英文【世界銀行】The Cost of Inaction

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THECOSTOFINACTION

QuantifyingtheImpact

ofClimateChangeonHealth

inLow-andMiddle-IncomeCountries

F

CLIMATE

INVESTMENT

FUNDS

WORLDBANKGROUP

?2024InternationalBankforReconstructionandDevelopment/TheWorldBank

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WashingtonDC20433

Telephone:202-473-1000

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Pleasecitetheworkasfollows:WorldBank.2024.TheCostofInaction:QuantifyingtheImpactofClimateChangeonHealthinLow-andMiddle-IncomeCountries.Washington,DC:WorldBank.

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Contents

Foreword

AcknowledgmentsAbbreviations

UnitsofMeasurementSummary

1.Introduction

2.Methods

2.1|SelectionofCountries

2.2|SelectionofClimateScenarios

2.3|ModelingandAnalyticalApproach

2.4|Data

3.ImpactsofClimateChangeonHealth

andtheEconomicCostofInaction

3.1|impactsofClimateChangeonHealth

3.2|EconomicCostofinaction

4.Discussion

4.1|SummaryofKeyFindings

4.2|ComparisonofFindingswithKeyLiterature

4.3|StudyCaveats

4.4|PolicyimplicationsandFutureDirections

Annexes

viviiviiiviii ix

1

4

5

5

8

13

14

15

16

19

20

21

23

25

26

iv

Annex1

|

CountriesincludedintheAnalysis

26

Annex2

|

SSPsandRCPs

29

Annex3

|

EstimatingtheimpactsofClimateChangeonMorbidityandMortality

33

Annex4

|

ModelingFatalityRates

38

Annex5

|

EstimatingYLLfromClimateChange

42

Annex6

|

EstimatingtheEconomicCostofClimate-RelatedHealthimpacts

45

Annex7

|

CumulativeEstimatesoftheimpactsofClimateChange

onMorbidityandMortalityintheShortTermandLongTerm

65

Annex8

|

EconomicCostoftheHealthimpactsofClimateChangeintheShortTermandLongTerm

67

References68

v

FIGURES

1SSPsandRCPs7

2DistributionoftheEconomicCostoftheHealthimpactsofClimateChange18

AcrossRegions:2026-2050

A.1PopulationGrowthunderSSPs29

A.2EconomicGrowthunderSSPs29

TABLES

1SharedSocioeconomicPathways6

2ComparativeAnalysisofApproaches:WHO(2014)andthisReport8

3CumulativeNumberofCasesAttributabletoClimateChange:2026-205015

4CumulativeNumberofDeathsAttributabletoClimateChange:2026-205016

5CumulativeEconomicCostoftheHealthimpactsofClimateChange:2026-205017

A.1LMiCsincludedintheAnalysis26

A.2TotalProjectedRegionalPopulation30

A.3TotalProjectedRegionalGDP(trillionUSD)30

A.4ModelingMalaria’sFatalityRate40

A.5EstimatingLifeExpectancies42

A.6AgeDistributionofDeathsfromMalariainNigeriain202043

A.7AgeDistributionofDeathsfromMalariainCameroonin202044

A.8EstimatedCountry-SpecificvaluesforvSL(USD)–SSP346

A.9EstimatedCountry-SpecificvaluesforvSL(USD)–SSP248

A.10EstimatedCountry-SpecificvaluesforCOiDengue(USD)–SSP351

A.11EstimatedCountry-SpecificvaluesforCOiDengue(USD)–SSP253

A.12EstimatedCountry-SpecificvaluesforCOiMalaria(USD)–SSP355

A.13EstimatedCountry-SpecificvaluesforCOiMalaria(USD)–SSP257

A.14EstimatedCountry-SpecificvaluesforCOiDiarrhea(USD)–SSP359

A.15EstimatedCountry-SpecificvaluesforCOiDiarrhea(USD)–SSP261

A.16CumulativeNumberofCasesAttributabletoClimateChange:2026-203065

A.17CumulativeNumberofDeathsAttributabletoClimateChange:2026-203065

A.18CumulativeNumberofCasesAttributabletoClimateChange:2026-210066

A.19CumulativeNumberofDeathsAttributabletoClimateChange:2026-210066

A.20EconomicCostoftheHealthimpactsofClimateChange:2026-203067

A.21EconomicCostoftheHealthimpactsofClimateChange:2026-210067

Foreword

vi

Climatechangehasprofoundandextensiveadverseimpactsonhealth,andtheseareexpectedtointensifyinthecomingdecades.Ascasualtiesandfatalitiesincrease,theclimate-relatedhealthcrisisrisksoverwhelminghealthcarefacilitiesandsystems,particularlyinlow-andmiddle-incomecountries.Asaresult,thehealthimpactsofawarmingplanetcouldpushmillionsofpeopleintoextremepoverty.

Avitalfirststeptowardaddressingthehealthemergencyarisingfromclimatechangeinvolvesidentifyingthemultiplehealthimpactsandestimatingthecostofinaction.BuildingonanearliereffortbytheWorldHealthOrganization,thisWorldBankreportquantifiestheimpactsandcostsofprojectedclimatechangeonhealthinlow-andmiddle-incomecountries.

Thestudyrevealsthatclimatechange-relatedhealthimpactswillbesevere,evenintheshortterm,andcertainregionslikeSub-SaharanAfricaandSouthAsiawillbearadisproportionateshareoftheglobalburden.Thecostofinactionisexpectedtobefarhigherthanprojectedinthereport,whichdidnotcoverallofthehealthriskslinkedtoclimatechange.

Theseprojectionsshouldgalvanizedecision-makersandspururgent,transformativeaction.Countriesmustadoptboldmeasurestolimittheimpactsofclimatechangeandsignificantlyboosttheresilienceoftheirhealthcaresys-tems.Thiscannotbeaboutaddressingtheimpactonspecificdiseasesalone.Instead,wemustfocusonstrengthe-ninghealthsystemssotheycanadaptandmitigatethebroaderimpactsofclimatechangeonhealthconditions.

TheWorldBankaimstoreach1.5billionpeoplewithqualityhealthservicesby2030.Thisgoalwillnotbereached,withoutexpandingourinvestmentsinclimateandhealthtohelpcountriesbuildhigh-quality,climate-resilient,andlow-carbonhealthsystems.Thesearenotjustwords.Infact,lastyearclimateinvestmentsinhealthprojectsamountedtoathirdoftheBank’stotalfinancingforhealth.

Furtherwearefocusingonassessingcountry-specificclimate-healthvulnerabilitiestoinformthedesignoftailo-redsolutionstoguideourinvestmentstobuildresilient,low-carbonhealthsystems;aswellasdeepeningpart-nershipsattheglobal,regional,andcountrylevelstosupporttheseefforts.Lookingahead,theWorldBankisdevelopingafullrangeoffinancinginstrumentsforbothadaptationandmitigationactivities,whichwillenableustoincreaseoursupporttohelplow-andmiddle-incomecountriestackleclimate-healthchallenges.

Climatechangeisaglobalcrisis–wemustjoinforcesnowtoaddressitsdirectandindirectimpactsonhealthandlimitthehighhumanandeconomiccosts.Thisisawake-upcallforallofustoactdecisivelyandurgentlyto

safeguardourfuture.

JuanPabloUribe

GlobalDirector,Health,NutritionandPopulationTheWorldBank

Acknowledgments

vii

ThisreportwasproducedbytheClimateandHealthProgramintheHealth,Nutrition,andPopulationGlobalPracticeoftheWorldBank.

ThereportisauthoredbyLorieRufo(SeniorClimateChangeSpecialist,WorldBank);BenoitLaplante(EconomicsConsultant,WorldBank);StevenCegliaSmith(DataAnalystConsultant,WorldBank);andDavidAlexanderClary(EconomicsConsultant,WorldBank).ThereportreceivedoverallguidancefromTamerSamahRabie(GlobalProgramLead,ClimateandHealth,WorldBank).

Thereportgreatlybenefitedfromthevaluablecontributionsofthefollowingpeerreviewers:PatrickHoang-VuEozenou(SeniorEconomist,WorldBank);JedFriedman,(LeadEconomist,WorldBank);XianFuLu(ClimateChangeConsultant,ClimateInvestmentFunds);andUrvashiNarain(ProgramLeader,WorldBank).

Theauthorswouldalsoliketothankthefollowingexternalpeerreviewersofthereportfortheirinsightfulcom-ments:EnisBaris(Director,GlobalHealthPolicy,InstituteforHealthMetricsandEvaluation);DiarmidCampbell-Lendrum(Head,ClimateChangeandHealthUnit,WorldHealthOrganization);SariKovats(AssociateProfessor,LondonSchoolofHygieneandTropicalMedicine);ChristopherMurray(FoundingDirector,InstituteforHealthMetricsandEvaluation);FrankPega(TechnicalOfficer,Environment,ClimateChangeandHealth,WorldHealthOrganization);andAlexanderPreker(AdjunctAssociateProfessor,ColumbiaUniversity).

TheauthorssincerelyappreciatethevaluablecontributionsprovidedbyAletheaCook(HealthConsultant,WorldBank);StephenDorey(SeniorHealthSpecialist,WorldBank);ToniJoeLebbos(Economist,WorldBank);YunaNakayasu(HealthConsultant,WorldBank);WameqAzfarRaza(SeniorHealthSpecialist,WorldBank);JyotirmoySaha(HealthConsultant,WorldBank);ZaraShubber(SeniorHealthSpecialist,WorldBank);andPennyWilliams(Manager,PeopleVice-Presidency,WorldBank).

SincerethanksarealsoextendedtotheWorldBankClimateChangeKnowledgePortalteamwhoprovidedgui-danceontheappropriateuseofthemostrecentclimatedataavailableontheportal.FurtherthankstoKahYingChoowhodiligentlyperformedthecopyeditingofthereport.

TheauthorswouldliketoexpresstheirgratitudetoJuanPabloUribe(GlobalDirector,Health,Nutrition,andPopulation,WorldBank)andMoniqueVledder(PracticeManager,Health,Nutrition,andPopulation,WorldBank)fortheirunwaveringsupport.

Finally,theauthorsarethankfultotheClimateInvestmentFundsforitsfinancialsupport.

viii

ABBREVIATIONS

AR6

SixthAssessmentReport(oftheIPCC)

CCKP

ClimateChangeKnowledgePortal

CMIP6

SixthPhaseoftheCoupledModelIntercomparisonProject

CO2

CarbonDioxide

COI

CostofIllness

COP

ConferenceoftheParties(totheUNFCCC)

COP26

26thConferenceoftheParties

EAP

EastAsiaandPacific

ECA

EuropeandCentralAsia

GDP

GrossDomesticProduct

IAM

IntegratedAssessmentModel

ILO

InternationalLabourOrganization

IPCC

IntergovernmentalPanelonClimateChange

LAC

LatinAmericaandtheCaribbean

LMICs

Low-andMiddle-IncomeCountries

MENA

MiddleEastandNorthAfrica

OECD

OrganisationforEconomicCo-operationandDevelopment

RCP

RepresentativeConcentrationPathway

SA

SouthAsia

SIDS

SmallIslandDevelopingStates

SRES

SpecialReportonEmissionsScenarios

SSA

Sub-SaharanAfrica

SSP

SharedSocioeconomicPathway

UN

UnitedNations

UNEP

UnitedNationsEnvironmentProgramme

UNFCCC

UnitedNationsFrameworkConventiononClimateChange

US

UnitedStates

USD

UnitedStatesDollar

VSL

ValueofStatisticalLife

WEF

WorldEconomicForum

WHO

WorldHealthOrganization

YLL

YearsofLifeLost

UNITSOFMEASUREMENT

°C

DegreeCelsius

Gt/yr

GigatonsPerYear

W/m2

WattPerSquareMeter

ix

Summary

Climatechangeisimpactinghumanhealthinmyriadways,includingbyincreasingthefrequencyofextremeweatherevents,theemergenceandspreadofinfectiousdiseases,anddisruptionstofoodsystems.Theimpactsofclimatechangeonhealth—alreadyprofound—areonlyexpectedtoworsenovertime.Notonlywillthenumberofdiseasesanddeathsfromclimate-sensitivehealthrisksincrease,butsotoowillthegeographicalrangeofthesediseases.Low-andmiddle-incomecountries(LMICs)areexpectedtofaceadisproportionateburdenoftheseimpactsduetotheirhigherlevelsofpovertyandincomeinequality,andweakhealthcaresystems.Withgrowingrecog-nitionthattheclimatecrisisisahealthcrisis,theinternationalcommunityhasexpressedurgentcallsforactiononclimateandhealth.

Theresponseofthehealthcommunityandresearchershasbeenlargelyfocusedonstudyingthelinkbetweenclimatechangeandhealth.Alimitednumberofstudieshaveestablishedempiricallinksbetweenclimateconditionsandthevariabilityinthenumberofdifferentdiseasesinspecificnational(orsubnational)contexts,particularlyfocusingonvector-borneandwaterbornedisea-ses.Inaddition,fewstudieshaveaimedtoassesstheeconomiccostassociatedwiththehealthimpactsofprojectedclimatechange.

Thisreportaimstoaddresstheexistingknowledgegapandprovideadeeperunderstandingoftheinterconnectionbetweenclimateandhealth,intermsoftheriskstohumanhealthandtheeconomicburdenoftheserisks.Specifically,itprovidesaquantitativeassessmentofthepotentialimpactsofclimatechangebasedonthenumberofcasesandthenumberofdeathsresultingfromselectedvector-andwater-bornediseases,stunting,andextremeheat.Anassessmentoftheeconomiccostofclimatechangeonhealth(intermsofbothmorbidityandmortality)isalsoprovided.

Theanalysiscovers69low-incomeandmiddle-incomecountrieswithnationalpopulationsexcee-ding10millionpeopleinthebaseyear2020.These69countriescomprise96percentofthetotalpopulationofallLMICs.

Estimatesoftheimpactsofclimatechangeonhealthareprovidedfordifferenttimeperiodsin-cluding2026-2030,2026-2050,and2026-2100inthecontextoftwosocioeconomicdevelopmentscenariosfeaturedintheSixthAssessmentReport(AR6)oftheIntergovernmentalPanelonClimateChange(IPCC)—namely,SSP3-7.0andSSP2-4.5(referredtohereafterasSSP3andSSP2).Thesetwoscenariosrepresentmiddle-of-the-roaddevelopmentpathsbetweentheworst-case(RCP8.5)andtheincreasinglyunlikelybest-casescenarios(RCP2.6andRCP1.9).SSP3representsacha-llengingpathway,assuminghighpopulationgrowth,limitedeconomicdevelopment,andreduced

x

investmentsinhealthandeducation,whereasSSP2presentsmoderatechallenges,characterized

bysteadypopulationandeconomicgrowth.Themainfindingsofthisreportareasfollows:

1.Theimpactsofclimatechangeonhealtharesignificantandcallforimmediateac-tionattheglobalandcountrylevels.Between2026and2050,climatechangeisprojec-tedtocausebetween4.1billion(SSP2)and5.2billion(SSP3)casesacrossLMICs.Theimpactofclimatechangeonmortalitywillbeequallystark.By2050,thenumberofdeathscausedbyclimatechangecouldreachbetween14.5million(SSP2)and15.6million(SSP3).Immediate,decisiveactionisneededtoavertthesedevastatingimpactsonhealthacrossLMICs.

2.Scalingclimate-healthactionisneededtoaverttrillionsofdollarsineconomiccostsarisingfromtheseselectedhealthimpactsofclimatechangeinthecomingdeca-des.By2050,theeconomiccostofthehealthimpactsofclimatechangeisprojectedtoreachbetweenUSD8.6-15.4trillionunderSSP3.Thesecoststranslatetobetween0.7percentand

1.2percentofthegrossdomesticproduct(GDP)ofLMICs.TheseestimatesarehigherunderSSP2,reachingbetweenUSD11.0-20.8trilliontranslatingto0.7percentand1.3percentofGDPinLMICs.

3.Sub-SaharanAfrica(SSA)andSouthAsia(SA)willbearthebruntofthehealthim-pactsofclimatechange.TheseimpactswillbeparticularlysevereinSSA,whichisprojectedtoexperienceapproximately71percentofallcasesandnearlyone-halfofalldeathscausedbyclimatechangebetween2026and2050underbothsocioeconomicdevelopmentscena-rios.SAisprojectedtoexperienceapproximately18percentofallcasesandone-quarterofalldeathsunderbothscenarios.Inthesetworegionscombined,thenumberofdeathscausedbyclimatechangeisprojectedtoreachbetween10.5million(SSP2)and11.7million(SSP3)by2050.TheeconomiccostwillbesignificantlyhigherforSSAthanforanyotherre-gion—by2050,thiscostwillamounttobetween2.7percentand3.6percentoftheregion’sGDPunderbothscenarios.

4.Thehealthimpactsofclimatechangepresentedinthisreportaresignificantbutli-kelytobejustthetipoftheiceberg.Theanalysispresentedinthisreportincludesthepo-tentialimpactsofclimatechangeonalimitednumberofhealthrisks.Thepotentialimpactsofclimatechangeonotherhealthrisks,suchasnon-communicablediseasesandmentalhealth,arenotincludedinthisreport.Moreover,theanalysisofthesehealthriskshasnotconside-redthechangeintheirgeographicaltrajectorybecausefactors,suchasmigrationandwaterstress,canonlybecapturedthroughadynamicmodel.Asaresult,theresultspresentedhere

xi

shouldbeunderstoodasanotableunderestimateofthescaleoftherealimpactsofclimatechangeonhealthinLMICs.

ThefindingsofthisreportconfirmtheAR6’sprojectionofasignificantincreaseincasesanddeathsduetoclimatechangeandtheunevengeographicaldistributionofthisfutureburden,withSSAand,toalesserextent,SAbearingthebruntoftheprojectedincrease.Furthermore,byestimatingtheassociatedeconomiccostsofthesehealthimpacts,thisreportarguesforintensifyingandacceleratingeffortstoreducegreenhousegasemissionsaswellasforLMICstoprioritizeinvest-mentsinhealthsystems.Theseinvestmentsareneededtobuildresilientandsustainablehealthsystemsthatcanweathertheadverseimpactsofclimatechangeonhealth.Itmustbeclearlysta-tedthatthisreportdoesnotadvocateforaverticalapproachtothehealthrisksincludedintheanalysis.Ahealthsystemsapproachisneededtotackletheprojectedimpactsofclimatechangeonhealtheffectivelyandefficiently.

THECOSTOFINACTION

QuantifyingtheimpactofClimateChangeonHealthinLow-andMiddle-incomeCountries

1.Introduction

1.Introduction

2

Climatechangehasbeenimpactinghumanhealthatanacceleratedpaceoverthepastdecade.Thisincludesincreasesinheat-relatedillnesses,waterborneandvector-bornediseases(includingoutbreaks),andmalnutritionfromreducedcropproductivity,amongnumerousothers.Theseeffectsareexpectedtoworsenovertime,withchangesnotonlyinthenumberofdiseasesanddeathsfromclimate-sensitivehealthrisksbutalsointheirgeographicalrange(Georgeetal.2024).Inadditiontoimpactinghealthoutcomes,climatechangeisprojectedtoadverselyimpacthealthsystems.Asaresultofpoverty,incomeinequality,andweakhealthcaresystems,low-andmidd-le-incomecountries(LMICs)areexpectedtofacedisproportionateincreasesinmorbidity,aswellasincreasinglossesanddamagestohealthfacilities.Urgentcallsforactionhavebeenexpressedbytheglobalcommunity(Fielding2023;IntergovernmentalPanelonClimateChange[IPCC]2023;Romanelloetal.2023;UnitedNationsEnvironmentProgramme[UNEP]2023).Over200healthjournalshaverecentlycalledontheUnitedNations(UN),politicalleaders,andhealthprofessionalstotreattheongoingclimateandnaturecrisesasoneglobalhealthemergency(Abbasietal.2023).

Despitethescaleofthiscrisis,evidencequantifyingtheimpactofclimatechangeonhealthre-mainslimited.Theunderlyingphysiologicalfactorslinkingclimatechangeandtheincidenceofvector-borneandwaterbornediseaseshavebeendiscussedbynumerousexperts(Georgeetal.2024;Semenzaetal.2023;Thomsonetal.2022;Wong2023).However,theextentoftheriskofclimatechangeonhealthremainspoorlyquantified(Moraetal.2022).Onlyalimitednumberofpapershaveaimedtotransformthisknowledgeintoquantifiedassessmentsofthepotentialimpactsofclimatechangeonspecifichealthrisks.1Giventhescarcityofpublicresources,futurepolicyresponsesontheirallocationsrequiregoingbeyondunderstandingtheunderlyingnatureofclimatechangeandhealthlinkstoquantifytheextentofthelinkagesintermsoffutureinci-dences,mortality,andeconomiccosts(Ebi2022,2024).Thislackofcomprehensivequantificationmaypartiallyexplainwhyhealth-specificclimateactionsrepresentonly6percentoftotaladapta-tionfunding(WorldHealthOrganization[WHO]2023).IthasbeenestimatedthatLMICsrequireatleastUSD11billioninfundingperyearthisdecadetoadapttoclimateandhealthimpactsandincreasetheresilienceoftheirhealthsystems(UNEP2023).

Toaddresstheevidencegap,thisreportprovidesestimatesoftheeconomiccostofinactiononselectedhealthriskslinkedtoclimatechange.Itprovidesaquantitativeassessmentofthe

1Alimitednumberofstudieshaveestablishedandestimatedempiricallinksbetweenclimateconditions,variability,andthe

incidenceofdiseasesinspecificnational(orsubnational)contexts.ExamplesincludeBrazil(Barcellosetal.2014);China(Xiangetal.2018;Zhengetal.2017);Colombia(Quinterro-Herreraetal.2015);Iran(Salahi-Moghaddametal.2017);Philippines(Su2008);SierraLeone(Georgeetal.2023);Singapore(Struchineretal.2015);Tanzania(Kulkarnietal.2016);Uganda(Boyceetal.2016);Vietnam(Xuanetal.2014);andZambia(Bennettetal.2016).

1.Introduction

3

potentialimpactsofclimatechangeon(1)thenumberofcasesanddeathsresultingfromselectedhealthrisks:extremeheat,waterbornediseases(diarrhea),stunting,andvector-bornediseases(dengueandmalaria);(2)thenumberofyearsoflifelost(YLL)fromdeathsarisingfromthesehealthrisksattributabletoclimatechange;and(3)theeconomiccostoftheincrementalnumberofcasesanddeathsattributabletoclimatechange.Theseimpactsareestimatedfor69LMICswhosepopulationexceeds10millionpeopleinthebaseyear2020.Estimatesoftheimpactsaregeneratedfortheshortterm(2026–2030),mediumterm(2026–2050),andlongterm(2026–2100)basedontwo(ofthefive)climatescenariosformingthebasisoftheSixthAssessmentReport(AR6)oftheIntergovernmentalPanelonClimateChange(IPCC)—SSP2andSSP3.

Thisreportbuildsonpreviousworkandleveragesnewanalysistofurtherdeepentheunders-tandingofthehealthimpactsofclimatechange.ItexpandsonanassessmentconductedbytheWorldHealthOrganization(WHO2014)ontheimpactsofclimatechangeonmorbidityandmor-talityresultingfromdengue,diarrhea,extremeheat,malaria,andstuntingfortheyears2030and2050.2ThisreportadoptsthesamemethodologicalapproachasastartingpointbutextendstheanalysisinnumerousdirectionsasexplainedinSection2below.

2WHO(2014)alsoincludedananalysisoftheimpactsofclimatechangeondeathsresultingfromfloods.Floodsarenotincludedinthecurrentanalysis:thenatureofthemodelingrequireddifferssignificantlyfromthemodelingoftheimpactsofclimate

changeondiseases.

THECOSTOFINACTION

QuantifyingtheimpactofClimateChangeonHealthinLow-andMiddle-incomeCountries

2.Methods

5

2.Methods

2.1SelectionofCountries

TheanalysispresentedinthisreportfocusesontheLMICsofthesixregionsbasedontheWorldBankGroup’sclassification.3Atotalof69countrieswithanationalpopulationexceeding10millioninthebaselineyear2020areincluded.ThelistofcountriesincludedintheanalysisisprovidedinAnnex1.These69countriesrepresent96.2percentofthetotalp