.greenland. ice.sheet.can.contribute.to.sea.level.rise.as.a.result.of.shift.in.the.gravitational.pull.created.by. significant.loss.of.mass.at.the.poles. ·.Evapotranspiration:.changes.in.temperature,.radiation,.atmospheric.humidity.and.wind.speed. affect.potential.evapotranspiration.(or.evaporative.demand)..in.addition,.increasing.atmospheric. co2.concentration.directly.alters.plant.physiology,.thus.affecting.evapotranspiration..Potential. evaporation.is.projected.to.increase.almost.everywhere..transpiration.may.increase.or.decrease. ·.Soil moisture:.Annual.mean.soil.moisture.content.is.projected.to.decrease.in.the.sub-tropics. and.the.mediterranean.region,.and.at.high.latitudes.where.snow.cover.diminishes..soil. moisture.is.projected.to.increase.in.east.Africa,.central.Asia.and.other.regions.with.increased. precipitation. table.2.1.summarizes.the.observed.trends.and.projections.for.the.21st.century.of.key.hydrologic. variables. Table 2.1 Changes in Key Hydrologic Variable Key Variables Observed Trends Projections for 21st Century Total Precipitation trend.is.unclear..general.increases.in. increase.(about.2%/oc).in.total. precipitation.over.land.from.30 n.to.85 n.. o o precipitation..High.latitude.areas.generally. notable.decreases.from.10os.to.30on. projected.to.increase..many.low.to.mid- latitude.areas.projected.to.decrease.. changes.at.the.regional.scale.vary. Atmospheric increasing.in.lower.atmosphere.(lower. increasing Water Vapor troposphere;.about.1%/decade).in.specific. Content humidity;.little.change.in.relative.humidity Intensity of disproportionate.increase.in.volume.of. increasing.(about.7%/oc) Precipitation precipitation.in.heavy.or.extreme.precipitation. events Droughts drought,.as.measured.by.the.Palmer.drought. increasing.in.many.areas,.particularly. severity.index,.increased.in.the.20 .century,. th lower.latitudes..decreasing.in.many.high. although.some.areas.became.wetter latitude.areas..Patterns.are.complex. Tropical Cyclones increases.in.intensity,.particularly.in.north. increase.in.intensity..changes.in.frequency. Pacific,.indian.ocean,.and.southwest.Pacific and.track.are.uncertain Glaciers and decrease.in.mass.of.glaciers,.but.not.in.all. continued.decrease.in.glacial.mass.and. snow cover regions..decrease.in.snow.cover.in.regions.in. snow.cover the.northern.Hemisphere..earlier.peak.runoff. from.glacier.and.snowmelt. Sea level increased.about.0.2.meters.over.the.20th. iPcc.projects.0.2.to.0.6.meters.by.2100,. century..A.rise.equivalent.to.0.3.meters.per. but.upper.end.could.be.much.higher. century.was.recorded.since.the.early.1990s,. but.it.is.not.clear.if.this.is.an.acceleration.of. long.term.sea.level.rise Source: derived.from.iPcc,.2007a;.kevin.trenberth,.national.center.for.Atmospheric.research..Personal.communication..may.19,. 2008;.trenberth.et.al.,.2003. 13 Hydrologic change and increased variability will have a significant impact on the water resource base Changes in the hydrologic cycle will have both direct and indirect effects on the magnitude and timing of runoff, groundwater recharge, water quality, and the frequency and intensity of extreme events (droughts and floods). Projected.impacts.on.each.on.these.components.of. the.water.resource.base--summarized.from.various.iPcc.reports--are.provided.below. Uncertainties in projected climate change impacts There are significant uncertainties in projections of the impact of climate change on the water resource base. these.uncertainties.derive.from.a.number.of.sources,.including. from.internal.variability.of.the.climate.system,.uncertainty.in.future.emissions,.the.translation.of. these.emissions.into.climate.change.by.global.climate.models,.and.model.uncertainty.(bates,. et.al.,.2008)..uncertainties.in.projections.increase.with.the.length.of.the.time.horizon,.and. temperature.is.projected.with.more.certainty.than.precipitation..where.hydrological.models.are. used.to.project.changes.on.water.resources,.uncertainties.arise.from.the.mismatch.between.their. respective.spatial.and.temporal.scales..downscaling.methods.have.been.used.to.address.the. scale.issues,.but.they.introduce.additional.uncertainties..the.greatest.uncertainties.in.the.effects.of. climate.on.river.discharge/runoff.arise.from.climate.change.scenarios,.as.long.as.a.conceptually. sound.hydrological.model.is.used..Additional.uncertainty.is.introduced.in.estimating.impacts.on. groundwater.recharge,.water.quality,.or.flooding/drought.as.translation.of.climate.into.response. is.less.well.understood.(Arnell,.2004)..uncertainties.in.climate.change.impacts.on.the.hydrologic. cycle.and.water.resource.base.are.discussed.in.more.detail.later.in.this.report.(also.refer.box.2.3). Runoff and river discharge The most dominant climatic drivers for runoff and river discharge are precipitation, temperature and evaporative demand (IPCC, 2007a)..changes.in.the.volume,.timing.and. Box 2.3 Primary sources of uncertainty in projections of hydro-climatic change uncertainties.in.projected.changes.in.the.hydrological.systems.due.to.climate.change.arise.from.a.number.of. sources..these.include.the.uncertainties.in.the.internal.variability.of.the.climate.system;.uncertainty.in.future. greenhouse.gas.and.aerosol.emissions.(and,.importantly,.the.populations,.levels.of.economic.development,. and.technologies.that.generate.them);.the.translation.of.these.emissions.into.climate.change.by.global.climate. models;.and.model.uncertainty..Further.uncertainties.in.hydrological.projections.arise.from.the.structure.of. current.climate.models..current.models.generally.exclude.some.feedbacks.from.vegetation.to.climate.change.. most.simulations.used.for.deriving.climate.change.projections.also.exclude.anthropogenic.changes.in.land. cover. incorporating.climate.model.results.in.freshwater.studies.also.adds.uncertainties,.which.are.associated.with.the. different.spatial.scales.of.climate.models.and.hydrologic.models.and.biases.in.long-term.mean.precipitation. as.computed.by.global.climate.models.for.the.current.climate..methods.that.have.been.used.to.address.the. scale.differences.­.including.dynamical.or.statistical.downscaling.methods.­.introduce.uncertainties.into.the. projection..methods.to.address.biases.in.simulated.mean.precipitation.do.not.take.into.account.inter-annual. or.day-to-day.variability.in.climate.parameters.and,.therefore,.risk.underestimating.future.floods.and.droughts.. (bates,.et.al,.2008). 14 intensity.of.precipitation,.and.whether.precipitation.falls.as.snow.or.rain,.have.an.impact.on.river. flows..temperature.is.particularly.important.in.snow-dominated.basins.and.in.coastal.areas.(due. to.the.impact.of.temperature.on.sea.level.rise)..changes.in.potential.evapotranspiration.can.offset. small.increases.in.precipitation.and.aggravate.further.the.effect.of.decreased.precipitation.on. surface.waters..different.catchments.respond.differently.to.the.same.changes.in.climatic.drivers,. depending.largely.on.catchment.physiogeographical.and.hydrogeological.characteristics.and.the. amount.of.lake.or.groundwater.storage.in.the.catchment.(kundzewicz,.et.al.,.2007). At the global scale, there is evidence of a broadly coherent pattern of change in annual runoff,.with.some.regions.experiencing.an.increase,.particularly.at.higher.latitudes,.and.others.a. decrease,.for.example,.parts.of.west.Africa,.southern.europe.and.southern.latin.America.(bates,. et.al.,.2007)..However,.attribution.to.long-term.climate.change.is.difficult.because.of.natural. variability.and.the.potential.influence.of.non-climatic.factors,.such.as.land.use.changes..there. is.more.robust.and.widespread.evidence.that.the.timing of river flows.in.many.regions.where. winter.precipitation.falls.as.snow.has.been.significantly.altered.due.to.rising.temperatures..world. bank.(2009).indicate.that.climate.change.is.expected.to.alter.the.surface.hydrology.of.Peru.as.a. result.of.changes.in.hydrology.and.runoff.from.the.Andean.lakes.and.mountain.wetlands--a.major. source.of.water.for.hydropower,.urban.water.supply.systems.and.agriculture--have.been.impacted. by.climate.change. Several hundred studies of the potential effects of climate change on river flows have been undertaken,.but.many.of.these.are.regional.and.heavily.focused.towards.europe,.north. America,.and.Australasia..of.the.global.scale.assessments,.milly,.et.al.,.2005.is.one.of.the.most. frequently.cited..Figure.2.2.shows.the.mean.runoff.change.until.2050.for.the.sres.A1b.scenario. from.an.ensemble.of.twenty-four.climate.model.runs.(from.twelve.different.gcms)..As.shown.in. the.figure,.total.annual.river.runoff.globally.is.projected.to.increase,.although.there.is.considerable. variability.across.regions.with.significant.decrease.in.mid-latitudes.and.some.parts.of.the.dry. tropics.and.significant.increase.in.high.latitudes.and.wet.tropics. Patterns depend primarily on changes in the volume and timing of precipitation, and whether precipitation falls as snow or rain..in.areas.where precipitation currently falls as snow,.a.very.robust.finding,.consistent.across.a.number.of.studies,.is.that.warming.would.lead. to.changes.in.the.seasonality.of.river.flows..in.areas fed by glaciers,.higher.temperatures.would. lead.to.increased.river.run-off.and.discharge.peaks.in.the.short.term,.but.the.contribution.of. glacier.melt.would.gradually.diminish.over.the.next.few.decades..in.areas with little or no snowfall,. changes.in.runoff.are.much.more.dependent.on.changes.in.rainfall.than.in.temperature..A.general. conclusion.of.studies.is.that.flow.seasonality.would.increase,.with.higher.flows.in.the.peak.flow. season.and.either.lower.flows.during.the.low.flow.season.or.extended.dry.periods.(kundzewicz,.et. al.,.2007). Groundwater Groundwater and soil moisture collectively account for over 98% of the available global freshwater resources. groundwater.levels.correlate.more.strongly.with.precipitation. than.with.temperature,.but.temperature.becomes.more.important.for.shallow.aquifers.and.in. warm.periods.(kundzewicz,.et.al.,.2007). In contrast to surface water systems, climate-related changes in groundwater levels have neither been well studied nor adequately observed..this.is.due.to.the.neglect.of.groundwater. 15 Figure 2.2 Large-scale relative changes in annual runoff (water availability, in percent) for the period 2090­2099, relative to 1980­1999 values.represent.the.median.of.12.climate.models.using.the.sres.A1b.scenario..white.areas.are.where.less.than.66%.of.the.12. models.agree.on.the.sign.of.change.and.hatched.areas.are.where.more.than.90%.of.models.agree.on.the.sign.of.change..the. quality.of.the.simulation.of.the.observed.large-scale.20th.century.runoff.is.used.as.a.basis.for.selecting.the.12.models.from.the. multi-model.ensemble..the.global.map.of.annual.runoff.illustrates.a.large.scale.and.is.not.intended.to.refer.to.smaller.temporal.and. spatial.scales..in.areas.where.rainfall.and.runoff.is.very.low.(e.g..desert.areas),.small.changes.in.runoff.can.lead.to.large.percentage. changes..in.some.regions,.the.sign.of.projected.changes.in.runoff.differs.from.recently.observed.trends..in.some.areas.with.projected. increases.in.runoff,.different.seasonal.effects.are.expected,.such.as.increased.wet.season.runoff.and.decreased.dry.season.runoff.. studies.using.results.from.few.climate.models.can.be.considerably.different.from.the.results.presented.here..source:.milly,.et.al.,. 2005;.iPcc,.2007b,.page.49,.Fig..3.5. management.in.general.as.well.as.due.to.the.hidden.nature.of.groundwater,.the.very.slow. reaction.of.groundwater.systems.to.changing.conditions,.and.measurement.difficulties..there.is.an. observed.decreasing.trend.in.groundwater.levels.during.the.last.few.decades,.but.this.has.been. attributed.to.over-extraction.(groundwater.pumping.exceeding.recharge.rates). Critical threats to groundwater as a result of climate change include: ·.reduced.groundwater.recharge--as.the.result.of.reductions.in.precipitation,.changes.in.its. seasonal.distribution.and/or.changes.in.the.distribution.of.precipitation.between.rainfall. and.snow..the.magnitude.of.change.in.groundwater.recharge.will.vary,.dependent.on.local. conditions..in.some.areas,.rainfall.may.fall.below.the.threshold.required.for.any.recharge.to. occur; ·.a.rapid.shift.towards.increased.utilization.of.groundwater.as.surface.waters.become.less.reliable. in.selected.parts.of.the.world; ·.contamination.of.coastal.aquifers.and.contraction.of.freshwater.lenses.on.small.islands--due.to. salt.water.intrusion.as.sea.level.rises,.coupled.with.contamination.by.more.extensive.storm.surge. incursions..salinisation.of.shallow.aquifers.could.also.result.from.increased.evapotranspiration,. particularly.in.semi-arid.and.arid.regions. 16 Figure 2.3 Global estimates of climate change impact on groundwater recharge impact.of.climate.change.on.long-term.average.annual.diffuse.groundwater.recharge..Percent.changes.of.30-year.averages.groundwater. recharge.between.1961­1990.and.the.2050s.(2041­2070),.as.computed.by.wgHm.applying.four.different.climate.change. scenarios.(climate.scenarios.computed.by.the.climate.models.ecHAm4.and.Hadcm3,.each.interpreting.the.two.iPcc.greenhouse. gas.emissions.scenarios.A2.and.b2)..source:.döll.(2009),.Figure.1,.page.6. Relative to surface water supplies, there have been very few studies on the future impacts of climate change on groundwater or on groundwater/surface water interactions.. According.to.the.results.of.a.global.hydrological.model,.groundwater.recharge,.when.averaged. globally,.increases.less.than.total.runoff.(doll.and.Florke,.2005)..while.the.distribution.of.impact. is.uneven,.the.projections.suggest.that.by.2050.there.may.be.significantly.less.recharge.(up.to. 70%.less).in.north-eastern.brazil,.western.southern.Africa.and.along.the.southern.rim.of.the. mediterranean.sea.(see.Figure.2.3)..recharge.may.increase.in.some.areas.where.rainfall.is. projected.to.increase.substantially..in.some.locations.where.groundwater.resources.are.already. stressed,.this.may.help.to.relieve.pressures.on.groundwater.and.surface.water.resources..However,. in.areas.where.water.tables.are.already.high,.increased.recharge.might.lead.to.problems.of.soil. salinisation.and.waterlogging..the.very.few.studies.of.the.impacts.of.climate.change.on.individual. aquifers.show.very.site.specific.results. Water quality There is relatively little information on water quality, although a climate-related warming of lakes and rivers has been observed over recent decades. this.has.led.to.changes.in. 17 species.composition,.organism.abundance.and.productivity,.and.phonological.shifts.in.some. freshwater.ecosystems..Higher.water.temperatures.have.been.reported.in.lakes.in.response.to. warmer.conditions,.prolonging.stratification.and.depleting.oxygen.in.deeper.layers..consistent. climate-related.trends.in.other.water.quality.parameters.(e.g.,.salinity,.pathogens,.or.nutrients).in. lakes,.rivers.or.groundwater.have.not.been.observed..likewise,.there.is.no.evidence.of.climate- related.changes.in.erosion.and.sediment.transport.(bates,.et.al.,.2008). According to IPCC and based on a number of studies, higher water temperatures and changes in extremes, including floods and droughts, are projected to affect water quality and exacerbate many forms of water pollution.(iPcc.rating:.high.confidence). more. specifically,.the.following.potential.effects.have.been.noted: ·.increased.water.temperatures.would.impact.oxygen.solubility,.stratification,.mixing,.and.other. biochemical.processes.in.lakes.and.reservoirs,.as.well.as.the.assimilative.capacities.of.rivers.to. breakdown.organic.wastes. ·.increased.precipitation.intensity.would,.on.the.one.hand,.increase.dilution,.but.would,.on.the. other,.potentially.increase.sediment.loads.(via.increased.erosion),.nutrients,.pathogens.and. toxins.transported.to.downstream.water.bodies. ·.longer.periods.of.low.flows.would.reduce.the.dilution.capacity,.reduced.dissolved.oxygen,. increase.algal.blooms,.and.magnify.the.impact.of.water.pollution,.effecting.human.health,. ecosystems,.and.water.supplies. ·.reduced.lake.levels.may.lead.to.re-suspension.of.bottom.sediments.and.nutrient.cycling. ·.sea.level.rise.could.increase.saltwater.intrusion.in.estuaries.and.coastal.aquifers,.and.may.also. interfere.with.storm.water.drainage.and.sewage.disposal. Floods and droughts There are a number of climatic and non-climatic drivers influencing flood and drought impacts, and the terms `flood' and `drought' capture a wide array of meanings reflecting these different influences..Floods.include.river.floods,.flash.floods,.urban.floods,.sewer.floods,. glacial.lake.outburst.floods,.and.coastal.floods.(bates,.et.al.,.2008)..`drought'.may.refer.to. meteorological.drought.(precipitation.well.below.average),.hydrological.drought.(low.river.flows. and.water.levels.in.rivers,.lakes.and.groundwater),.agricultural.drought.(low.soil.moisture).and. environmental.drought.(a.combination.of.the.above).(kundzewicz,.et.al.,.2007). Although floods depend on a number of non-climatic factors (including, for example, existence of dams or dykes), there are indications that climate change might already have had an impact on their intensity and frequency..globally,.the.number.of.great.inland.flood. catastrophes.during.from.1996­2005.is.twice.as.large,.per.decade,.as.between.1950.and.1980. (bates,.et.al..2008)..this.has.been.associated.with.an.increasing.frequency.of.heavy.precipitation. events;.no.ubiquitous.increase.is.visible.in.trends.in.high.river.flows.8 Since the 1970s, droughts have also become more common, especially in the tropics and sub-tropics..iPcc.concluded.that.it.is.likely.that.the.area.affected.by.drought.has.increased. since.the.1970s,.and.it.is.more likely than not.that.there.is.a.human.contribution.to.this.trend.. that.more.regions.are.experiencing.drought--as.measured.by.the.Palmer.drought.severity. index--is.associated.with.decreased.precipitation.and.increased.temperature,.which.increase. evapotranspiration.and.reduce.soil.moisture. 8 Milly,etal.(2005)foundanincreaseinthefrequencyof`large'floods(returnperiodgreaterthan100years)acrosstheglobefroman analysisofdatafromlargeriverbasins,butotherstudieshavenotfoundasimilartrend. 18 As discussed above, the frequency of heavy precipitation events is projected to increase over most regions throughout the 21st century, which could have a direct impact on flood events..milly,.et.al..(2005).found.that.for.fifteen.out.of.sixteen.large.basins.worldwide,.the. control.100-year.peak.volumes.of.monthly.river.flow.are.likely.to.be.exceeded.more.frequently. for.a.quadrupling.of.co2.levels..in.some.areas,.what.is.given.as.a.100.year.flood.now.(in.the. control.run).is.projected.to.occur.more.frequently,.even.every.2.to.5.years.(bates,.et.al.,.2008;. kundzewicz,.et.al.,.2007)..based.on.climate.models,.the.area.flooded.by.bangladesh.is.projected. to.increase.by.at.least.23­29%.with.a.global.temperature.rise.of.2.degrees.(bates,.et.al,.p..52). According to IPCC, it is likely that the area affected by drought will increase (Bates, et al.,2008)..one.study.found.that.the.proportion.of.the.land.surface.experiencing.extreme.drought. at.any.one.time,.the.frequency.of.drought.events,.and.the.mean.drought.duration.were.projected. to.increase.by.the.2090s.by.10-.to.30-fold,.two-fold,.and.six-fold,.respectively.(bates,.et.al.,. 2008)..in.the.low-flow.season,.droughts.in.snow-melt.fed.basins.may.increase.due.to.earlier.and. less.abundant.snowmelt..increased.drought.is.also.projected.for.regions.heavily.dependent.on. glacial-melt.water.for.their.main.dry-season.water.supply. Freshwater ecosystems the.responses.by.freshwater.ecosystems.to.a.changing.climate.can.be.described.in.terms.of.three. interrelated.components:.water.quality,.water.quantity.or.volume,.and.water.timing..A.change.in. one.often.leads.to.shifts.in.the.others.as.well. Water quality.refers.to.how.appropriate.a.particular.ecosystem's.water.is.for.some."use,".whether. biological.or.economic..many.fish.species,.for.instance,.have.narrow.habitat.quality.preferences. for.dissolved.oxygen,.water.temperature,.dissolved.sediment,.and.pH..Humans.generally.avoid. freshwater.for.drinking.or.cooking.if.it.has.excessive.levels.of.dissolved.minerals.or.has.a.very.high. or.low.pH..The changes in water quality (noted above) will contribute to changes in ecosystem composition, function and services, altering the resiliency of ecosystems..Higher.water.temperatures. in.lakes.will.impact.lake.productivity.and.distribution.of.fish.and.flora,.and.exacerbate.algal. blooms,.and.may.lead.to.odor.and.taste.problems.in.drinking.water..droughts.will.worsen. incidence.of.diarrheal.and.other.water-related.diseases,.especially.in.developing.countries.(wwF,. 2009). Water quantity.refers.to.the.water.volume.of.a.given.ecosystem,.which.is.controlled.through.the. balance.of.inflows.(precipitation,.runoff,.groundwater.seepage).and.outflows.(water.abstractions,. evapotranspiration,.natural.outflows)..At.a.global.scale,.precipitation.is.tending.to.fall.in.fewer. but.more.intense.events,.resulting.in.generally.more.precipitation..At.local.scales,.there.is.wide. variation..the.most.striking.changes.in.water.quantity.often.occur.with.precipitation.extremes.like. floods.and.droughts;.lake.and.wetland.levels.can.also.change.radically.as.a.result.of.even.slight. changes.in.the.balance.between.precipitation.and.evaporation..the.occurrence.of.precipitation. extremes.is.expected.to.increase.globally,.as.well.as.the.severity.of.extreme.events.themselves. (wwF,.2009). Water timing or seasonality of flows.is.the.expected or.average.variation.in.water.quantity. over.some.period.of.time,.usually.reported.as.a.single.year.in.a.hydrograph..many.terrestrial. and.most.aquatic.species.are.extremely.sensitive.to.water.timing..natural.selection.has.adapted. (in.an.evolutionary.sense).the.behavior,.physiology.and.developmental.processes.of.many. aquatic.organisms.to.particular.water.timing.regimes,.such.as.spawning.during.spring.floods.or. 19 accelerated.metamorphosis.from.tadpole.to.adult.frog.in.a.rapidly.drying.wetland..shifts.in.water. timing.mean.that.there.may.be.detrimental.mismatches.between.behavior.and.the.aquatic.habitat.. in.turn,.these.shifts.can.affect.fisheries.stocks.and.industries.that.depend.on.seasonal.water.flows. (wwF,.2009). 20 CHaPTer 3: imPaCT of ClimaTe CHange on waTer availabiliTy and use Climate change could profoundly alter future patterns of both water availability and use, thereby increasing levels of water stress and insecurity, both at the global scale and in sectors that depend on water. indeed,.there.is.already.evidence.that.the.impacts.of.hydrologic. change.and.increased.variability.are.already.being.felt.and.that.even.small.changes.(e.g.,.in.the. magnitude.of.extreme.events).can.have.exponential.losses.(see.chapter.4)..this.said,.it.should.be. emphasized.that.climate.change.is.just.one.of.many.factors.determining.future.patterns.of.water. availability.and.use. Climate change is expected to increase global water stress and insecurity Climate change has the potential to increase existing levels of global water stress and insecurity--in terms of both surface and groundwater supplies--and to negatively impact water dependent sectors,.from.health.to.agriculture,.transport.to.industry,.and.energy. to.ecosystems..indeed, the IPCC concluded with high confidence that, globally, the negative impacts of future climate change on freshwater systems are expected to outweigh the benefits. more.specifically,.the.negative.effects.of.increased.precipitation.variability.and.seasonal.runoff. shifts,.water.quality.and.flood.risks.are.projected.to.outweigh.benefits.from.increased.annual. runoff.overall. it.is.important.to.emphasize,.however,.that.projections.of.water.stress.are based.on. certain.assumptions.about.future.driving.forces--both.climatic.and.non-climatic--as.well.as.water. resource.management.and.delivery.systems..many.assume--in.line.with.the.iPcc's.projections-- increasing.water.use,.primarily.as.a.result.of.population.and.income.growth,.but.also.partly.due. to.climate.change.in.the.case.of.irrigation..Additionally,.they.largely.take.as.given.current.water. systems,.including.infrastructure,.institutions.and.technology,.which.will.in.actuality.have.a.major. influence.on.water.availability.and.use.patterns. Surface water stress assessments The potential climate-induced changes in hydrology may aggravate global `water stress.'. most.studies.have.found.that.levels.of.water.stress.will.increase.as.a.result.of.climate.change,. although.the.influences.of.other.factors--demographic,.socio-economic,.and.technological. changes--are.even.more.significant,.particularly.in.shorter.time.horizons.(impacts.beyond.the. 2050s.are.highly.dependent.on.the.population.projections.of.the.emissions.scenario.used)..there. are.large.differences.in.estimates.across.studies,.depending.not.only.on.how.climate.change. impacts.are.modeled,.but.also.on.which.other.drivers.are.included.in.the.assessment..Arnell. (2004)--who.accounts.for.population.growth.and.the.impact.of.climate.change--found.that.the. number.of.people.projected.to.experience.an.increase.in.water.stress.is.between.0.4.to.1.7.billion. in.the.2020s.and.between.1.and.2.7.billion.in.the.2050s.(using.the.A2.population.scenario.for. the.2050s).9 In terms of global water availability per capita, climate change would appear to reduce water stress, as projected increases in runoff are concentrated in the most populous parts of the world (mainly East and South-East Asia)..Further,.in.the.2050s,. differences.in.population.projections.were.found.to.have.a.larger.impact.on.the.number.of. people.living.in.water.stressed.basins.than.climate.change,.per se (kundzewicz,.et.al.,.2007).. 9 Wherewaterstressisdefinedasbasinswithpercapitawaterwithdrawalsoflessthan1000m3/year. 21 Alcamo,.et.al..(2002).assessed.water.stress.as.a.function.of.population.growth.and.climate. change,.in.addition.to.changes.in.water.use.and.other.non-climatic.drivers.(income,.water. use.efficiency,.water.productivity,.industrial.production)..water.stress.was.found.to.increase. on.62­76%.of.the.land.area.and.to.decrease.on.20­29%.by.the.2050s.10.increased.water. availability.due.to.increased.precipitation.is.the.main.cause.for.decreasing.water.stress;. growing.water.withdrawals.(stimulated.more.by.income.growth.than.by.population.growth).is. the.main.cause.of.increasing.water.stress..when.environmental.flow.needs.are.incorporated-- that.is,.the.amount.of.water.required.to.sustain.a.functioning.ecosystem--the.degree.of.water. stress.is.projected.by.some.to.increase.further.(smakhtin.et.al,.2003)..there.is.substantial. agreement.across.these.and.other.global.and.national-scale.assessments.that.semi-arid. and.arid.basins.are.the.most.likely.to.experience.water.stress..if.precipitation.decreases,. irrigation.water.use--which.dominates.in.most.semi-arid.river.basins--would.increase,.placing. additional.pressure.on.other.uses. Groundwater stress assessments Use of groundwater varies with the quality and availability of the resource, as well as with access to and the reliability of surface water..in.developing.and.developed.countries. alike,.it.contributes.to.human.health.and.socio-economic.development.through.the.provision. of.a.low.cost.and.often.high.quality.water.resource.that.is.somewhat.independent.of.short-term. climatic.variability..over.half.of.the.world's.population.are.thought.to.depend.on.groundwater.for. every.day.uses,.such.as.drinking,.cooking.and.hygiene..Across.the.developing.world,.groundwater. accounts.for.between.about.20.and.40%.of.total.water.use..Agriculture.is.the.dominant.use.of. both.groundwater.and.surface.water.across.the.developing.world..groundwater.also.plays.a. fundamental.role.in.sustaining.many.terrestrial,.aquatic.and.even.marine.ecosystems..For.some. ecosystems,.there.is.a.highly.specialized.dependency.on.groundwater,.with.groundwater.being. the.habitat,.the.only.water.supply,.or.being.critical.to.survival.during.periods.of.seasonal.water. shortage.or.extended.episodes.of.drought. The hidden nature of groundwater, its resilience in the face of short-term climatic variability and the difficulty in measuring it, have, among other factors, contributed to its poor management and the growing stress on groundwater resources..in.many. countries,.even.developed.countries.with.robust.surface.water.management.arrangements,. groundwater.use.is.unregulated.and.poorly.planned.and.managed..Although.data.on.the. `health'.of.groundwater.systems.at.a.global.level.is.scant,.what.is.available.demonstrates.the. challenges.it.faces..in.several.countries.in.north.Africa.and.the.middle.east,.groundwater. allocations.exceed.average.annual.recharge.by.a.factor.of.three.times.or.more..other. developing.and.developed.countries.have.many.zones.where.groundwater.resources.have.been. depleted.(Figure.3.1)..consequences.of.this.have.already.included.supply.shortages,.subsidence,. contamination.and.decline.in.groundwater.dependent.ecosystems..As.stresses.on.surface. water.increase--due.to.both.non-climatic.and.climatic.forces--it.is.expected.that.pressure.on. groundwater.resources.will.grow. Water security Aggregate indices of water stress--of the type presented above--are typically in terms of annual averages, and so cannot fully capture the global impacts of hydrological 10 Waterstressexpressedasthewaterwithdrawal-to-availabilityratio. 22 Figure 3.1 Reported countries with groundwater depletion Reported zones with groundwater depletion Many Few None No data NOVEMBER 2009 IBRD 37364 This map was produced by the Map Design Unit of The World Bank. The boundaries, colors, denominations and any other information shown on this map do not imply, on the part of The World Bank Group, any judgment on the legal status of any territory, or any endorsement or acceptance of such boundaries. Source: igrAc.global.groundwater.information.system.[http://igrac.nitg.tno.nl/ggis_map/start.html] variability and extremes. many.regions.of.the.world have,.what.has.been.loosely.termed,. a.`difficult.hydrology'..this.includes.not.only.those.areas.that.confront.absolute.water.scarcity. (or.`stress'),.but.also.those.which.suffer.from.high.inter-annual.and/or.intra-annual.hydrologic. variability.(including.extremes)..in.the.absence.of.adequate.capacity,.infrastructure.and.institutions. required.to.manage.and.mitigate.such.difficult.hydrologies,.`water.security'.is.threatened..water. security.is.defined.as.the.availability.of.an.acceptable.quantity.and.quality.of.water.for.health,. livelihoods,.ecosystems.and.production,.coupled.with.an.acceptable.level.of.water-related.risks. to.people,.environments,.and.economies..unlike.in.the.case.of.`water.stress,'.a.comprehensive. assessment.of.global.levels.of.water.security.has.not.been.undertaken..However,.several.regions. of.the.world.can.be.characterized.as.being.water.insecure,.either.because.of.extreme.hydrological. variability.(e.g.,.ethiopia).or.a.poor.endowment.of.water.resources.(e.g.,.yemen,.which.is.heavily. dependent.on.limited.groundwater),.or.because.of.the.dearth.of.adequate.capacity,.infrastructure. or.institutions..climate.change--which.is.projected.to.reduce.water.availability.in.regions.that.are. already.scarce.(as.discussed.above).and.increase.hydrologic.variability--is.likely.to.make.water. security.harder.to.achieve.and.maintain. Transboundary basins over.270.international.rivers.are.shared.by.some.90%.of.the.world's.nations.and.territories.. transboundary.river.basins.and.shared.rivers.present.both.challenges.and.opportunities.for. cooperation.and.growth..developed.economies,.in.europe.and.north.America,.have.in.most. cases.achieved.a.relative.equilibrium.in.managing.transboundary.basins.for.best.return.on. hydrology.through.transboundary.institutional.arrangements,.including.treaty.regimes.dealing. with.issues.of.river.infrastructure.and.the.quantity.and.quality.of.water.flows,.as.well.as. infrastructure.to.manage.variability.and.extreme.events..increasingly,.cooperative.efforts.are. focusing.on.the.sharing.of.benefits,.rather.than.water..the.developing.economies.sharing.river. basins.remain.challenged.by.weak.institutional.arrangements.and.inadequate.infrastructure.for. 23 optimum.benefit..regardless.of.the.level.of.economic.development,.climate.change.poses.a. threat.to.transboundary.basins..evidence.suggests.that.the.challenges.and.conflicts.among.the. riparian.states.depend.on.the.degree.of.variability.and.uncertainty.associated.with.the.resource. availability..Projected.changes.in.water.resources.variability.due.to.climate.change.can.impact.the. water.balance.and.consequently.the.hydropolitical.balance.in.transboundary.basins..wolf.et.al. (2003),.indicate.that.historically.extreme.events.of.conflict.over.water.have.been.more.frequent.in. water.scarce.regions.and.where.extreme.conditions.characterized.by.high.inter-annual.hydrologic. variability.occur. water dependent sectors and climate-induced hydrologic changes In the future, climate change could also impact water using sectors, affecting both the amount and/or quality desired (on the demand side) and/or the extent to which demands are met (on the supply/availability side).11 the.term.`water.dependent.sectors'. is.taken.broadly.to.mean.both.water.using.sectors.(including.in-stream.and.out-of-stream,. consumptive.and.non-consumptive),.as.well.as.sectors.that.are.affected.indirectly.or.directly. by.the.water.sector.(e.g.,.health.and.transport)..in.most.countries.water.use.has.increased.in. recent.decades.due.to,.amongst.others,.population.and.economic.growth.and.changes.in. lifestyle.(including.diets)..sectoral.water.use.patterns.can.be.expected.to.continue.to.change. over.time.in.response.to.such.non-climatic.drivers,.in.addition.to.water.resource.management. and.delivery.systems.(as.discussed.above)..this.includes.not.only.infrastructure.and.technology,. but.also.institutions.that.govern.water.use.within.sectors.(e.g.,.water.pricing),.amongst.sectors. (e.g.,.water.trading),.and.even.across.national.boundaries.(e.g.,.transboundary.river.basin. agreements)..it.is.important.to.emphasize.that.changes.in.variability.could.be.as.important.as. changes.in.long-term.averages,.particularly.if.water.is.not.withdrawn.from.groundwater.bodies. or.reservoirs. The potential impacts of climate change could extend beyond the water sector, per se, to all sectors that are linked to (or in some way dependent on) water..For.example,.pressure. on.water.supply.and.sanitation.facilities.could.have.a.wide.range.of.adverse.effects.on.human. health..reduced.availability.of.water.for.irrigation.could.threaten.food.security,.rural.development,. and.the.economies.of.countries.that.are.largely.dependent.on.the.agricultural.sector..the. potential.impact.of.climate-driven.hydrologic.change.and.increased.variability.for.some.key.water. dependent.sectors.is.discussed.below. Health water.is.essential.to.human.health.and.all.aspects.of.livelihood..table.3.1.shows.the.linkage. between.mediating.climate.change.factors.and.their.health.outcome..An.estimated.2.4.billion. people.are.without.access.to.proper.sanitation.and.1.billion.without.access.to.safe.drinking. water..with.projections.of.potential.decreases.in.water.availability,.these.statistics.are.likely.to.get. worse..decreasing.water.supplies.could.also.lower.the.efficiency.of.wastewater.and.sewer.systems,. leading.to.higher.concentrations.of.bacteria.and.other.micro-organisms.in.raw.water.supplies. (kabat.et.al.,.2003). 11 Theagriculturalsectoroffersagoodexampleoftheeffectsofclimatechangeonbothwaterdemandandwatersupply.Increasing CO2concentrationscouldincreasewateruseefficiencyforsometypesofcrops,therebyreducingthedemandforirrigation(often referredtoasirrigation`requirements').Onthesupplyside,increasedvariabilitycouldaffectthereliability/availabilityofirrigation supplies. 24 Table 3.1 Mediating processes and potential effects on health of changes in temperature and weather Mediating processes Health outcome Direct effects change.in.the.frequency.or.intensity.of.extreme.weather. deaths,.injuries,.psychological.disorders,.damage.to. events,.for.example.storms,.hurricanes,.cyclones public.health.infrastructure Indirect effects changed.local.ecology.of.water.borne.and.food.borne. changed.incidence.of.diarrheal.and.other.infectious. infective.agents diseases changed.food.productivity.(especially.crops).through. malnutrition.and.hunger,.and.consequent.impairment. changes.in.climate.and.associated.pests.and.diseases of.child.growth.and.development sea.level.rise.with.population.displacement.and. increased.risk.of.infectious.disease,.psychological. damage.to.infrastructure disorders social,.economic,.and.demographic.dislocation. wide.range.of.public.health.consequences.mental. through.effects.on.economy,.infrastructure,.and. health.and.nutritional.impairment,.infectious.diseases,. resource.supply civil.strife Source: kabat.et..al.,.2003.pg..33;.adapted.from.mcmichael.and.Haines,.1997. in.addition.to.drinking.water.and.sanitation,.there.are.also.water.and.vector.borne.diseases.that. are.affected.by.climate.change.via.the.water.sector..water.plays.a.role.in.propagating.diseases. by.direct.transmission.(contamination.by.feces,.urine.or.bacteria),.inadequate.personal.hygiene,. and.parasites.using.hosts.in.or.near.the.water..decreases.in.available.supply.and.also.floods. can.increase.contamination..warming.temperatures.can.increase.the.presence.of.vector.borne. diseases.such.as.malaria.causing.higher.transmission.rates.and.new.regions.to.become.infected. there.are.also.direct.health.effects.from.extreme.events.such.as.floods.and.droughts.which.include. changes.in.mortality.and.morbidity..Projections.show.an.increase.in.extreme.events.which.translates. into.real.losses.of.livelihoods.and.lives..some.indirect.effects.from.floods.include.overburdening.of. wastewater.and.sewer.systems,.disruption.of.safe.water.supply,.standing.water.in.low-lying.areas. (increase.in.mosquitoes.and.risk.of.malaria),.exposure.to.respiratory.and.infections,.disruption.and. increased.burden.to.medical.facilities,.and.inadequate.nutrition.following.disruption.to.incomes. and.food.distribution.systems..An.example.of.climate.change's.impact.on.malaria.in.Africa.is. described.in.box.3.1. Box 3.1 Malaria in Africa under climate change results.from.the.mapping.malaria.risk.in.Africa.project.(mArA/ArmA).indicate.changes.in.the.distribution.of. climate-suitable.for.malaria.by.2020,.2050.and.2080..by.2050,.and.continuing.into.2080,.a.large.part.of. the.western.sahel.and.much.of.southern-central.Africa.is.shown.to.be.likely.to.become.unsuitable.for.malaria. transmission..other.assessments,.using.sixteen.climate.change.scenarios,.show.that,.by.2100,.changes.in. temperature.and.precipitation.could.alter.the.geographical.distribution.of.malaria.in.Zimbabwe.with.previously. unsuitable.areas.of.dense.human.population.becoming.suitable.for.transmission..(bates.et.al.2008). 25 indirect.health.threats.of.climate.change.include.malnutrition.from.agriculture.disruption,.infectious. diseases.spread.by.insects.and.other.vectors.advantaged.by.climate.change,.as.well.as.the. increased.risk.of.infectious.diseases.due.to.infrastructure.damage.(kabat.et.al.,.2003)..climate. changes.that.would.adversely.affect.human.health.via.the.water.sector.are.expected.to.fall. disproportionately.on.the.poor.(iPcc.2001). Agriculture Agriculture is by far the largest user of water, accounting for almost 70 percent of global withdrawals--and 90 percent of global consumptive water use--and up to 95 percent of withdrawals in developing countries..while.a.person.may.drink.2­4.liters.of.water.a.day,. it.takes.2,000­5,000.liters.of.water.to.produce.a.person's.daily.food..water.is.important.for. food.security,.crop.growth,.livestock,.and.food.markets..Food.security,.defined.by.the.Food.and. Agriculture.organization.(FAo).as.the.regular.access.of.people.to.enough.high-quality.food.to. lead.active,.healthy.lives,.depends.heavily.on.water..lack.of.water.can.be.a.major.cause.of.famine. and.undernourishment,.especially.in.areas.where.people.depend.on.local.agriculture.for.food.and. livelihoods..erratic.rainfall.can.cause.temporary.food.shortages,.while.floods.and.droughts.can. lead.to.intensive.food.emergencies. Climate change can significantly impact crop growth. changes.in.precipitation.can.alter.soil. moisture.content,.which.can.lead.to.conditions.that.are.potentially.too.dry.or.too.wet.for.viable. crop.growth.and.alter.the.need.for.and.timing.of.irrigation..Precipitation.changes.can.occur.via. extreme.events.(floods.or.droughts),.erratic.rainfall,.or.seasonal.shifts.in.runoff..there.are.critical. stages.in.a.crop's.growth.(e.g..filling.of.the.corn.kernels).where.a.lack.of.water.during.that.short. time.can.reduce.crop.yield..rainfed.agriculture--which.supplies.over.60.percent.of.the.world's. food--is.particularly.at.risk. In addition to precipitation changes, increased CO2 levels and higher temperatures can affect crop growth..some.crops.may.actually.benefit.from.increased.co2.levels,.while. other.plants.will.not..in.general,.higher.temperatures.are.associated.with.higher.radiation.and. higher.water.use.which.could.put.stress.on.overall.water.availability..it.is.expected.that.higher. temperatures.will.promote.more.plant.growth.at.high.latitudes.and.altitudes.(northern.regions. of.former.soviet.union,.canada,.and.europe)..the.higher.yields.are.primarily.due.to.longer. growing.season.and.mitigating.the.negative.cold.weather.effects.on.plant.growth.(kabat.et. al.,.2003)..northern.middle.latitude.countries.(us,.western.europe,.and.most.of.canada).are. expected.to.see.negative.effects.on.crop.and.livestock.productivity.due.to.increased.temperatures. and.increased.evapotranspiration.(shortening.of.the.growing.season)..taken.together,.higher. temperatures.and.increased.variability.of.precipitation.would,.in.general,.lead.to.increased. irrigation.water.demand,.even.if.total.precipitation.during.the.growing.season.remains.the.same. (bates,.et.al.,.2008). Food markets are affected by climate change..As.mentioned.previously.climate.change.and. variability.can.lead.to.decreases.in.food.production..these.shortfalls.create.market.imbalances,. which.push.international.prices.upwards.and.provide.incentives.for.reallocation.of.capital.and. human.resources,.thus.reducing.climate-change.impacts.by.economic.adjustments..the.gdP.of. the.agricultural.sector.in.developing.regions,.with.the.exception.of.latin.America,.will.be.negatively. impacted.by.climate.change.(kabat.et.al.,.2003.).this.is.due.to.the.lack.of.high-tech.solutions.that. can.meet.the.needs.of.the.poorer.farmers,.who.most.often.partake.in.rainfed.agriculture. 26 Key drivers for future irrigation water demand are the extent of irrigated area, unit water use, cropping intensity, and irrigation water-use efficiency..According.to.the.Food.and. Agriculture.organization.(FAo).agriculture.projections.for.2030.suggest.that.developing.countries. are.likely.to.continue.to.expand.their.irrigated.area.and.to.increase.cropping.intensity.(e.g.,.double. cropping).while.irrigation.water-use.efficiency.will.increase.slightly..climate.change.will.worsen. these.estimates..most.of.this.expansion.is.projected.to.occur.in.already.water-stressed.areas,.such. as.southern.Asia,.northern.china,.the.near.east,.and.north.Africa..After.2050,.the.irrigated.area. is.assumed.to.stabilize.or.to.slightly.decline.in.most.cases. Industry and transport sector Many industries depend on water to create their product. Beverage companies require a reliable source of water that meets a strict quality..other.industries.use.water.in.their. manufacturing.process..some.power.industries.use.water.for.cooling..the.ski.industry.relies. on.snowpack/glacier.stability.for.operation.which.can.be.directly.affected.by.climate.change.. changes.to.the.availability.of.water.will.greatly.affect.the.success.of.these.industries..most.of. the.industries.will.release.the.water.after.they.have.used.it.into.streams.for.future.use..there.is.a. certain.standard.that.the.effluent.from.the.industry.must.meet.both.in.temperature.and.quality.. Predictions.of.lower.stream.flows.would.have.a.major.effect.on.effluent.standards..industries.would. have.to.spend.more.time.and.money.producing.higher.quality.effluent.to.meet.standards. Transport sector has close links with the water sector..transportation.via.water.is.directly. affected.by.water.levels.in.navigable.rivers..decreases.in.river.flow.will.potentially.reduce.and/or. eliminate.transportation.via.waterways..other.transportation.means.including.roads.and.bridges. and.railways.and.subways.will.be.most.affected.by.extreme.events.such.as.flooding..impacts.on. transportation.have.a.direct.affect.on.livelihoods;.including.the.ability.for.people.to.get.access.to. necessary.food.and.water,.and.make.a.living. Energy/Hydropower Hydropower generation is the energy source most likely to be impacted by climate change and climate variability because it directly deals with water quantity and timing.. An.example.of.hydropower.being.negatively.impacted.by.climate.change.is.described.in.box.3.2. for.the.Zambezi.basin..A.side.note.on.climate.change's.impact.on.the.demand.for.energy.is.that. while.it.is.likely.there.will.be.an.increased.energy.demand.for.space.cooling.due.to.higher.summer. temperatures,.there.will.also.likely.be.a.decreased.energy.demand.for.space.heating.due.to.higher. winter.temperatures.(kabat.et.al.,.2003). A reduction in river flow results in a decrease in hydropower production..First.because. there.is.less.water.going.through.the.turbines.and.second.because.the.lower.water.levels.reduce. the.water.pressure.and.the.amount.of.power.that.can.be.produced..while.hydroelectric.projects. are.designed.for.a.specific.flow.regime,.including.a.margin.of.safety;.projected.climate.changes. are.expected.to.change.those.flow.regimes,.in.some.instances.to.a.point.outside.the.current. safety.margins..this.will.result.in.a.need.to.retrofit.current.structures.or.tear.down.and.build.new. hydroelectric.projects..with.more.intense.rainfall.events.as.suggested.in.climate.projections,.more. conservative.water.storage.strategies.will.be.necessary.to.prevent.flood.damage.resulting.in.a. decrease.in.using.full.hydropower.potential.because.reservoirs.will.not.be.kept.full..the.projected. increase.in.droughts.will.also.require.more.conservative.water.storage.strategies.and.may. 27 decrease.the.amount.of.water.available.to.release.for.hydropower..lastly,.with.less.precipitation. falling.as.snow,.there.will.be.less.water.available.during.warm.months.when.energy.demand.is. highest.(kabat.et.al.,.2003). Natural ecosystems Freshwater ecosystems are essential components of the environment. climate.change. potentially.affects.the.water.sector.via.direct,.indirect,.and.synergistic.impacts.with.non-climate. forces..each.of.these.will.have.significant.impacts.on.freshwater.ecosystems..A.change.in.the. variability.or.trend.of.climatic.conditions.also.impacts.the.environment.as.seen.in.southern.Africa.. direct.impacts.of.reduced.rainfall.and.increased.temperature.include.lower.flows.in.rivers,.lower. level.in.water.tables,.lower.rates.of.groundwater.recharge,.and.higher.temperatures.in.rivers. and.lakes..direct.climate.change.impacts.on.water.quantity,.timing,.and.quality.regimes.are.also. expected.to.affect.the.performance.and.operation. of.existing.and.planned.water.infrastructure-- including.water.storage.and.transfer,.hydropower,. Box 3.2 Hydropower in Zambezi structural.flood.defenses,.urban.drainage,.water. Basin under climate change supply,.and.irrigation.systems. A.study.of.hydro-electric.power.generation. conducted.in.the.Zambezi.basin,.taken.in. indirect.impacts.of.the.climate.changes.include. conjunction.with.projections.future.runoff,. the.following.(kabat.et.al.,.2003): indicate.that.hydropower.generation.would. be.negatively.affected.by.climate.change,. ·.disruption.of.flowering.phenology particularly.in.river.basins.that.are.situated.in. ·.shifts.in.vegetative.season sub-humid.regions.(bates.et.al.2008). ·.species.invasions ·.changes.in.productivity.of.the.ecosystem ·.shifts.in.nutrient.cycles.related.to.fluctuations.in. water.levels ·.changes.or.declines.in.hydrological.connectivity.that.can.lead.to.loss.of.habitat.critical.to.faunal. life.stages,.i.e..fish ·.occurrence.and/or.shifts.in.intensity.and.frequency.of.structuring.processes.(fire,.flood,.pests) In addition, societal responses to anticipated climate threats could indirectly affect aquatic environments through new infrastructure development (e.g., to meet targets for renewable energy and reduce greenhouse gas emissions, or to protect against flooding), and changes in land use (e.g., to adapt to changed growing seasons and/or water availability, or to cultivate new crops such as bio-fuels)12. Finally,.non-climatic.pressures.on. freshwaters.linked.to.population.and.economic.growth,.or.to.land.use.change,.could.be.amplified. by.climate.change..For.example,.higher.volumes.of.groundwater.abstraction.associated.with. coastal.zone.development.will.hasten.ingress.of.saltwater.to.shallow.aquifers.that.are.also.at.risk. from.rising.sea.levels. Changes to the ecosystem can also impact human livelihoods such as ecotourism and fishing..in.addition,.ecosystem.changes.can.impact.human.health..For.example,.decreasing.fish. populations.can.diminish.the.main,.if.not.only,.protein.source.for.a.human.community. 12 SeeforexampleasectorbysectorreviewforEuropeBerry,P.,Paterson,J.,Cabeza,M.etal.2008.Mitigation measures and adaptation measures and their impacts on biodiversity.MinimisationofandAdaptationtoClimatechange:ImpactsonBiodiversity (MACIS).OxfordUniversity,320pp. 28 impact of non-climatic drivers on water availability and use patterns Non-climatic factors could aggravate or attenuate the adverse effects of climate change on surface water and groundwater availability, as well as have a significant influence on water use..Population.growth,.food.consumption.(including.type.of.diet),.economic.development. (and.by.extension,.changes.in.lifestyles.and.societal.views.on.the.value.of.water),.technology,.and. economic.policy.(including.water.pricing.and.trade.in.`virtual.water').will.play.a.major--if.not. dominant--role.in.influencing.water.use.patterns. Box 3.3 Fate of ecosystems in Southern Africa under climate change by.2050,.the.Fynbos.biome.(ericaceae-dominated.ecosystem.of.south.Africa,.which.is.an.iucn.`hotspot').is. projected.to.lose.51­61%.of.its.extent.due.to.decreased.winter.precipitation..the.succulent.karoo.biome,.which. includes.2,800.plant.species.at.increased.risk.of.extinction,.is.projected.to.expand.south-eastwards,.and.about. 2%.of.the.family.Proteaceae.are.projected.to.become.extinct..these.plants.are.closely.associated.with.birds.that. have.specialized.on.feeding.on.them..some.mammal.species,.such.as.the.zebra.and.nyala,.which.have.been. shown.to.be.vulnerable.to.drought.induced.changes.in.food.availability,.are.widely.projected.to.suffer.losses.. in.some.wildlife.management.areas,.such.as.the.kruger.and.Hwange.national.Parks,.wildlife.populations.are. already.dependent.on.water.supplies.supplemented.by.borehole.water.(bates.et.al.,.2008). Non-climatic factors are likely to have significant adverse effects on surface water and groundwater quality. These could be aggravated by climate change..industrial.development,. run-off.from.agriculture,.and.un-treated.sewerage.from.agglomerations.already.impact.adversely. on.the.quality.of.water..the.world.bank.recently.estimated.the.negative.effect.of.water.pollution.on. gdP.in.china.to.be.1%.annually,.the.threat.of.arsenic.pollution.in.drinking.water.in.bangladesh. and.other.places.has.been.exacerbated.by.over.extraction..these.effects.may.be.aggravated. by.climate.change.if.flows.and.groundwater.recharge.is.diminished.and/or.water.demand.is. increased. Human activities significantly influence water availability and land use, as well as critically impact the existing and future water resource management and delivery systems. systems.for.delivering.water.services.include.irrigation;.urban.water,.sanitation.and. drainage;.rural.water.and.sanitation;.and.ports.and.navigation..systems.for.managing.water. resources.include.those.for.delivery.of.bulk.irrigation.water,.watersheds,.and.water.resources. broadly,.as.well.as.multi-purpose.systems.(including.hydropower).and.flood.control..As. indicated.earlier,.the.term.`system'.is.intended.to.capture.all.elements--from.infrastructure.to. institutions--that.contribute.to.performance.of.the.intended.function. The impact of climate change could carry significant negative consequences for existing water resource management and delivery systems..For.example,.in.urban.environments,.more. heavy.rainfall.events.could.overload.the.capacity.of.storm.drain.systems.and.water.and.wastewater. treatment.facilities;.sea.level.rise.could.lead.to.salinization.of.water.supplies.from.coastal.aquifers.. climate.change.could.increase.irrigation.demand.due.to.the.combination.of.decreased.rainfall. and.increased.evapotranspiration,.placing.additional.pressure.on.irrigation.systems.that.are. in.many.cases.already.under.performing..changes.in.river.flows.could.have.a.direct.impact. on.hydropower.generation.facilities..soil.erosion.from.increased.rainfall.intensity.could.affect. watershed.sustainability.and.lead.to.sedimentation.in.reservoirs,.impacting.on.the.operation.of. 29 multi-purpose.facilities..extreme.variability.and/or.reduced.supplies.could.stretch.the.infrastructural. and.institutional.limits.of.systems.that.manage.water.across.sectors.and.even.national.boundaries.. some.of.the.non-climatic.factors,.as.identified.by.iPcc.are.given.in.box.3.4. Box 3.4 Non-climatic drivers of change in freshwater systems in.addition.to.the.discussion.of.hydrologic.and.climatic.impacts,.there.are.also.many.non-climatic.drivers. of.freshwater.systems..For.example,.water.use.is.driven.by.changes.in.population,.food.demand,.economy,. technology,.lifestyle,.and.societal.views.regarding.value.of.freshwater.ecosystems..land.use.change,.construction. and.management.of.reservoirs,.pollutant.emissions,.and.water.and.waste.water.treatment.all.influence.both.the. quantity.and.quality.of.freshwater..Also,.water.management.(i.e.,.how.a.reservoir.releases.water,.what.demands. have.priority,.etc.).plays.a.major.role.in.the.vulnerability.of.a.water.system.both.at.the.national.and.international. level.(bates.et.al.2008). 30 CHaPTer 4: THe CosT of vulnerabiliTy To HydrologiC CHange and inCreased variabiliTy The developing world is particularly vulnerable to climate change The impacts of a changing climate on the hydrologic cycle will be felt in developed and developing countries alike. However,.many.parts.of.the.developing.world.are.particularly. vulnerable..vulnerability.to.climate.change.has.been.defined.by.iPcc.as.the.degree.to.which. geophysical,.biological.and.socioeconomic.systems.are.susceptible.to,.or.unable.to.cope.with,. adverse.effects.of.climate.change,.including.climate.variability.and.extremes..it.is.a.function. of,.amongst.others,.the.character,.magnitude.and.rate.of.climate.variation.to.which.a.system.is. exposed,.its.sensitivity.and.its.adaptive.capacity..the.financial.cost.of.vulnerability.is.difficult.to. assess.and.even.more.difficult.is.the.cost.of.adaptation.to.uncertain.future..work.is.in.progress.to. address.financial.costs..Here,.the.focus.is.primarily.on.the.non-financial.costs. A number of factors make many developing countries--and the poorest within them-- particularly vulnerable to the potentially adverse impacts of climate change. these.include. weak.institutions.and.limited.institutional.capacity,.high.levels.of.poverty,.insufficient.stock.of.water. management.and.services.infrastructure,.lack.of.access.to.technology.and.capital.to.invest.in.risk. reduction,.and.dependence.on.climate-sensitive.sectors.such.as.agriculture,.forestry.and.fisheries.. more.precisely,.several.factors,.both.physical.features.and.societal.characteristics,.have.been. associated.with.high.levels.of.vulnerability.(Arnell,.2003)..these.include: ·.Physical.Features ·.A.current.hydrological.and.climatic.regime.that.is.marginal.for.agriculture.and.livestock ·.Highly.seasonal.hydrology.as.a.result.of.either.seasonal.precipitation.or.dependence.on. snowmelt ·.High.rates.of.sedimentation.of.reservoir.storage ·.topography.and.land-use.patterns.that.promote.soil.erosion.and.flash.flooding.conditions ·.lack.of.variety.in.climatic.conditions.across.a.region,.leading.to.inability.to.relocate.activities. in.response.to.climate.change ·.societal.characteristics ·.Poverty.and.low.income.levels,.which.prevent.long-term.planning.and.provisioning.at.the. household.level ·.lack.of.infrastructure,.or.poor.maintenance.and.deterioration.of.existing.infrastructure ·.lack.of.human.capital.skills.for.system.planning.and.management ·.lack.of.appropriate,.empowering.institutions ·.Absence.of.appropriate.land-use.planning ·.High.population.densities.and.other.factors.that.inhibit.population.mobility ·.increasing.demand.for.water.because.of.rapid.population.growth ·.conservative.attitudes.toward.risk.(unwillingness.to.live.with.some.risk.as.a.tradeoff.against. more.goods.and.services) ·.lack.of.formal.links.among.various.parties.involved.in.water.management 31 many,.if.not.all,.of.the.above.factors.are.prevalent.in.the.developing.world,.and.so.the. implications.of.climate.change.are.likely.to.be.greatest.here..indeed,.this.is.precisely.the.finding.of. the.more.rigorous.`vulnerability.assessments,'.which.are.presented.below. Vulnerability to surface water stress Several attempts have been made to estimate vulnerability on a global scale..this.is. done.by.incorporating.some.proxy.for.adaptive.capacity.(`economic.coping.capacity',.raskin. et.al,.1997;.the.Human.development.index,.Alcamo.and.Heinrichs,.2002)..Perhaps.the.most. comprehensive.is.the.climate.vulnerability.index.(cvi),.which.is.an.extension.of.the.water. Poverty.index..six.major.components.are.included.in.the.cvi--resource,.access,.capacity,.use,. environment,.and.geospatial--each.of.which.is.comprised.of.several.variables..Figure.4.1. compares.vulnerabilities.of.different.regions.at.present.and.how.they.might.be.affected.over.the. next.thirty.years..As.can.be.seen,.most.of.the.developing.world.falls.in.the.range.of.medium.to. high.vulnerability. Figure 4.1 Some preliminary results for applying the Climate Vulnerability Index (CVI) for comparison of vulnerability by region at present and in 30 years Barbados R A C U E G CVI 2000 67.8 0.0 10.2 46.3 45.6 35.8 34.3 2030 78.5 0.0 8.8 53.6 53.2 35.8 38.3 Examining potential change using the CVI illustrating change in future component values High (52.0­60.0) Bangladesh R A C U E G CVI Medium high (44.0­51.9) 2000 55.1 31.0 49.6 38.3 55.2 76.7 50.1 Medium (36.0­43.9) 2030 64.0 7.8 33.7 50.7 78.0 86.8 53.5 Medium low (28.0­35.9) Low (20.0­27.9) Bolivia R A C U E G CVI No data 2000 2030 32.1 26.3 42.0 42.9 43.2 54.7 40.2 47.5 6.6 28.4 61.0 50.4 59.7 42.3 NOVEMBER 2009 key to Cvi components: r- resources, a- access, C- Capacity, IBRD 37365 This map was produced by the Map Design Unit of The World Bank. The boundaries, colors, denominations and any other information shown on this map do not imply, on the part of The World Bank u- use, e- environment, g- geospatial Group, any judgment on the legal status of any territory, or any endorsement or acceptance of such boundaries. Source: sullivan.and.meigh,.2005.and.sullivan.and.Huntingford,.2009 Vulnerability to groundwater stress A preliminary assessment of the vulnerability of groundwater in World Bank regions to climate change was recently undertaken by the World Bank (World Bank, 2009b).. vulnerability.is.assessed.for.2050,.assuming.all.non-climatic.conditions.as.current..the. assessment.is.at.regional.scale.and.is.intended.as.a.general.indicator.only..Four.criteria.were. considered.in.the.regional.vulnerability.assessment.(table.4.1): ·.current.level.of.exploitation.of.groundwater.resources--as.indicated.by.the.use.of.groundwater. relative.to.average.annual.recharge.(after.igrAc,.2004); 32 Table 4.1 Preliminary assessment of vulnerability of groundwater in World Bank regions to climate change Sensitivity Exposure Adaptive capacity Climate change SLR1 & World Bank Utilisation of impact on storm surge Per capita region groundwater recharge exposure GNI1 Vulnerability2 east.Asia.&. moderate increase medium moderate moderate Pacific europe.&.. low increase low High low central.Asia latin.America.&. moderate reduction medium moderate moderate caribbean middle.east.&. High uncertain low moderate moderate north.Africa south.Asia moderate negligible High low High sub-saharan. moderate reduction low low High Africa 1 .slr--sea.level.rise;.gni--gross.national.income.(in.$us) 2 .vulnerability.assessed.from.the.sum.of.average.of.sensitivity.and.exposure.ratings.and.adaptive.capacity.rating. ·. groundwater.utilisation--low.(2),.moderate.(4),.high.(6) ·. impact.on.recharge--increase.(2),.uncertain/negligible.(4),.reduction.(6) ·. slr.exposure--low.(1),.medium.(2),.high.(3) ·. Per.capita.gni--low.(6),.moderate.(4),.high.(2)--relative.to.each.other low.vulnerability.(<6),.moderate.(6­9),.High.(>9) Additional.note:.Although.such.a.regional.scale.analysis.masks.country-to-country.differences.in.vulnerability--which.are.expected.to. be.large--it.provides.some.insight.into.potential.`hot.spots'.of.climate.change.vulnerability. ·.the.magnitude.and.trend.in.changes.in.rates.of.groundwater.recharge.under.2050.climate. change.projections.(after.döll.and.Flörke,.2005); ·.the.exposure.of.regional.water.resources.to.sea.level.rise.and.contamination.due.to.storm.surge. (based.on.the.authors'.assessment.of.cyclone.incidence,.the.extent.of.coastal.areas.in.the.region. and.population.density.in.these.areas); ·.wealth,.as.measured.by.per.capita.gross.national.income.(gni;.world.bank,.200813) Groundwater utilization is used as an indicator of sensitivity to climate change..the.second. and.third.criteria.were.indicators.of.exposure.and.gni.was.used.to.indicate.adaptive.capacity.. these.factors.were.combined.to.provide.a.vulnerability.indicator..Adaptive.capacity.and.the. combination.of.exposure.and.sensitivity.indicators.were.weighted.evenly..weighting.to.sea.level.rise. and.storm.surge.risk.was.reduced.to.reflect.its.uneven.application.to.world.bank.regions. While there remains significant uncertainty with this assessment, it suggests that groundwater in the World Bank Europe and Central Asia region is the least vulnerable to 13 Datafromhttp://go.worldbank.org/GKIIAZEJR0 33 the effects of climate change..this.reflects.the.relatively.low.level.of.utilization.of.groundwater,. the.projected.increase.in.rainfall.(in.many.areas),.minimal.exposure.of.groundwater.to.risks.from. sea.level.rise.and.storm.surge.and.higher.per.capita.income..groundwater.resources.in.the.south. Asia.and.sub-saharan.Africa.regions.were.considered.to.be.most.vulnerable. Costs to the most vulnerable The most vulnerable regions of the world are already suffering huge costs associated with climate and hydrologic variability, and this could be worsened by longer-term changes in climate. in.particular,.the.incidence.and.severity.of.both.floods.and.droughts.has. been.growing.globally,.as.have.the.economic,.social.and.environmental.damages.associated. with.them..yearly.economic.losses.from.large.extreme.events--including.floods.and.droughts-- have.increased.ten-fold.between.the.1950s.and.1990s..From.1990.to.1996.alone,.there.were. six.major.floods.throughout.the.world.in.which.the.number.of.fatalities.exceeded.1,000.and.22. floods.with.losses.exceeding.us$1.billion.each.(kabat.et.al.,.2003)..the.developing.world--and. particularly.in.south.and.east.Asia--have.been.the.worst.hit.by.disastrous.floods..Although.part. of.the.increase.in.losses.is.attributable.to.socio-economic.factors--including.population.growth,. expansion.into.flood.prone.areas,.land.use.changes,.manipulation.of.water.within.channels-- climatic.factors.are.also.partly.responsible..droughts.have.been.equally.devastating,.particularly. in.Africa,.which.has.been.exposed.to.more.recurrent.droughts.than.any.other.part.of.the.world.. Again,.non-climatic.factors--including.poor.management.of.water.resources,.urbanization. and.degrading.watersheds,.and.in.the.worst.cases,.civil.war--have.played.a.significant.role.in. increasing.vulnerabilities.to.drought. Studies that have assessed the economic impacts of climate variability--and in particular floods and droughts--in the developing world have found these to be substantial. one. of.the.earliest.study.estimated.the.cost.to.kenya.of.two.extreme.events,.finding.that.the.1997/8. el.niño.floods.cost.the.country.11.percent.of.its.gdP.and.the.1998/2000.la.niña.drought,. 16.percent.(world.bank,.2004)..According.to.the.study,.given.their.regularity.and.over.the.long. term,.floods.and.droughts.are.estimated.to.cost.kenya.about.2.4.percent.of.gdP.annually,.and. water.resources.degradation.a.further.0.5.percent.of.the.gdP.annually,.representing.a.serious. drag.on.the.country's.economy..the.calculation.of.annualized.cost.was.based.on.the.frequency. and.intensity.of.historical.floods.and.droughts..As.these.are.likely.to.become.more.pronounced. with.climate.change,.economic.costs.can.be.expected.to.be.even.more.substantial.in.the.future,. all.else.equal..in.ethiopia,.economy-wide.models.incorporating.hydrological.variability.show. that.the.projections.of.average.annual.gdP.rates.drop.by.as.much.as.38.percent,.as.compared. to.when.hydrological.variability.is.not.included.(mogaka.et.al.,.2006)..the.economy--heavily. dependent.on.rainfed.agriculture--was.found.to.be.so.intimately.tied.to.hydrological.variability. that.even.a.single.drought.event.within.a.twelve.year.period.would.diminish.average.growth.rates. across.the.entire.twelve.year.period.by.10.percent..both.of.these.cases.have.`difficult.hydrologies'.. However,.it.is.not.hydrological.variability.per.se--but.extreme.vulnerability.to.it.due.to.a.lack.of.the. `minimum.platform'.of.necessary.capacity,.infrastructure.and.institutions.to.mitigate.the.impacts-- that.makes.them.water.insecure..As.just.one.indicator,.installed.reservoir.capacity.per.capita.is.only. 40.m3.in.ethiopia.(a.nation.with.greater.climate.variability).as.compared.to.over.6000.m3.in.north. America.(an.area.with.much.less.climate.variability). Climate change is projected to alter the amount, intensity and frequency of precipitation, directly affecting not only the magnitude and timing of floods and droughts, but also runoff patterns, groundwater recharge, and water quality..For.example,.glacial.meltdown.in. 34 several.regions.of.the.world--including.the.Andes.and.the.Himalayas--is.already.occurring.and. the.rate.is.projected.to.increase.with.a.continual.warming.of.the.climate..the.Himalaya.glaciers. are.reducing.at.a.rate.of.33­49.feet.per.year..glacial.melt.is.expected.to.lower.water.levels.in. river.basins,.including.the.indus.and.the.ganges,.by.as.much.as.two-thirds,.affecting.over.500. million.people.in.india..on.a.per.capita.basis,.water.availability.is.projected.to.decline.by.over. 30.percent.in.the.next.four.decades..india.has.one.of.the.world's.most.ambitious.hydropower. programs,.but.there.might.not.be.sufficient.water.available.to.run.the.new.turbines.by.the.time.that. the.dams.are.built..india's.megacities.in.coastal.areas--such.as.mumbai.and.chennai--are.also. at.risk..some.experts.have.estimated.that.india's.gdP.could.drop.by.as.much.as.nine.percent,. largely.due.to.submergence..it.is.estimated.that.mumbai.alone.could.lose.up.to.$48.billion. (tehelka,.2008). implications for sustainable development and the bank's mission for poverty reduction For regions that are already highly vulnerable to climate variability, the potential impacts on all sectors that depend on water--from domestic water supply and agriculture to health and the environment--could strain economies and livelihoods..in.many.regions.of. the.globe,.climate.change.may.put.at.risk.progress.that.has.been.made.over.several.decades. in.sustainably.developing.economies.and.societies..indeed,.according.to.the.iPcc,."even.with. optimal.water.management,.it.is.very.likely.that.the.negative.impacts.on.sustainable.development. cannot.be.avoided".(bates,.et.al.,.2008)..Figure.4.2.shows.some.key.cases.around.the.world. where.water-related.climate.change.impacts.on.various.sectors.and.systems.are.a.threat.to.the. sustainable.development.of.affected.regions. The current financial crisis and various sector crises have already and will continue to impact financing of adaptation to climate change..A.theme.that.has.been.emphasized. throughout.this.report.is.that.climate.change.is.not.the.only--or.even.the.primary--factor.exerting. stress.on.the.water.sector,.and.by.extension.societies,.economies,.and.the.environment..the. current.financial.crisis.and.the.sector.crises.(e.g.,.rising.food.prices,.energy.cost).have.forced. many.governments.in.developing.countries.to.defer.urgent.operation.and.maintenance,.as.well. as.water.investment.needs..this.can.exacerbate.efforts.of.the.governments.in.tackling.their.current. water.challenges,.such.as.provision.of.safe.drinking.water.and.improved.sanitation,.jeopardizing. achievement.of.the.millennium.development.goals.targets..the.private.sector.capital.flight.is. expected.to.continue.in.these.financially.uncertain.times,.affecting.investment.decisions.with. climate.adaptation.aspects..in.the.near-.to.medium-term,.the.situation.is.expected.to.worsen. unless.investment.funds.are.channeled.to.the.sector..Here,.a.combination.of.the.new.financial.and. climate.change.architectures.such.as.the.vulnerability.Fund,.the.climate.investment.Fund,.and. other.mechanisms.to.alleviate.the.investment.bottle.neck.should.be.made.available.to.the.client. bank.countries..this,.at.a.minimum,.can.help.protect.infrastructure.assets.through.coverage.of. cost.of.operation.and.maintenance..current.hydrologic.variability.and.magnitude.and.frequency. of.extreme.events.may.make.meeting.water-related.mdgs.(targets.1,.6.and.7).by.2015.more. difficult..but.it.is.highly.unlikely.that.these.alone.will.hamper.achievement..the.significance.of. climate.change.lies.in.its.interaction.with.other.pressures,.both.current.and.future..making.systems,. societies.and.economies.less.vulnerable.to.the.potential.impacts.requires.that.climate.change.be. addressed.within.this.broader.context..viewed.in.the.long.term,.the.current.financial.crisis.and.the. stimulus.packages.to.respond.to.this.crisis.can.be.designed.to.take.into.account.the.wider.risk.of. climate.change.in.the.recovery.and.rebuilding.process. 35 Figure 4.2 Illustrative map of future climate change impacts related to freshwater which threaten the sustainable development of the affected regions 1:.bobba.et.al..(2000),.2:.barnett.et.al..(2004),.3:.doll.and.Floke.(2005),.4:.mirza.et.al..(2003),.5:.lehmer.et.at..(2005).6:.kistemann et.al..(2002),.7:.porter.and.semenov.(2005)..background.map:.ensemble.mean.change.of.annual.runoff,.in.percent,.between. present.(1980­1999).and.2090­2099).for.the.sres.A1b.emissions.scenarios.(based.on.milly.et.al.,.2005)..Areas.with.blue.(red). colors.indicate.the.increase.(decrease).of.annual.runoff..[bates.et.al,.2008,.Fig..3.4.pg..47] 36 CHaPTer 5: ClimaTe and Hydrology ProjeCTions for invesTmenT deCisions introduction The purpose of these projections is to gain insight into potential future hydrology and to establish a common platform of information on the behavior of key hydrologic drivers across World Bank regions at a scale appropriate for policy and investment decisions.. the.catchment.level.was.selected.because.it.is.the.most.appropriate.scale.for.water.planning.and. investment..Projected.impacts.on.runoff.and.basin.yield,.extreme.events.(floods.and.droughts),. minimum.base.flow.(a.proxy.for.groundwater.recharge),.and.net.irrigation.demand.are.assessed. here,.as.these.variables.are.particularly.relevant.for.water.planning.and.investments..the. methodological.approach.used.for.this.analysis.was.developed.to.explicitly.tackle.two.difficult. issues.that.plague.climate.change.assessments:.(i).how.to.`match'.model.outputs.generated.at.a. course.resolution.with.the.desired.(and.typically.finer).scale.and.(ii).how.to.take.advantage.of.all. information.generated.from.climate.models,.specifically.by.capturing.the.full.spectrum.of.model. projections..twenty-two.gcms.along.with.three.emissions.scenarios.(A1b,.A2.and.b1).are.used. to.analyze.changes.in.the.key.hydrologic.variables.in.the.years.2030.and.2050..For.each.world. bank.region,.the.wettest,.driest.and.a.middle.scenario.are.identified.based.on.the.climate.moisture. index..these.scenarios.serve.as.the.basis.for.estimating.changes.in.the.key.hydrologic.variables. key issues in climate change impact assessments Resolution and scale in impact assessments One potential difficulty with using climate information in impact assessments--including in the water sector--is the `mis-match' between the low spatial (and temporal) resolution of GCMs, on the one hand, and the scale at which assessments need typically to be conducted for investment purposes, on the other..gcms.provide.climate.change.projections. at.a.low.spatial.resolution.(~2.5°.x.2.5°.grid;.table.5.1).while.water.planning.and.management. analyses.often.require.a.much.finer.resolution.(~0.5°.x.0.5°.grid.or.even.finer.for.project.level. analyses)..table.5.2.provides.a.list.of.areas.for.1°grid.cells.at.various.latitudes.for.reference..the. goal.of.the.assessment--i.e..what.is.it.trying.to.answer;.who.is.it.trying.to.inform?--should.drive. the.decision.on.both.the.relevant.scale,.and.the.most.appropriate.technique.to.use.for.matching. gcm.output.with.that.scale. There are several methods available for addressing scale issues,.including.statistical. downscaling.(using.empirical.relationships),.dynamical.downscaling.(using.regional.climate. models).and.`spatial.techniques'14.(linear.interpolation,.krigging,.spline.fitting,.and.intelligent. interpolation). downscaling.involves.methods.used.to.map.the.large.scale.signals.from.gcms.to.a. finer.resolution.(tens.of.kilometers.versus.hundreds.of.kilometers). Care needs to be taken in selecting the method of analysis..beyond.reproducing.the. underlying.uncertainties.of.gcms,.many.introduce.additional.uncertainty.and.biases..For.example,. downscaling.techniques.increase.the.detail.of.information,.but.also.the.uncertainties.associated. with.that.information.due.to.fact.that.the.gcm.output.is.manipulated.below.the.scale.at.which. 14 `Spatialtechnique'isoftenandcommonlyreferredtoas`spatialdownscaling'buttechnicallydoesnotinvolvedownscalingalgorithm. Themajorityof`downscaling'beingdoneiswiththismethod. 37 Table 5.1 Spatial Resolution of AR4 IPCC Archived GCMs GCM Latitude Longitude Area at 40° lat (km2) bccr_bcm2_0 2.81 2.81 75,115 cccma_cgcm3_1 3.75 3.75 133,538 cccma_cgcm3_1_t63 2.81 2.81 75,115 cnrm_cm3 2.81 2.81 75,115 csiro_mk3_0 1.88 1.88 33,384 csiro_mk3_5 1.88 1.88 33,384 gfdl_cm2_0 2 2.5 47,480 gfdl_cm2_1 2 2.5 47,480 giss_aom 3 4 113,952 giss_model_e_h 3.91 5 185,792 giss_model_e_r 3.91 5 185,792 iap_fgoals1_0_g 3 2.81 80,123 inmcm3_0 4 5 189,920 ipsl_cm4 2.5 3.75 89,025 miroc3_2_hires 1.13 1.13 12,018 miroc3_2_medres 2.81 2.81 75,115 mpi_echam5 1.88 1.88 33,384 mri_cgcm2_3_2a 2.81 2.81 75,115 ncar_ccsm3_0 1.41 1.41 18,779 ncar_pcm1 2.81 2.81 75,115 ukmo_hadcm3 2.47 3.75 87806 ukmo_hadgem1 1.24 1.88 22,103 Average 2.6 3 72,420 Table 5.2 Coverage area of 1-degree latitude by 1-degree longitude 1 Degree Longitude 1 Degree Latitude 1 Square Degree Latitude km km e km2 0 111 111 12,393 40 85 111 9,496 60 56 111 6,181 80 17 111 1,876 38 the.physics.of.the.gcm.itself.are. Figure 5.1 The cone of uncertainty in scale and resolution mathematically.described..under. of modeling some.downscaling.schemes,.mass. balances.of.water.and.energy. over.the.gcm.scale.are.violated. by.the.downscaling.algorithm.. use.of.dynamical.and.statistical. downscaling.techniques.requires. extensive.quantification.of.the. sensitivities.of.the.underlying. assumptions.of.both.the.gcms. and.the.downscaling.algorithms,. resulting.in.the.need.for.exhaustive. numerical.experimentation..time. and.cost.constraints.often.do.not. allow.use.of.more.than.a.couple. of.gcms.in.downscaling.exercises.. running.multiple.gcms.at.a. coarse.resolution.may.provide. more.insight.into.the.range.of. possible.futures.than.more.detailed.information.obtained.from.fewer.gcms. There is no one `best' method; the most appropriate method for a particular application will strike a careful balance between precision (resolution) and accuracy (confidence in projections)..Figure.5.1.provides.a.visual.representation.of.the.trade-off.between.precision. and.accuracy..As.resolution.increases,.so.does.the.uncertainty.associated.with.the.more.detailed. information..in.other.words,.more.`precise'.information.comes.at.a.cost,.and.the.additional. uncertainty.must.be.recognized.and.taken.into.account.in.assessing.impacts..given.the.trade-off,. it.is.critical.to.establish.at.the.outset.of.any.impact.assessment.whether.the.goal.is.to.have.finer. resolution.or.`better'.(that.is,.more.reliable).information. In this analysis, the catchment level is selected as it is the most appropriate scale for water planning and investment..this.analysis.does.not.employ.dynamical.or.statistical.downscaling. techniques.for.the.reasons.stated.above..instead,.projections.from.22.gcms.and.3.sress.were. applied.at.their.native.spatial.grid.scale.(~2.5°.x.2.5°),.and.the.changes.in.climate.variables. between.the.model.runs.and.the.20th.century.runs.were.applied.directly.to.0.5°.by.0.5°.gridded. monthly.historic.climatology..the.advantage.of.this.approach.is.that.it.allows.investigation.of.all.the. iPcc.gcms.and.emissions.scenarios.at.the.native.spatial.resolution,.thereby.capturing.a.range.of. potential.climate.change.impacts.and.achieving.a.balance.between.precision.and.accuracy. To reduce the uncertainties inherent in obtaining climate variables at high resolution, the 0.5° by 0.5° gridded data are `re-aggregated' to the catchment level..the.average.scale.of. a.catchment.is.approximately.the.size.of.the.native.spatial.grid.scale.of.the.gcm.(~2.5°.x.2.5°). which.results.in.less.uncertainty.in.final.projections..Figure.5.2.shows.the.three.relevant.scales:.0.5°. x.0.5°.grid,.2.5°.x.2.5°.grid,.and.the.catchments..the.catchments.are.obtained.from.the.usgs. Hydro1k,.a.geographic.database..Hydro1k.has.six.levels.of.catchments..For.this.analysis.level.4. is.selected.for.all.bank.regions.except.AFr,.where.level.3.is.used..there.are.8,406.catchments. covering.the.world.bank.regions,.which.translate.into.an.average.of.six.0.5°.x.0.5°.grids.per. catchment..using.gis,.the.catchment.boundaries.are.overlaid.with.the.grids.and.the.cells.are. 39 aggregated.by.their.weighted.area. Figure 5.2 Section of the SAR region showing 0.5° by in.the.catchment. 0.5° grid scale, 2.5° by 2.5° (GCM) grid scale (dark larger grids), and catchment boundaries in color Generating and capturing climate change projections 67°30'0"E 70°0'0"E 72°30'0"E 75°0'0"E 77°30'0"E 80°0'0"E 82°30'0"E 85°0'0"E 32°30'0"N 32°30'0"N In the context of downscaling, 30°0'0"N 30°0'0"N relying on results from a single or a few GCMs is not advisable.. 27°30'0"N 27°30'0"N this.is.because.there.are.model. errors.in.any.one.model.and. 25°0'0"N 25°0'0"N natural.variability.(randomness).in. 22°30'0"N 22°30'0"N any.particular.run..A.single.model,. if.run.multiple.times.with.differing. 20°0'0"N 20°0'0"N initial.conditions,.can.provide.an. estimate.of.the.uncertainty.due.to. 17°30'0"N 17°30'0"N natural.variability..However,.for. any.given.model,.there.are.also. 15°0'0"N 15°0'0"N uncertainties.associated.with.the. 12°30'0"N 12°30'0"N assumptions.made.about.model. physics.and.parameterizations,.as. 10°0'0"N 10°0'0"N well.as.with.the.structural.aspects. of.the.model.itself..using.a.group. 7°30'0"N 7°30'0"N of.gcms.(multi-model.ensembles),. 67°30'0"E 70°0'0"E 72°30'0"E 75°0'0"E 77°30'0"E 80°0'0"E 82°30'0"E 85°0'0"E as.opposed.to.one.individual. gcm,.can.account.for.biases.and. errors..the.use.of.multi-model.ensembles.raises.the.question.of.how.to.capture.the.full.range.of. results.from.model.runs. Strong caution is advised when using the mean of multiple models with the rationale that the mean is a good representation of all runs..this.can.lead.to.wrong.conclusions..the. problem.with.relying.on.the.mean.is.that.it.masks.extreme.values..A.model.`average'.of.near.zero. could.be.the.result.of.models.predicting.near-zero.change,.but.also.the.result.of.two.opposing. changes.that.differ.in.sign,.as.seen.in.Figure.5.3..in.water.management,.it.is.in.the.`tails'.of.the. full.spectrum.of.model.projections.where.the.risk.lies,.and.so.failing.to.capture.the.extremes.could. be.dangerous. Potential exists for the range of model outcomes to vary so much that it could be construed as "noise"..However,.there.is.evidence.that.suggests.a.degree.of.consistency.in.some. of.the.more.salient.changes.generated.by.a.collection.of.model.outcomes..As.an.example,.the. trend.in.precipitation.intervals.as.simulated.by.the.iPcc.Ar4.models.show,.statistically.and/ or.probabilistically.speaking,.agreement.in.the.projection.of.the.change.in.precipitation.interval. across.latitudes,.as.climate.warms..this.implies.that.although.one.should.not.rely.solely.on.a. single.model,.each.run.could.potentially.contain.important.information.that.is.more.than.merely. `noise'..indeed,.there.are.regions.where.a.sign.change.is.consistent.amongst.the.climate.models-- but.with.a.range.that.is.important.to.consider.explicitly.for.assessment.of.potential.impacts. A related issue is filtering or screening of GCM and SRES scenarios that are implausible, or at the very least, extremely unlikely..this.is.difficult--if.not.impossible--to.unequivocally. 40 determine.as.there.are.no.definitive. Figure 5.3 Range of relative change from historical climate criteria.for.determining.whether.a. for different GCMs. Mean is shown in heavy line given.climate.change.projection. can.or.should.be.excluded..one. approach.in.impact.assessments. is.to.consider.all.modeled. projections.as.`equally.likely'.at. the.outset.of.the.assessment,.and. then.to.exclude.in.a.secondary. step.those.scenarios.with.minimal. or.limited.impacts.(and.so.to. focus.on.those.that.could.cause. significant.damage/consequence).. techniques.are.being.developed. for.undertaking.a.full.probabilistic. analysis.of.scenarios.to.determine. which.are.most.applicable.to. each.region,.but.these.are.not.yet. available.for.practical.use. In this analysis, the full spread of model projections--including extremes--is captured by identifying dry, medium and wet climate scenarios, as defined by a change in the climate moisture index (CMI).15.model. projections.are.not.screened.. Source: giannini.et..al.,.2008.pg..376,.Fig..6. dry,.middle.and.wet.scenarios. are.identified,.specific.to.each. world.bank.region.(e.g.,.the.driest. scenario.for.lcr)..A.wet.scenario. means.that.the.location.experienced.the.smallest.impact.(or.change.in).cmi;.a.dry.scenario,.the. largest.impact;.and.a.medium.scenario,.an.impact.in.between.the.two.extremes..the.advantage. of.this.approach.is.that.it.provides.a.representation.of.the.full.range.of.available.scenarios.in.a. `manageable'.way.(further.details.are.given.below). analytical framework Key hydrologic variables for water planning and management A number of hydrologic variables or indicators have been proposed in the literature to assist policy-makers and planners in decision-making..themes.emerging.from.this.literature. suggest.a.set.of.indicators.that.provide.key.information.on.the.performance.of.water.resource. development.projects.in.the.near.future,.as.well.as.in.the.distant.future.under.the.threat.of.climate. 15 Notethatemissions scenariosaredistinctfromclimate scenarios,whichareaplausibleandoftensimplifiedrepresentationofthe futureclimate.Climateprojections--theresponseoftheclimatesystemtoemissions/concentrationscenariosofgreenhousegassesand aerosols,orradiativeforcingscenarios,baseduponsimulationsbyclimatemodels--oftenserveastherawmaterialforconstructing climatescenarios.Aclimate change scenarioisthedifferencebetweenaclimatescenarioandthecurrentclimate(Bates,etal,2008). 41 change..the.indicators.chosen.for.this.analysis.provide.information.on.mean and extreme values of runoff, the storage requirements for reliable basin yield, groundwater recharge, and net irrigation water demand. SRES scenarios and GCMs In this analysis, three SRES scenarios are used: B1, A1B, and A2..these.scenarios.are. chosen.because.they.are.included.in.the.marker.scenarios.identified.by.the.iPcc.and.are.in.the. middle.range.of.sres.scenarios.(Figure.5.4).16 There are 22 GCMs available via the IPCC 4th Assessment Report (AR4) to use in climate change analyses (Table 5.3)..in.this.analysis.all.of.the.gcms.are.evaluated.to.identify.dry,. medium.and.wet.projections.for.each.of.the.world.bank.regions.as.discussed.below. Timeframe of analysis Typical climate change Figure 5.4 Multi-model averages and assessed ranges for analyses evaluate impacts surface warming anywhere from the 2030's to the 2100's..it.is.important.to. keep.in.mind.the.purpose.of.the. analysis,.i.e..near.term.planning. or.long.range.potential,.to.help. guide.which.future.decades.are. most.important.to.evaluate.for. investment.purposes..in.this.study. the.years.2030.and.2050.are. used.to.evaluate.the.impacts. of.climate.change.on.various. hydrologic.variables..these.years. are.chosen.for.two.reasons:.(i). this.is.the.relevant.timeframe.for. current.infrastructure.planning.and. Source: (iPcc.2007a,.pg14,.Figure.sPm.5.).solid.lines.are.multi-model. (ii).beyond.2050.uncertainties.in. global.averages.of.surface.warming.(relative.to.1980­1999).for.the. scenarios.A2,.A1b.and.b1,.shown.as.continuations.of.the.20th.century. projections.increase.dramatically.. simulations. As.shown.in.Figure.5.4,.sres. scenarios.are.tightly.bunched.until. 2050,.at.which.time.they.start.to.diverge.significantly. The years 2030 and 2050 here represent decadal averages of monthly GCM output.. in.other.words,.when.reporting.changes.in.2030.relative.to.historical.climate,.these.are.actually. average.changes.from.2025.to.2035.relative.to.average.historical.climate..the.same.is.true.for. the.year.2050.(which.represents.the.average.from.2045.to.2055)..Average.monthly.changes.from. the.gcms.over.the.two.separate.decades.are.applied.to.historical.monthly.hydro-climatology.from. 1961.to.1990. 16 Thereareatotalof40SRESscenarios,organizedintofourscenariofamilies(A1,A2,B1andB2).Markerscenariosrepresentagiven scenariofamily,althoughtheyarenotconsideredtobeanymore`likely'thantheotherscenarios.Thesemarkerscenariosinclude A1B1,A2,B1,andB2,andtwoadditionalscenariosforthegroupsA1F1andA1T. 42 Table 5.3 Available AR4 models, scenarios, and variables via IPCC Models bccr:. bcm2 mPim:. ecHAm5 cccmA:. cgcm3_1-t47 mri:. cgcm2_3_2 cccmA:. cgcm3_1-t63 nAsA:. giss-Aom cnrm:. cm3 nAsA:. giss-eH csiro:. mk3­5 nAsA:. giss-er csiro:. mk3­0 ncAr:. ccsm3 gFdl:. cm2 ncAr:. Pcm gFdl:. cm2_1 nies:. miroc3_2-Hi inm:. cm3 nies:. miroc3_2-med iPsl:. cm4 ukmo:. HAdcm3 lAsg:. FgoAls-g1_0 ukmo:. HAdgem1 Application of Tools to Dialogues at National, River Basin and Project Level Analysis The level of analysis reflected in this report is designed for use at the Country Assistance Strategy discussions, national water strategy planning and identification of investment potential at river basin scale..Projections.at.the.catchment.level.allow.for.analysis.of.inter- regional.variation.at.the.project.planning.scale..the.general.pattern.is.consistent.with.projections. of.runoff.made.directly.from.climate.model.runs..Here,.specific.indicators.provide.a.deeper.and. more.water.specific.insight.regarding.potential.changes.in.the.water.availability.and.distribution. for.various.uses.and.by.various.water.infrastructure.interventions..For.each.region,.detailed. information.for.each.of.these.indicators.is.available.at.the.0.5.x.0.5.degree.resolution,.as.well. as.aggregated.to.catchment.level..it.is.planned.that.this.information.will.be.made.available.via.a. web-based.interface. Various hydrologic models can be used..the.hydrologic.model.used.for.this.study.clirun- ii.and.its.predecessors.have.been.used.extensively.since.1992.specifically.for.climate.change. analysis..while.there.are.a.number.of.global.hydrologic.models.that.could.be.used,.the.results. would.not.differ.significantly.since.they.solve.the.same.set.of.governing.equations..in.this.analysis. the.model.was.calibrated.and.validated.using.separate.historical.time.series.(see.below). Prior to using the methodology at project level it is important to consider that the analysis is based on natural flows.and.does.not.take.into.account.specific.basin.development.and. structural.interventions..these.will.have.to.be.taken.into.consideration.for.detailed.project.design. and.risk.assessment..the.same.is.true.for.expected.changes.in.land.use.and.vegetation.which. impacts.on.the.hydrology. Project specific design will have to continue to be done taking into account historical, local scale surface data..in.addition.down-scaling.from.the.local-scale.surface.weather.may.be. carried.out.using.the.technique.which.the.responsible.task.manager.in.each.case.deems.to.be. most.appropriate..Following.such.down-scaling.it.is.possible.to.project.hydrologic.variables.for.the. 43 investment.project.in.question..these.may.then.be.compared.to.projections.based.on.historical. data.only;.and.a.choice.will.have.to.be.made.with.regard.to.how.to.take.the.climate.change. based.projections.into.account..these.calculations.and.the.ensuing.design.will.be.carried.out.by. the.responsible.engineer.and.will.be.based.on.the.hydraulic.model.of.his.choice.and.the.design. parameters.and.safety.factors.which.he.deems.appropriate.in.the.light.of.the.project.and.local. regulations..A.key.value.of.the.approach.presented.in.this.report.is.that.it.provides.an.easy.to.use. database.which.can.provide.alternative.scenarios.as.background.for.the.project.analysis.to.be. undertaken. Hydrologic drivers and data Historical climate The historical climate is taken from a database provided by the Climate Research Unit (CRU), University of East Anglia, Norwich, UK..the.cru.2.1.data.set.provides.a.time. series.of.monthly.precipitation.data.and.the.climate.variables.required.to.compute.potential. evapotranspiration.from.1901.to.2002..these.data,.provided.on.a.0.5°.longitude/latitude.grid,. represent.the.world.meteorological.organization's.(wmo).standard.reference."baseline".for. climate.change.impact.studies..the.climate.change.scenarios.(i.e..plausible.descriptions.of.how. things.may.change.in.future).are.expressed.as.changes.from.this.baseline..there.are.67,420.grids. (0.5°.x.0.5°).over.the.global.land.area,.excluding.Antarctica. Historical observed runoff Long-term average monthly runoff has been developed by the University of New Hampshire for the WMO Global Runoff Data Centre..the."unH-grdc.composite.runoff. Fields.v1.0".data.set.is.derived.from.observed.discharge.information,.using.a.climate-driven. water.balance.model..the.dataset.utilizes.a.gridded.river.network.at.0.5°spatial.resolution.to. represent.the.riverine.flow.pathways.and.to.link.the.continental.land.mass.to.oceans.through.river. channels..the.data.set.provides.12.monthly.mean.values.and.a.mean.annual.value.of.runoff.for. over.50,000.grids.(0.5°.x.0.5°).over.the.global.land.area.excluding.permanent.ice.cover.such.as. much.of.greenland.and.all.of.Antarctica. Historical indicators as baseline for future water investment assessment Assessment of the impacts of climate change on water investments requires historical time series of runoff and projection of hydrologic drivers..An.observed.global.runoff.time. series.does.not.exist..the.disadvantage.of.the.unH-grdc.database.(discussed.above).is.that.the. discharge.is.gauged,.with.all.of.the.developments.implicit.in.the.measured.data..For.the.purposes. of.this.analysis,.a.new.dataset.based.on.natural.flows.has.been.developed..using.both.the.cru. Historical.climate.database.and.the.unH-grdc.composite.runoff.Fields.v1.0.database.as. input.to.the.global.runoff.model,.clirun-ii.(strzepek,.et.al,.2008),.30-year.monthly.time.series. of.runoff.at.the.50,000.plus.grids.of.the.unH-grdc.data.set.was.produced..the.time.series.uses. the.monthly.data.from.1961.to.1990.to.produce.a.historic.or.base.condition.against.which.the. projections.are.compared..clirun-ii.calibration.is.carried.out.using.the.cru.data.from.1961­ 1980.and.validation.was.performed.using.the.cru.data.from.1981­2002. indicators.for.assessment.of.specific.water.services.and.water.management.investment.types.are. modeled.as.historic.baselines.(Figure.5.5)..these.indicators.are:.basin.runoff,.basin.yield,.10%. 44 Figure 5.5 Modeled historical baseline indicators at catchment scale for Bank regions (1961­1990). Units are in mm/yr. Basin Runoff Yield <10 10­100 100­500 500­1000 >1000 <10 10­100 100­500 500­1000 >1000 Base Low Flow Flow <10 10­100 100­500 500­1000 >1000 <10 10­100 100­500 500­1000 >1000 High Irrigation Flow Deficit <10 10­100 100­500 500­1000 >1000 <10 10­100 100­500 500­1000 >1000 and.90%.exceedance.probability.flows,.base.flow,.and.irrigation.demand.deficit..A.description.of. each.indicator.and.their.application.in.investment.types.is.provided.in.the.subsequent.sections.. the.hydrologic.indicators.are.aggregated.to."level.4.catchment"17.(approximately.2.x.2.degree. resolution). Figure.5.6.shows.the.modeled.indicators.for.the.Africa.region.at.the.catchment.scale..the.entire. data.set.reflecting.the.historical.baseline.conditions.at.the.level.4.catchment.scale.is.now.available. for.all.bank.regions.upon.request. 17 ThecatchmentsareselectedfromtheUSGSHydro1KDrainageBasinDatabase.Level4catchmentdelineationhasanapproximate areaof2x2degree.Level4wasselectedinordertogaugethehydrologyresultstotheresolutionlevelofGCMclimateprojections. Thislevelalsolendsitselftowaterinvestmentsinriverbasins. 45 Figure 5.6 Modeled historical baseline indicators at catchment scale for Africa (1961­1990). Lines on the map delineate catchment boundaries. Units are in mm/yr. Runoff Basin yield < 50 < 20 100 ­ 200 40 ­ 80 400 ­ 800 160 ­ 320 50 ­ 100 20 ­ 40 200 ­ 400 80 ­ 160 > 800 > 320 q90 Base flow < 25 <5 125 ­ 250 25 ­ 50 500 ­ 1000 100 ­ 200 25 ­ 125 5 ­ 25 250 ­ 500 50 ­ 100 > 1000 > 200 q10 Irrigation demand <5 < 500 25 ­ 125 750 ­ 1000 250 ­ 500 1500 ­ 2000 5 ­ 25 500 ­ 750 125 ­ 250 1000 ­ 1500 > 500 > 2000 46 Projections using Climate moisture index The full spread of model results is captured by selecting the driest, the wettest, and middle climate projections..the.historical.model.simulations.and.all.22.gcm.projections. for.the.three.emissions.scenarios.are.analyzed.for.2030.and.2050..the.driest,.middle,.and. wettest.projections.are.identified.for.each.world.bank.region.(see.table.5.4.and.table.5.5)..the. projection.categorization.is.defined.by.the.climate.moisture.index.(cmi),.which.is.an.indicator.of. the.aridity.of.a.region..the.cmi.depends.on.average.annual.precipitation.and.average.annual. , Table 5.4. GCM and associated base CMIs used for each scenario and regions EAP ECA, and LCR EAP ECA LCR ­0.069 ­.205 ­0.075 Base Model CMI Model CMI Model CMI A2-dry csiro_mk3_5 ­0.143 ipsl_cm4 ­0.252 gfdl_cm2_0 ­0.228 A2-middle mri_cgcm2_3_2a ­0.082 ukmo_hadcm3 ­0.215 ukmo_hadcm3 ­0.151 A2-wet cccma_cgcm3_1_t63 ­0.033 giss_model_e_r ­0.177 cnrm_cm3 ­0.068 A1b-dry csiro_mk3_5 ­0.135 ipsl_cm4 ­0.251 ukmo_hadgem1 ­0.202 A1b-midde inmcm3_0 0.097 mpi_echam5 ­0.212 mpi_echam5 ­0.129 A1b-wet cccma_cgcm3_1 ­0.054 cccma_cgcm3_1 ­0.184 bccr_bcm2_0 ­0.076 b1-dry csiro_mk3_5 ­0.122 ipsl_cm4 ­0.243 miroc3_2_hires ­0.153 b1-middle mri_cgcm2_3_2a ­0.084 mpi_echam5 ­0.216 cccma_cgcm3_1 ­0.11 b1-wet cccma_cgcm3_1_t63 ­0.048 gfdl_cm2_1 ­0.177 cnrm_cm3 ­0.074 Table 5.5. GCM and associated base CMIs used for each scenario and regions MNA, SAR, and AFR MNA SAR AFR ­0.91 ­0.372 ­0.5 Base Model CMI Model CMI Model CMI A2-dry gfdl_cm2_1 ­0.942 ipsl_cm4 ­0.466 inmcm3_0 ­0.552 A2-middle ukmo_hadgem1 ­0.920 ukmo_hadcm3 ­0.312 mpi_echam5 ­0.519 A2-wet ncar_pcm1 ­0.898 mri_cgcm2_3_2a ­0.055 ncar_ccsm3_0 ­0.488 A1b-dry gfdl_cm2_1 ­0.941 ipsl_cm4 ­0.496 gfdl_cm2_1 ­0.537 A1b-midde ukmo_hadcm3 ­0.916 ukmo_hadgem1 ­0.294 ukmo_hadgem1 ­0.501 A1b-wet mpi_echam5 ­0.891 mri_cgcm2_3_2a ­0.003 cnrm_cm3 ­0.484 b1-dry gfdl_cm2_1 ­0.930 csiro_mk3_5 ­0.433 ipsl_cm4 ­0.539 b1-middle inmcm3_0 ­0.907 inmcm3_0 ­0.291 miroc3_2_medres ­0.517 b1-wet mpi_echam5 ­0.882 mri_cgcm2_3_2a ­0.051 cnrm_cm3 ­0.486 47 Figure 5.7 Climate Moisture Index range for each climate scenario and each Bank region CMI Historic and Range of 2050 Climate Change Impacts 0 ­0.1 ­0.2 EAP ­0.3 LCR ECA ­0.4 ­0.5 SAR ­0.6 AFR ­0.7 MNA ­0.8 ­0.9 A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1 Legend Top of box: 25th percentile Red line: median CMI Bottom of box: 75th percentile Dashed line: historical CMI (1960­1990) Whiskers: extreme CMI values Cross hairs: model outliers potential.evapotranspiration.(Pet).18.if.Pet.is.greater.than.precipitation,.the.climate.is.considered. to.be.dry.whereas.if.precipitation.is.greater.than.Pet,.the.climate.is.moist..calculated.as.cmi.=. (P/Pet)­1.{when.Pet>P}.and.cmi.=.1­(Pet/P).{when.P>Pet},.a.cmi.of.­1.is.very.arid.and.a. cmi.of.+1.is.very.humid..cmi.is.dimensionless. Figure 5.7 shows the projected range of CMI for each scenario and each region of the World Bank for 2050..the.red.line.represents.the.median.cmi,.and.the.top.of.the.box.represents. the.25th.percentile.while.the.bottom.of.the.box.represents.the.75th.percentile..the.whiskers.show.the. extremes.and.the.cross-hairs.show.the.model.outliers..the.dashed.lines.represent.the.historical.cmi. (averaged.from.1960­1990)..For.example,.in.the.lcr.region,.there.is.a.75%.chance.of.drying.with. all.3.scenarios..the.cmi.for.the.sAr.region.has.the.largest.spread.because.of.the.way.the.different. gcms.model.the.monsoons..in.the.mnA.region,.there.is.little.variation.because.the.area.is.so.dry. In this analysis the CMI is calculated over land masses only. many.climate.change.analyses. discuss.gcm.projections.over.land.and.sea,.but.for.hydrologic.impacts,.the.interest.in.cmi.is.over. land.only..moreover,.note.that.the.land-based.cmi.in.the.box.and.whiskers.plot.are.all.negative.. Figure.5.8.shows.the.projected.range.of.cmi.for.bank.regions,.non-bank.regions.and.the.globe.. note.that.the.land-based.cmi.projections.for.the.bank.regions.are.more.negative.than.non-bank. regions.(e.g.,.oecd)..However,.the.relative.aridity.(compared.with.the.historical).for.both.bank. and.non-bank.regions.remains.the.same. 18 AverageannualPETisaparameterthatreflectstheamountofwaterlostviaevaporationortranspiration(waterconsumedbyvegetation) duringatypicalyearforagivenareaifsufficientwaterwereavailableatalltimes.Averageannualevapotranspiration(ET)isameasure oftheamountofwaterlosttotheatmospherefromthesurfaceofsoilsandplantsthroughthecombinedprocessesofevaporationand transpirationduringtheyear(measuredinmm/yr).ET,whichisbothconnectedtoandlimitedbythephysicalenvironment,isameasure thatquantifiestheavailablewaterinaregion.Potentialevapotranspirationisacalculatedparameterthatrepresentsthemaximumrate ofETpossibleforanareacompletelycoveredbyvegetationwithadequatemoistureavailableatalltimes.PETisdependentonseveral variablesincludingtemperature,humidity,solarradiationandwindvelocity.Ifamplewaterisavailable,ETshouldbeequaltoPET. 48 Figure 5.8 Climate Moisture Index range comparison of Bank and non-Bank regions CMI Historic and Range of 2050 Climate Change Impacts ­0.18 ­0.2 ­0.22 Globe ­0.24 WB Regions ­0.26 Non WB ­0.28 ­0.3 ­0.32 ­0.34 A2 A1b B1 A2 A1b B1 A2 A1b B1 Legend Top of box: 25th percentile Red line: median CMI Bottom of box: 75th percentile Dashed line: historical CMI (1960­1990) Whiskers: extreme CMI values Cross hairs: model outliers runoff projections A variety of approaches/models exist for generating runoff projections.19.in.this.analysis,. gcm.output.is.used.as.input.into.the.hydrologic.model.clirun-ii.(strzepek,.et.al,.2008)..this. model.was.developed.specifically.to.assess.the.impact.of.climate.change.on.runoff.and.to.address. extreme.events.at.the.annual.level.by.modeling.low.and.high.flows..this.analysis.advances.an. earlier.and.much.referenced.effort.by.milly,.et.al.(2005)..clirun-ii.is.an."offline".hydrologic.model. designed.for.application.in.water.resource.projects..milly.uses.runoff.estimates.derived.directly.from. approximately.2.5°.x.2.5°.gcm.precipitation.projections.and.reports.annual.runoff.at.5°.x.5°. resolution.with.some.degree.of.confidence..in.this.analysis,.runoff.is.projected.at.a.monthly.time. scale.at.a.resolution.0.5°.x.0.5°,using.clirun-ii..the.results.are.then.aggregated.to.about.2°.x. 2°.for.a.higher.level.of.confidence. table.5.6.provides.the.projected.percentage.change.in.runoff.at.catchment.scale.for.2030.and. 2050.for.all.bank.regions..the.results.are.reported.for.three.sres.scenarios.and.for.the.identified. dry,.medium.(middle).and.wet.projections..Projected.change.in.runoff.for.2030.is.mapped.for.all. bank.regions.and.presented.in.Figure.5.9..An.example.of.the.regional.distribution.of.change.in. runoff.for.the.Africa.region.is.provided.in.Figure.5.10. basin yield projections Annual runoff provides information on potential water resource availability, but not its accessibility which is a function of reservoir storage..basin.yield--which.is.directly.related.to. reservoir.storage--is.a.measure.of.the.firm.yield.and.reliability.of.water.supply.and.is.estimated. with.the.aid.of.a.`storage.yield.curve'..A.storage.yield.curve.is.an.estimated.time.series.of.annual. 19 Thevariousapproachesarediscussedindetailinthecompanionreportonthescienceofwaterandclimatechange. 49 or.monthly.flows.in.a.basin.and.is.used.to.provide.information.on.(i).the.storage.needed.to.provide. a.specific.amount.of.reliable.yield.and.(ii).for.any.given.storage,.the.reliable.yield.that.can.be. expected..difference.between.k.and.k'.is.storage.needed.to.compensate.for.basin.yield.loss.between. Table 5.6 Summary changes in runoff projections for Bank regions SRES Scenario Year Projection AFR EAP ECA LCR MNA SAR A2. 2030 dry ­5% ­13% 5% ­16% ­17% ­7% medium 6% ­4% 9% ­3% ­17% 26% wet 30% 7% 13% 15% 24% 31% 2050 dry ­13% ­11% 8% ­31% ­50% ­52% medium 14% 3% 18% ­9% ­5% 20% wet 31% 11% 18% 7% 31% 39% A1b. 2030 dry ­5% 7% 9% ­9% ­25% 18% medium 3% 5% 13% ­5% 12% 18% wet ­1% 11% 10% 9% 15% 43% 2050 dry ­20% ­12% 14% ­25% ­46% 24% medium 0% ­2% 21% ­16% ­16% 24% wet 6% 21% 19% 7% 20% 37% b1. 2030 dry ­1% ­8% 6% ­13% ­15% ­20% medium ­9% 2% 11% ­11% 12% ­5% wet 10% 14% 16% 11% 18% 36% 2050 dry ­8% ­8% 5% ­9% ­30% ­14% medium ­12% ­1% 14% ­9% 19% 38% wet 23% 15% 19% 9% 49% 33% Figure 5.9 Projected percent change in runoff for 2030 < ­50 ­20 to ­10 0 to +10 20 to 50 ­50 to ­20 ­10 to 0 10 to 20 > +50 50 2005.and.2050.due.to.climate.change..the.maximum.yield.of.the.storage.yield.curve.is.generally. equivalent.to.the.average.annual.runoff.(ignoring.evaporation).and.the.minimum.yield.is.the.lowest. flow.in.the.time.series..climate.change.has.the.potential.to.impact.not.only.the.average.annual. runoff.in.a.basin,.but.also.the.variability.and.the.shape.of.the.storage.yield.curve.(Figure.5.11). table.5.7.shows.the.percentage.change.in.basin.yield.at.a.catchment.level.in.the.years.2030.and. 2050..the.results.are.reported.for.three.sres.scenarios.and.for.the.identified.dry,.medium.(middle). and.wet.projections..Projected.change.in.basin.yield.for.2030.is.mapped.for.all.bank.regions.and. Figure 5.10 Projected percent change in runoff for 2030 at catchment level ­ Africa Region. Catchment boundaries are not delineated < ­50 ­19 to ­5 0 to +5 +20 to +50 ­50 to ­20 ­5 to 0 +5 to +20 > +50 51 Table 5.7 Summary changes in basin yield projections for Bank regions SRES Scenario Year Projection AFR EAP ECA LCR MNA SAR A2. 2030 dry 21% 42% ­2% 44% 61% 40% medium 9% 14% ­9% 17% 60% ­14% wet ­22% ­7% ­13% ­10% ­4% ­22% 2050 dry 38% 42% ­3% 74% 136% 53% medium ­2% 0% ­14% 39% 24% ­5% wet ­19% ­13% ­18% 5% 4% ­29% A1b. 2030 dry 26% ­4% ­9% 29% 85% ­19% medium 3% ­2% ­16% 26% ­17% ­19% wet 7% ­12% ­7% ­1% ­11% ­29% 2050 dry 53% 49% ­12% 57% 141% ­18% medium 12% 10% ­24% 53% 55% ­18% wet ­4% ­25% ­21% 6% ­19% ­32% b1. 2030 dry 8% 35% ­2% 38% 46% 45% medium 27% 1% ­15% 35% 13% 27% wet ­5% ­17% ­15% ­6% ­7% ­26% 2050 dry 30% 26% 4% 27% 103% 30% medium 37% 7% ­16% 30% 26% ­31% wet ­14% ­20% ­21% ­5% ­29% ­28% presented.in.Figure.5.12..An.example.of.the.regional.distribution.of.change.in.runoff.for.the.Africa. region.is.provided.in.Figure.5.13. extreme events projections Annual runoff and basin yield provide information on Figure 5.11 Impact of climate change on reservoir yield and adaptations average conditions, more is needed..it.is.in.the.`extremes'. where.the.risks.of.climate.change. to.water.investments.and.planning. lie..this.assessment.is.one.of. the.first.attempts.to.develop. indicators--for.floods.and. droughts--based.on.time-series. rather.than.long-term.averages.. As.compared.to.`mean'.value. indicators,.indicators.of.extreme. events.carry.more.uncertainty. due.to.the.limited.data.at.the.tail. 52 Figure 5.12 Projected percent change in basin yield for 2030 < ­50 ­20 to ­5 0 to +5 +20 to +50 ­50 to ­20 ­5 to 0 +5 to +20 > +50 Figure 5.13 Projected percent change in basin yield for 2030 at catchment level ­ Africa Region. Catchment boundaries are not delineated < ­50 ­19 to ­5 0 to +5 +20 to +50 ­50 to ­20 ­5 to 0 +5 to +20 > +50 53 of.the.probability.distribution..However,.it.is.useful.to.have.some.indication.of.extreme.events,. even.while.bearing.this.additional.uncertainty.in.mind. Drought and flood indicators are estimated based on flow frequency analysis. ·.drought.indicator:.this.indicator.is.taken.as.the.flow.that.is.exceeded.90%.of.the.time.(q90),. which.means.there.is.a.10%.chance.in.each.time.period.of.a.flow.lower.than.this..A.decrease.in. q90.means.that.the.likelihood.of.low.flows.and.droughts.will.increase. ·.Flood.indicator:.this.indicator.is.taken.as.the.flow.that.is.exceeded.10%.of.the.time.(q10),.which. means.there.is.a.90%.chance.in.each.time.period.of.a.flow.lower.than.this..An.increase.in.q10. means.that.the.likelihood.of.high.flows.and.floods.will.increase. the.relative.changes.in.the.q90.and.q10.from.the.historical.values.will.provide.an."indication".of. the.projected.changes.in.droughts.and.floods. table.5.8.and.table.5.9.show.the.percentage.change.in.q90.and.q10,.respectively,.at.a. catchment.level.for.2030.and.2050..the.results.are.reported.for.three.sres.scenarios.and.for. the.identified.dry,.medium.(middle).and.wet.projections..Projected.changes.in.drought.and.flood. for.2030.are.mapped.for.all.bank.regions.and.presented.in.Figure.5.14.and.Figure.5.15..An. example.of.the.regional.distribution.of.change.in.floods.and.droughts.for.the.Africa.region.is. provided.in.Figure.5.16.and.Figure.5.17. Table 5.8 Summary changes in low flow projections for Bank regions SRES Scenario Year Projection AFR EAP ECA LCR MNA SAR A2. 2030 dry ­4% ­14% 7% ­18% ­19% ­5% medium 6% ­4% 10% ­2% ­18% 31% wet 37% 8% 14% 19% 18% 31% 2050 dry ­15% ­11% 10% ­35% ­52% ­55% medium 19% 3% 21% ­11% ­8% 21% wet 40% 13% 19% 9% 17% 41% A1b. 2030 dry ­5% 7% 11% ­11% ­29% 20% medium 3% 5% 15% ­5% 9% 20% wet ­1% 12% 10% 9% 13% 47% 2050 dry ­23% ­13% 18% ­32% ­50% 25% medium 0% ­2% 23% ­18% ­24% 25% wet 7% 21% 19% 8% 3% 40% b1. 2030 dry 0% ­9% 9% ­17% ­19% ­22% medium ­12% 2% 13% ­15% 9% ­3% wet 13% 14% 17% 10% 12% 37% 2050 dry ­8% ­9% 7% ­13% ­34% ­17% medium ­14% ­1% 17% ­13% 8% 48% wet 30% 14% 20% 9% 37% 37% 54 Table 5.9 Summary changes in high flow projections for Bank regions SRES Scenario Year Projection AFR EAP ECA LCR MNA SAR A2. 2030 dry ­4% ­13% 5% ­16% ­15% ­8% medium 5% ­3% 8% ­2% ­16% 23% wet 27% 7% 13% 14% 25% 32% 2050 dry ­11% ­10% 7% ­28% ­48% ­50% medium 13% 3% 17% ­9% ­4% 21% wet 27% 11% 17% 7% 36% 39% A1b. 2030 dry ­4% 7% 8% ­8% ­24% 18% medium 3% 5% 13% ­4% 10% 18% wet ­1% 10% 10% 9% 13% 43% 2050 dry ­18% ­12% 12% ­21% ­43% 24% medium 1% ­2% 20% ­14% ­13% 24% wet 6% 20% 19% 7% 27% 35% b1. 2030 dry ­1% ­8% 6% ­11% ­13% ­18% medium ­7% 2% 10% ­9% 12% ­5% wet 9% 13% 17% 11% 22% 36% 2050 dry ­7% ­8% 4% ­7% ­26% ­12% medium ­10% ­1% 13% ­7% 20% 34% wet 20% 15% 19% 8% 52% 32% Figure 5.14 Projected percent change in low flows (drought) for 2030 < ­50 ­20 to ­5 0 to +5 +20 to +50 ­50 to ­20 ­5 to 0 +5 to +20 > +50 55 Figure 5.15 Projected percent change in high flows (floods) for 2030 < ­50 ­20 to ­5 0 to +5 +20 to +50 ­50 to ­20 ­5 to 0 +5 to +20 > +50 Figure 5.16 Projected percent change in low flows (drought) for 2030 at catchment level ­ Africa Region. Catchment boundaries are not delineated < ­50 ­19 to ­5 0 to +5 +20 to +50 ­50 to ­20 ­5 to 0 +5 to +20 > +50 56 Figure 5.17 Projected percent change in high flows (floods) for 2030 at catchment level ­ Africa Region. Catchment boundaries are not delineated < ­50 ­19 to ­5 0 to +5 +20 to +50 ­50 to ­20 ­5 to 0 +5 to +20 > +50 base flow projections Much of water resources development, particularly rural water supply and small scale irrigation, is dependent on groundwater resources..it.is.important.to.provide.an.indicator. of.the.impact.of.climate.change.on.local.groundwater.resources..modeling.of.the.global. groundwater.system.is.highly.complex.and.well.beyond.the.scope.of.this.analysis..However,.a. screening.level.proxy.indicator--base.flow--can.provide.important.information,.and.provide. some.indication.of.the.water.available.in.the.basin.(deep.groundwater.excluded).for.basin. management.interventions.and.conjunctive.water.use..For.each.catchment,.the.30-year. monthly.time.series.is.analyzed.for.estimation.of.the.base.flow.as.the.contribution.of.shallow. groundwater.to.the.runoff. table.5.10.shows.the.percentage.change.in.base.flow.at.catchment.level.for.2030.and.2050..the. results.are.reported.for.three.sres.scenarios.and.for.the.identified.dry,.medium.(middle).and.wet. projections..Projected.change.in.base.flow.for.2030.is.mapped.for.all.bank.regions.and.presented. in.Figure.5.18..An.example.of.the.regional.distribution.of.change.in.base.flow.for.the.Africa. region.is.provided.in.Figure.5.19. 57 Table 5.10 Summary changes in base flow projections for Bank regions SRES Scenario Year Projection AFR EAP ECA LCR MNA SAR A2. 2030 dry ­14% ­32% 21% ­24% ­7% ­14% medium ­7% ­13% 12% ­7% ­19% 33% wet 27% 6% 19% 17% 4% 32% 2050 dry ­12% ­30% 26% ­37% ­51% ­44% medium ­8% ­6% 33% ­18% ­9% 25% wet 12% 10% 33% 21% 58% 35% A1b. 2030 dry ­9% 2% 20% ­11% ­30% 27% medium 5% 2% 24% ­10% 4% 27% wet 0% 9% 23% 16% 5% 47% 2050 dry ­17% ­34% 33% ­33% ­57% 27% medium ­3% ­12% 40% ­19% ­17% 27% wet 13% 35% 29% 8% 17% 37% b1. 2030 dry ­4% ­19% 19% ­14% ­18% ­10% medium ­10% ­2% 6% ­6% ­13% ­16% wet 8% 23% 20% 21% 15% 28% 2050 dry ­14% ­21% 18% ­14% ­39% ­5% medium ­13% ­13% 33% ­2% 12% 24% wet 10% 21% 23% 2% 87% 29% Figure 5.18 Projected percent change in base flow for 2030 < ­50 ­20 to ­5 0 to +5 +20 to +50 ­50 to ­20 ­5 to 0 +5 to +20 > +50 58 Figure 5.19 Projected percent change in base flow for 2030 at catchment level ­ Africa Region. Catchment boundaries are not delineated ­100 to ­50 ­20 to ­5 0 to +5 +20 to +50 ­50 to ­20 ­5 to 0 +5 to +20 +50 to +200 net irrigation demand projections Irrigation is a major user of water and could be significantly impacted by climate change..detailed.crop.modeling.at.the.global.grid.scale.is.well.beyond.the.scope.of.this. analysis,.but.`simpler'.methods.can.provide.important.information.on.net.irrigation.demand.at.a. broader.scale..water.deficit.index.(wdi).can.be.used.as.an.indicator.of.irrigation.performance.. the.wdi.has.recently.been.developed.for.the.reference.crop,.grass,.as.a.generic.index.for. quantifying.crop.water.stress.for.various.crops..this.simple.method.has.been.employed.for. climate.change.analyses.at.local.and.regional.levels. the.water.deficit.index.(wdi).is.an.estimate.of.the.difference.between.precipitation.and.crop. water.requirements,.on.a.monthly.time.scale: wdi.=..(cwr.­.Precip)..t.if.cwr.t.­.Precip.t.>.0.else.0 where, cwr.=.kc(t).*.Pet(t) kc.=.crop.factor.(crop.per.drop) Pet.=.Potential.evapotranspiration 59 wdi.assumes.a.reference.perennial.grass.crop.factor,.kc,.which.has.a.value.of.one..the.modified. Hargreaves.methodology.is.used.for.calculating.Pet..Pet.data.are.consistent.with.what.is.used.in. the.runoff.and.basin.yield.analysis.(refer.above.discussion).and.clirun-ii.model..the.calculation. of.the.cwr.is.performed.at.the.gridded.scale.and.aggregated.to.the.catchment.and.regional. levels. table.5.11.shows.the.percentage.change.in.water.deficit.index.at.catchment.level.for.2030. and.2050..the.results.are.reported.for.three.sres.scenarios.and.for.the.identified.dry,.medium. (middle).and.wet.projections..Projected.change.in.water.deficit.index.for.2030.is.mapped.for.all. bank.regions.and.presented.in.Figure.5.20..An.example.of.the.regional.distribution.of.change.in. water.deficit.index.for.the.Africa.region.is.provided.in.Figure.5.21. Table 5.11 Summary changes in water deficit index projections for Bank regions SRES Scenario Year Projection AFR EAP ECA LCR MNA SAR A2. 2030 dry 0% 122% 10% 40% ­5% 9% medium ­1% 91% ­15% 30% ­1% ­6% wet ­10% 70% ­18% 12% ­4% ­10% 2050 dry ­2% 127% 17% 69% 6% 26% medium 4% 87% ­16% 37% 0% ­3% wet 5% 74% ­16% 21% ­12% ­5% A1b. 2030 dry 13% 106% 30% 59% 14% 33% medium 13% 97% 19% 59% 7% 4% wet 10% 90% 19% 25% 7% 3% 2050 dry 29% 141% 44% 87% 23% 33% medium 18% 114% 28% 64% 15% 4% wet 5% 65% 19% 39% 11% 11% b1. 2030 dry 15% 125% 35% 41% 10% 23% medium 16% 104% 9% 23% 10% 22% wet 9% 71% 6% 13% 8% 5% 2050 dry 20% 132% 44% 48% 14% 17% medium 18% 117% 25% 22% 8% 12% wet 16% 67% 5% 44% ­5% 10% 60 Figure 5.20 Projected percent change in water deficit index for 2030 < ­50 ­20 to ­5 0 to +5 +20 to +50 ­50 to ­20 ­5 to 0 +5 to +20 > +50 Figure 5.21 Projected percent change in water deficit index for 2030 at catchment level ­ Africa Region. Catchment boundaries are not delineated < ­50 ­19 to ­5 0 to +5 +20 to +50 ­50 to ­20 ­5 to 0 +5 to +20 > +50 61 62 CHaPTer 6: ClimaTe CHange and THe world bank waTer PorTfolio introduction climate.change.poses.risk.to.world.bank.investments.in.the.water.sector..in.order.to.understand. the.magnitude.of.water.challenges.and.the.exposure.of.bank's.investments.to.climate.change,. a.detailed.analysis.of.the.water.portfolio.was.conducted..this.chapter.attempts.to.review.bank's. investments.in.the.water.sector.over.the.period.fiscal.year.2006­2010.and.establish.potential. linkages.to.climate.variability.and.change..more.specifically,.the.objective.of.this.chapter.is.to. assess.the.exposure.of.bank's.water.investment.to.current.hydrologic.variability.and.future.climate. change..to.this.end,.this.chapter.covers.the.following: ·.Assess.the.world.bank's.current.portfolio.and.pipeline.in.the.water.sector,.identifying.the. financing.directed.to.the.different.water.systems.(services.and.resources). ·.Analyze.the.extent.in.which.bank.projects.adopt.measures.with.respect.to.climate.variability. or.climate.change.at.the.project.design.level..the.focus.is.on.adaptation,.but.projects.with. mitigation.measures.were.also.identified. ·.identify.the.exposure.of.bank's.investments.to.the.hydrologic.aspect.of.climate.change. framework for analysis Classification of water systems used for the 2003 Water Resources Sector Strategy is adopted here..this.allows.the.project.lending.information.to.be.disaggregated.into.different. water.systems..A.single.project.may.have.one.or.more.water.systems.assigned.to.it..this.level.of. detail.is.not.available.in.the.bank's.institutional.database,.thus.the.reason.for.this.comprehensive. review..by.definition,.a."system".includes.all.elements.and.components.that.make.it.perform.its. intended.function.under.a.defined.set.of.conditions..this.includes.hardware,.software,.institutions,. and.more..For.the.purposes.of.this.review.and.clarity,.the.definitions.provided.here.are.divided. into.the.physical.(infrastructure).and.institutions.(all.other.aspects).parts..this.will.allow.addressing. the.climate.impact.and.vulnerability.for.each.aspect.separately.while.recognizing.that.the. infrastructure.and.institutional.aspects.of.a.system.are.inseparable. The investments in the water sector are divided into two major categories/systems: those that help deliver services and those that manage the resource..Figure.6.1.shows.the. classification.of.water.systems.used.in.this.review..the.reason.for.this.categorization.is.that.impact. of.climate.change.on.services.delivery.systems.is.expected.to.be.different.from.systems.designed. for.management.of.the.resources..the.same.is.true.for.adaptation.options.that.may.be.selected.. naturally,.the.exposure.to.climate.change.and.the.need.for.adaptation.are.more.pronounced.the. longer.the.lifetime.of.the.infrastructure. The Project Appraisal Document (PAD) was reviewed in detail for each project in order to identify the different water systems and allocate the costs to each system..when.the. PAd.was.not.available.(which.was.the.case.in.some.pipeline.projects),.the.Project.information. document.(Pid).or.the.integrated.safeguard.data.sheet.was.used.for.cost.allocation..in.order.to. ensure.consistency.with.the.total.lending.of.the.sector,.the.total.lending.allocated.to.each.water. system,.with.exception.of.multi-purpose.facilities,.did.not.exceed.that.reported.by.the.bank's. institutional.database..since.multi-purpose.facilities.(e.g..dams,.hydropower).are.not.captured. 63 Figure 6.1 Classification of water systems Irrigation and Drainage Water Services Urban Water and Sanitation Rural Water and Sanitation Water Projects Flood Control Water Resources Management Water Resources Watershed Management Multi-purpose facilities automatically.in.the.bank's.institutional.database,.additional.lending.was.allocated.to.the.total. water.lending..For.projects.in.the.pipeline.with.limited.information,.the.project's.file.(in.the. operations.Portal).was.examined.to.obtain.more.information.about.the.project..in.some.cases,.the. project.task.manager.was.contacted.for.additional.information. The global water challenges bring increasing demands for World Bank engagement in developing countries..in.2003,.the.board.of.directors.of.the.bank.approved.a.water.resources. sector.strategy.which.delivered.several.key.messages.regarding.the.sector..As.part.of.this.strategy,. an.assessment.of.the.world.bank.water.portfolio.was.conducted.to.understand.the.magnitude. of.bank.investments.in.the.water.sector..the.assessment.showed.that.the.composition.and.value. of.water.investments.in.the.bank.are.very.diverse.with.wide.regional.variations.in.the.patterns.of. lending.for.water-related.projects..Following.the.first.assessment.of.the.bank's.water.portfolio,.a. similar.review.of.the.bank's.investments.in.water.over.the.period.Fy06­10.is.made.with.focus.on. potential.linkages.to.climate.variability.and.change..the.objective.of.this.assessment.is.to.determine. the.extent.to.which.the.bank's.water.portfolio.is.exposed.to.hydrologic.variability.and.change,.and. whether.potential.actions.to.mitigate.the.negative.impacts.have.been.considered.in.project.design. Content of the water portfolio The composition of the World Bank investments in water is very diverse with wide regional variations in the lending for water projects..For.the.Fy06­08.period,.water. investments.were.committed.in.83.countries.across.the.six.regions.of.the.bank.(Figure.6.2.and. Figure.6.3). The World Bank's water portfolio selected for this review consists of 191 active projects approved in FY06­08 with total net commitments of $8.8 billion..For.approvals.in.Fy06­08,. the.water.lending.represents.11%.of.the.total.world.bank's.investments.(Figure.6.4)..the.regions. that.invested.the.most.in.water.relative.to.their.total.wb.regional.investment.are.mnA.(14%).and. sAr.(14%).and.the.region.that.invested.the.least.is.lcr.(8%)..on.a.yearly.basis,.the.share.of.water. 64 Figure 6.2 Location of World Bank water projects for FY06­08 (active) and FY09­10 (pipeline) Figure 6.3 World Bank water lending volume (shading) and class (bar) for FY06­08 lending.relative.to.the.overall.world.bank's.investments.has.increased.from.8%.in.Fy06.to.12%.in. Fy08..yearly.average.water.lending.for.the.Fy06­08.period.amounts.to.$2.9.billion..A.pipeline.of. projects.with.expected.approvals.in.Fy09­10.consists.of.220.projects.corresponding.to.a.volume. of.us$11.3.billion20.(Figure.6.5). 20 Pipelineresultsshouldbeconsideredwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthe preparationphaseoftheproject. 65 AFR region has led the lending Figure 6.4 Water lending as a share of overall regional in water with a total of $2 lending in the FY06­08 billion for the past three fiscal years (24% of Bank's overall 20 water investments) consisting of 52 active projects..the. Water Lending Share (%) second.largest.share.of.water. 15 commitments.is.in.sAr.(23%). corresponding.to.28.projects,. followed.by.eAP.(19%),.ecA.(14%). 10 and.lcr.(13%)..mnA.region. accounts.for.the.smallest.share. both.in.terms.of.investments.(7%). 5 and.number.of.projects.(8%).as. shown.in.Figure.6.6. 0 AFR EAP ECA LCR MNA SAR Bank- The water portfolio continues to wide be dominated by projects that primarily deliver water services (Figure.6.7)..For.the.Fy06­08. period.lending.for.water.services. Figure 6.5 World Bank's water lending and number of prevails.over.water.management. projects for FY06­08 and FY09­10 not.only.in.volume.(70%).but.also. 12 in.number.of.projects.(63%)..it.is. 200 important.to.note.that.investments. 10 towards.water.services.exceed. investments.in.water.resources. 150 8 No. of Projects for.all.bank.regions..For.the. US$ billion active.period,.a.good.portion.of. 6 the.lending.in.water.resources,. 100 is.going.to.AFr.($926.million),. 4 followed.by.sAr.($703.million). 50 and.eAP.($364.million).regions..in. 2 terms.of.project.number,.there.is.a. similar.trend.with.AFr.accounting. 0 0 for.the.largest.share.(26%).of. AFR EAP ECA LCR MNA SAR Total water.resources.systems..similar.to. water.resources,.the.three.regions. with.the.largest.investment.in.water.services.systems.are.eAP.($1,327.million),.sAr.($1,241. million).and.AFr.regions.($1,128.million)..in.terms.of.number.of.projects,.lcr.(24%).leads.with. the.most.number.of.projects.with.water.services.systems.closely.followed.by.AFr.(23%). Urban water supply and sanitation active projects account for almost half of the total investments (45%) for the FY06­08 period..this.pattern.is.seen.in.all.regions,.except.for.sAr,. where.irrigation.and.drainage.systems.dominate.investment.in.the.region..the.second.largest.share. of.investments.is.in.multi-purpose.facilities.(17%).followed.by.irrigation.and.drainage.(16%),.and. rural.water.and.sanitation.(10%)..A.small.percentage.of.the.total.commitments.are.directed.towards. other.water.systems.such.as.flood.control.(6%),.water.resources.management.(6%),.and.watershed. management.(1%)..it.is.of.relevance.to.mention.that.most.of.investments.in.multi-purpose.systems. 66 in.the.Fy06­08.period.are.in.AFr. Figure 6.6 Regional distribution of the World Bank water (48%).and.sAr.(38%),.and.most. lending for the FY06­08 of.the.investments.in.irrigation.and. drainage,.and.rural.water.are.in. MNA sAr.(49%.and.31%.respectively). LCR 7% 13% The pipeline21 follows a SAR ECA 23% similar pattern with regards to 14% distribution of lending by water systems. Projects involving EAP delivery of water services are 19% AFR 24% expected to constitute nearly 70% of the total lending in the pipeline..Following.the.historical. trend,.urban.water.supply.and. sanitation.systems.are.expected.to.lead.in.terms.of.lending.volume.(48%).while.irrigation.and. drainage.and.multi-purpose.facilities.are.also.expected.to.account.for.a.considerable.portion.of.the. pipeline.(16%.and.13%.respectively)..the.pipeline.shows.growth.in.investments,.with.the.average. yearly.lending.expected.to.almost.double.compared.to.the.Fy06­08.period..most.regions.are. projected.to.have.an.increase.in.water.investments,.notably.the.lcr,.eAP.and.sAr.regions..Although. AFr.is.showing.a.small.percentage.decrease.in.terms.of.water.investments.(yearly.average).for. Fy09­10,.there.is.a.considerable.increase.in.terms.of.number.of.projects.per.year..the.largest.share. of.projects.in.the.pipeline.is.in.AFr.(25%),.followed.by.lcr.(23%).and.eAP.(19%).regions. Climate change content of the portfolio Adaptation to climate change in the portfolio The portfolio and the pipeline were reviewed to determine whether hydrologic variability and climate change actions are considered and if so, to what degree incorporated into Figure 6.7 Lending distribution in water services and water resources for the FY06­08 Water Services FY06­FY08 Water Resources LCR MNA LCR MNA 9% 3% 15% 9% Water ECA Resources 12% SAR $2,620m SAR ECA 20% (30%) 27% 15% EAP Water Services 14% EAP AFR $6,153m AFR 23% 18% (70%) 35% 21 Pipelineresultsshouldbeconsideredwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthe preparationphaseoftheproject. 67 the design of projects..this.review.does.not.attempt.to.assess.the.efficacy.of.those.interventions,. but.rather,.attempts.to.give.a.general.idea.of.whether.climate.change.is.reflected.in.the.current.and. future.portfolio.of.the.water.sector..climate.interventions.are.identified.and.distinguished.between. mitigation.and.adaptation.measures..Adaptation.is.further.classified.in.two.broad.categories--`no. regret'.and.`climate-justified',.and.further.grouped.into.several.areas.of.intervention. Review of the portfolio suggests an increasing level of attention to climate change. the.review.of.water.projects.for.inclusion.of.mitigation.and.adaptation.measures.yielded.the. following.results..of.191.active.projects.approved.in.Fy06­08,.35%.(67.projects).considered. strategies.to.reduce.the.impacts.of.climate.variability.and.change,.including.adaptation.and/or. mitigation.measures..of.the.67.projects.with.some.strategy,.58%.are.related.to.adaptation,.31%. related.to.mitigation.and.10%.related.to.both. Water sector projects are primarily focused on adaptation..For.the.active.portfolio,.20%.of. the.projects.addressed.climate.variability.and.change.through.adaptation.measures..on.average,. there.were.13.projects.with.potential.adaptation.actions.each.year.for.the.Fy06­08.period,.with. a.promising.growth.expected.for.the.Fy09­10.period..of.the.20%.of.projects.taking.adaptation. measures,.it.is.important.to.note.that.these.measures.address,.for.the.most.part,.strategies.to. reduce.vulnerability.to.climate.variability.more.than.looking.at.the.long-term.effects.of.climate. change..of.the.total.number.of.projects.at.the.regional.level,.lcr.had.the.largest.portfolio.with. adaptation.measures.(28%).followed.by.sAr.(25%).and.mnA.(25%).(Figure.6.8)..the.pipeline. shows.an.increased.attention.to.the.adaptation.agenda.for.most.regions,.with.mnA.and.eAP.in. the.forefront.in.terms.of.considering.adaptation.measures.in.their.overall.pipeline.of.projects.. Although.mnA.shows.a.high.percentage.of.adaptation.measures.in.the.active.portfolio.and. pipeline,.the.total.number.of.projects.(with.and.without.adaptation).is.very.low.compared.to. other.regions..overall,.there.is.clearly.a.higher.level.of.awareness.among.the.bank.and.client. countries.towards.climate.change.and.climate.variability.issues..note.that.the.pipeline.results. should.be.viewed.with.caution.as.there.is.some.degree.of.volatility.with.regards.to.approval.dates,. commitment.amounts,.etc. The mitigation agenda is more visible in the energy sector than the water sector, but increasing Figure 6.8 Projects with potential adaptation measures (%) attention is given to how the 50 sector can contribute to the reduction of greenhouse gases.. of.the.total.active.portfolio,.11%.of. 40 the.actions.were.aiming.at.reducing. % Water projects greenhouse.gas.emissions..only. 30 projects.in.which.the.role.of.low. carbon.technology,.as.well.as. 20 the.reduction.of.greenhouse.gas. emissions,.are.explicitly.mentioned. in.the.documents.are.classified. 10 here.as.mitigation.projects..many. mitigation.strategies.are.also.linked. 0 to.adaptation,.such.as.the.case.of. AFR EAP ECA LCR MNA SAR Bank- wide some.hydropower.projects..some. FY06­08 (Active) FY09­10 (Pipeline) examples.of.mitigation.measures. 68 identified.are.improvement.of.energy.efficiency.of.water.supply.systems.(e.g..replacing.pumps),. wastewater.treatment.technologies.to.reduce.methane.emissions,.mangrove.carbon.sequestration,. methane.collection.in.anaerobic.lagoons,.restoration.of.natural.drainage.regime.for.carbon. sequestration,.and.so.on..the.reduction.of.carbon.emissions.in.these.projects.is.for.the.most.part. linked.to.carbon.finance.investments,.which.is.a.strong.business.at.the.bank. The portfolio shows two broad categories of actions: `no regret' and `climate justified'.. many.of.the.actions.to.reduce.vulnerability.to.climate.variability.are.no.different.in.a.world.with. climate.change.than.they.are.in.a.world.without.it..these.actions.are.called.`no.regret'.and.some. examples.include.reform,.institutional.and.infrastructure.measure.to.increase.water.use.efficiency. and.productivity,.such.as.water-conserving.irrigation.technologies;.increased.water.availability. through.storage.and.better.management.of.bulk.water;.wastewater.recycling;.economic.incentives,. including.pricing;.and.the.encouragement.of.water.markets.that.move.water.to.high-valued.uses.. these.options.carry.`no.regrets'.in.that.they.would.go.a.long.way.in.confronting.the.climate. change.challenges,.yet.they.are.by.definition.justifiable.even.under.expected.climatic.conditions. without.anthropogenic.climate.change..on.the.other.hand,.other.actions.might.be.justifiable.under. conditions.of.anthropogenic.climate.change..`climate-justified'.actions.include.those.taken.solely. for.the.purpose.of.adapting.or.coping.with.such.impacts..those.typically.include.constructing.new. infrastructure.(dams,.underground.storage,.irrigation.systems),.retrofitting.existing.infrastructure,. changing.rules.of.operation,.tapping.new.sources.of.water,.water.transfers,.conjunctive.use.of. surface.and.groundwater,.innovative.demand.management,.etc..it.should.be.noted.that.some.of. these.action.types.may.be."no.regret".in.one.set.of.circumstances.and."climate.justified".in.another. The review shows strong emphasis on `no regret' actions, with 67% of the adaptation projects adopting measures that meet current economic, social and environmental objectives but also serve the dual purpose of reducing vulnerability to climate change.. At.the.regional.perspective,.most.of.the.`no.regret'.actions.are.in.AFr.and.lcr..the.pipeline. follows.the.same.pattern,.with.`no.regret'.actions.prevailing.over.`climate-justified',.and.showing. a.distribution.of.actions.prevailing.in.AFr,.eAP.and.lcr. `Climate-justified' actions are less predominant in the portfolio, representing 33% of the adaptation projects, or 8% of all active projects..For.the.Fy06­08.period,.most.of.these. actions.were.concentrated.in.lcr.and.eAP ..examples.of.actions.include--mainstreaming.climate. change.considerations.in.public.policy;.institutional.consolidation.of.flood.control.for.a.medium. and.long-term.intervention.strategy.(to.help.the.country.adapt.to.sea.level.rise);.implementation. of.pilot.adaptation.measures.for.wetland.restoration.strategies,.implementation.of.climate.resilient. measures.such.as.rainwater.harvesting,.creating.better.capacity.and.awareness.among.farmers. for.adoption.of.new.techniques.for.coping.with.the.effects.of.climate.change;.among.others..the. pipeline.shows.a.larger.percentage.of.projects.with.`climate-justified'.measures,.most.of.which.are. in.lcr,.sAr,.and.eAP . Types of Adaptation Interventions as Identified in the Portfolio Building resilience to current climate variability or adapting to future climate change will require interventions in several areas..some.of.the.overarching.areas22.highlighted.in.this. review.are:.policy/institutions,.management/operations,.infrastructure,.technology/innovation,. 22 Categoriesidentifiedfromabroadrangeofspecificactionstofacilitatepresentationandutilizationofreport.Theseareconsistent categoriesfoundinpublicliterature.Thesecategoriesarenotexhaustive. 69 capacity.building/awareness.and. Figure 6.9 Types of climate change interventions monitoring/information.systems. (Figure.6.9)..to.increase.water. Type of Intervention security.stronger.institutions. are.needed,.as.well.as.more. Policy/Institution Technology investments.in.infrastructure.(small. and.large),.and.new.technologies. Water Management Monitoring/Information systems for.increasing.water.use. efficiency..moreover,.better.water. Infrastructure Capacity building management.and.operations,. awareness coupled.with.stakeholders.capacity. building.and.enhanced.monitoring. and.information.systems,.are.also. essential.elements.for.adapting.to.climate.change. For the active and the pipeline23 periods, policy/institution interventions dominate with 27% and 33% of the adaptation actions respectively (Figure 6.10)..Projects.with.these. interventions.are.mostly.concentrated.in.AFr,.lcr.and.sAr.for.the.active.period..these.involve. institutional.strengthening.and.capacity.for.multi-sectoral.planning,.development.and.management. of.water.resources..more.specifically,.these.actions.support.policy,.legal.and.regulatory. environment.for.the.efficient.and.sustainable.management.of.water.resources..in.some.cases,.the. institutional.interventions.are.more.specific.to.climate.as.to.developing.climate.change.policy.or. adaptation.strategies..Having.strong.institutions.with.the.right.institutional.framework.is.a.first.step. towards.adapting.to.changes.in.climate. Specific examples of adaptation options in the portfolio with policy/institution intervention are listed below without any particular preference on ranking: ·.consolidate.and.improve.water.resource.management.and.policy.through.institutional. strengthening.and.improved.planning,.regulation.and.financing.instruments. ·.strengthen.the.institutional.and.policy.development.capacity.of.the.water.agency.within.an. integrated.water.resources.management.framework.by.preparing,.enhancing.and.implementing. water.basin.plans. ·.improve.institutional.capacity.for.basin-scale,.participatory,.integrated.wrm.for.the.newly. created.national.water.Authority,.and.formulate.a.national.strategy.for.water.quality. management. ·.strengthen.institutional.capacity.for.managing.shared.trans-boundary.natural.resources. ·.institutional.consolidation.of.flood.control.to.create.a.consensus.around.a.medium.and.long. term.intervention.strategy.to.adapt.to.sea.level.rises. ·.strengthen.institutional.capacities.to.reduce.vulnerability.to.the.natural.and.manmade.hazards. and.to.limit.losses.due.to.disasters. ·.mainstream.climate.change.considerations.in.public.policy.as.part.of.the.national.climate. change.strategy. Interventions related to management/operations are the second highest share for both periods, with AFR, ECA and LCR in the forefront in terms of adopting management 23 Thepipelineresultsshouldbeconsideredwithcautionandviewedasillustrative,astherearemanyprojectsforwhichdocumentswere notavailableinthesystem. 70 instruments or tools for the effective operation and management of water systems.. more.specifically,.projects.with.these.actions.include.implementation.of.economic.incentives. such.as.water.markets,.water.pricing;.conjunctive.management.of.groundwater.and.surface. water;.watershed.and.flood.management.planning,.etc..A.wide.range.of.demand-side/supply- side.management.measures.are.considered.which.will.help.address.the.quality.and.availability. of.water.resources,.its.efficient.and.equitable.allocation.to.the.various.end-users,.and.help. reduce.the.vulnerability.to.extreme.climatic.events.and.long-term.climate.change..it.is.worth. mentioning.that.many.projects.adopted.integrated.water.resources.management.(iwrm). frameworks..iwrm.is.an.effective.way.to.position.water.issues,.address.water.quality.and. quantity.aspects.at.the.policy.and.local.level,.and.at.the.same.time.play.a.major.role.in.aiding. societal.adaptation.to.climate.change..iwrm.will.likely.decrease.the.vulnerability.of.freshwater. systems.to.climate.change. Specific examples of management/operations interventions extracted from the portfolio are listed below without any particular preference on ranking: ·.implement.improved.water.management.practices,.including.bench.marking,.administration.of. water.entitlements,.and.bulk.supply.of.water.to.users. ·.Participatory.and.integrated.ecosystem.management.by.carrying.out.programs.to.implement. integrated.watershed.and.wetlands.management.strategies. ·.restore.operational.performance.and.safety.of.dams. ·.develop.and.strengthen.key.wrm.instruments.such.as.the.formulation.of.a.detailed.participatory. and.integrated.wrm.plans.for.basins,.bulk.water.distribution.models.and.decision.aid.tools. ·.optimize.water.resource.utilization.and.enforce.water.use.rights. ·.implement.conjunctive.management.of.groundwater.and.surface.water. ·.invest.in.watershed.development.and.flood.management.for.climate.resilience. ·.increase.water.flows.in.rivers.through.conservation.of.the.paramos.ecosystem.and.its.associated. vegetation. ·.implement.cyclone.risk.mitigation.investments.through.mangrove.plantations.and.coastal.zone. management.works. ·.develop.new.sustainable.financing.mechanisms.for.the.payment.of.environmental.services. (watershed.conservation).through.water.tariff. Infrastructure interventions are also represented in the active and pipeline projects with most interventions in LCR, SAR, EAP and AFR..water.infrastructure.is.defined.by.the. rehabilitation,.optimization.and.development.of.small.and.large.hydraulic.infrastructure.to. improve.the.management.of.water.resources.and.delivery.of.water.services.by.making.the. systems.more.resilient.to.the.changes.in.climate..some.examples.include--retrofitting.existing. infrastructure;.developing.multi-purpose.storage.and.attenuation.structures;.creating.long-term. structural.solutions.to.flooding;.rehabilitation.of.irrigation.schemes,.etc..it.is.important.to.note.that. infrastructure.rehabilitation.for.projects.categorized.as.recovery.or.emergency.operations.are.not. included.in.this.class. Specific examples of infrastructure interventions extracted from the portfolio are listed below without any particular preference on ranking: ·.rehabilitate.and.modernize.water.infrastructure.(irrigation,.hydropower,.etc). ·.create.long-term.structural.solutions.to.flooding,.including.the.construction.of.substantial.multi- purpose.storage.and.attenuation.structures. 71 ·.develop.hydropower.resources.in.an.environmentally.sustainable.and.socially.responsible.manner. ·.build.long-term.preparedness.by.supporting.cyclone-resistant.infrastructure.rehabilitation,. livelihood.restoration.and.vulnerability.reduction. ·.support.the.construction.and/or.installation.of.storage/conveyance.structures.and.distribution. networks.to.optimize.the.storage,.delivery,.and.use.of.water.supplies. ·.build.water.harvesting.infrastructures,.including.valley.dams.and.reservoirs,.and.hillside.irrigation. infrastructure. ·.develop.groundwater.infrastructure.in.a.sustainable.manner. ·.develop.small-scale.storage.structures,.crop.diversification.and.water.harvesting.for.farmers. Capacity building and awareness are also important elements for the effective management and decision making of water resources, as well as for adaptation to climate change. with.most.interventions.in.AFr,.lcr,.eAP.and.sAr,.these.actions.will.build.local.capacity. and.raise.awareness.for.water.users.and.communities.about.how.they.can.play.an.expanded.role. in.the.management.and.decision.making.of.water.resources.and.adaptation.to.climate.change.. this.is.achieved.by.building.local.capacity;.empowering.water.users.and.water.users'.associations;. engaging.communities.in.the.decision.framework,.offering.trainings,.and.implementing.awareness- raising.campaigns.at.the.community.and.user.level.to.promote.greater.responsibility.in.managing. water.resources.in.view.of.the.changing.climate.conditions. Specific examples of this type of intervention taken from projects in the portfolio are given below without any particular preference on ranking: ·.technical.assistance.for.water.sector.capacity.building.to.carry.out.water.resources.investment. planning. ·.increase.climate.change.adaptation.awareness.of.water.user.associations,.technical.staff,.and. officials. ·.increase.civil.society.participation.in.the.decision.making.process.for.water.resource. management. ·.empower.water.users.and.strengthen.water.user.associations.in.order.to.enhance.their. capacities,.and.carry.out.necessary.operation,.maintenance.and.cost.recovery.functions. ·.Promote.participation.of.local.governments,.concerned.agencies.and.stakeholders.in.improving. flood.management.plans. ·.engage.communities.in.co-management.of.water.and.forest.resources. ·.create.a.participatory.approach.to.sustainable.watershed.management.by.formation.of. community.associations.to.manage.watershed.conservation.plans. , With a moderate representation in the portfolio, EAP SAR and ECA are the regions that have invested the most in monitoring and information systems..Monitoring and information system interventions are vital actions to better forecast and monitor hydrological variability in water systems for the efficient, sustainable and equitable management of water resources and adaptation to climate change. Actions.include. the.development.and.improvement.of.water.resources.information.systems.with.monitoring,. modeling.and.prediction.capabilities,.weather.forecasting,.hydro-meteorological.data. collection,.early.flood.warning.and.response.systems,.etc..Any.action.involving.analysis.of. hydrological.trends.and.improvement.in.the.accuracy.of.forecasting.methods.is.key.for.effective. management.of.water.systems.and.for.the.design.of.new.ones..this.type.of.intervention.is. essential.for.long-term.planning,.and.especially.for.detecting.and.quantifying.the.impacts.of. climate.change. 72 Figure 6.10 Type of intervention for projects in FY06­08 and FY09­10 FY06­08 FY09­10 Capacity Bldg and Monitoring and Capacity Bldg and Monitoring and Awareness Information System Awareness Information System 15% 12% 15% 9% Technology/ Technology/ Policy/ Innovation Innovation Institution 8% Policy/ 11% 27% Institution 33% Management/ Infrastructure Management/ Infrastructure 11% 16% Operations Operations 19% 24% Specific examples on Monitoring/Information System interventions extracted from the portfolio are listed below, without any particular preference on ranking: ·.upgrade.flood.and.storm.monitoring;.modeling.and.forecasting.capabilities;.and.enhance.early. warning.and.response.systems. ·.strengthen.capacity.in.data.analysis,.mapping.and.vulnerability.assessments. ·.strengthen.water.quality.monitoring.laboratories. ·.develop.hydro-meteorological.forecasting.systems. ·.develop.vulnerability.and.ecological.mapping.(including.vulnerability.to.flood.and.erosion),.and. create.demarcation.of.hazard.zones.susceptible.to.natural.disasters.and.flooding. ·.establish.a.telemetry.system.for.real-time.measurement.of.water.availability. Technology as an adaptation measure has much unexploited potential for scaling up..the. adaptation.interventions are.more.prominent.in.AFr,.eAP.and.lcr.with.a.wide.variety.of.measures. aiming.to.increase.water.use.efficiency,.or.incorporation.of.new.technologies.to.make.water. systems.more.resilient.to.climate.variability.and.change..some.examples.include.the.adoption.of. water.saving.technologies.such.as.treated.wastewater.reuse,.water.harvesting,.evapo-transpiration- based.water.resources.planning,.or.any.other.innovative.measure.to.increase.water.use.efficiency.. some.technologies.are.applied.at.the.pilot.level.for.later.implementation.at.a.larger.scale. Specific examples of technology interventions extracted from the portfolio are listed below without any particular preference on ranking: ·.develop.water-saving.technologies.(e.g..drip.irrigation). ·.Promote.treated.wastewater.reuse.in.irrigation.on.a.sustainable.basis. ·.improve.irrigation.systems.by.enhancing.water.use.efficiency.in.tank.areas. ·.develop.improved.irrigation.technology.including.pressurization.of.surface.flows.to.replace. groundwater. ·.Adopt.evapotranspiration.measuring.technology. ·.Adopt.soil.and.water.conservation.technologies. ·.develop.water.harvesting.techniques. 73 74 CHaPTer 7: exPosure of THe waTer PorTfolio To CurrenT HydrologiC variabiliTy and fuTure ClimaTe CHange introduction The World Bank's investments in the water sector are highly exposed, both to current variability and future climate change..the.purpose.of.this.assessment.is.to.provide.some.sense. of.magnitude.of.the.exposure.of.the.projects.and.the.financial.investments.they.represent..results.of. the.projections.of.the.hydrologic.drivers.for.2030.and.2050,.discussed.earlier,.are.used.to.assess.the. exposure.of.the.portfolio..in.this.chapter,.investment.exposure.to.the.impact.of.climate.change.for.the. following.water.systems.is.assessed:.irrigation.and.drainage,.urban.water.supply.and.sanitation,.rural. water.supply.and.sanitation,.flood.control,.river.basin.management,.and.multi-purpose.(supply.water. for.multiple.purposes). Risk is generally defined as the product of probability and consequence..given.that.the. probabilities.of.occurrence.of.different.climate.change.scenarios.are.not.known,.a.formal.risk.assessment. cannot.be.carried.out..rather,.an.evaluation.of.the.impacts.of.climate.change.on.bank.investments.is. carried.out.in.terms.of.changes.in.hydrologic.indicators.and.changes.in.the.level.of.exposure.of.the. investments.to.these.indicators..in.this.context,.exposure.is.loosely.equated.to.consequence. For this assessment the A1B emissions scenario is chosen..this.scenario.is.suggested.by. many.to.be.the.closest.to.a."business.as.usual.future"..Additionally.it.is.the.middle.range.of. emissions.and.resulting.global.mean.temperature.of.all.the.Ar4.sres.scenarios.as.discussed. earlier..given.that.the.interest.here.is.a.broad.overview.of.the.potential.exposure.of.world.bank. infrastructure.projects.particularly.those.with.the.life.extending.to.2050,.the.A1b.scenario.provides. the.central.tendency.of.scenarios.to.the.year.2050..Additionally.all.the.scenarios.are.tightly. bunched.until.2050.where.at.that.point.they.start.to.diverge.greatly. Hydrologic indicator selected for assessment of each water system is given in Table 7.1.. these.indicators.have.been.defined.earlier.in.connection.with.the.projections.analysis..An.indicator. has.been.chosen.to.represent.each.water.system.as.listed.below. Table 7.1 List of water systems and indicators Water System Indicator irrigation.and.drainage change.in.annual.net.irrigation.deficit urban.water.supply.and.sanitation change.in.runoff.reliability rural.water.supply.and.sanitation change.in.minimum.base.flow Flood.control change.in.runoff.reliability river.basin.management.and.multi-purpose.infrastructure change.in.basin.yield exposure criteria and investment exposure Each water sector is given an exposure level based on an agreed exposure criteria.. For.the.current.variability.analysis,.the.exposure.level.represents.the.water.sector's.exposure.to. current.variability..For.the.future.exposure.analysis,.the.exposure.level.represents.the.water.sector's. 75 exposure.to.climate.change.and.future.variability..the.exposure.criteria.is.categorized.as.low,. medium.or.high..A.low.exposure.level.means.that.there.is.little.to.no.concern.about.the.water. sector's.exposure.to.current/future.climate.variability/change,.where.a.high.exposure.level.means. that.there.is.an.immediate.concern..A.medium.exposure.level.means.that.there.is.some.concern. and.further.analysis.is.necessary..the.ranges.for.the.low,.medium,.and.high.exposure.level. classifications.were.determined.for.each.indicator. Exposure of the World Bank's investment portfolio to future climate change is evaluated using the exposure level for each system and placing the investment (lending) value on that exposure..the.investment.exposure.is.calculated.by.multiplying.the.cost.of.each.project.allocated.to. the.water.system.times.the.number.of.gcm.results.that.fall.into.each.of.the.three.exposure.criteria-- low.medium,.or.high..results.for.each.exposure.class.were.summed.to.yield.regional.values..the. total.investment.value.for.each.region.is.the.sum.of.the.cost.of.each.water.system.in.each.project. Results of current and future exposure to variability and climate change are reported by World Bank regions and Bank-wide..the.exposure.is.represented.as.low,.medium,.or.high. as.previously.discussed..results.of.investment.portfolio.exposure.are.by.water.system,.world. bank.regions.and.the.world.bank.as.one.region..the.investment.portfolio.exposure.is.reported. as.monetary.amounts..Future.exposure.based.on.climate.change.is.reported.for.2030.and. 2050..these.years.were.chosen.because.they.represent.times.in.the.future.that.are.important. for.current.infrastructure.planning.intersected.with.the.expected.realization.of.potential.climate. change.impacts..For.this.analysis,.reporting.changes.in.2030.relative.to.historical.is.the.decadal. average.from.2025.to.2035.relative.to.the.average.historical..this.is.also.true.for.reporting.2050;. represented.by.the.average.from.2045.to.2055.relative.to.the.average.historical. exposure to current hydrologic variability and future climate change For each project on the review list, an approximate latitude and longitude was estimated based on the information available in the project documents..For.projects.with.multiple. locations,.only.one.location.was.selected.based.on.the.size.of.the.city.or.population.and.its. proximity.to.the.water.source..each.project.was.then.mapped.to.a.0.5.degree.by.0.5.degree. grid.on.the.globe..the.percentage.change.of.the.related.hydrologic.indicator.for.the.projected. hydrologic.variables.for.2030.and.2050.was.also.mapped.on.the.same.grid.as.the.project. location.for.assessment.of.the.exposure..Assessment.of.exposure.for.each.water.system.for.each. region.is.described.and.the.results.reported.in.the.subsequent.sections. A word on the limitation of this approach..it.should.be.noted.that.this.analysis.is.focused.on.the. future.changes.of.the.mean.of.the.hydrologic.drivers.only,.as.they.are.derived.from.the.mean.runoff. projections..in.many.cases.the.future.changes.of.variability.in.runoff.may.be.much.more.important.than. the.change.in.the.mean..many.projections.show.increases.in.variability.which.lead.to.more.extreme. events..For.example,.a.10%.change.in.runoff.variance.may.be.much.more.important.(potentially.many. times.more.damage).than.a.10%.change.in.the.mean.runoff..evaluating.the.impacts.of.variability.on. investments.is.outside.the.scope.of.this.analysis,.but.should.be.highly.considered.for.future.work. Irrigation and drainage Irrigation and drainage is represented by the change in annual net irrigation deficit..this.is. determined.using.the.water.deficit.index.(wdi).which.is.the.difference.between.the.precipitation.and. crop.water.requirement..table.7.2.shows.the.criteria.used.to.assess.the.levels.of.exposure..Figure.7.1. 76 shows.the.exposure.map.for.2030.for.the.middle.projection.for.all.bank.regions..Figure.7.2.shows. exposure.map.for.2030.and.2050.for.the.driest,.middle,.and.wettest.projections.for.the.Africa.region. Table 7.2 Irrigation and drainage exposure level descriptions Exposure Level Description low %.change.in.annual.water.deficit.index.<.5% medium %.change.in.annual.water.deficit.index.between.5%.and.15% High %.change.in.annual.water.deficit.index.>15% Urban water supply and sanitation Urban water supply and sanitation is represented by the change in runoff reliability.. runoff.reliability.is.determined.using.a.flow.duration.(frequency).curve.(Fdc)..A.Fdc.is. generated.by.plotting.the.percentage.of.time.that.a.flow.rate.is.greater.than.or.equal.to.a. given.flow.rate..this.indicator.is.taken.as.the.flow.that.is.exceeded.90%.of.the.time.(q90). which.means.there.is.a.10%.chance.in.each.time.period.of.a.flow.lower.than.this..if.this.q90. decreases.it.means.that.the.likelihood.of.low.flows.and.droughts.will.likely.increase..table.7.3. shows.the.criteria.used.to.assess.the.levels.of.exposure..Figure.7.3.shows.the.exposure.map.for. 2030.for.the.middle.projection.for.all.bank.regions..Figure.7.4.shows.the.exposure.map.for. 2030.and.2050.for.the.driest,.middle,.and.wettest.projections.for.the.Africa.region. Table 7.3 Urban water supply and sanitation exposure level description Exposure Level Description low %.change.in.runoff.reliability(­90%).>­5% medium %.change.in.runoff.reliability(­90%).between.­5%.and.­15% High %.change.in.runoff.reliability(­90%).<­15% Rural water supply and sanitation Rural water supply and sanitation is represented by change in minimum base flow as a proxy for groundwater availability..it.is.assumed.that.the.groundwater.contribution.to.runoff. can.be.model.as.a."linear.reservoir".where.base.flow.is.combination.of.a.groundwater-surface. water.interaction.coefficient.multiplied.by.the.groundwater.storage.in.the.month..table.7.4.shows. the.criteria.used.to.assess.the.levels.of.exposure..Figure.7.5.shows.the.exposure.map.for.2030. Table 7.4 Rural water supply and sanitation exposure level description Exposure Level Description low %.change.in.minimum.base.flow.>­5% medium %.change.in.minimum.base.flow.between.­5%.and.­15% High %.change.in.minimum.base.flow.<­15% 77 for.the.middle.projection.for.all.bank.regions..Figure.7.6.shows.the.exposure.maps.for.2030.and. 2050.for.the.driest,.middle,.and.wettest.projections.for.the.Africa.region. Flood Control Flood control is represented by the change in runoff reliability..runoff.reliability.is. determined.using.a.flow.duration.(frequency).curve.(Fdc)..A.Fdc.is.generated.by.plotting.the. percentage.of.time.that.a.flow.rate.is.greater.than.or.equal.to.a.given.flow.rate..this.indicator. is.taken.as.the.flow.that.is.exceeded.10%.of.the.time.(q10).which.means.there.is.a.90%.chance. in.each.time.period.of.a.flow.lower.than.this..if.this.q10.increases.it.means.that.the.likelihood. of.higher.flows.and.floods.will.likely.increase. table.7.5.shows.the.criteria.used.to.assess.the.levels.of.exposure..Figure.7.7.shows.the.exposure. map.for.2030.for.the.middle.projection.for.all.bank.regions..Figure.7.8.shows.the.exposure.maps. for.2030.and.2050.for.the.driest,.middle,.and.wettest.projections.for.the.Africa.region. Table 7.5 Flood control exposure level description Exposure Level Description low %.change.in.runoff.reliability(-10%).<5% medium %.change.in.runoff.reliability(-10%).between.5%.and.15% High %.change.in.runoff.reliability(-10%).>15% River basin management and multi-purpose infrastructure River basin management is represented by the change in basin yield..the.basin.yield.is. a.measure.of.annually.reliable.water.supply.from.the.basin..basin.yield.is.directly.related.to.the. amount.of.reservoir.storage.in.a.basin..A.storage-yield.curve.is.used.to.mathematically.represent. the.basin.yield..table.7.6.shows.the.criteria.used.to.assess.the.levels.of.exposure. Figure.7.9.shows.the.exposure.map.for.2030.for.the.middle.projection.for.all.bank.regions..Figure. 7.10.shows.the.exposure.maps.for.2030.and.2050.for.the.driest,.middle,.and.wettest.projections. for.the.Africa.region. Table 7.6 River basin management exposure level description Exposure Level Description low %.change.in.basin.yield.<5% medium %.change.in.basin.yield.between.5%.and.15% High %.change.in.basin.yield.>15% Note: Historic.yield.=.75%.of.Historical.Annual.runoff 78 Figure 7.1 Projected 2030 exposure map to change in water deficit index Irrigation Deficit Low Medium High Figure 7.2 Projected 2030 and 2050 exposure maps to change in water deficit index ­ Africa Region Low Medium High 79 Figure 7.3 Projected 2030 exposure map to change in low flows (drought) Low Flow Low Medium High Figure 7.4 Projected 2030 and 2050 exposure maps to change in low flows (drought) ­ Africa Region Low Medium High 80 Figure 7.5 Projected 2030 exposure map to change in base flow Base Flow Low Medium High Figure 7.6 Projected 2030 and 2050 exposure maps to change in base flow ­ Africa Region Low Medium High 81 Figure 7.7 Projected 2030 exposure map to change in high flows (floods) High Flow Low Medium High Figure 7.8 Projected 2030 and 2050 exposure maps to change in high flows (floods) ­ Africa Region Low Medium High 82 Figure 7.9 Projected 2030 exposure map to change in basin yield Basin Yield Low Medium High Figure 7.10 Projected 2030 and 2050 exposure maps to change in basin yield ­ Africa Region Low Medium High 83 Potential exposure of the investment portfolio The World Bank's investments in the water sector are highly exposed, both to current variability and future climate change..the.purpose.of.this.assessment.is.to.provide.some. sense.of.magnitude.of.the.exposure.of.the.projects.and.the.financial.investments.they.represent.. using.threshold.criteria.for.changes.in.each.indicator,.maps.were.created.for.high,.medium,. and.low.exposure.categories.for.each.indicator..water.projects,.classified.by.water.systems,.are. superimposed.on.the.appropriate.exposure.map..the.outcome.is.an.exposure.categorization.of. each.water.system.according.to.its.respective.indicator..in.this.analysis,.exposure.to.the.impact.of. climate.change.for.the.following.water.systems.on.the.bank.portfolio.is.assessed:.irrigation.and. drainage,.urban.water.supply.and.sanitation,.rural.water.supply.and.sanitation,.flood.control,. river.basin.management,.and.multi-purpose.(supply.water.for.multiple.purposes)..results.of.the. potential.exposure.of.the.active.bank.water.investments.were.they.to.operate.in.2030.and.2050. are.available. Bar charts on Figures 7.11 and 7.12 show the level of exposure of the Bank water investments to climate change by volume of investment and number of projects by region and Bank-wide..similar.charts,.categorized.by.water.systems,.are.available.for.each.region.and. bank-wide. Projections indicate that about half of the Bank water projects reviewed would potentially be at high to medium level of exposure to climate change impacts in 2030 (Figure 7.11)..within. each.regional.portfolio,.eAP.shows.close.to.two-third.of.projects.with.potential.exposure.to.high/ medium.risk,.possibly.due.to.increased.flooding..AFr.and.lcr.show.about.half.of.the.projects.and. mnA.some.40%.at.potential.high.to.medium.risk.of.exposure..ecA.and.sAr.show.about.one-third.of. the.projects.at.potential.risk.of.exposure.to.hydrologic.changes..Projections.for.2050.show.exposure. increasing.for.all.regions.except.eAP ..obviously,.the.level.of.uncertainty.related.to.projecting.climate. change.so.far.in.time.would.be.too.high.to.make.much.of.this.difference. Figure 7.11 Exposure of water projects to climate change in 2030 and 2050 2030 2050 100 100 80 80 % of water projects % of water projects 60 60 40 40 20 20 0 0 EAP ECA LCR MNA SAR AFR Bankwide EAP ECA LCR MNA SAR AFR Bankwide Low Med High 84 In terms of investments, about half of the total water investments (including the pipeline) are projected at high/medium exposure level to climate change impacts in the 2030 decade (Figure 7.12)..this.translates.to.approximately.$.10.billion.on.the.Fy06­10.water.projects. reviewed.here,.risk.associated.with.approval,.delay,.or.drop.of.pipeline.projects.notwithstanding.. the.pattern.of.risk.of.exposure.of.investment.roughly.follows.that.of.the.projects..For.2050,.climate. change.projections.show.an.increase.in.mnA,.AFr,.lcr,.and.ecA,.while.expected.to.decrease. in.eAP,.and.sAr..Again,.the.uncertainty.associated.with.the.climate.change.projections.in.2050.is. considered.quite.high.and.therefore.this.conclusion.should.be.viewed.with.caution. Figure 7.12 Exposure of water investments to climate change in 2030 and 2050 2030 2050 100 100 80 80 % of water projects % of water projects 60 60 40 40 20 20 0 0 EAP ECA LCR MNA SAR AFR EAP ECA LCR MNA SAR AFR Bankwide Bankwide Low Med High 85 86 CHaPTer 8: risk-based deCision making for `ClimaTe smarT' invesTmenTs introduction There is evidence of an intensification and acceleration of the hydrologic cycle due to climate change, but this is subject to a high degree of uncertainty. Analysis.in.the.previous. chapter.illustrates.the.exposure.of.the.bank's.water.investments.to.the.potential.impact.of. hydrologic.variability.and.climate.change..while.the.best.available.science.was.used,.there.is.still. substantial.uncertainty.regarding.the.real.effects.of.climate.change,.generally,.and.by.extension. on.the.hydrologic.cycle.and.ecosystem.responses..there.have.been.major.advances.in.projecting. impacts--both.from.general.circulation.models.and.downscaling/statistical.methods--which.allows. reporting.general.trends.with.some.degree.of.confidence.(including.in.temperature,.precipitation,. and.extreme.events)..However,.there.are.still.significant.unknowns,.and.even.more.challenging. "unknown.unknowns"..there.is.no.way.around.these.uncertainties.given.the.current.state.of.the. science--even.agreement.on.a.particular.phenomenon.across.multiple.models.does.not.`prove'. that.a.given.projection.will.indeed.come.to.pass. Reducing the water sector's vulnerability to climate change means managing water under conditions of uncertainty. there.are.three.options.for.dealing.with.uncertainties.(i).wait. until.science.is."better".at.making.projections;.(ii).insist.on.pushing.modeling.efforts.to.their. limits,.and.beyond;.and.(iii).take.uncertainty.as.a.given.and.try.manage.it..the.first,.wait.and. see,.approach.could.be.dangerous.and.costly.in.the.longer.run.24.the.second.could.also.be. hugely.risky,.that.is,.such.an.approach.could.lead.to.projections.and.actions.based.on.them.that. are.`precisely.wrong.'.it.is.the.third.that.holds.the.most.promise..this.approach.is.relevant.to.all. sectors,.but.it.is.particularly.so.in.the.case.of.the.water.sector.because.of.the.direct.link.between. climatic.conditions.and.hydrology.and.environmental.sustainability. Water professionals have traditionally dealt with climate variability, but climate-change introduces uncertainties in both the future mean values and variability. water.professionals. have.routinely.dealt.with.natural.climate.variability.(inter.and.intra-annual).and.climate-related. hazards.such.as.droughts.and.floods.in.delivering.water.services.and.managing.water.resources.. but,.they.have.historically.done.so.under.the.key.assumption.of.a.stationary.hydrologic.pattern:. the.mean,.variance.and.standard.deviation.of.hydrologic.time.series.is.fixed.over.time..this. assumption.enabled.decision-makers.to.estimate.hydrologic.risks.to.water.systems,.or,.in.other. words,.to.establish.with.some.degree.of.certainty.both.potential.outcomes/impacts.and.the. probability.of.their.occurrence..climate.change.introduces.new.uncertainties,.both.in.respect.to.the. future.mean.values.and.variability,.but.also.in.respect.of.uncertainty.and.the.chance.of.outcomes. that.may.be.very.different.from.any.historic.experience. Climate change calls into question the classical assumption that past hydrologic knowledge provides a good guide to future conditions in planning, designing and operating water investments..it.is.now.well-accepted.that.the.future.hydrologic.regime.will. not.be.a.statistical.replica.of.the.past,.but.there.are.significant.unknowns.as.to.precisely.how. hydrologic.characteristics.will.change..thus,.the.challenge.confronting.water.professionals.is. 24 Indeed,ThomasSchelling,winnerofthe2005NobelPrizeinEconomics,notesthattheideathatactionsareunwarrantedifthe dangersareuncertainisalmostuniquetoclimatechange.Inotherareasofpolicy,suchasterrorism,nuclearproliferation,inflation,or vaccination,some`insurance'principleseemstoprevail:ifthereissufficientlikelihoodofsignificantdamage,typicallysomemeasured anticipatoryactionistaken.(Economists'Voice,www.bepress.com/ev,July2007). 87 how.to.plan,.design.and.manage.when.the.confidence.in.calculations.of.risk.are.substantially. lowered.because.either.the.potential.outcomes.or.the.probability.of.their.occurrence--or.both-- are.largely.unknown..there.are--and.have.always.been--many.sources.of.uncertainty.other.than. hydrology.that.are.important.to.water.management,.including.changes.in.population,.income. levels,.technology,.ecosystem.functions.and.services.and.societal.values..However,.it.is.the.increase. in.hydrologic uncertainty.and.the.reduced.ability.to.calculate.hydrologic risks.that.make.water. management.with.and.without.climate.change.fundamentally.different. Water investment planning, design and operations require a formal risk-based analysis in all aspects of the project/program cycle..water.systems.are.subject.to.both.climate.and. non-climate.related.stresses,.but.there.are.certain.types.of.water.investments.where.uncertainties. related.to.climate.change.could.have.a.significant.impact,.and.so.particular.care.needs.to.be. taken.in.undertaking.a.detailed,.rigorous.risk.assessment..these.include.highly.capitalized.or. unique.projects,.irreversible.investments,.engineering.structures.with.long.lifetimes,.long-lived. benefits.and.costs,.etc..examples.include:.single.and.multi-purpose.hydraulic.infrastructure,. interbasin.water.transfer.schemes,.water.conveyance.systems.for.irrigated.agriculture,.and. regional/transboundary.investments..yet,.there.are.water.systems.that.are.inherently.resilient.to. some.degree.of.hydrologic.variability.and.climate.change,.are.not.significantly.impacted,.or.the. consequents.of.impact.can.be.readily.remedied..in.these.cases,.a.less.rigorous.risk.assessment. (screening.level).may.be.sufficient. Bayesian decision analysis framework one that allows for explicit characterization of risks, options, and management of risks..the.approach.incorporates.unfolding.uncertainties.over. time.and.accounts.for.the.performance.of.those.options.(Hobbs,.et.al,.1997)..in.bayesian.decision. analysis,.the.`decision.problem'.is.structured.as.a.decision.tree,.in.this.specific.case.for.evaluating. options.under.various.climate.scenarios..uncertainty.is.incorporated.through.the.use.of.subjective. probabilities.for.the.scenarios.in.evaluating.the.expected.outcome.of.the.options. this.chapter.addresses.the.necessity.for.incorporation.of.a.formal.risk-based.approach.in.water. investments,.the.overarching.themes/issues.to.be.considered.at.various.phases.of.project/ program.cycle,.a.framework.for.risk-based.decision.making.adapted.from.the.current.state-of-the- knowledge,.and.how.such.a.framework.may.be.applied.to.the.bank's.project.cycle. sector investment decisions must be made under increased risk and uncertainty Risk management is a good practice for water management that makes sense even if the climate were not a consideration..the.application.of.risk.management.is.more.applicable. when.climate.change.is.considered..Although.we.know.the.climate.is.changing.and.will.continue. to.change,.it.is.not.possible.to.make.a.precise.prediction.as.to.exactly.how.and.when.climate. will.change..At.best,.a.range.of.potential.changes.in.climate.can.be.identified..this.wide.range. of.potential.changes.in.climate.provides.justification.for.applying.principles.of.risk.management. to.manage.water.resources..it.is.more.imperative.to.consider.the.risks.that.climate.change.can. bring.and.manage.systems.appropriately.to.reduce.or.minimize.risks,.particularly.those.of.greatest. concern. Water managers now face unprecedented challenges to investments in and management of water resources and services..in.the.past,.water.managers.often.recognized.that.the.systems. they.built.and.managed.were.vulnerable.to.hydrologic.variability,.population.growth,.and.other. 88 pressures.and.challenges..the.typical.response.to.such.vulnerabilities,.however,.was.to.factor.in. large.margins.of.safety.that.reduced.the.risk.of.an.adverse.event.(e.g.,.for.potential.water.supply. shortages--transfer.water.between.river.basins;.for.potential.urban.flooding--install.high.capacity. storm.water.infrastructure)..Furthermore,.they.assumed.the.climate.was.stationary--the.likelihood. and.magnitude.of.extreme.climate.events.as.well.as.average.climate.conditions.were.known.based. on.historical.records..thus,.it.was.thought.that.systems.could.be.designed.and.operated.to.better. manage.adverse.events.(e.g.,.inadequate.water.supplies,.floods).by.reducing.the.frequency.and/ or.magnitude.of.failure..Past.investment.decisions.have.incorporated.uncertain.future.trends,. such.as.population.movement.from.rural.to.urban.areas.shifting.the.geographical.distribution.of. water.demand,.population.growth.increasing.total.water.demand,.new.irrigation.technologies. increasing.effective.supply,.new.thermoelectric.power.plants.causing.spikes.in.water.demand,.the. possibility.of.drought.affecting.water.supply.in.any.given.year,.and.more..many.past.water.systems. have.successfully.provided.safe.and.reliable.water.supplies.and.other.services.despite.these. uncertainties--climate.change.simply.adds.one.more.uncertainty.to.the.list.water.managers.have. successfully.tackled.for.generations. The margin of safety built into water projects often entails investing significant resources to avoid low probability, high consequence risks..the.opportunity.cost.of.factoring.in.such. large.safety.margins.was.once.non-controversial,.but.resource.scarcity,.escalating.costs,.and. expansion.in.demand.for.water.resources.and.services.as.well.as.increasing.environmental.and. degradation.and.awareness.have.put.significant.pressure.on.water.managers.to.reduce,.manage. or.contain.costs.while.expanding.services..consequently,.the.acceptable.margin.of.safety.for.water. resources.and.services.has.narrowed..compounding.these.difficult.realities,.climate.change.adds.a. new.challenge.that.further.complicates.the.operational.environment.by.replacing.the.conventional,. stable,.but.variable,.hydrological.baseline.with.a.new.one.to.include.changing.average.conditions. as.well.as.changing.variability..However,.this.new.baseline.cannot.be.estimated.with.a.great. degree.of.certainty. Current understanding of climate and climate change indicates that historical data is no longer the only reliable guide to future climate events.25.whereas.scientists,.engineers,. and.water.managers.previously.considered.the.climate.to.be.stationary,.we.now.understand. that.climate.is.subject.to.a.number.of.forces.that.cause.averaged.conditions.and.extremes.to. change.over.time..For.example,.engineers.typically.design.flood.control.structures.based.on.an. engineering.standard.(e.g.,.design.to.withstand.a.100-year.flood).and.historic.stream.flow.and. flooding.data.inform.that.standard.(e.g.,.a.1%.chance.of.flood.waters.exceeding.10.meters.in. any.given.year.based.upon.150.years.of.historical.data)..in.other.words,.designing.for.a.100.year. flood.under.the.recent.past.might.equate.to.designing.for.a.50.or.even.a.20.year.event.in.future. decades.(or,.alternatively,.to.design.for.the.100.year.flood.of.the.future,.we.may.need.to.design. for.what.we.currently.consider.to.be.a.500.year.flood). Future decision making will be further complicated because climate is changing and the rate of that change is likely to accelerate..even.accounting.for.recent.climate.trends.e.g.,. the.observed.rate.of.sea.level.rise,.may.not.be.sufficient.to.prepare.for.climate.change..but,.it. is.not.possible.to.precisely.forecast.future.climate.conditions:.we.cannot.precisely.predict.future. emissions.of.greenhouse.gases,.nor.can.we.accurately.project.the.change.in.climate.variables. that.will.result.from.those.changes.in.greenhouse.gases,.or.the.change.in.hydrology.that.will.result. 25 Tobesure,climatehasneverbeenstationary.Climateshavealwayschangedfornaturalreasonssuchaschangesinsolarradiation, theearth'sorbitaroundthesun,andotherfactors.Whatisnewistheadditionofhumancausedclimatechange. 89 from.those.changes.in.climate..this.is.particularly.true.at.the.geographic.scale.relevant.to.most. water.resources.and.services,.which.are.typically.managed.at.the.river.basin.level,.the.individual. water.supply.source,.or.the.specific.treatment.facility.or.other.water.system..consequently,.water. managers.must.always.make.investment.and.operational.decisions.under.uncertainty. The good news: making decisions under uncertainty is neither new nor unique to water investments..making.decisions.under.uncertainty.requires.an.adequate.accounting.of. the.risks.faced.under.different.options.and/or.different.projected.future.conditions..Armed.with. an.understanding.of.the.options.available.to.them,.water.managers.must.weigh.the.tradeoffs. associated.with.making.alternative.choices.about.which.risks.to.reduce.and.which.ones.to. bear..in.some.cases,.a.risk.will.be.so.unacceptable.that.the.old.paradigm.of.simply.building. in.expensive.safety.factors.may.be.the.best.choice.(e.g.,.overbuilding.dams.to.ensure.they.will. not.fail)..in.other.cases,.strategies.exist.to.reduce.the.consequences.of.an.adverse.event.while. reducing.the.costs.of.a.water.investment.(e.g.,.instead.of.retrofitting.inadequate.storm.water. drainage.infrastructure,.build.above.ground.culverts.and.protect.low.lying.land.downstream. from.development.to.provide.a.natural.floodplain)..such.strategies,.discussed.below,.allow.for. less.expensive.and.oftentimes.more.effective.water.systems.and.services. Given the policy, financial implications of making water investment decisions, a more systematic approach is needed for water investment decision making..we.call.the.systematic. approach.proposed.in.this.chapter.risk-based decision making..risk-based.decision.making. considers.uncertainty.explicitly.(not.only.applicable.where.`risk'.can.be.quantified).in.the.evaluation. of.probabilities.and.consequences.associated.with.alternative.investment.strategies.as.well.as. strategies.to.make.informed.decisions.in.the.face.of.irreducible.uncertainty. Water managers have two choices--to ignore the changing risks posed by altered climate and hydrology and rely only on historic data or to use risk-based decision making..in.spite. of.the.problematic.uncertainty.associated.with.changing.climate.baselines,.precedents.of.risk- based.decision.making.by.water.managers.exist..this.chapter.first.discusses.risk-based.decision. making..it.includes.a.discussion.of.tools.for.implementing.a.risk.management.approach.and. measuring.vulnerability..then,.the.chapter.builds.on.the.analysis.of.risk.management.to.examine. adaptation.to.climate.change..the.focus.will.be.on.the.types.of.adaptations.that.make.sense.given. what.is.known.about.climate.change. a framework for risk-based decision making for water investments Definitions and terminology According to the U.S. National Research Council, risk analysis has two components--risk assessment and risk management..risk.assessment.is.the.factual.basis.for.defining.adverse. events.and.determining.their.probabilities.and.consequences..risk.management.is.the.process. of.weighing.policy.alternatives.in.response.to.risk..risk.assessment.is.further.decomposed.into. risk.identification--determining.whether.a.particular.event.has.adverse.consequences,.and.risk. characterization--describing.the.nature.and.magnitude.of.the.risk.(nrc.1983,.1994)..However,. various.institutions,.fields.of.study,.and.sectors.use.these.terms.differently.or.use.their.own. language.to.describe.these.or.similar.concepts..For.example,.the.u.s..Army.corps.of.engineers. identifies.four.steps.to.risk.analysis:.risk.characterization,.risk.quantification,.risk.evaluation,.and. risk.management.(usAce.1992)..while.some.overlap.with.the.nrc.terminology.is.evident,.there. are.some.differences. 90 Box 8.1 Risk and Uncertainty risk.and.uncertainty.are.typically.differentiated.on.the.basis.of.probability.uncertainty,.specifically.whether.or.not. objectively.known.probability.distributions.can.be.used.to.describe.potential.outcomes..in.risk.situations,.they. can;.in.uncertain.situations,.they.cannot..the.boundaries.between.risk.and.uncertainty.are,.however,.not.clear- cut..risk.and.uncertainty.can.be.envisioned.as.intermediary.points.on.a.continuum.of.knowledge.from.complete. certainty.to.complete.ignorance,.as.shown.in.the.below.diagram..the.right.end.of.the.continuum.is.comprised. of.objective.risks..Proceeding.to.the.left,.probabilities.become.less.statistically.sound.and.gradually.merge.into. subjective.probabilities..Finally,.at.the.end.of.the.continuum,.no.probabilities.can.be.assigned. Complete Ignorance Uncertainty Risk Complete Certainty No Probabilities Subjective Probabilities Objective Probabilities Because these differences in terminology permeate all discussions of risk, establishing some basic terminology is necessary..in.the.most.basic.sense,.risk.itself.has.two.components:. a.consequence.component.(the.magnitude.of.harm.should.the.event.occur).and.a.probability. component.(the.likelihood.that.an.adverse.event.will.occur)..risks.can.quickly.be.classified.along. these.lines.as.shown.in.Figure.8.1..this.view.of.risk.has.become.quite.commonplace. The consequence component of risk refers to the magnitude of harm should an adverse event occur..consequence.is.a.function.of.both.the.adverse.event.itself.and.the.affected.system.. A.tropical.cyclone.striking.an.uninhabited.area.may.have.little.consequence.for.society..the.same. storm.striking.a.populated.area.may.have.greater.consequences. The probability component refers to the likelihood of an adverse event occurring..by. convention,.the.word.risk.sometimes.refers.only.to.this.probability.component,.also.known.as. event.risk..we.define.risk.more.broadly.to.include.the.consequence.component..establishing.the. probability.of.an.undesirable.event.can.be.challenging,.especially.when.conditions.are.changing. (e.g.,.socioeconomic.conditions)..establishing.reliable.probability.estimates.under.climate.change. is.even.harder,.and.in.many.cases,.impossible. Figure 8.1 displays probability and consequence of events with similar and different Figure 8.1 Consequence and probability components of risk effects..events.A.and.c.have. similar.consequence..but,.event. c.has.higher.probability.than. A C event.A..so,.event.c.would.be.of. Consequence greater.concern.to.a.risk.manager.. event.d.is.as.likely.to.happen.as. frequently.as.event.c,.but.has.less. D consequence..so,.event.d.would. B be.of.lesser.concern..event.b.has. moderate.probability,.but.relatively. Probability low.consequence..it.would.be.of. less.concern.than.events.d.and. Extreme High Moderate Low 91 c,.which.have.higher.probabilities.of.occurring.and.have.greater.consequence..whether.event.b. would.be.of.greater.concern.than.event.A.depends.on.the.relative.consequences.and.probabilities. of.these.two.events..in.this.diagram,.event.b.is.considered.to.be.of.moderate.concern,.less.than. event.A,.but.this.is.a.value.judgment..it.may.be.possible.that.a.relatively.low.probability.event. such.as.A.may.be.of.higher.concern.than.event.d.because.the.consequences.of.A.are.quite. high.or.unacceptable.(e.g.,.the.probability.of.an.upstream.ice.dam.breaking.free.and.flooding. downstream.may.be.extremely.low,.but.the.consequences.may.be.unacceptably.high,.e.g.,.if. flooding.will.result.in.loss.of.many.lives.and.destruction.of.much.property). Distinctions exist between exposure, sensitivity, and adaptive capacity (e.g., Smit et al., 2001)..exposure.is.the.frequency.of.a.climate.event.occurring.and.the.magnitude.of.the.event. itself.(e.g.,.the.likelihood.of.a.category.3.tropical.cyclone.striking.a.coastal.area)..exposure.is.also. a.function.of.the.location.and.size.of.a.system.that.can.be.affected.by.the.event..nairobi.is.not. exposed.to.sea.level.rise,.but.mombasa.is..sensitivity.is.the.extent.to.which.an.exposed.system.will. be.affected.(e.g.,.a.low.lying.heavily.populated.coastal.area.may.be.very.sensitive.to.a.category. 3.tropical.cyclone)..the.dutch.are.less.sensitive.to.sea.level.rise.because.they.have.built.defenses,. while.bangladesh.lacks.sufficient.defenses.and.is.more.exposed..Finally,.adaptive.capacity.is.the. ability.of.the.system.to.cope.or.adapt.to.the.event.or.change.in.conditions.such.as.change.in.climate.. developed.countries.generally.have.more.adaptive.capacity.than.developing.countries..the.exposure,. sensitivity,.and.adaptive.capacity.of.the.affected.system.are.collectively.known.as.vulnerability. In water management, the probability of occurrence of an event of significant consequence (e.g., a flood) often cannot be controlled..However,.exposure.(e.g.,.location. of.critical.assets),.sensitivity.(e.g.,.hard.versus.soft.infrastructure),.and.adaptive.capacity.(e.g.,. evacuation.capability,.level.of.development).are.factors.that.to.some.degree.can.be.controlled.. because.there.is.often.little.a.water.manager.can.do.to.decrease.the.probability.of.an.adverse. climate.event,.water.managers.must.look.to.policy.interventions.that.reduce.exposure.of.affected. systems.and.sensitivity.in.order.to.address.most.climate-related.risks.to.water.investments. Top-down approach to decision making focuses on the probability of an adverse event resulting from climate change..An.attempt.is.first.made.to.characterize.the.likelihood.that.there.will. be.an.adverse.event..this.characterization.is.often.difficult.to.establish.under.the.best.of.circumstances. due.to.nonlinearities.in.the.climate.and.biophysical.system,.multiple.interacting.variables,.temporal. effects,.ignorance.of.confounding.variables,.and.so.forth..nevertheless,.an.assessment.of.probability. is.generally.worthwhile.as.part.of.a.holistic.approach.to.risk-based.decision.making..in.regards.to. climate.change,.top-down.assessments.use.the.output.of.computer.models.to.project.changes.in. climate.and.the.consequent.impacts.on,.for.example,.water.systems..results.are.used.to.understand. the.vulnerability.of.a.system,.and.adaptations.can.then.be.designed.to.reduce.those.vulnerabilities. Bottom-up decision making involves investigating the exposure, sensitivity, and adaptive capacity of the system of concern..water.managers.often.use.a.bottom.up.approach.in.their. operational.decision.making.to.determine.the.consequences.of.an.adverse.event.without.getting. bogged.down.in.modelling.of.probabilities.resulting.from.multiple.climate.models.as.models.of. biophysical.systems..Assessments.of.potential.damages.from.a.flood.event,.the.flow.capacity.of. storm.water.systems,.or.the.ability.of.different.water.users.to.sustain.a.period.of.water.unavailability. are.all.examples.of.focusing.on.the.consequences.and.system.vulnerability..Again,.this.is.an. important.element.of.risk-based.decision.making.and.should.generally.be.done.in.conjunction. with.identifying.system.objectives..in.regards.to.climate.change,.bottom-up.assessments.look.at. the.affected.system.instead.of.climate.models..such.assessments.determine.thresholds.at.which. 92 changes.in.climate.may.pose.significant.consequences.in.terms.of.operational,.safety,.or.other. concerns..the.bottom-up.approach.starts.with.knowledge.of.the.project.or.system,.rather.than.of. climate..this.can.be.easier.for.water.managers.to.apply.because.they.can.rely.on.their.knowledge. of.their.water.resource.systems,.rather.than.trying.to.master.output.of.climate.change.models. Because climate change risk-based decision making is inherently concerned with the future, it must incorporate information about projected changes that may not be reflected in historical records..this.entails.significant.uncertainty.both.about.the.probability.and. the.consequence.of.an.adverse.event..while.the.best.possible.information.should.be.gathered. about.the.probabilities.of.adverse.events,.recognizing.the.limitations.of.such.knowledge.allows. water.managers.to.consider.different.types.of.policy.responses.to.manage.the.risks,.such.as. those.discussed.below..both.top-down.and.bottom-up.approaches.can.be.used.to.identify.the. change.in.climate.that.can.increase.vulnerability.beyond.some.critical.threshold..while.top-down. assessments.are.often.limited.to.the.outputs.of.models,.development.of.adaptations.typically. requires.extensive.knowledge.of.a.system,.that.is,.a.bottom-up.approach. Risk-based decision framework Risk-based decision making is the systematic consideration of the probabilities, consequences, and values associated with different decision alternatives..risk-based. decision.making.is.the.process.of.choosing.among.alternative.courses.of.action.to.achieve. a.defined.objective.based.upon.an.assessment.of.the.probability.of.an.adverse.event,.the. vulnerabilities.of.the.system.(e.g.,.the.water.investment).to.that.adverse.event,.and.values. associated.with.outcomes.(e.g.,.which.risk.should.most.be.avoided)..there.are.many.risk. assessment.frameworks.in.many.sectors.(willows.and.connell,.2003,.broadleaf.and.mjA,.2006).. A.brief.review.of.two.frameworks.for.risk-based.assessment.of.climate.change.is.provided.in.Annex. b..the.discussion.below.is.adapted.from.these.two.sources.and.for.application.to.the.water.sector.. in.general,.risk-based.approach.involves.the.following.general.stages:.project.objectives.definition. and.characterization.of.the.system.components;.knowledge.of.the.likelihood.and.consequences.of. adverse.events.that.could.compromise.those.objectives;.identification.of.the.options.for.adapting. the.system.or.project.to.render.it.less.vulnerable.in.the.face.of.the.identified.risks;.and.assessment. (either.quantitatively.or.qualitatively).of.adaptation.options..A.schematic.of.the.decision.framework. is.given.in.Figure.8.2..these.stages.are.described.below.in.more.details. Figure 8.2 Stages in risk-based decision making Objectives Characterization Adaptation Options Risk Assessment Analysis Identification & Assessment Stage 1 ­ Identify problem, objectives, performance criteria and rules for decision-making this.initial.stage.includes.the.following.steps: 1..define.decision.problem.and.objectives--identify.exposure.units/receptors.(i.e.,.system.of. interest).and.timeframe,.establish.overall.objectives. 93 2..establish.`success'.or.`performance'.criteria.and.associated.thresholds.of.tolerable.risk..success. criteria.are.measures.(indicators.and.values).against.which.adaptation.options.will.eventually.be. appraised.(e.g.,.effectiveness,.flexibility,.implementability,.economic.efficiency,.etc.)..criteria.may. express.the.risk.preference.of.decision-makers.(e.g.,.system.reliability.reached.90%.of.the.time).. criteria.that.are.of.particular.relevance.to.water.systems.are.reliability,.robustness.and.resilience. (discussed.in.depth.later.in.this.chapter)..these.are.sometimes.referred.to.as.the.`threshold-type'. metrics.(stakhiv,.2009).as.opposed.to.`absolute'.metrics.such.as.reservoir.elevation,.in-stream. flow.minima,.electricity.generation,.or.monetary.flood.damages). 3..identify.rules.for.decision-making.that.will.be.applied.to.evaluate.options.(below),.also.reflecting. risk.preference.of.decision-makers..rules.could.include.cost.benefit.analysis;.cost.effectiveness. analysis;.multi-criteria.analysis..risk.preference.could.include.risk.aversion,.etc..Figure.8.3. shows.the.template.for.stage.1. Figure 8.3 Stage 1 ­ Objectives identification and system characterization Objectives Bottom Up (Threshold) Top Down (Scenario) Characterization Analysis Define driving climate and Define driving climate and non-climate variables non-climate variables Risk Select climate change Assessment Define thresholds scenario Define performance Perform downscaling criteria Adaptation Options Identification Assess sensitivities to climate Carry out hydrologic & Assessment variables analysis Stage 2 ­ Assess risks this.stage.includes.the.following.steps: 1..identify.the.climate.and.non-climate.variables.that.could.influence.potential.outcomes,.i.e.,.that. the.exposure.unit.is.potentially.sensitive/vulnerable.to.(e.g..create.pathways.linking.important. variables.to.exposure/units.and.decision.criteria). 2..identify.the.alternative.future.states.or.circumstances.that.may.occur.(both.climate.and.non- climate),.and.the.impact.of.these.on.the.exposure.unit.and.performance.criteria.(including.the. relative.importance.of.climate.and.non-climate.drivers)..For.climate.impacts,.identify.coping. ranges.and.critical.thresholds.(biophysical.and/or.behavioral)..estimate.likelihood.of.impact. (quantitatively.or.qualitatively,.as.feasible)..Prioritize.risks.and.determine.extent.of.uncertainties. knowledge.of.the.probability.of.an.adverse.event.can.range.from.well.known.(e.g.,.the.likelihood. of.sea.level.rise.eventually.inundating.a.coastal.water.treatment.facility).to.probabilistic.(e.g.,.the. variability.of.streamflows.during.a.rainstorm).to.based.on.expert.judgment.(e.g.,.the.recurrence.period. under.climate.change.of.what.we.historically.defined.as.a.100.year.flood).to.relatively.unknown.(e.g.,. the.probability.of.decade-long.drought.under.climate.change)..the.level.of.uncertainty.associated.with. 94 an.adverse.event.is.a.significant.factor.entering.into.the.choice.of.decision.making.strategies.and.tools. that.a.water.manager.might.utilize.as.discussed.below..Figure.8.4.gives.the.template.for.stage.2. Figure 8.4 Stage 2 ­ Assessment of risks Objectives Bottom Up Top Down Risk Assessment Characterization (Threshold) (Scenario) Mode Analysis Determine system Determine system Screening Risk response response Assessment Risk Assessment Determine consequences Assess consequences Qualitative Risk of the response of the response Assessment Adaptation Options Identification Assess system Assess impacts Quantitative Risk & Assessment vulnerabilities and vulnerabilities Assessment Stage 3 ­ Identify and evaluate options to manage risk this.stage.includes.the.following.steps: i 1..dentify.(any).potential.adaptation.options.to.meet.`success'.criteria.(and.are.within.thresholds.of. tolerable.risk)..A.list.of.adaptation.options.identified.in.the.review.of.the.bank's.water.portfolio. is.given.in.chapter.6..Figure.8.5.shows.the.template.for.this.stage..A.typology.of.adaptation. options.adapted.from.burton.(1996).is.imbedded.in.this.template. Figure 8.5 Stage 3 ­ Options identification and assessment to reduce risk Objectives Determine system Determine system Determine system Characterization response response response Analysis Share the loss Risk Bear the loss Assessment Structural, technological Modify the events Legislative, regulatory, financial Prevent the effects Institutional, administrative Adaptation Change use Options Market-based Identification Change location & Assessment On-site operations Research Education and behavioral change 95 e 2.. valuate.adaptation.options.according.to.degree.of.uncertainty.and.established.rules.of. decision-making..in.all.circumstances,.look.for.no.regrets,.low.regrets.particularly.so.when.there. is.high.uncertainty..if.`risk'.cannot.be.quantified,.can.also.use.approaches.for.decision-making. under.`uncertainty'.(willows.and.connell,.2003)..the.options.of.`do.nothing'.or.`delay.decision'. are.possible..Avoid.climate.decision.errors.(over-adaptation,.under-adaptation.and.associated. maladaptation). Considerations for the water sector Susceptibility of water systems to climate change A special class of diagnostic indicators identified as threshold-type or dynamic indicators are applied to the analysis of specific water resource systems or system design configurations..several.measures.of.the.robustness.of.water.systems.to.climate.change.have. been.proposed.that.permit.the.evaluation.of.a.specific.design.configuration.over.a.range.of. system.inputs.and.service.levels.(Hashimoto.et.al.,.1982a,.1982b)..each.indicator.is.based.on. the.probability.that.a.system,.characterized.by.a.given.set.of.design.parameters,.will.provide.the. intended.level.of.services.under.a.range.of.dynamic.inputs.and/or.demand.conditions..these. indicators.enable.an.analysis.that.extends.beyond.climatic.means.to.encompass.seasonal.and. interannual.variability,.serial.correlation.properties,.and.the.occurrence.of.extreme.events..the. measures.of.system.performance.are.defined.over.a.sequence.of.discrete.time.periods..within. each.period,.the.system.either.performs.(provides.an.acceptable.level.of.services).or.fails.to.do.so,. which.leads.to.the.following.complementary.metrics. ·.Reliability.is.how.often.a.system.fails.according.to.some.defined.criteria..it.is.also.defined. as.the.likelihood.that.services.are.delivered.(no.failure).within.a.given.period,.expressed.as.a. probability..High.probabilities.indicate.high.reliability. ·.Resiliency.is.how.quickly.a.system.recovers.from.a.failure ·.Robustness in.a.water.resources.system,.this.is,.conceptually,.the.extent.to.which.a.system. design.is.able.to.deliver.optimal.or.near-optimal.levels.of.service.over.a.range.of.demand. (input).and.supply.(resource).conditions..one.common.definition.of.robustness.emphasizes. flexibility:.the.ability.of.a.system.to.adapt.to.a.wide.range.of.operating.conditions.through. relatively.modest.and.inexpensive.levels.of.redesign,.refitting,.or.reoperation. Adaptation Options for Water Systems There are two perspectives from which water management under climate change can be considered. One focuses on potential adaptation options for reducing vulnerability and the other, on the decision-making process under uncertainty..each.of.these.provides.slightly. different.insights.into.the.question.of.`when.and.how.should.water.managers.behave.differently'.. there.is.a.common.thread.between.the.two.in.highlighting.that.traditional.approaches.in.many. cases.suffice,.although.there.are.also.instances.when.the.`additional'.element.of.uncertainty. arising.from.climate.change.will.call.for.innovative.responses..A.brief.description.of.some. indicators.used.for.assessment.of.vulnerability.at.the.systems.level.is.given.in.box.8.2. Potential options for adapting to climate change and variability in the water sector can be categorized into those that carry `no regrets' and those that are `climate justified'. many.of.the.options.to.reduce.vulnerability.to.climate.variability.are.no.different.in.a.world.with. climate.change.than.they.are.in.a.world.without..these.include.demand.management.measures. 96 Box 8.2 Standardized indicators to assess the vulnerability of regions and systems to climate change standardized.indicators.can.help.identify.regional.patterns.of.water.sector.vulnerability.to.changes.in.climate. and.hydrology..using.indicators.to.diagnose.the.vulnerability.of.water.systems.increases.the.insight.of.water. managers.into.how.climate.change.may.affect.the.functioning.of.infrastructure.design.and.the.efficacy.of. alternative.management.practices,.and.can.be.used.proactively.to.diagnose.vulnerability.before.planning,. financing,.and.implementing.a.water.project..vulnerability.to.climate.change.with.respect.to.water.systems.is. strongly.related.to.three.factors: ·. Climate and hydrology:.the.status.of.regional.water.resources.­.mean,.trends,.and.variability.in.usable. supplies; ·. Water demand, use, and depletion:.the.level,.structure.and.timing.of.abstractive.and.consumptive. demand.for.water,.including.groundwater. ·. Water storage and management infrastructure,.which.mediate.between.hydro-climatic.conditions.and. societal.demand.by.regulating.water.availability.in.space.and.time. indicators.can.be.used.to.quantify.each.factor.discretely,.or.to.examine.the.overlay.of.supply,.demand.and. management.infrastructure.within.a.given.region..one.example.of.a.supply-related.indicator.is.the.runoff ratio,. defined.as.the.percentage.of.annual.precipitation.converted.to.surface.runoff.and.renewable.groundwater. recharge..low.values.of.the.runoff.ratio.are.associated.with.high.vulnerability,.since.modest.changes.in. temperature.or.precipitation.can.lead.to.large.relative.changes.in.available.water.supplies. water.demand.vulnerability.indicators.place.emphasis.on.demand.relative.to.available.supply,.since.the.extent. of.unused.capacity.provides.the.buffer.between.uncertain.future.supply.and.demand.conditions..one.indicator. is.water crowding,.defined.as.the.number.of.people.per.million.cubic.meters.of.water.per.year.(vörösmarty.et. al.,.2005)..A.crowding.index.greater.than.1,000.indicates.potential.scarcity..A.closely.related.indicator.is.the. ratio.of.annual.withdrawals.to.renewable.water.supply,.identified.as.relative water demand.(vörösmarty.et.al.,. 2000)..these.concepts.have.been.extended.to.water use regimes..this.two-dimensional.indicator.distinguishes. between.(i).undeveloped.or.natural.flow-dominated,.(ii).human.flow.dominated,.(iii).depleted.or.withdrawal. dominated,.and.(iv).surcharged,.or.return-flow.dominated.regimes. the.extent.to.which.water.storage.and.management.infrastructure.provides.a.buffer.for.societies.facing.climatic. variability.or.change.is.an.important.component.of.vulnerability.and.resilience..A.simple.indicator.is.the. storage-to-flow ratio,.defined.as.the.ratio.of.total.basin.storage.capacity.to.annual.renewable.discharge..A. special.class.of.infrastructure-related.indicators.can.also.be.used.to.diagnose.the.vulnerability.of.specific.water. resource.systems.or.system.design.configurations.to.alterations.in.supply.and/or.demand.conditions..they.are. identified.as.reliability.(how.often.a.system.fails),.resiliency.(how.quickly.a.system.recovers.from.a.failure),. vulnerability.(how.significant.are.the.consequences.of.a.failure),.and.robustness.(how.well.a.system.performs. over.a.range.of.conditions)..these.indicators.are.described.in.Hashimoto.et.al..(1982a,.1982b). to.increase.water.use.efficiency.and.productivity,.such.as.water-conserving.irrigation.technologies;. wastewater.recycling;.economic.incentives,.including.water.pricing;.and.the.encouragement.of. water.markets.that.move.water.to.high-valued.uses..they.also.include,.for.example,.measures.to. improve.early.warning.systems.and.risk-spreading.(e.g.,.disaster.insurance)..these.options.carry. `no regrets'.in.that.they.would.go.a.long.way.in.confronting.the.climate.change.challenge,.yet.they. are.often.justifiable.even.under.current.conditions.of.variability..on.the.other.hand,.other.actions. might.be.justifiable.under.significant.change.in.climatic.variability..`Climate justified'.actions. 97 include,.for.example,.constructing.new.infrastructure.(dams,.underground.storage,.irrigation. systems),.retro-fitting.existing.infrastructure,.changing.rules.of.operation,.tapping.new.sources.of. water.(e.g.,.desalinization),.water.transfers,.conjunctive.use.of.surface.and.groundwater,.innovative. demand.management,.etc. The distinction between `no regrets' and `climate-change justified' options is important in near-term and long-term decision making..For."no.regrets".options,.uncertainties.in. climate.projections.are.to.a.large.extent.immaterial..by.definition,.these.actions.should.be.taken. in.order.to.meet.current.economic,.social.and.environmental.objectives,.but.they.also.serve.the. dual.purpose.of.reducing.vulnerabilities.to.future.climatic.conditions..it.is.in.the.realm.of.the. `climate-justified'.that.water.managers.will.have.to.make.difficult.decisions.about.how.to.balance. the.political,.economic,.social.and.environmental.costs.of.action.versus.of.non-action,.given.an. uncertain.future..they.will.have.to.seek.and.apply.new.technologies.and.management.methods.to. ensure.that.system.reliability.is.maintained.under.changing.climate.circumstances..they.will.have. to.shift.their.thinking.on.how.to.plan.and.design.more.resilient.water.interventions..And,.they.will. need.to.develop.`intelligent systems'.that.are.robust.in.the.sense.that.they.are.able.to.deliver. (near).optimal.levels.of.service.or.management.over.a.range.of.conditions,.including.through. relatively.modest.re-design,.retrofitting.or.re-operation..implicit.in.robustness.is.also.flexibility,. that.is,.the.ability.to.anticipate.and.react.to.a.wider.and.largely.unknown.range.of.future.climatic. conditions..All.of.these.actions.will.require.use.of.a.variety.of.new.and.innovative.tools.in.the. areas.of.economics,.finance,.institutions,.infrastructure.and.technology. Categories of adaptation options One of the most operational and often-used classifications of adaptations was introduced in the Intergovernmental Panel on Climate Change's (IPCC's) Third Assessment Report, based on Burton, et al. (1996)..below.is.an.updated.list,.revised.for.focus.on.the.water.sector. ·.No action. All.adaptation.measures.may.be.compared.with.the.baseline.response.of."doing. nothing".and.accepting.the.economic,.social,.environmental,.or.other.losses.caused.by. the.impacts.of.a.changing.climate..in.addition.to.providing.a.baseline.for.comparison,."no. action".occurs.where.the.costs.of.adaptation.are.considered.too.high.relative.to.benefits,. when.information.about.risks.is.lacking,.and.where.political.will.does.not.coalesce.to.address. adaptation,.among.other.situations. ·.Insurance. many.communities.face.some.risk.of.high.consequence.climate.events,.such.as. hurricanes,.floods,.tornadoes,.wildfires,.and.so.forth..one.way.to.hedge.against.these.risks. is.by.sharing.the.losses.among.a.wider.community..Private.or.public.insurance.mechanisms. can.share.risks.by.raising.revenues.from.a.large.insured.pool.to.provide.coverage.for.relief. and.reconstruction..insurance.includes.mechanisms.such.as.private.insurance.policies,.public. insurance.programs,.and.public.or.institutional.relief.efforts,.but.it.also.includes.a.variety.of. less.formal.mechanisms.such.as.reliance.on.church.and.non-governmental.organization.relief. efforts..insurance.is.typically.used.to.compensate.victims.for.losses.and.the.compensation.is. typically.used.to.repair.or.rebuild.damaged.structures.or.compensate.for.losses.that.cannot.be. repaired.or.rebuilt..note.that.when.insurance.regulations.or.policies.promote.an.increase.in. vulnerability.to.climate.events,.insurance.acts.instead.as.a.form.of.maladaptation..correcting. such.maladaptations.can.go.a.long.way.toward.reducing.vulnerability.and.protecting.people,. their.property,.and.their.environment.from.climate.risks..governments.can.also.serve.to.share. loss.by.providing.financial.and.other.aid.following.disasters..government.funds.can.be.used.to. rebuild.destroyed.property.or.compensate.victims.for.losses..this.tends.to.be.more.feasible.in. 98 larger.countries.(where.it.is.more.likely.that.an.adverse.event.only.strikes.a.small.portion.of.the. country's.land.mass).and.wealthier.countries.which.have.more.financial.resources.to.devote.to. insurance. ·.Engineered protection. For.some.climate.impacts,.it.is.possible.to.engineer.protective.measures. that.reduce.the.risks.or.consequences.of.the.impact..examples.include.flood.control.works. (e.g.,.dams,.dikes,.levees,.sea.walls),.creating.fire.breaks.near.the.built.environment.to.reduce. fire.hazard,.and.building.new.or.improved.water.storage.facilities.to.hedge.against.drought.. one.of.the.challenges.of.engineering.adaptations.to.climate.change.is.the.uncertainty.about. the.magnitude.of.change.in.variables.for.which.even.the.direction.of.change.is.unknown,. e.g.,.uncertainty.the.magnitude.of.temperature.increase,.sea.level.rise,.or.increase.in.intense. precipitation. ·.Managing the risk. A.frequently.used.set.of.adaptation.measures.involves.steps.to.manage. the.effects.of.climate.change..examples.include.improved.warning.systems.and.evacuation. centers.for.flood.or.cyclones,.and.diversifying.a.community's.water.supply.portfolio.to.increase. resilience.to.drought..other.examples.might.include.limiting.development.in.vulnerable.areas. or.promoting.water.efficiency.measures.to.reduce.demand.for.water.and.vulnerability.to. droughts. ·.Change use. where.the.threat.of.climate.change.makes.the.continuation.of.a.climate.sensitive. activity.too.risky,.consideration.can.be.given.to.changing.its.use..governments.and.institutions. can.play.an.important.role.in.this.adaptation.option,.for.example,.by.regularly.revising.flood. zones.based.on.projections.of.altered.precipitation.regimes.or.sea.level.rise..As.a.result,.lands. once.slated.for.development.may.be.better.suited.as.buffers.for.floods.or.natural.floodplain. migration..government.subsidies,.regulations,.taxes,.and.other.incentives.can.play.a.large.role. in.facilitating.or.impeding.this.adaptation.option..For.example,.subsidies.for.specific.crops.may. provide.an.economic.disincentive.for.farmers.to.change.from.water.sensitive.crops.to.drought. tolerant.ones.in.areas.where.such.a.changed.use.makes.sense. ·.Change location. in.many.instances.the.location.of.physical.infrastructure.or.climate.sensitive. activities.is.the.primary.source.of.vulnerability.to.the.impacts.of.climate.change..For.example,. buildings.in.floodplains.or.along.the.coasts.will.face.increasing.vulnerability.to.floods.and. coastal.storms;.water.intensive.crops.grown.in.arid.environments.may.require.more.water.than. can.be.reliably.delivered.to.those.locations.in.places.where.drought.frequency.increases;.and. some.fisheries.may.migrate.northward.to.cooler.waters..settlements.or.economic.activities. may.need.to.be.relocated.in.response.to.such.changes..this.adaptation.can.carry.significant. to.extremely.high.costs,.but.may.be.the.unavoidable.adaptation.of.last.resort..the.need.to. abandon.some.areas.has.been.advocated.by.many,.including.sachs.(2008). ·.Research..For.many.adaptations,.improved.understanding.of.climate.change.and.its.impacts.is. needed..more.geographically.and.temporally.precise.climate.projections.can.aid.adaptation. as.it.could.reduce.uncertainties.about.the.direction.and.magnitude.of.change.in.key.climate. variables.such.as.precipitation..many.potential.impacts.of.climate.change.are.inadequately. understood..Adaptation.itself.is.not.well.understood,.particularly.how.individuals.and.societies. will.respond.to.changing.climate..this.is.not.an.option.for.individual.water.managers,.but.the. need.for.research.needs.to.be.communicated.to.the.research.community. ·.Education and behavioral change. Another.type.of.adaptation.focuses.on.changing.the.practices. of.individuals.or.institutions..this.often.involves.the.dissemination.of.knowledge.through. education.and.public.information.campaigns..one.example.is.waste.of.water,.for.example,.by. leaving.taps.on.or.not.attending.to.leaks..changing.behavior.can.be.fostered.through.education. campaigns,.appropriate.regulatory.instruments,.pricing,.incentives,.taxes,.and.subsidies.or.the. removal.of.such.instruments.if.they.impede.adaptation. 99 Class of projects for which risk-based analysis would be particularly essential Climate change will affect most water systems to some degree..However,.some.water. services.or.resources.by.their.very.nature.are.more.vulnerable.to.climate.change.than.others..For. example,.small.or.distributed.water.supply.systems.that.can.easily.make.incremental.changes.at. low.cost.are.vulnerable.to.climate.change,.but.may.face.less.exposure.to.changes.in.climate,.may. be.less.sensitive.to.climate.changes,.or.may.have.sufficient.adaptive.capacity.to.manage.those. changes..the.systems.below,.however,.are.particularly.vulnerable.and.special.care.should.be. taken.to.flag.such.water.investments.for.risk-based.decision.making..these.systems.would.likely.be. designed.differently.if.climate.change.were.taken.into.account,.and.failing.to.do.so.would.likely. cause.significant.economic.loss.(Hobbs,.et.al.1997). ·.Highly capitalized or unique projects:.Any.project.that.requires.a.very.large.investment.or.has. a.high.opportunity.costs,.such.as.most.infrastructure.systems.or.large.watershed.protection. projects,.needs.to.include.consideration.of.climate.change.because.the.stakes.of.failing.to. accurately.assess.risk.are.simply.too.high,.often.on.the.order.of.many.millions.of.dollars. ·.Engineering structures with long lifetimes:.water.infrastructure.projects.often.have.lifetimes.of.50. years.or.more..the.best.available.science.indicates.that.climate.changes.may.not.be.significant. for.planning.purposes.over.just.a.few.years,.but.over.the.course.of.many.decades,.changes.in. climate.are.expected.to.manifest.in.ways.significant.for.planning.purposes. ·.Multi-purpose infrastructure systems:.some.systems.serve.multiple.purposes,.such.as.dams.that. provide.water.supply.storage.and.flood.control..the.management.of.such.systems.often.involves. tradeoffs.between.these.purposes.(e.g.,.how.much.water.to.keep.in.a.reservoir.is.driven.in.part. by.ensuring.enough.additional.capacity.to.capture.flood.waters.should.a.flood.occur)..because. these.systems.must.balance.risk.related.to.multiple.purposes,.it.increases.the.importance.of. incorporating.climate.change.considerations. ·.Long-lived benefits and costs:.similarly,.any.project.whose.benefits.or.costs.are.spread.out.over. a.long.timeframe.may.need.to.incorporate.potential.future.changes.in.climate.to.see.how.it. affects.those.benefits.or.costs..this.could.radically.alter.the.justifiability.of.a.water.project. ·.Systems susceptible to climate anomalies or extreme events:.Any.water.investment.or. management.regime.that.can.be.significantly.affected.by.floods,.droughts,.hurricanes,.or. other.climate.anomalies.needs.to.consider.the.potential.increase.in.risks.from.climate.change. because.these.extreme.events.account.for.the.bulk.of.climate-related.damages.to.water. projects..small.increases.in.the.frequency.or.severity.of.these.events.can.lead.to.exponential. increases.in.damages. ·.Urban water supply:.urban.water.demand.is.increasing.in.most.places,.but.it.can.be.managed. on.both.the.demand.and.the.supply.side..because.of.the.multiple.adaptation.possibilities. (e.g.,.leak.reduction,.metering,.eliminating.unauthorized.taps),.urban.water.supply.provides.an. excellent.opportunity.to.relieve.stress.on.basin-wide.water.systems.and.thus.makes.the.entire. system.less.vulnerable. ·.Water systems facing non-climate stress:.many.water.systems.are.vulnerable.to.non-climatic. trends.such.as.urbanization,.deforestation,.changes.in.agricultural.or.industrial.water.demands,. and.so.on..because.these.water.systems.become.more.stressed,.they.also.become.more. vulnerable.to.changes.in.hydrology.and.hence.climate.change. Identification of water systems or projects that merit consideration of risk-based decision making involve a two step process..First.we.recognize.the.need.to.incorporate.risks.of.future. events.into.our.planning.decisions..next.we.must.figure.out.what.kinds.of.remedial.action.can.be. taken.to.reduce.those.risks,.and.what.the.costs.and.benefits.of.those.risk.management.options. 100 may.be..the.term.adaptation.refers.to.policy.actions.intended.to.reduce.the.vulnerability.of. systems.to.climate.variability.and.change. assessing risk: application to multi-purpose infrastructure projects26 Depending on the class of project and the expected risk and consequences of exposure to climate change, the level of analysis varies..As.an.illustration.of.the.application.of.the. risk-based.decision.making,.the.process.for.assessment.of.risk.associated.with.multi-purpose. infrastructure.is.presented.here..this.multi-purpose.example.focuses.on.elements.of.stages.2.and.3. of.the.risk-based.assessment.framework.described.above. Hydrologic drivers for multi-purpose hydraulic infrastructure The primary driver of climate change impacts on dams and reservoirs is temperature.. current.climate.models.suggest.that.the.effects.of.temperature.increases.are.felt.throughout. the.climatic.regime,.leading.to.hydrologic.changes.(e.g.,.seasonal.redistribution.and.duration. of.rainfall).and.other.related.impacts..these.hydrologic.changes.are.manifested.as.periods. of.increased.rainfall.or.floods,.as.well.as.periods.of.reduced.rainfall.or.drought..in.addition. to.precipitation.effects,.increased.temperatures.are.impacting.glacier.and.snowmelt.patterns,. while.also.creating.more.extreme.hurricane.or.typhoon.conditions.with.associated.high.winds.. A.representative.list.of.temperature,.rainfall,.and.wind.related.effects.that.may.impact.a. multipurpose.hydraulic.infrastructure.is.provided.in.box.8.3. While acknowledging the myriad effects on multi-purpose infrastructures from all of the above drivers, this assessment of climate change impacts is focused on the primary hydrologic drivers of vulnerability as described earlier in this report: ·.Annual.Average.Precipitation; ·.Precipitation.extremes; ·.glaciers.and.snow; ·.sea.level; ·.evapotranspiration; ·.soil.moisture; ·.runoff.and.river.discharge. Project components The project components are first described and assessed in terms of their sensitivity to the major hydrologic climate change drivers. the.risk-based.analysis.framework.is.then.developed. in.a.matrix.format.to.characterize.the.severity.or.sensitivity.of.climate.change.impacts.on.each. component..the.analysis.framework.is.then.applied,.using.a.defined.methodology.for.evaluation. and.scoring.of.impacts,.to.obtain.an.overall.picture.of.project.vulnerability.to.climate.change. ·.dam.structure; ·.reservoir.storage; 26 ThismethodologyisdescribedinmoredetailinthebackgroundreportWaterandClimateChange:AssessmentofClimateChange ImpactsonMultipurposeInfrastructure 101 Box 8.3 Potential impact some of key hydrologic drivers Temperature ·. increased.mean.ambient.temperatures; ·. increased.peak.temperatures; ·. increased.evaporation; ·. increased.humidity.(if.accompanied.by.a.generally.wetter.climate); ·. increased.snowmelt.and.retreating.of.glaciers; ·. increased.vegetation.(if.accompanied.by.generally.higher.rainfall); ·. loss.of.vegetation.(if.accompanied.by.periods.of.prolonged.drought); ·. increased.desiccation.(if.accompanied.by.periods.of.prolonged.drought); ·. increased.insect.populations; ·. increased.methane.production.in.reservoirs.from.rotting.vegetation;.and ·. increased.stratification.and.water.quality.variations.in.reservoirs. Rainfall ·. increased.peak.runoff.and.river.discharge; ·. increased.reservoir.yields.(in.the.case.of.prolonged.wetter.conditions); ·. reduced.reservoir.yields.(in.case.of.prolonged.drought.periods); ·. Higher.river.floods; ·. Higher.localized.storm.intensities; ·. increased.vegetation.(in.case.of.prolonged.wetter.conditions); ·. increased.sediment.(in.the.case.of.prolonged.drought.periods.that.can.desiccate.watershed.soils); ·. increased.debris.flows; ·. increased.lightning.incidents.(in.the.case.of.high.energy.storms);.and ·. Prolonged.solar.exposure.(in.the.case.of.prolonged,.reduced.cloud.cover). Wind ·. increased.prolonged.wind.speeds; ·. Associated.increases.in.the.wave.heights.on.reservoirs; ·. Associated.increased."seiche".(wind.set-up).effects.on.reservoirs; ·. increased.gust.speeds; ·. Associated.increased.structural.wind.loading.on.exposed.structures; ·. greater.amounts.of.atmospheric.dust;.and ·. greater.amounts.of.windblown.debris. ·.service.&.Auxiliary.spillways; ·.intake.works; ·.Hydropower.Plants; ·.low-level.outlet.works; ·.tunnels; ·.open.channels. In order to prioritize and justify design accommodations to adapt to climate change, it is desirable to have a logical, repeatable methodology..this.is.particularly.important. for.quantifying.the.risks.related.to.the.various.dam.and.reservoir.project.components.exposed. to.climate.change.drivers,.and.then.determining.the.most.attractive.adaptation.strategies.for. 102 implementation..For.a.given.exposure,.the.risks.are.identified.as.a.function.of.criticality,.sensitivity. and.adaptability.of.each.component. A risk-based approach to evaluating the sensitivity of multi-purpose infrastructure components to climate change begins with assessing the risk factors (or attributes) that are important to defining the component's response to a climate-change induced stressor..these.risk.attributes.can.be.organized.in.three.indicative.categories.as.follows: Criticality ·.likelihood.of.Failure ·.consequence.of.Failure sensitivity ·.robustness ·.resilience adaptability ·.Adaptive.capacity ·.cost.of.Adaptation Mapping the climate change impact onto project components The component risk analysis starts with mapping the project components to their primary climate change impact drivers..in.order.to.frame.the.criticality.of.a.given.component,.the. major.drivers.of.climate.change.impacts.on.multi-purpose.infrastructures.are.mapped.against.the. principal.structural.components.of.the.project. while.the.matrix.on.table.8.1.indicates.that.there.are.multiple.drivers.acting.upon.a.given. component,.a.methodology.for.identifying.the."alpha".driver.that.governs.the.design.or. configuration.of.the.component.is.needed..to.do.so,.it.is.necessary.to.delve.more.deeply.into. these.relationships.in.order.to.assess.the.vulnerability.of.the.components.to.climate.change. impacts..this.component.assessment.represents.an.essential.initial.step.in.ultimately.making.valid. recommendations.for.adaptive.measures.to.manage,.reduce,.or.eliminate.these.impacts. Scoring of component risk Each component is scored according to the risk attribute within each indicator category.. An.example.of.the.scoring.range.and.scale.is.given.in.table.8.2. Each major project component is scored for each indicator..this.results.in.a.ranking.in.each. category.for.each.component..this.assessment.can.first.be.done.on.a.generic.basis,.using.expert. knowledge.of.the.planning.and.design.process.for.a.dam.or.reservoir.project..it.is.then.further. refined.and.quantified.for.a.particular.project,.as.further.study.and.available.information.warrant.. the.scoring.process.involves.three.basic.steps: ·.Assess.and.score.criticality,.vulnerability,.and.adaptability.of.the.component; ·.Apply.weighting.factor.in.each.category.in.order.to.reflect.the.relative.importance.of.the. category.in.the.decision.process;.and ·.Prioritize.components.on.which.to.focus.based.on.the.highest-to-lowest.scores.obtained. 103 Table 8.1 Matrix of hydrologic drivers and infrastructure components Service & Low-Level Dam Reservoir Auxiliary Intake Hydropower Outlet Open Driver of Impact Structure Storage Spillways Works Plants Works Tunnels Channel Average Annual X X X X X X Precipitation (AP) Precipitation X X X X X X X X Extremes (EP) Glaciers and Snow X X X X X X X X (GS) Sea Level (SL) Evapotranspiration X X (ET) Soil Moisture (SM) X X X Runoff and River X X X X X X X X Discharge (RR) Table 8.2 Scoring by category for each component Key to Scoring Indicator Category (based on 10 point scale)* Weight Criticality likelihood.of.Failure 1* low.=.1;.med.=.3;.High.=.5 consequence.of.Failure: low.(affects.reliability/availability).=.1; med.(affects.performance).=.3; High.(affects.safety).=.5 Sensitivity robustness**:.low.=.5;.med.=.3;.High.=.1 1* resilience**:.low.=.5;.med.=.3;.High.=.1 Adaptive.capacity.(Planned.Projects)**:.low.=.5;.med.=.3;.High.=.1 1* Adaptability Adaptive.capacity.(existing.Projects):.low.=.1;.med.=.3;.High.=.5 cost.of.Adaptation.(Planned.Projects):.low.=.1;.med.=.3;.High.=.5 cost.of.Adaptation.(existing.Projects)**:.low.=.5;.med.=.3;.High.=.5 * scoring.scale.and.weight.may.be.varied.as.needed. ** score.is.inversely.proportional.to.the.attribute..the.highest.total.score.is.assigned.to.the.project.component.that.as.the.highest. criticality,.highest.vulnerability.(i.e.,.least.robust.and.resilient),.and.lowest.adaptability.(i.e.,.low.adaptive.capacity.and.highest.cost.of. adaptation). 104 For a given project analysis, the scoring for the risk attributes in each category should be done on a consistent and replicable basis that does not introduce a bias into the analysis.. the.weighting.factors,.on.the.other.hand,.should.be.varied.to.test.the.sensitivity.of.the.category. weights.on.the.prioritization.of.the.actions..the.dam.and.reservoir.project.component.risk.analysis. enables.means.to.identify.the.project.features.that.are.the.most.sensitive.to.climate-induced. changes.in.hydrologic.conditions..the.following.sequence.for.application.of.the.assessment. framework.defines.a.methodology.for.evaluating.the.impacts.of.climate.change.on.multi-purpose. infrastructures.on.a.logical,.replicable.basis. Assessment of project components most at risk The results of the scoring exercise provide information on the components which are most critical, most sensitive, and least adaptable as priority components for early attention in the planning and design stages of a proposed project..Analysis.of.existing.and.future. projects.differ.in.that.there.is.more.opportunity.for.planning.and.designing.against.vulnerabilities. and.providing.means.of.adaptation,.than.for.existing.projects..table.8.3.provides.a.generic.matrix. template.for.assessment.and.ranking.for.multi-purpose.infrastructure.projects..opportunities.and. strategies.for.adaptation.of.multi-purpose.infrastructure.components.to.climate.change.is.outlined. in.Annex.c. Table 8.3 Scoring matrix template Adaptability Component Criticality Score Sensitivity Score Score Total Score Priority dam.structure reservoir.storage spillways intake.works enter.score.for.each.component.and. Hydropower. under.each.category. Plants sum.scores.and.rank. Caution:.to.be.used.to.gain.insight. low.level.outlet. and.in.conjunction.with.non-numerical. works assessments. tunnels open.channels Top Component in Category 105 106 CHaPTer 9: nexT sTePs: an agenda on ClimaTe CHange for THe waTer PraCTiCe Insight into the various dimensions of water and climate change has identified the gaps and guides the next steps..As.the.world.bank.water.agenda.mainstreams.adaptation. to.the.impact.of.climate.change,.the.questions.raised.at.the.beginning.of.this.report.continue. to.remain.valid.and.should.be.an.integral.part.of.the.ongoing.work.at.the.water.anchor.in. support.of.the.regions..these.questions.are:.(i).what.are.the.impacts.of.climate.variability.and. change.on.water.systems,.both.natural.and.engineered;.(ii).what.are.adaptation.strategies.to. reduce.vulnerability.of.water.systems.to.these.impacts;.and.(iii).how.can.the.bank.assist.client. countries.in.making.informed.decisions.regarding.adaptation.options.in.their.water.investments?. in.relation.to.the.latter.question,.it.is.obvious.that.factors.other.than.climate.change.also.exert. pressure.on.water.resources..in.some.cases.these.factors.may.dominate.climate.change,.in. other.cases.climate.change.induced.pressure.may.dominate..in.all.cases,.informed.decisions. regarding.water.investments.have.to.take.into.account.both.the.climate.and.the.non-climate. induced.pressures. below.the.report.briefly.describes.how.this.flagship.effort.has.provided.tools.to.make.better. informed.decisions.regarding.water.investments.and.the.proposed.areas.of.activity.to.be.carried. out.in.the.future.by.the.water.anchor.in.support.of.the.regions.to.provide.a.basis.for.continuous. improvements.in.decision.making.in.conjunction.with.the.continuous.expansion.of.information.and. knowledge.available.about.the.effects.of.climate.change. Continue to strengthen the analytical foundation Improve the hydrologic projections and exposure assessment methodology for application in project preparation. A.critical.step.in.the.bank's.effort.in.addressing.climate. change.adaptation.is.an.agreed.set.of.future.climate.change.scenarios.for.each.region.to. ensure.consistency.and.compatibility.across.work.in.all.sectors..this.flagship.effort.has.provided. projections.of.the.hydrologic.drivers.for.water.investment..Hydrologic.variability.and.climate. change.signals.have.been.translated.to.indicators.with.quantitative.measures.of.magnitude.and. variability..the.next.step.would.be.to.make.them.readily.available.to.the.regional.staff.for.use..this. will.require.additional.analysis.of.the.projections,.as.well.as.development.of.a.user.interface.(or. adoption.of.an.existing.one).to.facilitate.use..At.the.same.time,.a.plan.shall.be.made.for.updating. the.projections.of.hydrologic.drivers.(and.their.indicators.with.quantitative.measures.of.magnitude. and.variability).for.water.investments.on.a.regular.basis.(say.every.2.to.3.years).as.improved.and. additional.climate.change.scenarios.become.available. Improve the procedure for risk-based approach to adaptation options assessment and decision making. most.conventional.interventions.in.the.water.sector.are.not.likely.to. be.effective.under.increased.conditions.of.variability.and.uncertainty.because.they.have.been. predicated.on.the.assumption.of.hydrologic.stationarity..the.flagship.report.has.considered. the.issue:.how.to.deal.with.projections.in.a.world.where."stationarity.is.dead"..the.report. strongly.argues.for.the.necessity.for.incorporation.of.a.formal.risk-based.approach.in.water. investments..A.framework.for.risk-based.analysis.is.proposed.in.the.report.together.with.an. example.of.how.such.a.framework.may.be.applied.to.the.bank's.project.cycle..the.next.step. would.be.to.further.expand.and.formalize.this.process.to.allow.for.explicit.characterization. of.risks,.options,.and.management.of.risks..the.approach.should.incorporate.unfolding. uncertainties.over.time,.and.account.for.the.performance.of.adaptation.options..this.requires. 107 increased.capability.to.understand,.to.quantify,.and.manage.risk.in.an.environment.of. increased.uncertainty. Improve decision making by expanding economic considerations to explicitly include climate change..the.main.focus.of.this.flagship.effort.was.to.understand.and.characterize.the. behavior.of.the.hydrologic.drivers.that.can.impact.design.and.operation.of.various.water.systems. and.investments..the.current.work.sets.the.stage.for.and.provides.the.needed.information.for.a. risk-based.approach.to.the.assessment.of.the.economics.of.water.investment. In any investment decision, economics figure prominently. Two future areas of work are suggested: 1..it.is.proposed.at.the.country,.river.basin.or.even.sub-river.basin.level.to.prepare.assessments.of. the.cost.of.adaptation..different.interventions.will.have.different.costs.and.in.order.to.focus.on. cost-effective.interventions.early.in.the.project.cycle.it.will.be.valuable.to.have.an.assessment. of.the.cost.of.adaptation.to.address.climate.change.induce.and.non-climate.change.induced. water--related.risks.(whether.flooding,.water.scarcity.or.other)..work.is.already.under.way.to. assess.marginal.cost.curves.for.alleviation.of.water.scarcity..similar,.but.country.or.water.basin. specific.work,.which.also.considers.the.effects.of.pricing.and.other.institutional.policies,.may. contribute.to.focus.on.cost-effective.interventions.and.may.provide.very.useful.guidance.for.dPl. type.interventions..the.division.of.responsibilities.between.the.water.Anchor's.role.to.provide. methodological.guidance.and.the.responsibilities.of.the.bank's.regions.and.country.offices.for. implementation.need.careful.consideration.in.designing.such.work. 2..it.is.proposed.to.initiate.review.of.the.current.methodology.for.project.economic.analysis.and. develop.methodology.for.incorporation.of.climate.change.impacts.at.the.project.level..specific. areas.of.focus.would.be.i).economic.valuations.and.other.metrics.for.ranking.the.potential. impacts.of.climate.change,.and.ii).approaches.to.comparison.of.costs.and.benefits.over.time,. risk.attitudes,.and.distributional.concerns. Finally, in the future work is needed on the impact of climate change on social and economic development..recognizing.that.climate.change.has.real.effects.on.people's. livelihoods,.recognizing.that.these.effects.make.themselves.felt.mainly.via.the.water.cycle,.and. recognizing.that.by.analyzing.the.cumulative.and.cross-sectoral.impacts.it.is.possible.to.gain.an. understanding.of.where.the.bank.may.most.cost-effectively.support.countries.in.their.own.efforts. to.improve.the.livelihoods.of.poor.people,.work.has.been.proposed.(for.example.by.the.china. country.office).to.study.the.impact.of.climate.change.on.social.and.economic.development.at.the. country.level..it.would.be.useful.to.expand.such.work.to.many.bank.client.countries.and.the.water. Anchor.may.contribute.by.providing.back.ground.material.including.but.not.limited.to.typologies. of.countries.and.check.lists.of.impacts.and.dynamics.to.be.considered. incorporate hydrologic variability and climate resiliency considerations in bank operations Guidelines for incorporation of hydrologic variability and climate change in project preparation. this.would.include.use.of.the.improved.methodology.above.to.broadening.the. risk-based.framework.to.include.all.water.systems..A.related.useful.product.would.be.a.response. matrix.of.the.appropriate.coping/adaptation.strategies.to.the.hydrologic.projections.by.water. system,.usage.and.by.climate-sub-region..development.of.a.systematic.process.for.incorporation. 108 of.response.matrix.in.the.project.cycle.would.help.streamline.the.work.of.task.managers..A.series. of.case.studies.to.illustrate.the.process.would.also.be.useful. Develop practitioners notes for feasibility studies, planning and design studies for infrastructure projects. these.notes.should.address.planning.and.design.issues.within.a.basin- wide.context,.rather.than.as.individual.projects..this.would.help.with.optimization.of.infrastructure. design.for.water.storage,.supply,.or.hydropower.taking.into.account.climate.change.factors..the. case.studies.carried.out.as.part.of.the.Flagship.study.can.be.beneficial.in.this.regard..A.note. on.methodology.for.evaluating.projects.on.a.component.(or.water.system).level,.for.criticality.to. project.function,.vulnerability.to.climate.change.impacts,.and.adaptability.in.the.face.of.climate. change,.could.be.helpful.to.task.managers. Implications of climate change in managing ecosystems..the.objective.of.this.activity.would. be.to.first.better.understand.the.climate.change.impacts.on.aquatic.ecosystem.functions.and. resiliency.and.incorporate.a.structured.approach.for.factoring.them.into.integrated.water.resources. planning,.design,.and.operation.decisions. the.guideline.developed.for.this.purpose.should.address.both.environmental.flow.and.water. quality.implications.of.climate.change..it.will.review.how.ecosystem.services.will.be.affected.by.the. changes.in.flow.volumes,.timing.and.quality.due.to.both.natural.climate.variability.and.climate. change..the.implications.of.altered.demand.for.agriculture,.municipal.and.industrial.supply.due. to.climate.change.on.environmental.services.should.be.discussed..the.various.impacts.of.climate. change.on.water.quality.in.rivers.(e.g.,.sediment.loads),.lakes.and.reservoirs.(e.g.,.temperature,. dissolved.oxygen,.mixing,.stratification).and.groundwater.(e.g.,.saltwater.intrusion.in.coastal. aquifers).and.their.implications.on.magnifying.pollution.impacts,.including.on.human.health.and. ecosystem.health.should.be.defined..ecosystem.implications.of.adaptation.responses.including. supply.side.options.and.demand.management,.including.reoperations.should.be.described. Water and carbon footprint of water investments. As.part.of.project.planning.and. implementation,.an.analysis.of.the.carbon.and.water.footprint.of.intervention.could.provide.insight. into.the.sustainability.of.the.proposed.action. strengthen bank expertise on water and climate change Bank staff experience and expertise..climate.change.has.become.a.major.area.of.focus.at. the.bank,.drawing.a.great.deal.of.attention.at.the.corporate.and.the.regional.levels..many.water. professionals.are.engaged.in.climate.change.work.as.evidenced.by.the.increasing.volume.of. climate-related.lending.and.non-lending.activities,.as.well.as.seminars,.workshops,.and.briefings. to.management..with.some.exceptions,.most.of.the.bank.water.staff.lack.practical.experience. in.climate.change.and.hydrologic.variability.related.to.water.resources.management.and.water. services.delivery.systems..much.of.the.current.expertise,.information.and.data.related.to.the.impact. of.climate.change.and.adaptation.strategies.exist.outside.of.the.bank..For.the.bank.to.position.itself. at.the.forefront.of.climate.change.work.in.the.water.sector,.it.is.proposed.that.in-house.expertise. be.strengthened.and.to.the.degree.appropriate,.complemented.by.external.expertise.through.easily. accessible.mechanisms..the.following.specific.actions.are.suggested.as.a.starting.point. ·.expand.the.external.technical.team.of.experts.and.high-level.advisory.group.beyond.hydrologic. drivers.to.include.economics,.and.environmental/social.aspects.of.water.and.climate.change. 109 ·.Formalize.partnerships.with.leading.international,.academic,.and.research.organizations.that.are. reputable.in.the.field.of.climate.change.in.the.water.sector. ·.develop.and.implement.programs.for.building.capacity.based.on.assessment.of.the.knowledge. and.experience.of.bank.staff.and.identified.gaps. ·.engage.the.newly.established.water.resources.management.thematic.group.to.investigate. the.operational.implications.of.incorporating.climate.change.adaptation.options.in.water. investments. 110 10. referenCes Alcamo,.j..and.t..Henrichs..2002..critical.regions:.A.model-based.estimation.of.world.water. resources.sensitive.to.global.changes..Aquatic.sciences.64:.352­362. 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Water Resources Sector Memorandum..report.no..28398.­.ke..washington.dc:.the.world.bank. world.bank..2006..Ethiopia: Managing Water Resources to Maximize Sustainable Growth..country. water.resources.Assistance.strategy. world.bank..2007..idA.and.climate.change:.making.climate.Action.work.for.development.. report.number:.41280..washington.dc:.the.world.bank. world.bank..2008a..development.and.climate.change:.A.strategic.Framework.for.the.world. bank.group:.technical.report..report.number:.47893..washington.dc:.the.world.bank. world.bank,.2008b..Ethiopia: A country Study on Economic Impacts of Climate Change..report. no..46946-et..washington.dc:.the.world.bank. world.bank,.2009a..Assessment.of.climate.impact.on.Peru's.hydrology..development.of.a. methodology..Progress.report.no..1. world.bank..2009b..water.and.climate.change:.impacts.on.groundwater.resources.and. adaptation.options..water.Anchor..energy,.transport.and.water.department..washington.dc:. the.world.bank. wwF.(world.wildlife.Fund)..2009..Flowing Forward: Informing Freshwater Biodiversity and Sustainable Management in a Shifting Climate.(draft.report.prepared.for.the.world.bank). 113 114 annex a: summary of waTer PorTfolio by region africa region Overall water investment Africa.has.committed.a.total.of.$2.billion.in.water.investments.in.Fy06­08,.which.account.for. 12%.of.the.bank's.lending.in.the.region.(Figure.A1)..Among.the.regions,.Africa.has.the.highest. level.of.water.investments,.both.in.terms.of.volume.(23%).and.number.of.projects.(27%)..the. 2003.water.resources.sector.strategy.report.projected.growth.in.the.water.sector.to.this.region,. which.has.been.confirmed.by.the.increase.in.lending.in.the.Fy06­08.period.with.a.yearly. average.of.$685.million,.the.highest.among.all.the.regions.for.a.total.of.52.projects.for.the. entire.period. Water investment by country the.water.investments.are.distributed.among.27.countries.in.the.region.including.regional. projects..countries.with.the.most.number.of.projects.are.ethiopia.(seven),.kenya.(six).and. tanzania.(four).representing.a.third.of.all.water.projects.in.AFr..in.terms.of.volume,.the.largest. investments.went.to.specific.regional.projects,.and.countries.such.as.ethiopia,.kenya.and.nigeria.. there.are.many.small.water.resources.investment.projects.in.the.region,.however.three.of.them. are.worth.mentioning.for.their.large.investment.amounts:.Regional and Domestic Power Markets Development Project-Inga Rehabilitation ($271.million),.Niger Basin Water Resources Development and Sustainable Ecosystems Management ($162.million).and.the.Private Power Generation (Bujagali).project ($115.million)--all.in.the.category.of.multi-purpose.systems. Figure A1 Africa region water investment for the FY06­08 period Lending US$M 0 Lending (%) $1,128 M 0­5 (55%) $926 M 5­25 Services (45%) 25­125 Resources >125 Source: world.bank,.2009. 115 Future water investments AFR expects a major increase in number of water projects in the next two fiscal years27, from an average of 17 projects per year (FY06­08) to an average of 27 projects per year (FY09­10)--the highest among the regions..in.terms.of.lending.volume,.the.pipeline.is.weaker. than.the.current.portfolio..Africa's.pipeline.represents.11%.of.the.total.water.lending.among.the. regions.in.Fy09­10,.a.significant.decrease.compared.to.the.active.period.with.23%.of.the.total. water.investment..moreover,.water.services.systems.are.expected.to.dominate.with.71%.of.the. projected.lending.and.61%.of.the.total.number.of.projects. looking.at.the.pipeline.distribution.by.system,.the.largest.share.of.the.projected.lending.is.directed. towards.urban.water.and.sanitation.(53%).followed.by.irrigation.and.drainage.(16%),.water. resources.management.(14%).and.multi-purpose.facilities.(10%)..A.similar.trend.is.seen.in.terms. of.number.of.projects,.with.urban.water.and.sanitation.systems.dominating.the.water.pipeline..in. comparison.to.the.active.period,.most.increase.is.expected.in.water.resources.management.for. Fy09­10. east asia and Pacific region Overall water investment the.total.active.water.investments.approved.in.Fy06­08.is.$1.7.billion.representing.12%.of.the. total.bank's.lending.in.the.region.(Figure.A2)..water.investment.in.eAP.accounts.for.19%.of.the. Figure A2 East Asia and Pacific region water investment for the FY06­08 period Lending US$M 0 Lending (%) $1,327 M 0­5 (78%) 5­25 Services $364 M 25­125 (22%) >125 Resources Source: world.bank,.2009. 27 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthe preparationphaseoftheproject. 116 overall.bank's.investment.in.water,.which.is.the.third.highest.share.compared.to.other.regions..in. spite.of.the.significant.investment,.water.lending.in.the.region.has.decreased.significantly.through. the.active.period.with.a.yearly.average.lending.of.$564.million.for.a.total.of.26.projects.for.the. entire.period. Water investment by country there.are.seven.countries.with.water.investments.in.the.region.for.the.Fy06­08.period..Following. the.same.pattern.identified.in.the.2003.water.resources.sector.strategy,.china.continues.to. dominate.regional.water.lending.with.almost.70%.of.the.overall.water.investments.in.the.region. (58%.in.terms.of.number.of.projects)..most.of.these.investments.are.concentrated.in.urban.water. and.sanitation.(60%).consisting.of.projects.of.significant.investment:.Henan Towns Water Supply and Sanitation project ($143.million),.Second Liaoning Medium Cities Infrastructure project ($142. million).and.Shanghai Urban Environment APL Phase 2.($126.million)..china.also.has.a.share.of. investment.going.into.irrigation.and.drainage.(14%).corresponding.to.a.lending.of.$136.million. (Irrigated Agriculture Intensification Loan III),.and.many.small.projects.with.water.resources.systems.. vietnam.accounts.for.the.second.largest.share.of.water.investments.(16%),.followed.by.indonesia. (11%).and.Philippines.(4%)..except.for.china,.there.is.little.investment.into.water.resources.systems. by.other.country.in.the.region. Future water investment water.investments.in.Fy09.and.Fy10.are.expected.to.increase.considerably.compared.to.the. Fy06­08.period..the.eAP.region.is.expected.to.account.for.24%.of.all.the.water.investments.(19%. in.terms.of.project.number)..water.services.systems.will.continue.to.dominate,.however.at.a.lesser. degree.(67%.in.terms.of.investments.and.57%.in.terms.of.number.of.projects). Projections.at.the.water.system.level.show.that.53%.of.the.lending.is.in.urban.water.and.sanitation. followed.by.19%.in.multi-purpose.systems..eAP.is.expected.to.have.the.largest.share.(36%).of. watershed.management.investment.among.all.regions..in.terms.of.number.of.projects,.urban. water.and.sanitation.system.is.also.expected.to.dominate.the.pipeline..most.increase.for.the. Fy09­10.period.is.expected.in.water.resources.systems28,.more.specifically.in.multipurpose. facilities. europe and Central asia region Overall water investment the.total.active.water.investments.approved.in.Fy06­08.is.$1.3.million,.which.represents.10%.of. the.total.bank's.lending.in.the.region.(Figure.A3)..Among.the.regions,.europe.and.central.Asia. (ecA).region.accounts.for.14%.of.the.total.water.investments.and.15%.of.total.number.of.projects.. in.the.2003.sector.strategy.portfolio.review,.ecA.was.identified.as.the.region.with.the.smallest. share.of.water.investments.in.the.bank..this.is.no.longer.the.case.as.the.region.is.increasing.its. lending,.and.has.shown.an.average.lending.of.$421.million.with.a.total.of.29.projects.for.the. entire.Fy06­08.period. 28 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthe preparationphaseoftheproject. 117 Water investment by country water.investment.is.distributed.between.16.countries.in.the.region.with.the.bulk.of.water. investment.concentrated.in.Azerbaijan.(39%)..investment.in.the.country.is.all.going.into.urban. water.supply.and.sanitation.with.two.significant.projects,.National Water Supply & Sanitation.($225. million).and.Second National Water Supply and Sanitation project.($257.million)..the.second. and.third.largest.share.of.investments.is.in.Poland.(13%).with.a.project.in.flood.control.and.water. resources.management,.and.croatia.(10%).with.a.project.mainly.in.urban.water.and.sanitation. with.components.in.flood.control.and.water.resources.management..the.remaining.lending.is. distributed.among.13.countries..in.terms.of.number.of.projects,.Azerbaijan.has.four.projects. followed.by.Armenia.and.kyrgyz.(with.three.projects.each). Future water investment water.investments.in.the.ecA.region.have.increased.substantially.over.the.last.couple.of.years.and. this.trend.is.anticipated.to.continue.over.the.Fy09­10.period..the.pipeline.for.ecA.represents.12%. of.the.total.bank's.water.investment..water.services.systems.is.expected.to.continue.to.dominate,. both.in.terms.of.investments.(73%).and.number.of.projects.(67%),.with.an.average.lending.of.over. $300.million.per.year..At.the.system.level,.significant.increase.in.investment.is.expected.for.rural. water.and.sanitation,.irrigation.and.drainage.and.multi-purpose.facilities..urban.water.and.sanitation. will.continue.to.be.the.main.driver.of.water.investments,.however,.irrigation.and.drainage.and.multi- purpose.facilities.are.expected.to.account.for.a.considerable.share.of.total.investments..investments. in.flood.control.represent.a.smaller.share.(10%).in.the.pipeline;.however,.when.compared.to.other. regions,.ecA.still.represents.a.substantial.share.(20%).of.flood.control.investments.in.the.bank29. Figure A3 Europe and Central Asia region water investment for the FY06­08 period Lending US$M 0 $949 M Lending (%) 0­5 (75%) 5­25 Services $314 M 25­125 (25%) Resources >125 Source: world.bank,.2009. 29 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthe preparationphaseoftheproject. 118 latin america and Caribbean region Overall water investment the.total.active.water.investments.approved.in.latin.America.and.caribbean.region.(lcr).in.the. Fy06­08.period.is.$1.2.billion.which.represents.8%.of.the.total.bank's.lending.in.lcr,.the.lowest. compared.to.other.regions.(Figure.A4)..the.lcr's.portfolio.corresponds.to.13%.of.the.overall. bank.investments.in.water..yearly.average.lending.for.lcr.in.Fy06-Fy08.is.$390.million.for.a.total. of.40.projects.for.the.entire.period. Water investment by country For.the.Fy06­08.period,.there.are.40.projects.in.16.countries.with.most.of.the.lending.going. to.Argentina.(23%),.mexico.(23%).and.brazil.(17%)..the.large.amount.of.lending.in.Argentina. and.mexico.represent.only.three.projects.in.each.country:.Argentina.focuses.on.urban.water.and. sanitation.with.a.small.portion.towards.watershed.management,.while.mexico.has.a.balanced. investment.between.urban.water.and.sanitation.and.water.resources.management..there.is.one. project.in.each.country.worth.mentioning.due.to.their.large.investment:.Infrastructure Project for the Province of Buenos Aires APL2 ($146.million).in.Argentina.and.Climate Change DPL ($250. million).in.mexico..Although.there.is.significant.water.investment.in.brazil.(a.total.of.$200.million),. the.lending.is.well.distributed.between.ten.projects.with.most.investment.going.into.water.resources. management.and.urban.water.and.sanitation. Future water investment total.water.investment.for.the.Fy09­10.is.expected.to.double.in.comparison.to.the.Fy06­08. period.accounting.for.24%.of.the.overall.bank's.pipeline.for.water..this.increase.is.the.highest.of. Figure A4 Latin America and Caribbean region water investment for the FY06­08 period Lending US$M 0 $931 M Lending (%) (80%) 0­5 5­25 Services $239 M 25­125 (20%) Resources >125 Source: world.bank,.2009. 119 any.region.with.most.lending.directed.towards.water.services.(74%),.although.lending.for.water. resources.is.also.expected.to.increase.by.almost.threefold. Projection.at.the.water.system.level.is.not.expected.to.vary.significantly.from.the.current.portfolio.. About.64%.of.lending.and.42%.of.projects.is.expected.to.be.in.urban.water.and.sanitation. followed.by.25%.of.lending.and.29%.of.projects.into.water.resources.management..significant. increase.in.investment.is.expected.not.only.for.water.resources.management,.but.also.for.rural. water.and.sanitation..increase.in.lending.is.also.expected.in.urban.water.and.sanitation.and. irrigation.and.drainage,.though.to.a.lesser.degree30. middle east and north africa region Overall water investment the.middle.east.and.north.Africa.(mnA).region.has.committed.a.total.of.$650.million.in.water. investments.for.Fy06­08,.which.accounts.for.14%.of.the.overall.regional.investments.(Figure. A5)..Although.a.significant.portion.of.investment.is.going.to.water,.compared.to.other.regions,. this.represents.a.small.portion.(7%).of.the.bank's.total.commitment.in.water..despite.the.relative. low.water.investment,.lending.increased.during.the.last.three.fiscal.years.with.a.yearly.average. investment.of.$217.million.corresponding.to.a.total.of.16.projects.for.the.entire.period. Water investment by country water.investments.are.distributed.among.eight.countries.in.the.region..of.the.16.projects.approved. in.the.Fy06-Fy08.period.(with.ten.projects.corresponding.to.2008.alone),.egypt.has.the.largest. Figure A5 Middle East and North Africa region water investment for the FY06­08 period Lending US$M 0 $576 M Lending (%) (89%) 0­5 5­25 Services 25­125 $74 M Resources >125 (11%) Source: world.bank,.2009. 30 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthe preparationphaseoftheproject. 120 share.of.commitments.(40%),.followed.by.iraq.(26%),.tunisia.(16%),.morocco.(9%),.and.yemen. (6%)..there.are.three.significant.projects.in.the.region,.two.in.egypt.(West Delta Water Conservation and Irrigation Rehabilitation project of.$141.million.and.the.Integrated Sanitation & Sewerage Infrastructure project.of.$120.million).and.one.in.iraq.(Emergency Water Supply Project.of.$104. million).corresponding.to.56%.of.the.total.water.regional.investment..of.the.six.projects.with.water. resources.systems,.the.one.with.the.largest.commitment.is.in.iraq--Dokan and Derbandikhan Emergency Hydro Power Project ($40.million). Future water investment For.the.Fy09­10.period31,.the.region.is.expected.to.increase.its.yearly.average.lending. investment.in.the.sector..Among.the.regions,.mnA.would.represent.5%.of.the.overall.water. commitments.in.the.bank,.slightly.lower.than.the.Fy06­08.period..most.of.the.lending.is.again. expected.for.projects.with.water.services.(86%).and.will.continue.being.the.highest.share.of.any. region. Projection.at.the.water.system.level.show.most.of.the.lending.going.to.urban.water.and.sanitation,. irrigation.and.drainage,.and.water.resources.management,.each.representing.a.significant.portion. of.the.total.water.pipeline.in.the.region.(44%,.37%.and.14%.respectively)..there.is.a.percentage. increase.in.lending.expected.for.water.resources.management.and.irrigation,.while.there.is.a. percentage.decrease.expected.for.rural.water.and.sanitation,.showing.a.significant.decline.from. the.Fy06­08.period. south asia region Overall water investment south.Asia.region.(sAr).has.committed.a.total.of.$1,945.million.in.water.investment.for.Fy06­08,. accounting.for.14%.of.the.overall.regional.investment.(Figure.A6)..Among.the.regions,.sAr. represents.22%.of.the.overall.water.investment.(15%.in.terms.of.number.of.projects),.which.is.the. second.largest.share.after.AFr..water.investment.in.the.region.has.steadily.increased.during.this. period,.with.yearly.average.of.$648.million.corresponding.to.a.total.of.28.projects.for.the.entire. period. Water investment by country water.investment.in.sAr.for.Fy06­08.is.distributed.among.six.countries.in.the.region..india.is.the. driver.in.the.region.representing.68%.of.water.investments.(less.so.in.terms.of.number.of.projects. ­36%)..Pakistan.has.a.considerable.share.of.investments.(10%),.followed.by.bangladesh,.nepal,. Afghanistan.(6%.each),.and.sri.lanka.(4%)..the.projects.with.the.largest.investments.for.this.period. are.in.india:.Rampur Hydropower Project.($400.million).and.Tamil Nadu Irrigated Agriculture Modernization and Water-Bodies Restoration and Management Project.($291million)..Pakistan.has. also.a.large.irrigation.project:.Sindh Water Sector Improvement Project Phase I ($120.million). 31 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthe preparationphaseoftheproject. 121 Figure A6 South Asia region water investment for the FY06­08 period Lending US$M 0 Lending (%) $1,241 M 0­5 (64%) $703 M 5­25 Services (36%) 25­125 Resources >125 Source: world.bank,.2009. Future water investment in.the.coming.two.fiscal.years.(Fy09-Fy10),.the.projection.for.water.lending.in.the.sAr.region. is.expected.to.increase.to.an.average.lending.of.over.$1.billion.compared.to.$648.million.per. year.for.the.Fy06­08.period..sAr.is.expected.to.represent.26%.of.the.bank's.lending.in.water.. Projects.with.water.services.systems.are.anticipated.to.dominate.62%.of.the.investments,.with.a. stronger.focus.on.urban.water.and.sanitation.(37%).and.irrigation.and.drainage.(26%)..likewise,. lending.for.multi-purpose.facilities.(25%).is.expected.to.continue.strong.and.to.be.the.highest. of.any.region..there.is.also.a.large.lending.increase.expected.for.flood.control.and.watershed. management.systems..unlike.the.Fy06­08.period,.sAr.is.expected.to.decrease.its.investment. in.rural.water.and.sanitation.systems,.thus.the.region.is.no.longer.expected.to.be.the.largest. contributor.of.investments.towards.that.system.32 32 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthe preparationphaseoftheproject. 122 annex b: risk-based deCision making frameworks united kingdom Climate impacts Programme in.may.2003,.ukciP.published.a.technical.report.titled.Climate Adaptation: Risk, Uncertainty and Decision-making.(willows.and.connell,.2003)..this.report."recommends.a.structured.framework. and.associated.guidance.to.promote.good.decision-making".(willows.and.connell,.2003,.p..v).. the.framework.consists.of.the.eight.stages.listed.here.and.illustrated.in.Figure.b1. ·.stage.1:.identify.problem.and.objectives ·.stage.2:.establish.decision-making.criteria ·.stage.3:.Assess.risk ·.stage.4:.identify.options ·.stage.5:.Appraise.options ·.stage.6:.make.decision ·.stage.7:.implement.decision ·.stage.8:.monitor,.evaluate,.and.review. According.to.ukciP:."the.aim.of.using.the.framework.is.for.the.decision-maker.to.identify.where. climate.change.is.a.material.consideration..where.climate.or.climate.change.are.significant,. the.decision-maker.should.aim.to.identify.adaptation.options.for.the.decision.(such.as.no.regret. options).that.are.robust.to.the.key.sources.of.uncertainty".(willows.and.connell,.2003,.p..6). Pros this.framework.focuses.on.the.entire.decision-making.context..issues.of.problem.definition.are. addressed.in.stage.1.and.rechecked.in.stage.6.."Formulating.the.issue.represents.a.critical. stage.for.the.decision-maker..before.embarking.on.a.decision-making.process,.it.is.essential.to. understand.the.reasons.for.the.decision.being.made,.the.decision-maker's.broad.objectives,.and. the.wider.context.for.the.decision".(willows.and.connell,.2003,.p..10). this.framework.quickly.addresses.substantive.issues.by.operationalizing.the.stage.1.problem. definition.in.stage.2.."this.stage.sets.out.the.establishment.of.criteria.for.decision-making.. the.broad.objectives.of.the.decision-maker,.set.out.under.stage.1,.need.to.be.translated. into.operational.criteria.that.can.be.used.in.a.formal.risk.assessment,.and.against.which.the. performance.of.different.options.and.the.subsequent.decision.can.be.appraised".(willows.and. connell,.2003,.p..14)..Although.not.every.adaptation.policy.is.amenable.to.such.formal.analysis,. using.formal.criteria,.when.possible,.maximizes.accountability,.enables.unambiguous.evaluation.of. policy.success.or.failure,.and.assists.in.identifying.informational.needs. ukciP.attempted.to.make.its.framework.context.sensitive.at.key.points.such.as.the.stage.3.risk. assessment.and.the.stage.5.option.appraisal.by.indicating.that.under.certain.circumstances,. resource-.and.time-intensive.steps.can.be.skipped.entirely..the.conditional.nature.of.these.steps,. however,.faces.severe.practical.limitations,.as.discussed.below.under."cons." ukciP.included.stage.7.implementation.and.stage.8.monitoring.as.part.of.their.framework.. However,.these.elements.of.the.decision-making.process.are.not.discussed.because:."the.prime. 123 purpose.of.these.guidelines.is.to.help.the decision-maker.reach.a.decision.and.we.do.not therefore.discuss.in.detail.the."best".means.to.implement.and.monitor.a.decision" (willows.and. connell,.2003,.p..39). Cons the.stage.3.risk.assessment.in.this.framework.is.a.detailed.analysis.that,.in.our.judgment,.requires. expert.practitioners.to.implement..despite.the.attempt.to.simplify.this.step.by.subdividing.it.into. three."tiers":."risk.screening,"."generic.quantitative.risk.assessment,".and."detailed.quantitative. risk.assessment,".its.complexity.may.be.a.barrier.to.its.use.by.decision-makers..namely,.by. subdividing.and.contextualizing.this.step.in.the.framework,.decision-makers.may.either.ignore. this.step.or.delegate.it.to.technical.experts..it.is.not.clear.that.technical.experts.are.either.needed. for.many.decisions.or.the.appropriate.authority.for.deciding.when.sufficient.knowledge.has.been. accumulated.given.time.and.resource.constraints..the.stage.5.option.appraisal.also.has.three.tiers. and.may.suffer.from.similar.problems. stage.4,."identify.options,".follows.the.stage.3.risk.assessment..in.reality,.many.adaptations.exist. that.are.no.regret.policies.which.offer.benefits.under.current.climate.as.well.as.under.projected. changes.in.climate..such.policies.do.not.require.the.preceding.stage.3.risk.assessment.for.their. justification..in.many.circumstances,.engaging.in.stage.4.before.stage.3.can.reduce.the.time. and.resource.demands.of.decision-making.by.identifying.policy.options.that.do.not.require.a.risk. assessment..indeed,.it.is.our.contention.that.options.should.be.identified.early.in.the.decision- making.process. Figure B1 The UKCIP framework 1 Identify problem & objectives 2 Establish decision-making criteria Receptors, exposure units & 8 Monitor risk assessment endpoints 3 Assess risk 7 Implement decision 5 Appraise options 4 Identify options NO NO YES Problem Criteria defined correctly? met? YES 6 Make decision Source: willows.and.connell,.2003,.p..7,.Fig..1. 124 Although.this.framework.claims.to.be."circular".and."iterative".by.incorporating."feedback". mechanisms.and.promoting."adaptive.management,".many.people,.including.decision-makers,. may.have.difficulty.understanding.how.different.stages.of.a.process.like.this.feedback.on.one. another..According.to.Figure.b1,.almost.every.stage.in.this.framework.should.feed.back.to.earlier. stages..only.stage.6,."make.decision,".has.formal.logical.criteria.for.deciding.whether.to.revisit. previous.stages..in.essence,.the.interrelationships.between.framework.stages.may.be.too.complex. to.be.useful.to.many.decision-makers.who.are.limited.by.incomplete.information.and.multiple. demands.on.their.time. australian greenhouse office in.2006,.the.Australian.greenhouse.office.published.a.report.titled.Climate Change Impacts & Risk Management: A Guide for Business and Government.(broadleaf.and.mjA,.2006).. According.to.the.report,."the.guide.provides.a.framework.for.managing.the.increased.risk.to. organizations.due.to.climate.change.impacts..the.prime.focus.of.the.guide.is.on.the.initial. assessment.and.prioritization.of.these.risks".(broadleaf.and.mjA,.2006,.p..9)..notably,.this. framework.uses.the.Australian.and.new.Zealand.standard.for.risk.management,.As/nZs. 4360.(standards.Australia,.2004),.to.extend.the.application.of.this.widely.used.guidance.on. risk.management.in.the.public.and.private.sectors.to.risks.generated.by.climate.change.and. its.impacts..the.framework.consists.of.the.five.steps.and.two.umbrella.activities.listed.here.and. illustrated.in.Figure.b2. ·.step.1.establish.the.context ·.step.2.identify.the.risks ·.step.3.Analyze.the.risks ·.step.4.evaluate.the.risks ·.step.5.treat.the.risks ·.umbrella.activities ·.communication.and.consultation ·.monitor.and.review Figure B2 The Australian framework COMMUNICATE AND CONSULT ESTABLISH IDENTIFY ANALYSE EVALUATE TREAT THE CONTEXT THE RISKS THE RISKS THE RISKS THE RISKS Objectives What can Review controls Evaluate risks Identify options Stakeholders happen Likelihoods Rank risks Select the best Criteria How could it Consequences Screen minor risks Develop plans Key elements happen Level of risk Implement Climate scenarios MONITOR AND REVIEW source:.broadleaf.and.mjA,.2006,.p..19,.Fig..5. 125 Pros the.Australian.framework.offers.a.simple,.linear.decision.process.that.can.be.implemented.by.a. wide.range.of.people.without.requiring.specific.expertise.in.risk.assessment.methodologies..this. is.particularly.important.in.creating.a.framework.that.can.be.used.by.decision-makers..According. to.the.Australian.greenhouse.office,."the.process.requires.only.standard.climate.scenarios,.a. general.understanding.of.the.impacts.of.climate.change,.comprehensive.understanding.of.the. business.or.organization.and.sound.professional.judgment".(broadleaf.and.mjA,.2006,.p..18). even.though.the.decision.process.as.outlined.is.linear,.it.also.allows.for.interconnectedness. through.the.two.umbrella.functions.of.communication/consultation.and.monitor/review..According. to.the.greenhouse.office,."communication.and.consultation.are.key.components.of.any.risk. management.process.and.are.required.at.each.step..success.relies.on.achieving.a.high.level.of. creative.input.and.involving.all.parties.with.a.role.to.play.in.identifying,.assessing.and.managing. climate.change.risks..in.both.the.planning.and.execution.of.the.risk.management.process.it.is. important.to.ensure.that.all.those.who.need.to.be.involved.are.kept.informed.of.developments.in. the.understanding.of.risks.and.the.measures.taken.to.deal.with.them".(broadleaf.and.mjA,.2006,. p..20)..Also,.regarding.the.monitor/review.umbrella.function,."the.outputs.of.all.steps.of.the. risk.management.process.must.be.kept.under.review.so.that,.as.circumstances.change.and.new. information.comes.to.hand,.plans.can.be.maintained.and.kept.up.to.date".(broadleaf.and.mjA,. 2006,.p..20). the.Australian.framework.also.allows.for.multiple.levels.of.analysis.as.circumstances.dictate.. "to.allow.effort.to.be.directed.towards.the.highest.priority.issues,.a.two-stage.approach.to.risk. assessment.is.recommended.to.users.of.this.guide:.(1).An.initial.assessment.identifies.and.sifts. risks.quickly,.followed.by.treatment,.planning,.and.implementation.for.those.risks.that.clearly. require.it;.and.(2).detailed.analysis.is.used.where.additional.information.is.needed.to.determine. whether.treatment.is.required.or.what.form.of.treatment.to.adopt".(broadleaf.and.mjA,.2006,.p.. 21)..this.allows.for.the.differential.treatment.of.policy.actions.that.are.no.regret.and.those.that. may.have.significant.costs.or.externalities.that.merit.greater.analysis.and.consideration. Cons the.front.end.of.this.framework.includes.many.critical.tasks.within.step.1,."establish.the. context,".such.as."clarifying.explicitly.the.objectives.of.the.organization,"."establishing.success. criteria.against.which.risks.to.the.organization's.objectives.can.be.evaluated,".and."identifying. stakeholders.and.their.objectives.and.concerns".(broadleaf.and.mjA,.2006,.p..19)..However,. because.so.many.important.tasks.are.aggregated.into.a.single.step.in.the.framework,.some.of. those.tasks.could.be.neglected.or.presumed,.and.decision-makers.might.proceed.to.the.technical. aspects.of.risk.assessment.without.critically.considering.these.front-end.tasks. the.Australian.framework.does.not.contain.any.information.or.guidance.about.turning.a.decision. into.action..essentially,.this.framework.neglects.the.important.tasks.of.policy.construction,. promotion,.and.implementation--failing.not.only.to.discuss.them,.but.even.to.mention.them.as. part.of.the.decision.process. this.framework.proposes.to.execute.a.decision.process.and.risk.assessment.through.a.single. methodology--the.workshop.format..this.includes.steps.2,.3,.and.4,.the.identification,.analysis,. and.evaluation.of.risks..Although.qualitatively.assessing.risks.can.be.very.useful.for.involving. 126 stakeholders.and.for.avoiding.the.tendency.to.get.bogged.down.in.technical.analyses.that.may.not. be.necessary.to.take.action,.there.are.times.when.a.more.formal.risk.assessment.is.appropriate.. this.is.particularly.the.case.when.the.decision-maker.is.a.technical.expert,.when.costs.may.be.very. high,.when.the.range.of.risks.due.to.climate.change.is.very.wide,.when.significant.uncertainties. prevent.an.accurate.assessment.of.risk.likelihood.or.consequence,.and.so.on..Although.the. detailed.risk.assessment.is.meant.to.address.these.issues,.the.Australian.greenhouse.office.still. claims,."the.process.of.implementing.the.detailed.analysis.will,.in.most.cases,.be.particular.to. your.organization.and.to.the.different.risks.faced.by.your.organization..For.this.reason,.it.is.not. feasible.or.appropriate.to.offer.specific.guidance.on.the.detailed.analysis".(broadleaf.and.mjA,. 2006,.p..54). 127 128 annex C: adaPTaTion oPTions for mulTi-PurPose infrasTruCTure dam structure concrete.dams.have.greater.adaptive.capacity.than.embankment.dams,.owing.to.the.fact.that. they.are.normally.founded.on.rock,.and.can.be.strengthened.to.withstand.higher.flood.loadings-- including.overtopping.in.some.circumstances..embankment.dams.cannot.be.modified.readily.to. the.same.extent,.and.are.therefore.more.challenging.to.adapt. since.foundation.conditions.often.dictate.the.type.of.dam.that.can.be.economical.for.a.given. project.site,.criteria.that.involve.climate.change.impacts.will.likely.not.drive.the.decision.. nonetheless,.climate.factors.should.be.considered.in.evaluating.the.type.and.size.of.dam.to. be.constructed..siting.studies.may.consider.configuring.the.dam.in.such.a.way.as.to.enable. economical.future.raising,.perhaps.through.the.use.of.saddle.dams.along.reservoir.rims..Another. strategy.would.be.to.consider.use.of.multiple.sites.to.achieve.the.head.or.storage.objectives.of. a.single-dam.development..in.such.cases,.it.may.be.that.two.smaller.developments.can.have.a. smaller.environmental.footprint.than.one.large.dam,.thereby.providing.added.value.to.this.solution. reservoir storage reservoir.storage.and.yield.is.a.function.of.the.storage.volume.required.to.produce.the.desired. yield.against.a.certain.probability.of.exceedance.(or.failure)..it.is.one.of.the.early.planning. activities.because.much.of.the.built.infrastructure.and.the.configuration.of.dam.components. depend.upon.this.parameter. once.a.given.site.for.the.reservoir.is.selected.(based.on.a.host.of.geologic,.hydrologic,.and. topographic.criteria).then.the.ability.to.provide.the.desired.yield.is.a.function.of.the.minimum. and.maximum.reservoir.levels.necessary.to.provide.the.active.storage..the.minimum.level.is. determined.based.upon.sedimentation.criteria,.while.the.top.of.dam.elevation.is.set.by.the. optimization.of.flood.routing.studies.and.dam.stability.in.order.to.establish.the.optimum.trade-off. between.flood.storage.and.peak.reduction.versus.spillway.head.and.discharge.capacity. so.this.component.governs.the.dam.height.and.spillway.capacity,.which.are.often.the.two.most. expensive.components.of.the.project..this.also.has.socioeconomic.implications.relating.to. resettlement.of.marginal.populations. use.of.the.term."optimum".immediately.raises.a.flag,.because.it.implies.that.a.host.of.competing. criteria.has.been.used.to.determine.a.trade-off.that.is.invariant..this.is.counter.to.the.entire. concept.of.potential.unknown.climate.change.impacts.that.must.be.designed.against..For.future. projects.in.the.planning.and.design.stage,.it.is.now.prudent.to.consider.more.variability.and. another.degree.of.freedom.than.has.traditionally.been.the.case. use.of.top.down.probabilistic.analysis.may.require.information.and.data.that.is.not.available.(or. highly.uncertain)..An.interesting.alternative.hereto.is.the.use.of.risk--based.decision.models,.which. generate.a.large.number.of.scenarios.based.on.monte-carlo.simulations.and.then.analyze.the. outcomes.for.a.range.of.scenarios. For.existing.project.vulnerabilities,.adaptation.will.involve.means.of.enlarging.the.reservoir.storage. volume,.either.by.raising.the.maximum.operating.level,.or.lowering.the.minimum.level,.or.both.. 129 lowering.the.minimum.level.is.problematic,.since.it.is.a.function.of.sedimentation.and.would. require.expensive.underwater.construction..raising.the.maximum.level.could.require.modifications. to.upgrade.dam.stability.or.increase.spillway.capacity,.or.both..these.modifications.can.also.be. very.expensive..Another.option.for.projects.which.are.part.of.a.multi-project.basin.development. is.to.distribute.the.storage.among.multiple.locations,.either.at.existing.reservoirs.or.at.new.sites,. where.additional.storage.can.economically.be.provided. service & auxiliary spillways depending.upon.the.project.configuration,.the.service.and.auxiliary.spillway.system.can.be.the. second-most.expensive.component.of.the.project,.after.the.dam..An.exception.would.be.a.low- head.run-of-river.project.where.the.dam.itself.serves.as.an.overflow.spillway. For.large.storage.reservoirs,.a.reservoir.routing.analysis.is.done.to.analyze.and.optimize.the. trade-off.between.flood.inflow,.reservoir.storage,.and.project.outflow.so.that.the.spillway.system.is. properly.designed..service.spillways.are.generally.massive.concrete.structures,.founded.on.sound. rock.or.constructed.integrally.with.a.concrete.dam..Auxiliary.spillways.normally.traverse.one.of.the. dam.abutments,.and.can.consist.of.an.overflow.weir.and.channel,.or.may.have.an.erodible."fuse- plug".control.to.prevent.premature.operation.of.the.auxiliary.spillway. the.primary.criterion.for.designing.spillways.for.climate.change.is.the.selection.of.the.flood. peak.discharge.and.volume.that.will.govern.the.design..in.most.cases,.this.is.the.Probable. maximum.Flood.(PmF),.which.is.derived.from.the.Probable.maximum.Precipitation.(PmP),.along. with.watershed.characteristics..since,.in.the.climate.changed.future,.both.the.precipitation. and.the.watershed.characteristics.(due.to.temperature,.vegetation,.and.soil.moisture.and. groundwater.conditions).can.vary,.solutions.must.consider.variations.in.both.rainfall.and.runoff. characteristics. even.in.the.absence.of.a."return.period".concept.in.the.case.of.the.PmF,.the.uncertainty.of.how. PmP.and.watershed.characteristics.may.change.in.future.presents.a.challenge.to.the.designer..in. the.developed.world,.hydrometeorology.advances.have.been.incorporated.into.PmP.and.PmF. studies.to.enable.site-specific.assessments.that.provide.a.more.rational.basis.for.project.planning. and.design..the.cost.of.such.investigations.is.often.economical.when.compared.to.the.cost.of. providing.additional.spillway.capacity. retrofitting.existing.spillways.to.provide.additional.capacity.has.been.a.routine.activity.in.the. developed.world,.where.advances.in.hydrologic.analysis,.dam.failures,.and.large.populations.at. risk.have.led.to.regulatory.requirements.to.provide.increased.flood.protection.at."high-hazard". dams..these.measures.can.include: ·.Providing.gates.atop.existing.ungated.spillways; ·.raising.gate.heights,.or.adding.additional.gated.bays; ·.stability.improvements.to.allow.overtopping.of.critical.structures.without.failure; ·.Provision.of.additional.auxiliary.spillway.capacity;.or ·.combinations.of.the.above. A.common.thread.among.all.of.these.options.is.high.cost,.underscoring.the.benefits.of.designing. and.building."adequate".spillway.systems.from.the.beginning. 130 For.less.severe,.more.frequent.flood.conditions,.operational.measures.to.predict.flood.events. either.seasonally.or.in.real-time.may.be.employed..this.may.enable.pre-lowering.("voiding").of. the.reservoir.storage.in.order.to.better.manage.expected.flood.runoff.or.events..For.example,.the. city.of.new.york.uses.snow.survey.data.to.enable."voiding".of.downstream.water.supply.reservoirs. in.order.to.provide.flood.control.benefits.without.adversely.impacting.water.supply..the.volume.of. voiding.is.limited.to.one-half.of.the.predicted.snowpack,.thereby.ensuring.that.the.reservoir.will. refill.for.the.coming.supply.season. intake and low-level outlet works Intakes..much.of.the.above.discussion.on.options.for.increasing.reservoir.storage.is.applicable.to. the.intake.works,.as.this.is.the.means.of.exploiting.the.available.storage..raising.the.intake.works. along.with.a.raised.reservoir.is.likely.required,.since.criteria.for.maximum.allowable.entrance. velocities.(to.prevent.debris.and.fish.entrainment).govern.the.size,.location.and.number.of.intake. ports.required. modification.of.existing.intakes.to.accommodate.lower.operating.levels.is.difficult.and.expensive.to. achieve..building.such.flexibility.into.the.planning.and.design.of.new.intakes.is.the.recommended. approach..of.equal.importance.is.to.provide.proper.watershed.management.to.minimize.soil. erosion.and.siltation.problems.in.the.reservoir..in.tropical.and.subtropical.areas,.vegetation. management--both.terrestrial.and.aquatic--is.also.necessary..Hydropower.production.in.Zambia. has.been.recently.impacted.due.to.excessive.aquatic.vegetation.clogging.hydropower.plant. intakes. Low-Level Outlets..Adapting.low-level.outlet.works.to.climate.change.impacts.presents.many. of.the.same.challenges.as.tunnels..often.designed.to.a.fixed.capacity.and.size,.and.imbedded. within.project.structures.below.normal.operating.levels,.such.outlets.are.not.easily.or.economically. adapted..Possible.strategies.may.include: ·.design.outlet.works.with.redundant.water.passages.that.can.be.closed.off.or.opened.as.future. conditions.warrant;.or ·.Provide.parallel.component.systems--water.supply.outlets.and.spillway.outlets,.for.example-- that.can.be.used.interchangeably.or.in.tandem.as.needs.arise. Hydropower plant key.design.elements.of.hydropower.plants.are.the.intakes,.water.conductors,.and.turbine- generator.sets..once.these.elements.are.sized.and.built,.they.are.not.readily.changed..in.the. past,.it.has.been.common.practice.in.the.planning.and.design.stages.to.consider.provisions.for. staged.development.of.the.power.component,.providing.block-outs.and.skeleton.bays.for.future. construction.of.additional.water.conductors.and.installation.of.turbine-generator.sets..However,. this.adds.to.the.upfront.cost.while.risking.a.stranded.investment,.if.the.need.for.the.expansion.does. not.arise. Hydroelectric.equipment.is.designed.to.operate.within.a.given.range.of.head,.discharge.and. efficiency.conditions..there.is.some.flexibility.within.a.given.equipment.design.for.(less).efficient. operation.above.and.below.the.design.optimum..However,.the.number.of.units,.sizes.of.intakes. and.water.conductors,.and.related.structural.components.are.relatively.fixed.once.they.are.sized. and.constructed. 131 Another.key.factor.in.adapting.hydroplants.to.climate.change.is.the.dispatch.criteria.for.fitting.the. hydropower.plant.into.the.overall.system.demand.profile..Hydroplants.are.frequently.operated. as."load-following".or."peaking".plants,.because.of.their.inherent.ability.to.increase.or.decrease. generating.capacity.and.energy.output.on.a.short-term.time.horizon. Adapting.hydropower.plants.to.a.climate-change.future.requires.comprehensive.analysis.of. power.and.energy.demand.to.be.served,.water.availability.under.a.relevant.range.of.future. climate.scenarios,.and.cost.of.power.versus.cost.of.construction.to.achieve.the.required.return. on.investment.(roi).from.the.plant..consideration.of.these.factors.will.inevitably.lead.to. providing.multiple.units.of.equal.or.varying.capacity,.so.that.a.wide.range.of.production.and. demand.scenarios.can.be.accommodated. Tunnels tunnels.often.serve.project.performance.needs,.taking.maximum.advantage.of.the.available. driving.head.from.the.reservoir..sizing.of.these.structures.is.usually.done.to.a.fairly.tight. specification.of.design.discharge,.and.they.have.specific.requirements.(e.g.,.requiring.plant. shutdown.to.effect.any.modifications).that.can.make.post-construction.modifications.difficult.and. expensive. in.certain.applications,.use.of.tunnels.as.water.conductors.for.hydropower.plants,.outlet.works,. and.even.spillway.systems.is.a.sound.technical.and.economic.decision..However,.for.many.of.the. same.reasons.described.above.for.hydroplants,.they.are.not.readily.modified.or.retrofitted.post- construction. this.again.speaks.to.the.premium.placed.upon.the.upfront.planning.and.design.activities. necessary.to.size.the.works.and,.where.possible,.climate-proof.them..one.option.for.tunnels.is. to.design.them.to.operate.as.open.channels,.but.with.the.ability.to.function.safely.and.reliably.as. pressure.conduits.at.higher.discharge.levels. open channels open-channel.conveyances.or.canals.provide.some.measure.of.adaptability.in.response.to. climate.change.impacts..solutions.will.generally.involve.reducing.freeboard,.or.widening.or. deepening.the.cross-section.by.excavation..it.is.more.expensive.to.modify.a.lined.channel.than.an. unlined.channel,.and.even.deepening.of.an.unlined.channel.might.require.the.introduction.of.a. lining.if.significantly.different.foundation.materials.are.encountered..depending.upon.freeboard. and.lining.conditions,.canals.can.operate.at.higher-than-design.discharges.by.modifying.the. control.structures.to.allow.it..it.may.therefore.be.that.the.adaptability.of.the.control.structures. governs.the.adaptability.of.the.canal,.rather.than.the.channel.itself. 132 annex d: glossary of Terms (source:.bates.et.al,.2008,.except.where.noted) adaptation initiatives.and.measures.to.reduce.the.vulnerability.of.natural.and.human.systems.against.actual.or. expected.climate.change.effects..various.types.of.adaptation.exist,.e.g..anticipatory.and.reactive,. private.and.public,.and.autonomous.and.planned..examples.are.raising.river.or.coastal.dikes,.the. substitution.of.more.temperature-shock.resistant.plants.for.sensitive.ones,.etc. adaptive capacity the.whole.of.capabilities,.resources.and.institutions.of.a.country.or.region.to.implement.effective. adaptation.measures. Climate climate.in.a.narrow.sense.is.usually.defined.as.the.average.weather,.or.more.rigorously,.as.the. statistical.description.in.terms.of.the.mean.and.variability.of.relevant.quantities.over.a.period.of. time.ranging.from.months.to.thousands.or.millions.of.years..the.classical.period.for.averaging. these.variables.is.30.years,.as.defined.by.the.world.meteorological.organization..the.relevant. quantities.are.most.often.surface.variables.such.as.temperature,.precipitation.and.wind..climate.in. a.wider.sense.is.the.state,.including.a.statistical.description,.of.the.climate.system. Climate change climate.change.refers.to.a.change.in.the.state.of.the.climate.that.can.be.identified.(e.g.,.by.using. statistical.tests).by.changes.in.the.mean.and/or.the.variability.of.its.properties,.and.that.persists. for.an.extended.period,.typically.decades.or.longer..climate.change.may.be.due.to.natural. internal.processes.or.external.forcings,.or.to.persistent.anthropogenic.changes.in.the.composition. of.the.atmosphere.or.in.land.use..note.that.the.united.nations.Framework.convention.on. climate.change.(unFccc),.in.its.Article.1,.defines.climate.change.as:.a.change.of.climate. which.is.attributed.directly.or.indirectly.to.human.activity.that.alters.the.composition.of.the.global. atmosphere.and.which.is.in.addition.to.natural.climate.variability.observed.over.comparable.time. periods'..the.unFccc.thus.makes.a.distinction.between.climate.change.attributable.to.human. activities.altering.the.atmospheric.composition,.and.climate.variability.attributable.to.natural.causes. Climate model A.numerical.representation.of.the.climate.system.based.on.the.physical,.chemical.and. biological.properties.of.its.components,.their.interactions.and.feedback.processes,.and. accounting.for.all.or.some.of.its.known.properties..the.climate.system.can.be.represented.by. models.of.varying.complexity,.that.is,.for.any.one.component.or.combination.of.components. a.spectrum.or.hierarchy.of.models.can.be.identified,.differing.in.such.aspects.as.the.number. of.spatial.dimensions,.the.extent.to.which.physical,.chemical.or.biological.processes.are. explicitly.represented,.or.the.level.at.which.empirical.parameterisations.are.involved..coupled. Atmosphere-ocean.general.circulation.models.(Aogcms).provide.a.representation.of.the. climate.system.that.is.near.the.most.comprehensive.end.of.the.spectrum.currently.available.. 133 there.is.an.evolution.towards.more.complex.models.with.interactive.chemistry.and.biology.. climate.models.are.applied.as.a.research.tool.to.study.and.simulate.the.climate,.and.for. operational.purposes,.including.monthly,.seasonal.and.interannual.climate.predictions. Climate projection A.projection.of.the.response.of.the.climate.system.to.emissions.or.concentration.scenarios.of. greenhouse.gases.and.aerosols,.or.radiative.forcing.scenarios,.often.based.upon.simulations. by.climate.models..climate.projections.are.distinguished.from.climate.predictions.in.order.to. emphasize.that.climate.projections.depend.upon.the.emission/concentration/radiative.forcing. scenario.used,.which.are.based.on.assumptions.concerning,.for.example,.future.socioeconomic. and.technological.developments.that.may.or.may.not.be.realised.and.are.therefore.subject.to. substantial.uncertainty. Climate scenario A.plausible.and.often.simplified.representation.of.the.future.climate,.based.on.an.internally. consistent.set.of.climatological.relationships.that.has.been.constructed.for.explicit.use.in.investigating. the.potential.consequences.of.anthropogenic.climate.change,.often.serving.as.input.to.impact. models..climate.projections.often.serve.as.the.raw.material.for.constructing.climate.scenarios,.but. climate.scenarios.usually.require.additional.information.such.as.about.the.observed.current.climate.. A.climate.change.scenario.is.the.difference.between.a.climate.scenario.and.the.current.climate. Climate system the.climate.system.is.the.highly.complex.system.consisting.of.five.major.components:.the. atmosphere,.the.hydrosphere,.the.cryosphere,.the.land.surface.and.the.biosphere,.and.the. interactions.between.them..the.climate.system.evolves.in.time.under.the.influence.of.its.own. internal.dynamics.and.because.of.external.forcings.such.as.volcanic.eruptions,.solar.variations.and. anthropogenic.forcings.such.as.the.changing.composition.of.the.atmosphere.and.land-use.change. Climate variability climate.variability.refers.to.variations.in.the.mean.state.and.other.statistics.(such.as.standard. deviations,.the.occurrence.of.extremes,.etc.).of.the.climate.on.all.spatial.and.temporal.scales. beyond.that.of.individual.weather.events..variability.may.be.due.to.natural.internal.processes. within.the.climate.system.(internal.variability),.or.to.variations.in.natural.or.anthropogenic. external.forcing.(external.variability). Confidence As.defined.by.the.iPcc,.the.degree.of.confidence.in.being.correct.is.described.as.follows: very.high.confidence.. At.least.9.out.of.10.chance.of.being.correct High.confidence.. About.8.out.of.10.chance medium.confidence.. About.5.out.of.10.chance low.confidence.. About.2.out.of.10.chance very.low.confidence.. less.than.a.1.out.of.10.chance 134 detection and attribution climate.varies.continually.on.all.time.scales. Detection of.climate.change is.the.process.of demonstrating.that.climate.has.changed.in some.defined.statistical.sense,.without providing.a. reason.for.that.change..Attribution of.causes.of.climate.change.is.the.process.of establishing.the. most.likely.causes.for.the detected.change.with.some.defined.level.of confidence. downscaling downscaling.is.a.method.that.derives.local-to.regional-scale.(10.to.100km).information. from.larger-scale.models.or.data.analyses..two.main.methods.are.distinguished:.dynamical. downscaling.and.empirical/statistical.downscaling..the.dynamical.method.uses.the.output.of. regional.climate.models,.global.models.with.variable.spatial.resolution.or.high-resolution.global. models..the.empirical/statistical.methods.develop.statistical.relationships.that.link.the.large- scale.atmospheric.variables.with.local/regional.climate.variables..in.all.cases,.the.quality.of.the. downscaled.product.depends.on.the.quality.of.the.driving.model. emissions scenario A.plausible.representation.of.the.future.development.of.emissions.of.substances.that.are.potentially. radiatively.active.(e.g.,.greenhouse.gases,.aerosols),.based.on.a.coherent.and.internally.consistent. set.of.assumptions.about.driving.forces.(such.as.demographic.and.socioeconomic.development,. technological.change).and.their.key.relationships..concentration.scenarios,.derived.from.emission. scenarios,.are.used.as.input.to.a.climate.model.to.compute.climate.projections..in.iPcc.(1992).a. set.of.emission.scenarios.was.presented.which.were.used.as.a.basis.for.the.climate.projections.in. iPcc.(1996)..these.emission.scenarios.are.referred.to.as.the.is92.scenarios..in.the.iPcc.special. report.on.emission.scenarios.(nakienovi.and.swart,.2000).new.emission.scenarios,.the.so-called. sres.scenarios,.were.published. ensemble A.group.of.parallel.and.model.simulations.used.for.climate.projections..variation.of.the.results. across.the.ensemble.members.gives.an.estimate.of.uncertainty..ensembles.made.with.the.same. model.but.different.initial.conditions.only.characterise.the.uncertainty.associated.with.internal. climate.variability,.whereas.multi-model.ensembles.including.simulations.by.several.models. also.include.the.impact.of.model.differences..Perturbed-parameter.ensembles,.in.which.model. parameters.are.varied.in.a.systematic.manner,.aim.to.produce.a.more.objective.estimate.of. modelling.uncertainty.that.is.possible.with.traditional.multi-model.ensembles. exposure in.this.context.of.this.report,.exposure.refers.to.bank.projects.and/or.regional.investments.being. subjected.to.negative.changes.in.annual.runoff.(from.present.day.values).in.the.year.2030.or. 2050..the.climate.change.exposure.index.was.defined.as.follows.for.all.projects.except.flood. control.projects: 135 Exposure Index Description Water systems (non flood control) low. %.reduction.in.annual.runoff.....less.than.5% medium. %.reduction.in.annual.runoff.....between.5.and.15% High. %.reduction.in.annual.runoff.....more.than.15% Flood control system low. %.reduction.in.annual.runoff.....more.than.15% middle. .%.reduction.in.annual.runoff.....between.5.and.15% High.. .%.reduction.in.annual.runoff.....less.than.5% flexibility the.flexibility.of.a.system.refers.to.its.ability.to.adapt.to.a.wide.range.of.operating.conditions. through.relatively.modest.and.inexpensive.levels.of.redesign,.refitting.or.reoperation.(Hashimoto,. t..et.al.,.1982a). general Circulation model see.Climate model. greenhouse effect greenhouse.gases.effectively.absorb.thermal.infrared.radiation,.emitted.by.the.earth's.surface,.by. the.atmosphere.itself.due.to.the.same.gases,.and.by.clouds..Atmospheric.radiation.is.emitted.to. all.sides,.including.downward.to.the.earth's.surface..thus.greenhouse.gases.trap.heat.within.the. surface.troposphere.system..this.is.called.the.greenhouse.effect..thermal.infrared.radiation.in.the. troposphere.is.strongly.coupled.to.the.temperature.of.the.atmosphere.at.the.altitude.at.which.it.is. emitted..in.the.troposphere,.the.temperature.generally.decreases.with.height..effectively,.infrared. radiation.emitted.to.space.originates.from.an.altitude.with.a.temperature.of,.on.average,.­19°c,. in.balance.with.the.net.incoming.solar.radiation,.whereas.the.earth's.surface.is.kept.at.a.much. higher.temperature.of,.on.average,.+14°c..An.increase.in.the.concentration.of.greenhouse.gases. leads.to.an.increased.infrared.opacity.of.the.atmosphere,.and.therefore.to.an.effective.radiation. into.space.from.a.higher.altitude.at.a.lower.temperature..this.causes.a.radiative.forcing.that.leads. to.an.enhancement.of.the.greenhouse.effect,.the.so-called.enhanced.greenhouse.effect. greenhouse gas (gHg) greenhouse.gases.are.those.gaseous.constituents.of.the.atmosphere,.both.natural.and. anthropogenic,.that.absorb.and.emit.radiation.at.specific.wavelengths.within.the.spectrum.of. thermal.infrared.radiation.emitted.by.the.earth's.surface,.the.atmosphere.itself,.and.by.clouds.. this.property.causes.the.greenhouse.effect..water.vapour.(H2o),.carbon.dioxide.(co2),.nitrous. oxide.(n2o),.methane.(cH4).and.ozone.(o3).are.the.primary.greenhouse.gases.in.the.earth's. atmosphere..moreover,.there.are.a.number.of.entirely.human-made.greenhouse.gases.in.the. atmosphere,.such.as.the.halocarbons.and.other.chlorine.and.bromine.containing.substances,. dealt.with.under.the.montreal.Protocol..beside.co2,.n2o.and.cH4,.the.kyoto.Protocol.deals.with. the.greenhouse.gases.sulphur.hexafluoride.(sF6),.hydrofluorocarbons.(HFcs).and.perfluorocarbons. (PFcs). 136 Hydrological cycle the.cycle.in.which.water.evaporates.from.the.oceans.and.the.land.surface,.is.carried.over.the. earth.in.atmospheric.circulation.as.water.vapour,.condensates.to.form.clouds,.precipitates.again. as.rain.or.snow,.is.intercepted.by.trees.and.vegetation,.provides.runoff.on.the.land.surface,. infiltrates.into.soils,.recharges.groundwater,.discharges.into.streams,.and.ultimately,.flows.out. into.the.oceans,.from.which.it.will.eventually.evaporate.again.(Ams,.2000)..the.various.systems. involved.in.the.hydrological.cycle.are.usually.referred.to.as.hydrological.systems. (Climate change) impacts the.effects.of.climate.change.on.natural.and.human.systems..depending.on.the.consideration.of. adaptation,.one.can.distinguish.between.potential.impacts.and.residual.impacts: ·.Potential impacts:.all.impacts.that.may.occur.given.a.projected.change.in.climate,.without. considering.adaptation. ·.Residual impacts:.the.impacts.of.climate.change.that.would.occur.after.adaptation. likelihood As.defined.by.the.iPcc,.the.likelihood.of.the.occurrence/outcome.is.described.below: virtually.certain.. >99%.probability.of.occurrence very.likely.. 90.to.99%.probability likely.. 66.to.90%.probability About.as.likely.as.not.. 33.to.66%.probability unlikely.. 10.to.33%.probability very.unlikely.. 1.to.10%.probability exceptionally.unlikely.. <1%.probability mitigation technological.change.and.substitution.that.reduce.resource.inputs.and.emissions.per.unit.of. output..Although.several.social,.economic.and.technological.policies.would.produce.an.emission. reduction,.with.respect.to.climate.change,.mitigation.means.implementing.policies.to.reduce. greenhouse.gas.emissions.and.enhance.sinks. no-regrets policy A.policy.that.would.generate.net.social.and/or.economic.benefits.irrespective.of.whether.or.not. anthropogenic.climate.change.occurs. Projection A.potential.future.evolution.of.a.quantity.or.set.of.quantities,.often.computed.with.the.aid.of. a.model..Projections.are.distinguished.from.predictions.in.order.to.emphasize.that.projections. 137 involve.assumptions.concerning,.for.example,.future.socioeconomic.and.technological. developments.that.may.or.may.not.be.realised,.and.are.therefore.subject.to.substantial.uncertainty. reliability reliability.is.defined.as.the.likelihood.that.services.are.delivered.(no.failure).within.a.given.period,. expressed.as.a.probability..High.probabilities.indicate.high.reliability.(Hashimoto,.t..et.al.,.1982b). resilience A..the.ability.of.a.social.or.ecological.system.to.absorb.disturbances.while.retaining.the.same. basic.structure.and.ways.of.functioning,.the.capacity.for.self-organization,.and.the.capacity.to. adapt.to.stress.and.change. b..resiliency.is.the.speed.at.which.the.system.recovers.from.a.failure,.on.average..shorter.recovery. periods.indicate.higher.resiliency.(Hashimoto,.t..et.al.,.1982b). risk the.potential.for.realization.of.unwanted,.adverse.consequences;.usually.based.on.the.expected. result.of.the.conditional.probability.of.the.occurrence.of.the.event.multiplied.by.the.consequence. of.the.event,.given.that.it.has.occurred..what.makes.a.situation.risky.rather.than.uncertain.is.the. availability.of.objective.estimates.of.the.probability.distribution..(usAce,.1992) robustness in.a.water.resources.system,.robustness.refers.to.the.extent.to.which.a.system.design.is.able.to. deliver.optimal.or.near-optimal.levels.of.service.over.a.range.of.demand.(input).and.supply. (resource).conditions.(Hashimoto,.t..et.al.,.1982a). scenario A.plausible.and.often.simplified.description.of.how.the.future.may.develop,.based.on.a.coherent. and.internally.consistent.set.of.assumptions.about.driving.forces.and.key.relationships..scenarios. may.be.derived.from.projections,.but.are.often.based.on.additional.information.from.other. sources,.sometimes.combined.with.a.narrative.storyline. sensitivity sensitivity.is.the.degree.to.which.a.system.is.affected,.either.adversely.or.beneficially,.by climate.variability.or.climate.change..the.effect.may.be.direct.(e.g.,.a.change.in.crop.yield.in. response.to.a.change.in.the.mean,.range,.or.variability.of.temperature).or.indirect.(e.g.,.damages. caused.by.an.increase.in.the.frequency.of.coastal.flooding.due.to.sea.level.rise). stationarity stationarity.assumes.that.natural.systems.fluctuate.within.an.unchanging.envelope.of.variability.. stationarity.is.a.foundational.concept.that.permeates.training.and.practice.in.water-resource. engineering..it.implies.that.any.variable.(e.g.,.annual.streamflow.or.annual.flood.peak).has.a. 138 time-invariant.(or.1-year­periodic).probability.density.function.(pdf),.whose.properties.can.be. estimated.from.the.instrument.record..under.stationarity,.pdf.estimation.errors.are.acknowledged,.but. have.been.assumed.to.be.reducible.by.additional.observations,.more.efficient.estimators,.or.regional. or.paleohydrologic.data..the.pdfs,.in.turn,.are.used.to.evaluate.and.manage.risks.to.water.supplies,. waterworks,.and.floodplains.(milly.et.al.,.2008). Threshold the.level.of.magnitude.of.a.system.process.at.which.sudden.or.rapid.change.occurs..A.point.or. level.at.which.new.properties.emerge.in.an.ecological,.economic.or.other.system,.invalidating. predictions.based.on.mathematical.relationships.that.apply.at.lower.levels. uncertainty A..An.expression.of.the.degree.to.which.a.value.(e.g.,.the.future.state.of.the.climate system).is. unknown..uncertainty.can.result.from.lack.of.information.or.from.disagreement.about.what. is.known.or.even.knowable..it.may.have.many.types.of.sources,.from.quantifiable.errors.in. the.data.to.ambiguously.defined.concepts.or.terminology,.or.uncertain.projections of.human. behaviour..uncertainty.can.therefore.be.represented.by.quantitative.measures,.for.example,. a.range.of.values.calculated.by.various.models,.or.by.qualitative.statements,.for.example,. reflecting.the.judgment.of.a.team.of.experts. b..uncertain.situations.are.those.in.which.the.probability.of.potential.outcomes.and.their.results. cannot.be.described.by.objectively.known.probability.distributions,.or.the.outcomes.themselves,. or.the.results.of.those.outcomes.are.indeterminate.(usAce,.1992) united nations framework Convention on Climate Change (unfCCC) the.convention.was.adopted.on.9.may.1992.in.new.york.and.signed.at.the.1992.earth.summit. in.rio.de.janeiro.by.more.than.150.countries.and.the.european.community..its.ultimate.objective. is.the."stabilisation.of.greenhouse.gas.concentrations.in.the.atmosphere.at.a.level.that.would. prevent.dangerous.anthropogenic.interference.with.the.climate.system"..it.contains.commitments. for.all.Parties..under.the.convention,.Parties.included.in.Annex.i.(all.oecd.member.countries.in. the.year.1990.and.countries.with.economies.in.transition).aim.to.return.greenhouse.gas.emissions. not.controlled.by.the.montreal.Protocol.to.1990.levels.by.the.year.2000..the.convention.entered. in.force.in.march.1994. vulnerability A..vulnerability.is.the.degree.to.which.a.system.is.susceptible.to,.and.unable.to.cope.with,.adverse. effects.of.climate.change,.including.climate.variability.and.extremes..vulnerability.is.a.function. of.the.character,.magnitude,.and.rate.of.climate.change.and.variation.to.which.a.system.is. exposed,.its.sensitivity,.and.its.adaptive.capacity. b..vulnerability.refers.to.the.severity.of.the.likely.or.expected.consequences.of.failure.(Hashimoto,. t..et.al.,.1982b). References Ams,.2000:.Ams.glossary.of.meteorology,.2nd.edition..American.meteorological.society,.boston,. mA..http://amsglossary.allenpress.com/glossary/browse.. 139 Hashimoto,.t.,.d.P ..loucks,.and.j.r..stedinger..1982a..robustness.of.water.resources.systems.. Water Resources Research.18(1):21­26. Hashimoto,.t.,.j.r..stedinger,.and.d.P ..loucks..1982b..reliability,.resiliency.and.vulnerability. criteria.for.water.resource.system.performance.evaluation..Water Resources Research. 18(1):14­20. iPcc,.1992..climate.change.1992:.the.supplementary.report.to.the.iPcc.scientific.Assessment. [Houghton,.j.t.,.b.A..callander,.and.s.k..varney.(eds.)]..cambridge.university.Press,. cambridge,.united.kingdom.and.new.york,.ny,.usA iPcc..1996..climate.change.1995:.the.science.of.climate.change,.contribution.of.working. group.i.to.the.second.Assessment.report.of.the.intergovernmental.Panel.on.climate.change.. j..t..Houghton,.l.g..meira.Filho,.b.A..callander,.n..Harris,.A..kattenberg,.and.k..maskell.. (eds.)..cambridge,.england:.cambridge.university.Press. iPcc,.2008,.technical.Paper.on.climate.change.and.water,.iPcc.secretariat,.geneva,. switzerland. milly.et.al..2008..stationarity.is.dead:.wither.water.management?.Science.vol.319. nakienovi,.n..and.r..swart.(eds.),.2000:.Special Report on Emissions Scenarios..cambridge. university.Press,.599.pp. usAce.(us.Army.corps.of.engineers)..1992..guidelines.for.risk.and.uncertainty.Analysis. in.water.resources.Planning,.vol.1.­.Principles..iwr.report.92-r-1..institute.for.water. resources..Fort.belvoir,.usA. 140