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United Nations Economic Commission for AfricaAfrican Climate Policy Centre
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Climate change and Health Across Africa: Issues and Options
Working Paper 20
i
United Nations Economic Commission for Africa
African Climate Policy Centre
Working Paper 20
CLIMATE CHANGE AND HEALTH ACROSS AFRICA:
ISSUES AND OPTIONS
November 2011
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Acknowledgment
This paper is the product of African Climate Policy Center (ACPC) of United Nations Economic Commission for Africa (UNECA) under the Climate for Development in Africa (ClimDev Africa) Programme. The paper is produced with guidance, coordination and contribution of ACPC and contributing authors from various institutions. Contributions to this paper are made by Owen C. Owens and Chuks Okereke from the University of Oxford, Smith School of Enterprise and the Environment; Jeremy Webb from the UNECA-ACPC, and Miriam Musa, York University, Ontario, Canada. This working paper is prepared as an input to foster dialogue and discussion in African climate change debate. The findings, interpretations and conclusions presented in this working paper are the sole responsibility of the contributing authors and do not in any way reflect the official position of ECA or the management team. As this is also a working paper, the ECA does not guarantee the accuracy of the information contained in this publication and will not be held responsible for any consequences arising from their use. Copyright © 2011, by UNECA. UNECA encourages the use of its material provided that the organization is acknowledged and kept informed in all such instances. Please direct inquiries and comments to: [email protected]
A free copy of this publication can be downloaded at http://www.uneca.org/acpc/publications
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TABE OF CONTENTS LIST OF FIGURES ......................................................................................................... iv LIST OF TABLES ........................................................................................................... iv LIST OF ACRONYMS .................................................................................................... v Abstract ............................................................................................................................. 1 Introduction ...................................................................................................................... 2 ClimatechangeandhealthacrossAfrica:criticalissues............................................................3 ClimatechangetrendsacrossAfrica...................................................................................................4 ImpactsonHealth.......................................................................................................................................5
Indirect impacts ................................................................................................................. 5 Malnutrition...................................................................................................................................................6 Communicablediseases............................................................................................................................7 NeglectedTropicalDiseases...................................................................................................................8 Waterborndiseases................................................................................................................................11 Diarrhoea................................................................................................................................................11
Vectorborndiseases...............................................................................................................................12 Malaria......................................................................................................................................................13
Meningitis–anairbornedisease.......................................................................................................16 HIV/AIDS......................................................................................................................................................18 Socialstatus.................................................................................................................................................18
Direct impacts ................................................................................................................. 21 Extremeweathereventsandtheirdirecteffects........................................................................21 UVrelatedcancersanddiseases........................................................................................................22 Temperatureandprecipitationeffects...........................................................................................23 Airquality....................................................................................................................................................25
Gaps in knowledge and research ..................................................................................... 25 Africa’s response to climate change and health ............................................................... 27 Options for consideration ................................................................................................ 28 References ....................................................................................................................... 31
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LIST OF FIGURES
Figure1:Potentialhealtheffectsofclimatechangeandhealth.AdaptedfromPatzetal.(2000).....................................................................................................................................................................2 Figure2:DistributionoftheprevalenceofNTDsinAfrica.Source:ImperialCollegeLondon,SchistosomiasisInitiative(availableat:http://www3.imperial.ac.uk/schisto/whatwedo/ntdsinafrica).................................................9 Figure3:Malariaendemicity:thespatialdistributionofP.falciparum(Hayetal.,2009)..................................................................................................................................................................................14 Figure4:Africanmeningitisbelt(Palmgren,2009;WHO/EMC/BAC/98.3)........................16 Figure5:AssociationbetweenGDP/personadjustedfor$USPurchasingPowerParityandlifeexpectancyfor155countriescirca1993(Lynchetal.,2000)....................................19 Figure6:AfricanCO2emissionscomparedwiththeworld(UNEP,2002)............................20 Figure7:TemperaturechangesinAfricacomparedwiththeworld(UNEP,2002)..........24
LIST OF TABLES
Table1:Healthrelatedimpactsofclimatechange(TheSmithSchoolofEnterpriseandtheEnvironment,2010).................................................................................................................................5 Table2:ExamplesofNTDsaffectedbyclimatechange.(Hotez&Kamath,2009[http://goo.gl/qgFIA&http://goo.gl/XJdpT])...................................................................................10 Table3:Examplesofvectorbornediseasesaffectedbyclimatechangeindecreasingorderofaffliction.............................................................................................................................................12 Table4:NumberofpeoplekilledinEWEsinthe1980’sand1990’sbyglobalregion(McMichaeletal.,2003)...............................................................................................................................22
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LIST OF ACRONYMS ACPC AfricanClimatePolicyCentreAIDS AcquiredImmuneDeficiencySyndromeCHWGClimateandHealthWorkingGroupDALYs DisabilityAdjustedLifeYearsEWE ExtremeWeatherEventHESA HealthandEnvironmentStrategicAlliancefortheImplementationofthe
LibrevilleDeclarationHIV HumanImmunodeficiencyVirusIPCC IntergovernmentalPanelonClimateChangeIRI InternationalResearchInstituteforClimateandSocietyNPJAs NationalPlansofJointActionsNTDs NeglectedTropicalDiseasesSANA SituationAnalysesandNeedsAssessmentSSA Sub‐SaharanAfricaUNFCCC UnitedNationsFrameworkConventiononClimateChangeUNDP UnitedNationsDevelopmentProgrammeUV Ultra‐VioletWHO WorldHealthOrganization
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Abstract
Climatechangeisexpectedtoaltertemperature,airmovement,andprecipitationinvariouswaysandtovaryingdegreesacrossAfricawithconsequencesforhumanhealth.Withthestrongconnectionbetweenapopulation’shealthandeconomicandenvironmentalhealth,theimpactofclimatechangeoneachisoneofthemajorwaysinwhichclimatechangemayimpedethedevelopmentoftheAfricancontinent.
AfricancountrieswillsufferhealthconsequencesduetoimpactsofclimatechangeasmanyAfricancountrieshavepopulationsthatareamongthemostvulnerabletoclimaticchangesintheworld.Thisvulnerabilityisdueinparttoexistingproblemsofpoverty,weakinstitutionsandarmedconflict,whichlimitapopulation’scapacitytodealwiththeadditionalhealthchallengesposedbyclimatechange.Therelativeimpactofclimaticandsocioeconomicfactorsisgenerallydifficulttoquantify.ThiscomplexityinturnaffectsthecertaintyofstudiesandpoliciesonthehealthimpactofclimatechangeonAfrica.
Themajorityofhumanhealthproblemsthatcanbelinkedtoclimatechangearenotstrictlyspeakingcreatedbychangesinclimatebutareproblemsexacerbatedbychangingweatherpatternsandclimaticconditionsleavingpopulationsillpreparedfornewhealthimpacts.Forexample,climatechangemayaffecthealththroughincreasedfrequencyandintensityofextremeweathereventswhicharedriversofmalnutritionandcandirectlyimpacthealthforexampleduringheatwaves.Risingtemperatureswillaffectpathogenlifecycleandrangeaffectingrateofinfections,especiallyvector‐bornediseases.TheoverallbalanceofeffectsfromclimatechangeonhealthgloballyislikelytobenegativeanditispredictedtobemuchgreaterinAfricanpopulationsthaninEuropeanpopulationsforexample.
WithinAfricathetypeandmagnitudeofthehealthimpactsofclimatechangewillvarysignificantlyamongcommunitiesandregions.Variationswillbeduetomanyfactorssuchasgeographicandmicroclimatedifferences,socio‐economicconditions,thequalityofexistinghealthinfrastructure,communicationcapacityandunderlyingepidemiology.
ThisworkingpaperlaysoutthecurrentstateofknowledgeregardingdirectandindirectimpactsofenvironmentalfactorsonhealthacrossAfrica.Whiletherearemanyuncertaintiesinmagnitudesofclimatechange,particularlywithtiming,theexistingliteraturemakesinterestingobservationsaboutpotentialhealthimpactsandthepopulationsthatcouldbemostatrisk.TheworkingpaperpresentsthepotentialimpactsclimatechangemayhaveonhumanhealthandanalysesthevariousdirectandindirectimpactsthatclimatechangewillhaveonAfricanpopulations.Duetotheemergingnatureoftheissueandliterature,therearemanygapsinknowledgeontheimpactsclimatechangewillhaveonhumanhealth.
ImportantlyAfricaisalreadyaddressingclimateandhealth,andexamplesinclude"TheLibrevilleDeclarationonHealthandEnvironmentinAfrica"byAfricanMinistersofHealthandMinistersofEnvironment,alongwithgrassrootsactionssuchthosebeingtakenbytheClimateandHealthWorkingGroupinEthiopiaandelsewhere.Intermsofpolicyanimportantquestionis:whatshouldbedonedifferentlytoaddresshealthconcernsacrossAfricagivenwhatweexpectintermsofclimatechange?Insomecasesitmaybemoreofthesame(e.g.theuseofmosquitonetsandothermeasurestopreventmalaria).Inothercaseseffectivepreparationorresponsemayrequirecompletelydifferentapproachestohealthcareacrossthecontinent.
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Introduction
Itiswellknownthatthehealthofapopulation,ifitistobesustained,requirescleanair,safewater,adequatefood,tolerabletemperature,stableclimate,andhighlevelsofbiodiversity(WHO,1995;IPCC,2007).Globally,climatechangeisexpectedtoaltertemperature,airmovement,andprecipitationinvariouswaysandtovaryingdegreesacrossAfricawithconsequencesonhumanhealth.Withthestrongconnectionbetweenapopulation’shealthandeconomicandenvironmentalhealth,theimpactofclimatechangeoneachisoneofthemajorwaysinwhichclimatechangemayimpedethedevelopmentoftheAfricancontinent(IPCC,2001;Sperling,2003;Stern,2006).
Africancountrieswillsufferserioushealthconsequencesduetoimpactsofclimatechange.ManyAfricancountrieshavepopulationsthatareamongthemostvulnerabletoclimaticchangesintheworld.Thisvulnerabilityisdueinparttoexistingproblemsofpoverty,weakinstitutionsandarmedconflict,whichlimittheircapacitytodealwiththeadditionalhealthchallengesposedbyclimatechange.Therelativeimpactofclimaticandsocioeconomicfactorsisgenerallydifficulttoquantify.ThiscomplexityinturnaffectsstudiesandpoliciesonthehealthimpactofclimatechangeonAfrica.Ingeneral,itisrarelypossibletoseparateclimaticandsocio‐economiceffectswhenassessingthehealthimpactsofclimatechangeonanyspecificpopulation(Figure1).
Figure1:Potentialhealtheffectsofclimatechangeandhealth.AdaptedfromPatzetal.(2000).
Health Effects
Temperature-related illness and death
Extreme weather related health effects
Effects of food and water shortages
Air pollution related health effects
Water and food-borne diseases
Vector-borne diseases
Regional Weather Changes Temperature
Heat waves
Precipitation
Extreme weather events
Modulating Influences Population growth
Standards of living
Health care facilities
Demographic change
DiseasePathways Air pollution levels
Contamination pathways
Transmission dynamics
Climate Change
Adaptation Measures
Themajorityofhumanhealthproblemsthatcouldbelinkedtoclimatechangearenotstrictlyspeakingcreatedbychangesinclimate.Rather,theyareproblemsexacerbatedorintensifiedbychangingweatherpatternsandotherclimaticconditionsleavingpopulationun‐or‐ill‐preparedfornewhealthimpacts.Forexample,climatechangemayaffecthealththroughincreasedfrequencyandintensityofextremeweatherevents(EWEs)(suchashurricanes,heat‐waves,floods,anddroughts)eachofwhicharedriversofmalnutritionandchangesinthedistributionofdiseases.Risingtemperatureswillaffectpathogenlifecycleandrangeaffectingrateofinfections,especiallyvector‐bornediseases(Costelloetal.,2009).Anincreaseinglobalmeantemperaturewillalso
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alterheatandcold‐relateddeathratesaroundtheglobe(Costelloetal.,2009).Whiletheremightbesomepositivebenefitsassociatedwithweatherchangessuchasareductionincold‐relateddeathsinsometemperateregions,theoverallbalanceofeffectsonhealthgloballyislikelytobenegative(IPCC,2007).Theseeffectswillnotbeevenlydistributedacrosstheworld’spopulationsaslossofhealthylifeyearsasaresultofclimatechangeispredictedtobe500timesgreaterinpoorerAfricanpopulationsthaninricherEuropeanpopulations(Ebi,2006;McMichaeletal.,2008).
EvenwithinAfrica,thetypeandmagnitudeofthehealthimpactsofclimatechangewillvarysignificantlyamongcommunitiesandregions.Variationswillbeduetomanyfactorssuchasgeographicdifferencesintemperatureandprecipitation,socio‐economicconditions,thequalityofexistinghealthinfrastructure,communicationcapacityandunderlyingepidemiology.Therefore,inthisreportwelayoutthecurrentstateofdirectandindirectimpactsofenvironmentalfactorsonhealthinAfrica.Whiletherearemanyuncertaintiesinmagnitudesofclimatechange,particularlywithtiming,theexistingliteraturemakesinterestingobservationsaboutpotentialhealthimpactsandthepopulationsthatcouldbemostatrisk.
Thesectionsbelowwill: identifycurrenthealthissuesacrossAfrica; introducethecurrentunderstandingofchangesintemperature,precipitation,
andextremeweathereventsexpectedaspartofclimatechangeacrossAfrica; presentthepotentialimpactsclimatehasonhumanhealth; analysethevariousdirectandindirectimpactsthatclimatechangewillhaveon
Africanpopulations; acknowledgeanddiscussgapsinknowledgeoftheimpactsclimatechangewill
haveonhumanhealth,and; assessoptionsandthewayforwardtoaddressclimatechangeandhealthacross
Africa.
Climate change and health across Africa: critical issues
Inouranalysis,carefulattentionispaidtodistinguishingclimateandhealthissuesfromclimatechangeandhealth.Theformerreferstotheexistingstatusquoandthehistoriclinksbetweenclimateandhealth.Thelatterrelatesmorespecificallytotherelationshipbetweencurrentandfutureanthropogenicclimatechangeandconditionsofhealth.Forexample,itisevidentthattheprevalenceofmalariainthecontinentisrelatedtotropicalclimateacrossAfrica.Infuture,however,thenatureandspreadofmalariaacrossthecontinentmaywellbeaffectedbythechangesintemperatureandprecipitationexpectedwithinthecontinent.
Ingeneral,climatechangewillacttoincreaseordecreasetheprevalenceofdisease,injuryorotherhealthissues.However,itisdifficulttogauge,intermsofnumbers,howmanymoreorlesspeoplewillbeaffectedindifferentpartsofAfrica,whatchangesinmortalitytheremaybeorthechangesinDisabilityAdjustedLifeYears(DALYs).Thisuncertaintyisduemainlytothescarcityofmodelsthatcanrobustlypredictpatternsofclimatechangeatnationalandlocalscales.Inadditiontothis,manyAfricancountriescurrentlyexperiencealotofsocio‐economicchallenges,whilecompoundingtheeffectsofclimatechangeonhealth,aredifficulttoseparateoutfromthosecausedbyclimatechange.
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Accordingly,acriticalissueforAfricancountriesandgovernmentsisnotjusttheinfluenceclimatechangemayhaveonhealth,butwhatneedstobedonetoimprovehealthservicesandconditionsgenerallyandespeciallytakingintoaccountclimatechange.ThiscanbereferredtoasthepolicydimensionofclimatechangeandhealthaimedatdrivingmitigationandadaptationmeasurestoimproveAfricanhumanhealth.Perhapsthemostimportantquestionis:whatshouldbedonedifferentlytoaddresshealthconcernsacrossAfricagivenwhatweexpectintermsofclimatechange?Insomecasesitmaybemoreofthesame(e.g.theuseofmosquitonetsandothermeasurestopreventmalaria).Inothercaseseffectivepreparationorresponsemayrequirecompletelydifferentapproachestohealthcareacrossthecontinent.
Climate change trends across Africa
TheIPCCreport(2007)andtheAfricanClimateTrendsandProjectionsreport(2007)provideagoodsummaryofkeytrendsandoutlinesbasedonthebestavailableprojectionsforclimatechangeinAfrica.Thesearesummarisedbelow:
Withrespecttotemperature:o LandareasoftheSaharaandsemi‐aridpartsofsouthernAfricamaywarmbyasmuchas1.6°C(Hernesetal.,1995;Ringiusetal.,1996).
o Inthattime,equatorialcountries(eg:Cameroon,Uganda,andKenya)mightwarmabout1.4°C.
o Sea‐surfacetemperaturesintheopentropicaloceanssurroundingAfricaareexpectedtoincreaselessthantheglobalaverage,onlyabout0.6‐0.8°C,thereforethecoastalregionsofthecontinentareexpectedtowarmmoreslowlythanthecontinentalinterior.
PrecipitationchangesexpectedbymostGCMsindicaterelativelymodestmoistureincreasesovermostofthecontinent.
o AlthoughsouthernAfricaandpartsoftheHornofAfricashouldexpectadeclinebyabout10%.
o Seasonalchangesinrainfallarenotexpectedtobelarge(Joubert&Tyson,1996;Hewitson&Crane,1996).
o PartsoftheSahelcouldexperiencethegreatestincreasesinrainfallbyasmuchas15%overrecentaverages.Itisimportanttonotehere,however,thatthisriseinrainfallwouldfollowadroughtthathaslasted30yearsintheregion.
o EquatorialAfricacouldexperienceasmall(5%)increaseinrainfall. Extremeweatherevents(EWEs)arestillpoorlyunderstoodandconclusive
evidenceastochangesintheirfrequencyisnotagreeduponintheliterature.o CurrentlyoccurringEWEsthattheAfricanpopulationneedtocontendwithareheatwaves,droughts,andheavyprecipitation).
o Althoughtheirprevalenceisnotexpectedtochangemuch(IPCC,2007),theircompoundingeffectsonotherclimatechangesareacauseforconcern.
Thelikelyandpotentialimpactsthesechangesinclimatemayhaveonhealtharediscussedbelow.
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Impacts on Health
Whenaddressingclimatechangeandhealthitisimportanttobeawarethatclimatechangecandirectlyandindirectlyimpacthealth.Directhealthimpactsaffecthumanbiologydirectlyandincludeinjury,morbidityandmortalitycausedbyclimate‐inducedEWEs(suchascyclones,floods,anddroughts),thermalstress(heatwavesandcoldperiods),skinandeyedamage(viaUVradiation),andcardio‐respiratorydiseasesdirectlyrelatedtochangesintemperatureandairquality(Table1).Howevermostofthehealthimpactsofclimatechangeareindirect.Indirectimpactsaffectnon‐humanbiogeochemicalsystemsandincludemalnutrition(duetodecreasecropsuccess),waterinsecurityandqualitychanges,lifecycleandrangeofpathogensviawaterandvectors.TheclassificationofdirectandindirectheathimpactsofclimateisabitcomplexbutTable1belowprovidesasummaryofthebreakdownusedforthepurposesofthispaper.
Table1:Healthrelatedimpactsofclimatechange(TheSmithSchoolofEnterpriseandtheEnvironment,2010).
ClimateChanges HealthImpacts
Direct
EWEs Highlevelsofmortalityandmorbidity,changeindiseaseprevalenceandpatterns
Temperature Thermalstress,skincancer,eyediseases
Airquality Cardio‐respiratorydiseases,allergicdisorders
Indirect
Temperature Foodavailability,malnutrition,famine,infectiousdiseasesofmigrants,droughts
PrecipitationWater‐bornediseases,vector‐bornediseases,droughts,foodandwateravailability
EWEs(+rainfall+temperature+ecosystem)
Diseasesofmigrants,conflicts,foodandwateravailability,malnutrition,famine
Ecosystemcompositionandfunction
Foodyieldsandquality,aeroallergens,vector‐bornediseases,water‐bornediseases
Itisimportanttostressthatclimateandclimatechangeareonlysomeoftheimpactshumanhealthisinfluencedby.Asstated,healthoutcomesareusuallytheresultofcomplexinteractionsbetweensocial,cultural,andeconomiccharacteristics,geographicsettings,andpre‐existinghealthstatus.GiventhatmuchofthehealthimpactofclimatechangeinAfricawillbeviatheindirectroute,wediscussthesefirstbeforeturningtothedirectheatheffects.
Indirect impacts
Thepotentialindirecthealtheffectsofclimatechangeonacommunities’healthwilloccurpredominantlythroughchangestonon‐humanbiologicalorbiogeochemicalsystems.Thisincludeschangesincropyield,geographicalrangeanddistributionofinfectiousdiseasesandtheirmethodsoftransportandresultsofadditionalsocial
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pressuresthatresultfromchangesinrainfallandtemperature.Ultimatelytheseclimaticchangesplacepressureonill‐preparedhumansupportsystemsbeyondfoodandwatersecurityandthecapacitytomanagealreadystressedhealthcaresystems.
Malnutrition
Goodnutritionisessentialforgoodhealth.Deficienciesinenergy,fat,protein,nutrientorvitaminintakeleadtomalnutritionwithmajorconsequencesforpeoples’physicalandmentalhealth.Malnutritionhasdetrimentalandlastinghealthconsequencesoftenlimitingaperson’sphysicalandintellectualdevelopment,particularlythosewhoareaffectedasinfantsorasyoungchildren.Additionally,malnutritionvastlyincreasespeoples’susceptibilitytoacquiring,anddyingfrominfectiousdiseases(Baro&Duebel,2006;Schaible&Kaufmann,2007;Confalonierietal.,2007).Itaffectsgroupsofpeoplewhoaremostvulnerabletochangingenvironmentalpatterns,suchasfarmersandcoastalcommunities,andthosewhoareleastabletopurchasefoodsuchasthepoorandlandlesswagelabourers.
Malnutritionisconsideredthemostimportanthealthriskgloballyasitaccountsforanestimated15%oftotaldiseaseburdeninDALYs.Atpresent,under‐nutritioncauses1.7milliondeathsperyearinAfricaandiscurrentlyestimatedtobethelargestcontributortoclimatechangerelatedmortalityaroundtheworld(Patzetal.,2005).Moreoverleadingscientistsindevelopmentandhumanitarianresearchagreethatclimatechangewilllikelyworsenexistingproductionandconsumptionstressesinfood‐insecurecountries(Bloemetal.,2010,p.133S;Schmidhuber&Tubiello,2007,p.19704).Bloemetal.(2010)explainthataccesstofoodreliesontwokeyfactors:availability(throughthemarketorsubsistentproduction)andaffordability(throughmonetaryincome).AvailableevidencestronglyindicatesthatclimatechangewillnegativelyaffectfoodavailabilityandaffordabilityacrossAfricancountries.
Intermsofavailability,changingtemperatures,humidity,andprecipitationareexpectedtodisruptagriculturalproductionsystemsindifferentpartsofAfricarequiringtheneedforadaptation.Examplesofclimateimpactsaffectingfoodsecurityincludesalinisationofagriculturalregions,changesincroprange,andmigratingcroppests(Confalonierietal.2007;Schmidhuber&Tubiello,2007,p.19704).InEthiopia,forexample,significantrainfallreductionshavealreadybeenobservedwithincriticalcrop‐growingareas(Funketal.,2007,p.11086)andthishasbeenattributedtoanthropogenicallyinfluencedwarmingoftheIndianOcean(Funketal.,2007).Effectsofthisarebeingobservednowasseveredrought,resultinginfamine,intheeasternAfricannationsofDjibouti,Somalia,EthiopiaandKenya.
ThereareanumberofothergrimpredictionsregardingclimatechangeandfoodproductioninAfrica.Forinstance:increasedtemperaturescanbeexpectedanddryareasareexpectedtoexperienceincreasedevaporationresultinginlowersoilmoisture;tropicalgrasslandsmaybecomemorearid.Therefore,semi‐aridandaridregionsshouldexpect:decreasedlivestockproductivity;wintersurvivalofpestspeciesshouldincreaseputtingmorespringcropsatrisk;and,humanpathogensurvivalisexpectedtoincreasealongwiththeprobabilityoffoodpoisoning.ThelatterhasbeenobservedasfoodbacteriasuchasSalmonellaproliferatemorerapidlyinwarmertemperatures(Schmidhuber&Tubiello,2007,p.19704;McMichaeletal.,2006.p,860).Whileclimatechangemayhavetheeffectofimprovingfoodproductioninsometemperateregionsof
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theworld‐duetoelevatedCO2concentrationsintheatmosphereandextendedgrowingseasons‐itislargelyexpectedtohavenegativeeffectsacrossAfricaandotherrelativelyfood‐insecureregions(Schmidhuber&Tubiello,2007,p.19704).
Withregardstoaffordability,decadesofdatashowcorrelationsbetweenfoodpricesandthenutritionalstatusofthepoor(Bloemetal.,2010,p.133S).WorldfoodpricesareparticularlyimportantforfoodaccessacrossAfricaanddevelopingcountriesingeneral,becausethesesocietiesaremorereliantonpurchasedfoodthandomesticallyproducedfood(Bloemetal.,2010,p.133S).Although,itisrecognisedthatevenforcountriesthatarenetfoodexporters,theremaystillbeinsecurityofaccesstofoodattheindividuallevel(SchmidhuberandTubiello2007).Withoutsignificantimprovementsinagriculturalyieldsthroughimprovedpractices,acrossAfrica,relianceonfoodimportswillmakeAfricancountriesvulnerabletotheglobalfoodprices.
Grainisasignificantindicatoroffoodproductionasitaccountsfor70%ofglobalfoodenergy(McMichael,etal.,2003).SomeoftheeffectsofincreasedfoodpriceshavealreadymanifestedinmanyAfricancountries.Theupsurgeinfoodpricesprecedingthefinancial,andglobaleconomiccrisisof2008,resultedinadeclineinfoodaccessandoverallmicro‐nutrientmalnutritionforthedevelopingworld,asindividualssimultaneouslylostpurchasingpowerasaresultofreducedincomeinfailingeconomies(Bloemetal.,2010,p.133S).
Generally,expectationsarethatfoodpriceswillrisemoderatelyinlinewithincreasesintemperatureuntil2050.After2050,however,foodpricesareexpectedtoincreasesubstantiallyastemperaturesfurtherincrease,withthevalueofsugarandrice,forexample,expectedtoriseby80%(Schmidhuber&Tubiello,2007,p.19706).Somestudiesindicatethefirstcoupleofdegreesofclimatewarmingmayleadtoanoverallincreaseinsomegrainoutputsbutthatanyprofitinthismaybecancelledoutbyincreasesinweedinfestations.Onestudypredictsthata1.1°Cincreaseintemperaturewouldreduceglobalgrainoutputby10%(Brown,2003).GiventhattheIPCCestimatesa2°Ctemperatureincreaseinthe21stcenturyonecan,onthebasisofBrown’sstudypredict20%reductioningrainoutputworldwidebytheendofthiscentury.Meanwhile,othersindicatethatgrainyieldmayincreasemarginallywithinanarrowrangeoftemperaturechange.Theseconflictingconclusionsarebasedonlackofcertaintyandunderstandingofchangingprecipitation.
AcrossAfrica,climatechangeisexpectedtohavetheeffectofcompoundingreducedaccesstofoodwhichasstatedisalreadyamajorprobleminmanyAfricancountries(Schmidhuber&Tubiello,2007,p.19703).AWHOreportindicatesthatmultiplesocialandpoliticalfactorswillgoverntheoveralleffectthatclimatechangewillhaveonfoodsecurity(McMichaeletal.,2003).Moreunderstandingofthecontributionofclimatechangetomalnutritionisanimportantsteptowardseffectiveadaptationthroughgoodgovernance.Similarly,furtherunderstandingoflocaleffectsofclimatechangeonfoodyields,nutritionalqualityandpricewillcontributetodevelopingstrategiestoprotectfuturepopulationsfromthepotentialdangerofchangingweatherpatterns.
Communicable diseases
Communicablediseasesresultfrominfectionbypathogenssuchasviruses,bacteria,fungi,protozoa,andparasites.Communicablediseasesaretransmittedbyphysical
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contactwithinfectedhumans,vectororganismsorwithcontaminatedsubstances(water,food,objects,andair).Climatechangesareexpectedtoaffectthelifecycleandmodesoftransmissionofmanyinfectiousdiseases.Theabilityofapathogentospreadisaffectedbyitsabilitytomatureandreplicate.Temperatureandmoistureavailabilityaretwoenvironmentalfactorsinfluencedbyclimatechangethataffectpathogenproliferation.Temperaturehasaparticularlystrongaffectontherateofpathogenreplicationandmaturation.Further,thesetwoclimatefactorsalsoaffectthesurvivabilityanddensityofvectorsinaparticularareathereforeincreasingthelikelihoodofinfectionuptocertainthresholds(WHO,2004).
Althoughtheenvironmenthasadominantinfluenceonthediversityofpathogensinaregion,thisdiversityisalsoinfluencedbyhumanpopulationsizeanddensity,theageofasettlementandthepopulation’sdiseasecontrolefforts(Shuster‐Wallaceetal.,2008;Dunnetal.,2010).Dependingontheregion,carrier(waterorvector),disease,andmitigationstrategies,thechangeinclimatewillimpactdiseasedistribution,rateofcontagionandtransmissionseasonswithdifferentlevelsofintensity.Thisreportfocusesonselectedwater‐borneandvector‐bornediseasesbasedontheircurrentandexpectedtollonpeopleacrossAfrica.
Transmissionofpathogensbetweenhumanscanoccurinvariouswaysthatincludephysicalcontact,contaminatedwaterorobjects,airborneinhalation,vectororganisms,orbodyfluids.Inourreport,wedivideourfocuscommunicablediseasesintoadiscussionofneglectedtropicaldiseases(NTDs);waterborndiseases,withemphasisondiarrhoea;thenontovectorborndiseases,withemphasisonMalaria;weintroducemeningitisseparatelyasanairbornedisease;followedbyHIVandsocialstatusfortheircompoundingeffectsoncommunityhealth.
Neglected Tropical Diseases
TheNeglectedTropicalDiseases1(NTDs)arethemostcommonconditionsaffectingthepoorest500millionpeoplelivinginSub‐SaharanAfrica(SSA).TheNTDsareagroupof13majordisablingconditions1thataredistributedthroughoutAfricatovaryingdegrees.InfactmanycountriesinAfricasufferundertheburdenofbeinghosttoabouthalfofallthepathogensdefinedasNTDsbytheWHO1(Figure2).Together,NTDsproduceaburdenofdiseasethatmaybeequivalenttouptoone‐halfofSSA'smalariadiseaseburdenandmorethandoublethatcausedbytuberculosis,twomuchmorecommonlyknowncausesofdeathinAfrica.HotezandKamath(2009)indicatesoil‐transmittedhelminthsinfections(seefootnote1)accountforupto85%ofthediseaseburdencausedbyNTDsandoccurinmorethanhalfofSSA’spoorestpeople(Table2;Hotez,2003&2009).Theysuggestthattheprevalenceofthisdiseaseisconnectedtoanumberoffactorsincludingflooding,irrigationprojectconstructionandclimatechange(Mangaletal.,2008).Otherfactorscitedincludedisplacementofpopulations,urbanization,otherEWEs,andairpollution(Campbell‐Lendrum&C.Corvalan,2007).Duetotheirconnectionwithwaterandotherorganisms,theeffectthatclimatechange
1 The WHO listed NTDs include soil transmitted helminths (roundworms such as Ascaris lumbricoides which causes ascariasis, whipworm which causes trichuriasis, hookworms which cause necatoriasis and ancylostomiasis), snail fever (schistosomiasis), lymphatic filariasis, Trachoma, leishmaniasis, Chagas disease (American trypanosomiasis), leprosy, Human African Trypanosomiasis, Guinea-worm (dracunculiasis), buruli ulcer, Cysticercosis, Dengue/dengue haemorrhagic fever, Echinococcosis, Fascioliasis, Onchocerciasis, Rabies, and Yaws.
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hasonthespreadingofcommunicablediseasesisinincreasingtherangeandseasonaldurationofsuitableconditionsforcommunicablepathogenstosurvive.Alsonotethatinthesurvivablerangeoftemperaturesapathogencansurvive,thereisamaximum.
Figure2:DistributionoftheprevalenceofNTDsinAfrica.Source:ImperialCollegeLondon,SchistosomiasisInitiative(availableat:http://www3.imperial.ac.uk/schisto/whatwedo/ntdsinafrica).
Note:Theboundaries,thenamesshown,andthedesignationsusedonthismapdonotimplyofficialendorsement
oracceptancebytheUnitedNations.
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Table2:ExamplesofNTDsaffectedbyclimatechange.(Hotez&Kamath,2009[http://goo.gl/qgFIA&http://goo.gl/XJdpT]).
NTDs Trans‐missionvia
Estimated%ofSSA*populationinfected
Africancountry
withhighestprevalence
SSAdiseaseburdenofGlobaltotal
Source
Hookworms H2O 29% Nigeria 34%Molyneuxetal.,2005;deSilvaetal.,2003
Ascariasis Vector 25% Nigeria 21%Molyneuxetal.,2005;deSilvaetetal.,2003
Schistosomiasis H2O 25% Nigeria 93% Steinmannetal.,2006
Trichuriasis H2O 24% Nigeria 27%Molyneuxetal.,2005;deSilvaetal.,2003
LymphaticfilariasisVector 6‐9% Nigeria 37‐44%
Michael&Bundy,1997;GAELF,2005&2008;Zagaria&Savioli,2002
Onchocerciasis Vector 5% Yemen >99% WHO,2008Trachoma H2O 3% Ethiopia 48% WHO,2008Drancunculiasis H2O <0.01% Sudan 100% WHO,2008
Leishmaniasis Vector <0.01% Sudan NoData
Alvaretal.,2008;Reithingeretal.,2007;Bernetal.,2008;Collinetal.,2004
HumanAfricanTrypanosomiasis Vector <0.01% DRCongo 100% WHO,2006;WHO,
2006Buruliulcer H2O <0.01% Coted’Ivoire57% WHO,2008,2008Leprosy H2O <0.01% DRCongo 14% WHO,2008*SSA–sub‐SaharanAfrica.
Untilrecently,veryfewstudieshavebeencarriedoutregardingtheconnectionofNTDswithclimatechange,althoughsomereviewershavediscussedthesituationwithafocusonvector‐borneNTDs(Campbell‐Lendrun,2003).Table2ranksNTDs(andtheirprimarycarrier)accordingtheproportionofSSA’spopulationaffected,fromthehighestpercentagetothelowest.
Thisisalargediseasecategorythat,basedonregionsofhighestprevalence(Table2),appearstobeprimarilytheresultofpoverty(Manderson,2009).Duetolackofattentionoutsidetheseareas,littleiscurrentlyknownaboutthepatternofthespreadofthesediseasesandtheirpotentiallinkstoclimatechangeormorebroadly,the“environmentalconstraintskeepingaspecieswithinitscharacteristicrange”(RogersandPacker,1993).Belowwelookatthediseasesintwocategoriesbasedonprimarymodesofpathogentransmission:waterbornandvectorborndiseases.
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Water born diseases
Water‐bornediseasesarecausedbyprotozoa,virusesorbacteriawhichtypicallypopulatetheintestinesofhumans.Waterisoftenconnectedtodiseasespreadduetoitsroleinthelifecycleofvectorsoritsdirecteffectonthehealthofpeople.Climatechangealterationstothehydrologiccyclewillaffectwaterdistributionsworldwide(IPCC,2007).TheIPCCexpectswateravailabilityandqualitytobeaffectedinvariouspartsofAfricaposingathreattohumanpopulations.
Currentlyalmosttwomilliondeathsayear,mostlyinyoungchildren,arecausedbyconditionsthatareattributabletounsafewaterandlackofbasicsanitation(Confalonierietal.,2007).Water‐bornediseaseisextremelyprevalentinAfrica(Figure2andTable2)where334water‐borneepidemicsoccurredbetween1980and2006(PWRI,2008;Leroy,2009).Thespreadofwater‐bornediseaseafterextremeclimate‐change‐relatedweatherevents,suchasfloodsorheavyrainfallorunseasonablywarmseasons(suchaslongerwarmperiods,extendinggrowingseasons)areexpectedtobeparticularlyhighinAfricaduetolimitedinfrastructureandcontrolprogramsatthesourcesofthesediseases(Schmidhuber&Tubiello,2007,p.19705).
Perhapssurprisingly,droughtsmayalsocauseincreasesincommunicablediseases,asreducedriverflowmayresultinincreasedpathogenloadingasseenintheAmazon,wherecholeraoutbreaksareassociatedwiththedryseason(Confalonierietal.,2007).Epidemicmeningitis,althoughadiseasespreadviaairborneparticlesanddroplets,alsoappearstobelinkedwiththeoccurrenceofdroughtsasreflectedbytherecentspreadofthediseaseintoWestAfrica.
ThewaterborneNTDsaremostlypreventablebywaterfiltration,casecontainment,andaccesstosafewater.ThistechniquealonehasbeensuccessinbringingthetransmissionandannualcasesofDrancunculiasis(guineaworm)downtoonly4countriesworldwidesinceaneradicationprogrambeganin1989.Infacttherehasbeenareductionincasesinthe20yearperiodfrom1986to2009of99.91%(from~3,500,000in1986to3,190in2009;WHO,2010).Asidefromsafewatersupplies,treatmentcampaignshavealsoincreasedinprevalence,withsomediseasetreatmentsprovingtoberelativelyinexpensive.
Diarrhoea
InSSA,diarrhoealdiseasesaresecondonlytoacuterespiratoryinfectionsasacauseofmortalityofchildrenunder5,withanestimated4.3episodesperchildperyearandanattributedmortalityrateof4.2/1000representing27%ofalldeathsinthisagegroup(ZimbabwePublicHealthReview,1987).Themajorityofpathogensthatinducediarrhoeainhumansarewaterborn,makingthissusceptibletoclimatechangeastemperatureandprecipitationchangesareexpected.Deathiscausedbyinfection,malnutrition,and/ordehydration.Inadditiontothewell‐documentednutritionaleffectsofdrought,causedbyreduceddietaryrangeandconsumption(Confalonierietal.,2007;Campbell‐Lendrum&Bertollini,2009).
In1998,diarrhoeawasthe10thbiggestcauseofdeathsforallagesinSouthAfrica(SA).By2005diarrhoeawasthethirdbiggestkillerinSA.Whenthisdatawascomparedwiththefactorscontributingtodiarrhoealdiseaseitindicatedaninterestingcorrelation
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betweenthenumberofpeoplewithHIV/AIDSandpeoplenothavingaccesstoprivatewatersupply.Essentially,itisexposuretonewdiseases,onesthatapersonmaynotalreadyhaveimmunitytothatputpeopleatthemostrisk.Thisexposuretonewdiseasesistheresultofshiftingpathogenhabitatsorhumanmovement(directlyorindirectlyinducedbyclimatechange).
EnvironmentallyinducedconditionsthatareexpectedtochangeunderanticipatedclimatechangeinAfrica,suchasprecipitationandtemperaturechangesaretheveryenvironmentalfactorsthatsupportdiarrhoea‐causingpathogensinwater.ConditionsthatmakeapopulationpronetodiarrhoeaoccurredinthemonthsfollowingMozambique’sfloodingin2000:8000additionalcasesofdiarrhoeaand447resultantdeathswererecorded(IPCC,humanhealthchapter,2007,p.399).Ahealthysupportsystemcoupledwithsufficientinfrastructurethatcanhandletheconditionswillincreasetheresilienceofanunsuspectingpopulationtothis,andotherhealthimpactsaffectedbywateravailability(cleanliness,access,regulatedavailability,etc.).
Vector born diseases
Therehasbeenaworldwideresurgencein,andaredistributionofmanyoldinfectiousdiseases(Table3).TheWHO(1996)estimates30newinfectiousdiseasesemergedfrom1975to1995withsomeexpertssuggestingthatsomeofthesearepossiblyconnectedtoclimatechange(Costelloetal.,2009;McMichael,2004).Globalclimatechangemayhaveamajorinfluenceonvector‐bornediseaseepidemiology(Dobson&Carper,1992;Epstein,2000;Epstein,2007;Githekoetal.,2000;Sutherst,2004).Vector‐borneinfectiousdiseasesmaybetransmittedtohumansbycontaminatedarthropods(i.e.fleas,mosquitoes,ticks,sandflies,andlice)andanimals(typicallymammalssuchasratsandlessoftenbirds).Morethan1,400speciesofhumanpathogenhavebeenidentified.Ofthese,58%aretransmittedfromanimalstohumansandaretwiceaslikelytobeemergingorre‐emergingasothervector‐borneandwater‐bornepathogens.Thetablebelowshowsthegeographicdistributionofvectorbornediseasesandtheprinciplevectorresponsibleforeach.Notethatthetop6vectorbornediseasesallexistinAfrica.Table2liststheprevalenceofvectorborndiseases,inrelationtowaterborndiseases.
Table3:Examplesofvectorbornediseasesaffectedbyclimatechangeindecreasingorderofaffliction.
Disease Vector Currentgeographicaldistribution
1.Malaria
Mosquitoes
Tropics
2.DengueFever Africa,Caribbean,Pacific,FarEast
3.WestNile Worldwide
4.YellowFever Africa,SouthAmerica
5.Leishmaniasis Sandflies Africa,Central&SouthAmerica
6.Trypanosomiasis Tsetseflies Africa,Central&SouthAmerica
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Mosquitospecies,suchasthegenusAnopheles(approximately40specieswhichspreadmalaria),Culex(C.quinquefasciatus;WestNileVirus)andAedes(A.aegypti;dengueandyellowfever)areresponsibleforthetransmissionofmostvector‐bornediseasesgloballyandacrossAfrica(Githekoetal.,2000).Mosquitoescarryingdiseasessuchasmalariaanddenguefever,twoofthemostprominentmosquito‐bornediseasesinAfrica,areamongthoseundergoingresurgenceandredistribution(Gubler&Kuno,1997;Gubler,2005;Coelho,2008).
Threeofthekeycomponentsthatdeterminetheoccurrenceofvector‐bornediseasesarepresentedintheWorldHealthOrganizationTaskGroup's(1990)reportPotentialHealthEffectsofClimaticChange.Theyare:
Occurrence:theabundanceofvectorsandreservoirhosts; Environment:theprevalenceofdisease‐causingparasitesandpathogenssuitably
adaptedtothevectors,thehumanoranimalhostandthelocalenvironmentalconditions,especiallytemperatureandhumidity,and;
Resilience:theresilienceandbehaviourofthehumanpopulation,whichmustbeindynamicequilibriumwiththevector‐borneparasitesandpathogens.
Thecombinedeffectsofchangingtemperatures,precipitationmayleadtoamoresuitableenvironmentforthespreadofvector‐bornediseasesandtheemergenceofnewonesindifferentpartsofAfrica.Forexample,temperaturechangesaffectvector‐bornediseasesbyinfluencingreproductivecyclesandbehaviours.BitefrequencygenerallyriseswithtemperatureandatmosphericCO2content(deLucia,2008).Ingeneral,higherambienttemperatures(toamaximum)shortentheviralincubationperiodandbreedingcycleinvectors(Campbell‐Lendrum&Bertollini,2009).Forinstance,reproductionofP.vivax(aprotozoalparasite)inmosquitoestakes55daysat16°C;29daysat18°Candonlysevendaysat28°C.ForP.falciparum,whichcausesthemajorityofseveremalaria,16.5–18°Cistherequiredminimumtemperaturefordevelopment.Thereishighmortalityinmosquitoesfrom32‐39°C,andat40°Ctheirdailysurvivalbecomeszero(Craigetal.,1999).
Someepidemiologicalmodelsillustratethepotentialofthesevector‐bornediseasestorapidlyspread.allieddatafromweatherstationswithsatellitedatatodeterminewhichcombinationofpredictorvariablesismostusefulfordescribingvectordistributionsofanumberofNTDs,andperhapsforforetellingalterationsindistributionwithclimatechange.Theresultsfoundonlyveryslightdifferencesbetweenthemeantemperaturesofplaceswheretsetsedoanddonotoccurnaturally(Rogers,1993;Rogers&Randolph,1993;Rogers&Packer,1993).Thisfinding,theysay,indicatesthatasmallchangeintemperaturemightconsiderablyaffecttheirdistribution.
Malaria
Outofthe700,000to2.7millionpeoplethatdieofmalariaannuallyaroundtheworld,94%occurredinAfricawith90%inSSA,and75%ofthesearechildren(Thompson,2004;Patzetal.,2005;Ramin&McMichael,2009;WHO,2008;Figure3).Asof2010,the41countrieswiththehighestdeathratefrommalariaper100,000populationareinAfrica,startingwithCoted'Ivoire(86.2),Angola(56.9)andBurkinaFaso(50.7;WHO,2010).ThesefiguressuggestthatperhapsoneofthegreatesthealththreatstoAfrica,aftermalnutrition,ismalaria.Themajorityofclimate‐malariaresearchinAfrica,suggeststhatmalariatransmission,especiallyepidemicoutbreaks,isassociatedwith
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increasedrainfallintypicallydryregionsandincreasedtemperaturesinhigh‐altitude,typicallycoolregions(Connoretal.,2006,p.22).Thereasonforthisisthatrainfallproducesthemoistureconditionsandsurfacewaterthatfacilitatesbreedingformalariatransmittingmosquitoesandwarmertemperaturesfacilitatefasterdevelopmentformosquitolarvaeandsurvivalforadultmosquitoes;moreimportantlythough,warmtemperaturesallowsthemalariaparasite,plasmodium,tomultiplymorequicklyinmosquitohosts(Grover‐Kopecetal.,2006,p.2).
Figure3:Malariaendemicity:thespatialdistributionofP.falciparum(Hayetal.,2009).
Note:Theboundaries,thenamesshown,andthedesignationsusedonthismapdonotimplyofficialendorsement
oracceptancebytheUnitedNations.
Therelationshipbetweenmalariaandclimatesystemshasbeenthemostextensivelystudiedclimate‐relatedillnessinAfrica(Connoretal.,2006).Thisispartlyduetothefactthatclimateinformationcanbeusedtoproducemalariariskmapsintheabsenceofhigh‐qualityepidemiologicalinformation(Connoretal.,2006)aswellasthefactthemalariaisamajorhealthissueinAfrica.Theresultingresearchhasshedlighton‘associations’,‘correlations,and‘links’betweenmalariatransmissionratesandclimateconditions(Grover‐Kopecetal.,2006,p.2).
AnumberofstudieshavelinkedwarmertemperaturestoincreasedmalariacasesinthehighlandsofeastAfricaanddecreasedmalariacasestothedroughtintheSahelregion(McMichaeletal.,2003,p.51).InEthiopia,analysisofmalariamorbiditydataindicatesthathigherminimumtemperaturescorrelatewithincreasedinstancesofmalariaoutbreaks(Confalonierietal.,2007).Furtherincreasingcaseloadoccurswhencouplingincreasedtemperaturewithasimultaneousincreaseinprecipitation(Confalonierietal.,2007).ForinstancefollowingtheElNinoeventin1997,Kenyaexperiencedasix‐foldincreaseinthenumberofmalariacasescomparedwiththepreviousyear(McMichael,etal.,2003).ResearchhasalsofoundastatisticallysignificantrelationshipbetweenElNinoeventsandmalariaepidemicsinColombia,Guyana,Peru,andVenezuela(Ibid.).Controversiesremainamongmalariologistsabouttheextentofthecontributionofclimatechangetomalaria‐changingpatterns.Somethinkitisrelativelyminor,withagreaterriskfordengueandotherviruses,eg,arboandhantaviruses.
Socialandpoliticalconditions,increasingresistancetoinsecticidesandanti‐malarialdrugs,andthedeteriorationofvectorcontroloperationsexplainmuchoftherecentresurgenceanddeathsduetomalaria(James,1929;Dobson,1980;Martens&Hall;
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Wingate,1997;Hutchinson&Lindsay,2006;Pascualetal.2006;Chavesetal.2008).ScientistsalsosaythereareanincreasingnumberofdeathsandmorbidityacrossAfricathatareduetomalaria(Snalletal.2009)anddenguefever(Cazellesetal.2005).
Asignificantbodyofresearchhassuggestedthatoverallglobalwarmingisexpectedtoincreasetheseasonalityandrangeofmalaria,bothacrossAfricaandonaglobalscale(McMichaeletal.,2003,).Malariainfectionrateisexpectedtoincreaseby16‐28%inperson‐monthsbytheyear2100inAfrica(Patzetal.,2005).TheMappingMalariaRiskinAfrica(MARA/ARMA)projectreportsthatbetween2050and2080,malariaisexpectedtodeclineinwesternSahelandsoutherncentralAfricaastheseareasarelikelytobecomeunsuitableforMalariatransmission(Thomasetal.,2004).TheIPCCreportsthatby2050previouslymalariafreeareasinBurundi,Ethiopia,KenyaandRwandamaysuffer“modestincursions”ofMalaria.Further,thechangedrangeofmalariacarryingmosquitosisexpectedtoincreasethelikelihoodofepidemicsinhighlandareassuchasEastAfricaduetoalackofgeneticresistanceinthepopulationtomalaria(IPCCWGII2007,Chapter9).Elsewhere,inDebreZeit,Ethiopia,withcontrolonchangesindrugresistance,mosquitocontrolprograms,andhumanmigration,warmingtemperatureshavebeenidentifiedasthemostlikelycauseforincreasedmalariatransmissionobservedbetween1968to1993(Patz,2005,p.311).Thisexamplereferstoan‘association’betweenmalariatransmissionandwarmingtemperaturesbecausetheremaybeotherfactors,perhapsunidentifiedthatcouldhaveplayedamajorrole(Patz,2005,p.311).
Whileamajorityofresearchsupportstheideathatmalariatransmissionratesareaffectedbyclimate,therearesomestudiesthatasserttheopposite.Confirminglinkswithclimatechangeastheprimarycauseforchangesinmalariatransmissionratesrequiresaseriesofotherfactorsthatcontributetotransmissionratestobeconsidered,suchas:theuseofdrugresistanceandmosquitocontrolprograms,humanmigrationandimmunestatus,andchangesinland‐usepatterns(Patzetal.,2005,p.311).Forexample,despiteseveralstudieslinkingmalariaprevalenceandclimatechangeinthehighlandsofEastAfrica(e.g.Pascualetal.,2006),Hayetal.(2002),studiedfoursitesinthatregionwhichexperiencedincreasedmalariatransmissionandfoundthatclimaticfactorsthatwouldhaveenhancedsuitabilityformalariatransmission,didnotchangeverymuch;thusmakingclimateunaccountableforincreasedmalariaprevalence.Similarly,Jacksonetal.(2010)foundverylittlecorrelationbetweenratesofmalariaprevalenceandclimateconditionsinamalaria‐endemicregionofWestAfrica.Veryfewstudieshavelinkedincreasedmalariatransmissiontochangesinclimatewhilecontrollingforotherconfoundingfactors.
Malariatransmissionrateshavenotrisensimplybecausehumansareencounteringmoremalaria‐carryingmosquitosandbeingbittenmorefrequently.Manyfactorsplayaroleinmalariatransmissionratesinapopulation.Socialandpoliticalconditions,increasingresistancetoinsecticidesandanti‐malarialdrugs,andthedeteriorationofvectorcontroloperationsexplainmuchoftherecentresurgenceanddeathsduetomalaria(James,1929;Dobson,1980;Martens&Hall;Wingate,1997;Hutchinson&Lindsay,2006;Pascualetal.2006;Chavesetal.2008).
Inspiteoftheconflictingfindingsregardingthecorrelationbetweenmalariaprevalenceandchangesinclimate,itremainsafactthatMalariaisaserioushealthproblemacross
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SSAandcontrolprogramsagainstthisdiseaseneedtobeamplifiedwhetherornotclimatechangewillexpanditsspread.
Meningitis – an airborne disease
MeningococcalmeningitisiscausedbythebacteriaN.meningitidisthatexistsallovertheworld.However,innoregionoftheworldisitasgreataproblemasintheSahelregionofAfrica(Figure4).ForAfricaasawhole,meningitisisoneofthecontinent’stopthreeclimatesensitivediseases,withroughly350millionpeoplelivinginendemiczonesforthisdisease(McMichaeletal.,2003;Palmgren,2009).Humansaretheonlynaturalreservoirforthisdiseaseanditisoftenspreadbetweenhumansviarespiratorydropletsorsaliva(i.e:throughcoughing,sneezing,kissingorotherformsofcloseanddirectcontact),withthesymptomsapparentonsomeindividualsandnon‐apparentonothers.Thedisease,asitischaracterizedbytheinfectionofthemeninges,canhavelifelongdamagingeffectstothecentralnervoussysteminsomesurvivorsandittendstokillfrom4‐17%ofitsvictims.Themostsusceptiblevictimsofthisdiseasearetypicallychildren,adolescentsandyoungadults(Menactra,2011).
Figure4:Africanmeningitisbelt(Palmgren,2009;WHO/EMC/BAC/98.3).
Note:Theboundaries,thenamesshown,andthedesignationsusedonthismapdonotimplyofficialendorsement
oracceptancebytheUnitedNations.
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Meningococcalmeningitisisanairbornedisease,forwhichepidemicsaremostoftenreportedinyearsofseveredrynessanddrought,industladenenvironmentsandrarelyinareasofdenseforestandhighhumidity.Theassociationbetweenthisdiseaseandduststemsoutofsuggestionsfromanumberofstudies,thatdustislikelythekeyelementthatconvertstheN.meningitidisbacteriafromitsbenignformtoitspathogenicone.Themechanismsforhowthisconversionmightoccur,however,areunclear.Althoughaclearcausallinkbetweenincreasedmeningitisincidenceandclimatefactorsismissing,thedistributionandseasonalityofmeningitisiswidelybelievedtobeassociatedwithdustyconditionsthatariseoutofdrynessanddrought(IPCC,2007,p.400).Forexample,SouthAfricahasbeensubjectedtoseasonalincreasesduringthewinterandspringmonths(May–October)ofendemicmeningococcaldiseaseoutbreaks(Küstner,1979).Thereforeareaspronetoincreasingdroughtconditionsasaresultofclimatechangecanexpecttobesubjecttoanincreaseinmeningitisoccurrences.
Meningitisisconcentratedinthesemi‐aridSahelregionofAfrica.InfactthestripoflandalongtheSahelwithhighestconcentrationsofmeningitisisoftenreferredtoasthe‘meningitis‐belt.’ThisspansfromEthiopiaandSudanintheEasttoSenegal,MaliandGuineainthewest(Figure4;Palmgren,2009).Epidemicsofmeningococcalmeningitisbreakoutin5to‐10yearsintervalsinthemeningitisbelt.Inrecentyears,thewidthofthismeningitisbeltappearstobeexpandingsouthwardasaresultofregionalclimatechangeandchangesinlanduse(IPCC,2007,p.400).CountriessuchasKenya,Uganda,Tanzania,Togo,Coted’Ivoire,CameroonandBenin,whicharetypicallynotaccustomedtoexperiencingsevereepidemicsofmeningitis,andwhichdonottechnicallybelongtothemeningitisbelt,havebeguntoexperiencelargescaleepidemicsofthedisease.Thissouthwardexpansionofthemeningitis‐beltintothesecountriesisalsoassociatedwiththeexpansionofincreasinglyhotanddryconditionsintotheseareas(McMichaeletal.,2003).
TheclimatechangeprojectionsfortheSahelregionincludemorefrequentandlongerdroughtasaresultofexpectedincreasesintemperatureanddecreasesinrainfall.Ithasbeensuggestedthatthiswillcauselongerdurationsoftheepidemicsandperhapsevenhigherratesofincidenceofthedisease.However,becauseepidemiologicalresearchhasnotbeenabletoconfirmthecorrelationbetweenthediseaseandclimate,thiscannotbedeclaredcertainly.
Furtherstill,thedisease’suniqueregionalcharacteristicsanditsprevalencedrivenbyenvironmentalconditionshasshownclearpatternsofoutbreaksofthediseaseinSouthAfrica.Thoughnotinthemeningitisbelt,inrecentdecades,SouthAfricahasbeensubjecttoincreasingnumberofepidemicoutbreaksofmeningitis(Küstner,1979).Here,theburdenofdiseaseoccursinacyclicalpatternatintervalsof8–10years(Bikitsha,1998).
Successhasbeenobserved,theincidenceofclinicalnotificationtothenationalDepartmentofHealth(Pretoria,SouthAfrica)hasdecreasedsincethelate1980s:fortheperiod1992–1997,therewere1–2casesper100,000persons(Bikitsha,1998).ByJuly2002(overthethreepreviousyears),854casesoflaboratory‐confirmeddiseasecaseswerereportedinSA.Thisisanannualdiseaseincidencerateof0.64/100,000population(Incidencewashighestininfants<1yearofage;Coulson,2007).Furthermore,withtherecentavailabilityofthegroupAconjugatevaccine,whichismeanttotargetthemostsignificantstrainoftheN.meningitidisbacteria,
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epidemiologistsarehopefulthattheproblemofmeningitis,acrossAfrica‐andnotjustthemeningitisbelt‐willbegintobecontrolled.ThedevelopmentofthisvaccineisnotthebeallandendallforcurbingmeningitisinAfrica,however.EpidemiologistsconferthatepidemiologicalandenvironmentaldatasetsofthedryseasoninAfrica,needtobeimprovedinordertoenhancemeningitisearlywarningsystems,andtherebyefficientlytargetanddispersethisvaccine.
HIV/AIDS
HIVisnotlikelytobedirectlyaffectedbyclimatechange.However,HIVinfectedindividualsareatincreasedriskofcommunicablediseasesandthosewhoaremalnourishedorunhealthymaybeatgreaterriskofHIV.Giventheselinksitislikelythatclimatechangewillhaveaneffectondiseasepatterns(BlaserandCohn,1986).By2007,anestimated33.2millionpeoplecontractedthediseaseworldwidekillinganestimated2.1millionpeople,withgreaterthan75%ofthesedeathsinSSA.
Theoccurrencesofopportunisticdiseases,whichdefinetheAcquiredImmuneDeficiencySyndrome(AIDS),includeprotozoans(Cryptosporidium,Microsporidium),bacteria(Mycobacteriumaviumcomplex)andviruses(Astroviridae,Adenoviridae,RotavirusandCytomegalovirus).Eachofthesecanbewaterandvectorbornpathogens,highlightingtheneedforeradicationprograms.Theseappeartobemoreheavily‐dependentongeographythanotherfactorssuchasdemographicsandsoitseemslikelythatasgeographicaldistributionofcommunicablediseasesevolves,infectionsinHIV‐affectedpopulationswillchangeaccordingly.
Theexpectationisthatclimatechangemaygeneratemoremigrantsaspeoplesearchforsecurity,whetheritisforfood,water,safety,orhealthcare.Aspopulationsareforcedtomigrateasaresultofclimatechange,HIVinfectionrateswouldincreaseincertainregions,aspeoplefromdifferentareasmixorifsexworkbecomesameansofsustenanceforrural/farmermigrantswhoareforcedtomakealifeforthemselvesinthecity(McMichael,2008).
Social status
Geopolitical,socioeconomic,demographicandtechnologicalevolutioncompoundsocialandeconomicunpredictability.Culturaladjustmentsintimethatprotectusfromsocialandeconomicuncertaintiesaretheretolessentheimpactontherelationshipbetweenenvironmentalstressandmortalityrates,forexample,improvementsinhousingconditionsandbetterclothing.Thereisstrongevidencethatdisadvantagedgroupshavepoorersurvivalchances,anddieatayoungeragethanmorefavouredgroups(Figure5).Thescaleofthedifferencesinmortalityisimmense(Marmotetal.,2008).Whileachildborninsomedevelopedcountriestoday,suchasJapanorSweden,canbeexpectedtoliveto80years,childrenborninacountryinSSAarenotexpectedtolivepast50years.Furthermore,whilethecarbonfootprintoftheworld’spoorest1billionpeopleaccountsforroughly4%oftheworld’stotalcarbonfootprint,itisthesevulnerablepopulationsthatwillbearthehighestcostsofclimatechange(Costelloetal.,2009).Infact,somehaveassertedthatthenegativeimpactsofclimatechangewillbesufferedmoreseverelyinSSA‐inspiteofthecontinentsrelativelylowemissions(seeFigure6)‐thaninotherregions(RaminandMcMichael,2009).Thisislargelyattributabletothecontinent’soveralllimitedadaptivecapacity.Manyofthehumanhealthissues
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discussedarenotjustcommonlyassociatedwithpovertybutarealsoacauseofpovertyandamajorhindrancetoeconomicdevelopment.Thesediseasesareassociatedwithmajornegativeeconomiceffectsinregionswheretheyarewidespread.Countrieswithpoororweakhealthservicesandwaterdistributioninfrastructurefindtheyareamajorfactorintheirsloweconomicdevelopment(forexample,MalariainSSA;Sachs&Malaney,2002).Incountrieswheremalariaiscommon,averagepercapitaGDPhasrisen(between1965and1990)only0.4%peryear,comparedto2.4%peryearinothercountries(Ettlingetal.,1994).TheestimatedeconomicimpactofmalariaonAfricais$12billionUSDeveryyear(Greenwoodetal.,2005;includescostsofhealthcare,workingdayslostduetosickness,dayslostineducation,decreasedproductivityduetobraindamagefromcerebralmalaria,andlossofinvestmentandtourism).
Figure5:AssociationbetweenGDP/personadjustedfor$USPurchasingPowerParityandlifeexpectancyfor155countriescirca1993(Lynchetal.,2000).
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Figure6:AfricanCO2emissionscomparedwiththeworld(UNEP,2002).
Note:Theboundaries,thenamesshown,andthedesignationsusedonthismapdonotimplyofficialendorsement
oracceptancebytheUnitedNations.
Asaresultofpoverty,conflict,andchangingenvironments,forcedmigrationanddisplacementisoccurringinvariousregionsoftheworld.SomecausesformigrationrelatedtoclimatechangeandhealthincludeincreasedEWEs,droughts,desertification,sealevelrise,anddisruptionofseasonalweatherpatternswhichcausediseaseoutbreaksandmalnutrition.Also,migrantsmaycarrytheinfectiousdiseasesoftheirplaceoforigintotheirdestinationsand,oncethere,theymaybesusceptibletodiseasestheyhadnotbeenpreviouslyexposedto.Oftentheyliveoutsidetheestablishedsocial
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systemandmaynothaveaccesstoadequatehealthcareservices.TheWorldDisastersReport2001publishedbytheInternationalFederationofRedCrossandRedCrescentSocietiesestimatesapproximately25millionpeoplearecurrentlyonthemoveasforcedmigrantsduetoclimatechangerelatedissues.
Direct impacts
Potentialdirecthealtheffectsofglobalclimatechangeuponanindividual’sorpopulation’shealthwilloccurpredominantlythroughtheimpactsofclimatevariablesuponhumanbiology.Themainclimatic‐environmentalvariablesconcernedherearetemperature,precipitationandairquality.Itisimportanttopointoutwhilstthemaindriversareclimaticvariables,impactsaremodulatedbyhumanpopulationdensity,thevulnerabilityoflocalsettlements,regionaleconomicwealthandthestrengthofinfrastructure.Asaresult,theseimpactsarefeltmorestronglyacrossAfricathaninricherregionswheretheyareoftenneglectedasissues.Theseissuesaretheresultofspecificevents,suchasheatwaves,floods,airqualitychanges,oftenleadingtoindirecteffects.Betterunderstandingoftheseconnectionscanleadtothedevelopmentofappropriateadaptationandmitigationtechniquesforthebenefitofapopulation’shealth.
Extreme weather events and their direct effects
Thedirecthealtheffectsofclimatechangewiththepotentialforgreatestimpactsaretheforcesthatcreatedroughtsandfloods.Unfortunatelythisisanareaforwhichthereisinsufficientdata(IPCCWGII2007,Chapter9).WorkingGroupIIoftheIPCC,initsdiscussionofclimatechangesinAfrica,isinconclusivewithregardstoanychangesinthefrequencyorsizeofEWEsbutsuggeststheremightbeaslightincreaseindroughtsforexampleinthesecondhalfofthe21stcenturyandthattheremaybemorefrequentandstrongertropicalstormsoffthesouthernIndianOcean.SinceEWEsarerelativelylocationspecific,regionswithahistoryofaspecificEWEwilltendtocontinuetoexperiencesuchevents.InlandandcoastalfloodshavebeenthemostfrequentEWE(EpsteinandMills,2005).
Evenwithoutclimatechange,theimpactofEWEscanbe,andhavebeen,devastating.TheimpactofEWEsistypicallythegreatestinthemostvulnerableregions,wherepopulationsareleastabletodefendthemselves,resultingindisproportionatedeathtolls,typicallyamongstthepoor.Extremeweatherevents,suchas,cyclones,droughtsandhurricaneshaveanextraordinaryimpactonhumanmortality.Table4outlinesthenumberofpeoplekilledbyEWEsbyregion.OfnoteisthatwhilethefrequencyofEWEsisincreasingthenumberkilledwassignificantlysmallerinthe1990sthaninthe1980s.
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Table4:NumberofpeoplekilledinEWEsinthe1980’sand1990’sbyglobalregion(McMichaeletal.,2003).
Region
Deathsin1980s Deathsin1990s
(‘000s) (%oftotal) (‘000s) (%oftotal)
1.Africa 416.9 60.3 10.4 1.72.EasternEurope 2.0 0.3 5.1 0.83.EasternMediterranean 161.6 23.4 14.4 2.44.LatinAmericaandtheCaribbean 11.8 1.7 59.3 9.9
5.SouthEastAsia 53.9 7.8 458.0 76.26.WesternPacific 35.5 5.1 48.3 8.07.Developed 102.1 14.8 5.6 0.9Total 691.9 100.0 601.2 100.0
TheeffectsonindividualsofEWEsarecompoundedbydamagetoinfrastructureandhealthsystems,forexampleitwasdifficultforHIVretroviraldrugstobedeliveredtoNorthernNamibiaduetothefloodsthereearlierthisyear.Oncetheinitialdisasterhaspassed,secondaryissuesmayemerge,suchasalackoffoodandadequatecleanwater(Shultzetal.,2005)andincreasesincommunicableandnon‐communicablediseases.Survivorshaveanincreasedriskofcontractingrespiratory,diarrhoealandcommunicablediseasesintheaftermathofanextremeeventduetopopulationovercrowding,limitedornoaccesstopotablewaterandfood,andexposuretochemicals,pathogensandwaste(Kovatsetal.,2003).Poordrainageandstorm‐watermanagementinlow‐incomeurbancommunitiesincreasesratesofinfectiousdiseasetransmission(Confalonierietal.,2007).Extremeweathereventscancausevariationinthepatternsofvector‐bornediseaseseitherbycreatingfavourableenvironmentsforvectorsorthroughthedestructionofavector’senvironment.Forexample,floodingcanintensifythetransmissionofhydrophilicvectorsanddiseases(Connor,1999).Long‐termimpactsincludeincreasesininfectiousdiseaseandmentalstresses,lossesofinfrastructureandterritoryandenvironmentally‐inducedmigrationwhichcanleadtofurtherincreasesininfectiousdiseases,conflictsoverwater,energyandotherincreasinglyscarceresources,resultinginpoliticaltension.
UV related cancers and diseases
Thisisarangeofhealtheffectsthatwillincreaseinimportanceaspopulation’slifespanbegintolengthen.ClimatechangemayalterhumanexposuretoUVRinseveralways,withlimitedpredictabilityandvariationamongregions(McMichaeletal.,2003).TheIPCCconcludedthatexcessiveUVRexposurewasresponsiblefor1.5milliondisability‐adjustedlifeyearsand60,000prematuredeathsworldwidein2000fromskin,eye,andcardio‐respiratorydiseases(Confalonierietal.,2007).SmallamountsofUVRarebeneficialtohealth,andplayanessentialroleintheproductionofvitaminD.However,excessiveexposuretoUVRisassociatedwithdifferenttypesofskincancer,sunburn,acceleratedskinageing,solarkeratoses,cataractandothereyediseasesthatreducetheeffectivenessoftheimmunesystem.
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Worldwide,approximately18millionpeopleareblindasaresultofcataracts,withtherateofcataractssurgerythelowestinAfrica(Yorstonetal.,2001).Asaresult,indevelopingcountriescataractscauses50–90%ofallblindness(Murray&Lopez,1996).Ofthese,5%ofallcataract‐relateddiseasesaredirectlyattributabletoUVRexposure.
Intheyear2000,UVRexposurehadledtomorethan200,000casesofmelanomaand65,000melanoma‐associateddeathsglobally.AprogramtoeliminatecataractblindnessinAfricaby2020hasbeenproposed,andtherearegroundsforthisoptimismthatthisispossible.Firstly,thenumberofcataractoperationsisincreasingrapidlyinsomecountries.InKenya,therewerealittleover5000cataractoperationsin1996(asreportedtotheNationalPreventionofBlindnessCommittee).By1999,thishadincreasedtoover12000,withthequalityofsurgeryalsoimproving(Yorstonetal.,2001).Secondly,humanresourcesdevelopmentandaccesstolowcostmaterialsismakingcataractsurgerymorewidelyavailable(Brian&Taylor,2001).ManysurgeonshavebeensuccessfullytrainedorretrainedinvarioustypesofcataractsurgerywitheducationclinicssetupinsuchcountriesasGhana,Nigeria,SouthAfricaandTanzania.IthasbeennotedthatFrancophoneandPortuguese‐speakingAfricahasfewertrainingprogrammesatthemoment(Alhassanetal.,2000).
TheWHOconfirmsthatinstancesofskincancerhavebeenincreasingsteadilyinthetwodecades,especiallyinregionswithhighUVRexposure,withSouthAfricahighlighted(McMichael,etal.,2003).Therelationshipbetweenozonedepletionandpoorskinandeyehealthisunclear.Scientistspointoutthedifficultiesofdistinguishingozonedepletionbetweenpollutionandclimate.Researchisneededonattitudestowardsunbathingandtheuseofprotectivemeasures.Protectivemeasures,suchassunscreenointmentsandcreams,andprotectiveeyewear,requireevaluation.Toomuchrelianceonsunscreenshasbeenidentifiedasapotentialcauseofincreasingskinandeyedisease(Garlandetal.,2002).
TheeffectUVRhasonthehumanimmunesystemappearstobeareductionineffectivenessbychangingtheactivityanddistributionofthecellsresponsiblefortriggeringimmuneresponses(DeFabo&Noonan,1983).Fortheeyesandtheimmunesystem,thisisindependentofskinpigmentation,soallpeopleeverywhereareatriskfrompotentialadverseeffectsincludingincreasedincidenceandseverityofinfectiousdisease,andenhancedriskofmalignantchanges(Last,1993).Theabilitytorespondtoincreasesofskinandeyediseaseswillbelowerinlowerandmiddleincomecountries.Populationsrequiredtoworkoutdoorswillbemostaffected,aswellasthosethatspendtheiryouthinthesun.
Temperature and precipitation effects
Increasesinaveragetemperaturerepresentaverysignificantsourceofpotentialdirectclimatechangeimpactsonhumanhealth.Amajorconcernisthatsuchincreasesmayleadtotemperaturesbeyondthosecomfortable(calledheatstress)foraregionaffectingmortalitythroughthermalstress(Figure7).Heatstressaffectsindividualsduringextremes(inintensityand/orfrequency)oflocalweather‐inthecoldestorwarmestseasonsforexample.Theseenvironmentalconditionscanbefurtherexacerbatedbyhumanactivitiessuchasdeforestationandurbanisationbyaffectinglocalclimatesbyincreasinglocaltemperaturesby3+°C(Hamilton,1989).
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Figure7:TemperaturechangesinAfricacomparedwiththeworld(UNEP,2002).
Seasonalvariationinmortalityhasbeendescribedinmanycountriesthroughouttheages.InancientGreece,Hippocrates(HippocratesVol.1.,McKEE,1989)describedtheoccurrenceofsuddendeathsandstrokeswhenacoldspringfollowedamildwinter.Researchsuggeststhatinwarmerclimatespatientsmayhaveoptimumcardiovascularhealthathighertemperatures(Panetal.1995).ForexampleinTaiwan,elderlypatientshaveoptimumcardiovascularhealthandthefewestdeathsfromcoronaryarterydiseaseatatemperaturerangecorrespondingto26‐29°C(Ibid).
Thoughrarelydiscussedintheliterature,mortalityduetoheatwaveshavebeenextensivelystudiedinEuropeandNorthAmerica,howeverdataisvirtuallyabsentforSouthAmericaandAfrica(McMichaeletal.,2006).Risingtemperatureswillbemostdangerousforpoorpeopleindevelopingcountriesandamongthemostvulnerable(youngandelderly,sickandpoor).AswiththeotherhealthaffectsafflictingAfrica,thisisexacerbatedduetolimitedresourcesavailabletopoorerpopulations.Thereisdifficultyinpredictingtheeffectsofchangesinfrequencyandintensityofheatwaveson
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mortalityratesinhightemperatureregionslikeinAfricaduetothelackofdataaboutmortalityintheseregions.
Air quality
Climatechangeisexpectedtoreduceairqualityinsomeareas(IPCC,2007)contributingtorespiratorydisorders(Kinney,2008;McMichael,etal.,2003).Therelationshipbetweenclimatechangeandairqualityiscomplexwithmanyinteractingmechanisms.Forexample,airqualityinfluencescanbeofclimatic/meteorologic(temperature,humidity,windspeed,winddirectionandmixingheight),natural(ground‐levelozoneandlight‐catalysedairchemistryreactions,aeroallergens,forestfires,anddustfromdrysoils),oranthropogenic(usingcarbonbasedfuelsforlocalenergyuse,transportation,andagriculture)origin,resultingineventualdepositionofairpollutants(Sapkota,2005;Confalonieri,etal.,2007;Kovats,Ebi,&Menne,2003).Particulatematterisapollutantofconcernasitisacomplexmixtureofextremelysmallparticlesandliquiddroplets.Wheninhaled,theseparticlescanreachthedeepestregionsofthelungs.Exposuretoparticlepollutionislinkedtoavarietyofsignificanthealthproblems.Vulnerabilityisdeterminedbythequalityofhousing,theavailabilityofairconditioningandtheurbanheatislandeffect,resultinginincreaseddeathsamongtheelderlyandurbanpoor(McMichealetal.,1996;Piver,1999aandb;Epstein&Mills,2005).
Sunlightandhightemperatures,combinedwithotherpollutantssuchasnitrogenoxidesandvolatileorganiccompoundscancauseground‐levelozonetoincrease.Ozoneformsinthetropospherebytheactionofsunlightonozoneprecursors(throughphotochemistry)fromtheby‐productsofburningcarbon‐basedfuels.Atthesurface,anincreaseintemperatureacceleratesphotochemicalreactionrates(strongcorrelationbetweenhigherozonelevelsandwarmerdays–butnotalways).Ground‐levelozonecandamagelungtissueandisespeciallyharmfulforthosewithasthmaandotherchroniclungdiseases.Eventhosewithmoderatediseasemaybeatriskfromtemperaturerisesabove16.5°C(Levy,2005).
Theincreasesofairpollutantsduetoclimatechangediscussedabovemayinfluencecardio‐respiratorydisease(McMichaeletal.,2003)aswellasbyexposingpatientswithpre‐existingconditionstodangeroustemperatureextremes,whichstressthecardiovascularsystem.TheWHO(2002)hasestimatedthatpoorairqualitycausedbyclimatechangewasresponsibleforover2.4millionprematuredeathsin2000alone(1/3byoutdoorand2/3byindoorpoorairquality)andaccountsforapproximately2%oftheglobalcardiopulmonarydiseaseburden(Prüss‐Üstün&Corvalán,2006;Watts,2009).Exposuretooutdoorairpollutionaccountedforapproximately2%oftheglobalcardiopulmonarydiseaseburden(WHO,2002;Cohenetal.,2004).Thearrayofhealthimpactsincludesheadaches,nausea,cardio‐respiratorydiseasesandcancer.
Gaps in knowledge and research
Climateandhealthresearchisstillinaratherprimitivestageandmanyofthedirectandindirecthealtheffectsofclimatechangeinbothregionalandglobalcontexthavenotbeenfullyidentifiedorunderstood.Hence,althoughalotisknownaboutthescienceofclimatechange,thereremainmanyuncertaintiesofitspotentialimpactonhealth(IPCC,2007).Theseuncertaintiesrelatemostlytothreemainareas:
1. Climatechangeuncertainties;
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2. Linksbetweenclimatechangeandhealthandtheirmechanisms,and;3. Humanmitigationandadaptationcapabilities.
Climatechangeuncertaintiesareduetoinsufficientdataanduncertainclimatedata.Theglobalclimatesystemiscomplex:simulationsinvolvemanyvariablesthatdescribeandrelatetonature'schemical,physical,andbiologicalprocesses.Theseleadtodifficultiesinpredictingfutureclimatetrendsintemperature,precipitation,cloudcover,windsandthetimingandscaleofweathereventsatregionalandlocallevelswithaccuracy.ThedifficultyinpredictingthesenaturalphenomenaarecompoundedbyuncertaintyinfutureratesofGHGemissionsandgovernments’willingnessandabilitytomitigateandadapttochangingconditions.Ultimately,newtechniquesandapproachestoclimatechangescienceareneededtodealwiththeuncertaintiesthatinevitablysurroundtheseestimates.Improvedmodellingofclimatechange,includingregionalmodelswillallowformorereliablepredictionsofthepotentialimpactsonhumanhealth,andimprovedregionalunderstanding.
Sofar,themajorityofwidescopingclimate‐healthresearchhasbeencarriedoutinthedevelopedworld,wherethetools,technologyandcapacityforcarryingoutthisresearchareavailable.Thisleadstoverytentativeresultsnottheleastbecausethegreatesthealthrisksduetoclimatechangeareexpectedtobeborneamongstthoseleastcapabletoresponding,inthedevelopingworld(RaminandMcMichael,2009).LimitedtoolsandtechnologyacrossAfricahasproducedinaccuratefindingsinclimate‐healthrelationships(Connoretal.,2006).Forexample,climatologydata,usedforsurveyingmalariahavenotgivenconsistentinformationonthelinksbetweenmalariaandclimate(e.g.Tulu,1996vs.Hayetal.,2002).Furthermore,thenumberofmeteorologicalstationsacrossAfricaisinsufficientformanyanalyticalpurposes,thusprovidinganobstacletotrackingclimatetrends(Connoretal.,2006).Also,climatologydatawidelyusedinAfricahasoftenbeenbasedonout‐datedandinconsistentobservations(Connoretal.,2006).
Thesecondsetofchallengesareuncertaintiesregardingmechanismswhichlinkhealthimpactstoclimatechange.Forinstance,accuracyinpredictingtheeffectofclimatechangeonimportanthealth‐relatedfactorssuchascropyieldandpests(weeds,insects,plantdiseases,etc)canbeimproved.Improvementscanalsobemadeinepidemiologicresearchmethodstopredicthealthimpactsthroughmodelaccuracyoftheprocessesthroughwhichimpactswilloccur.Partofthechallengeinachievingtheseimprovementsisthatclimateexpertsandhealthexperts(suchasepidemiologists)tendtooperateseparately,andarenotfullyinformedonhowtoeffectivelyemployinformationfrombothsectorstogenerateinsightfuldataontheinterrelationofclimateandhealth(Connoretal.,2006).Overall,ithasbeendifficulttobuildandmaintaincross‐sectoralrelationshipsbetweentheresearchersofclimate‐basedearlywarningsystemsandthesubsequentresponsesneededfromthepublicsector(Connoretal.,2006).
Thirdly,itisdifficulttopredicthowhumanswillmitigateandadapttoclimatechange,confoundingmodellingattempts.Mostoftheeffectsofclimatechangeonhealthdiscussedabovecanbeminimisedthroughappropriatemitigationandadaptivemeasures.Geopolitical,socio‐economic,demographicandtechnologicaladvanceswilldeterminetheultimateimpactofclimatechangeonhumanpopulations.Forinstance,developmentofnewvaccinesmayattenuatetherelationshipbetweentemperature
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increaseandmalariaspread.AgoodexamplecanbefoundinthecaseofmeningitiswheretherecentavailabilityofthegroupAconjugatevaccine,whichismeanttotargetthemostsignificantstrainofthemeningococcusbacteria,offerhopethattheproblemofmeningitisacrossAfricamightultimatelytobecontrolled.
Africa’s response to climate change and health
Theprecedingsectionsindicatethatdespiteabidinguncertaintiesandcomplexities,therearearangeofindirectanddirecthealthimpactsassociatedwithclimatechange.MinistersofHealthandMinistersofEnvironmentfromacrossAfricaareawareofthepotentialimpactofclimatechangeonhealthandassuchhaverespondedwith:
TheLibrevilleDeclarationonHealthandEnvironmentinAfrica(Libreville,2008);
TheAfricanMinistersofHealthandEnvironmentJointStatementonClimateChangeandHealth(Luanda,2010a),and;
TheHealthandEnvironmentStrategicAlliancefortheImplementationoftheLibrevilleDeclaration(Luanda,2010b).
TheseresponsesreflectaproactiveintentamongstAfricanleaderstoprotecttheirpeoplefromtheanticipatednegativehealthconsequencesofclimatechange.TheabovementioneddocumentscontainanumberofrecommendationsandactionsaimedatimprovingAfrica’sunderstandingofclimateandhealthandatthesametimeaddressingthehealthimpactsofclimatechangeacrossAfrica.
AnimportantelementcontainedintheLibrevilleDeclarationisthecommitmenttoestablishaHealthandEnvironmentStrategicAllianceasaplatformforplanningandcoordinatingjointcontinent‐wideaction.Similarly,theAfricanMinistersofHealthandEnvironmentJointStatementonClimateChangeandHealth(Luanda,2010a),whichrecalledtheLibrevilleDeclarationcontainsacommitmentbyAfricangovernmentstointeralia:
Undertakeacomprehensivehealth‐andenvironment‐climatechangevulnerabilityassessmentsbytheendof2012;
CompletetheSituationAnalysesandNeedsAssessment(SANA)processaswellastheyprepareNationalPlansofJointActions(NPJAs)
Developanessentialpublichealthpackagetoenhancetheclimatechangeresiliencestatusofallcountriesby2014,and;
Reducevulnerabilityanduseecosystemsservicestobuildnaturaladaptiveresilienceagainsttheimpactofclimatechange.
Already,followingthemeetinginLibrevilletheHealthandEnvironmentStrategicAlliancefortheImplementationoftheLibrevilleDeclaration(HESA)hasbeenestablishedtoserveastheprimarymechanismforcoordinatingeffortsataddressingclimatechangeandhealthacrossAfrica.ThecoremandateofHESAistosupportcountryeffortsinaddressinghealthandenvironmentissues(includingclimatechangeandhealth)throughadvocacy,collaboration,resourcemobilization,capacitybuilding,technicalsupportandprogressmonitoring.
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ItishopedthatthefullimplementationoftheLibrevilleDeclarationandtheJointStatementwouldhelpensureevidencebased,andproperlycoordinatedpolicies,plansandactions.
Atgrassrootsleveltherearealreadyclimateandhealthactivitiesunderway,notablyinEthiopiawheretheClimateandHealthWorkingGroup(CHWG)hasbeenoperatingforover10years,andhasbeenaddressingtheissueofclimateandmalaria.SimilargroupshavebeenestablishedinKenyaandMadagascar.
InAprilof2011,a“ClimateandHealth:10YearOn”washeldinAddisAbabaandco‐organisedbytheInternationalResearchInstituteforClimateandSociety(IRI),theAfricanClimatePolicyCentre(ACPC),CHWG,theWorldHealthOrganisation,UNDP,TheUKMetOffice,andtheUniversityofExeter.TheworkshopreflectedonnearlyadecadeofpracticeandexperienceinAfricasincetheBamakoWorkshop(1999)onClimatePredictionandDiseases/HealthinAfrica.FromtheClimateandHealth:10YearsOnWorkshop(2011)aseriesof23recommendations2tosupporttheeffectiveimplementationoftheJointStatementonClimateChangeandHealthinAfrica(Luanda,2010)wereagreedregardingpolicy,practice,servicesanddata,andresearchandeducation.Theseincluded,forexample:
Bridgingthegapbetweenpoliciesandpracticesthroughlegislationandguidelines,appropriateplanning,includingrelevantvulnerabilityassessments,programmaticsupportandmulti‐sectoralandparticipatoryprocessesthataregendersensitive.
Supportingcountriestoestablishintegratedhealthsurveillanceandclimateobservationandprocessingsystems;
Integratingclimatehealthriskmanagementintocross‐sectorplanningandpracticeforadaptationtoclimatevariabilityandchangebydevelopingclimateservicesandproductsthataddressdiseasepreventionatend‐userlevel.
Ensuringthatclimatechangemitigationandadaptationstrategiesareinformedbymultidisciplinaryresearch.
Options for consideration
Baseduponareviewoftheliterature,thereareaseriesofoptionsthatmaybeconsideredbyAfricangovernments,coordinatingbodiessuchasHESA,andbyotherorganizationstoaddressclimatechangeandhealth.Theseoptionsneedadeeperinvestigationandmuchfurtherresearch,dialogueanddiscussion,butforthepurposesofstimulatingsuchaprocess,optionsthatmightbeconsideredinclude:
Giventhattheabilitytoaddressthehealthimpactofclimatechangedependsinpartonthequalityofpre‐existinghealthcareandfacilities,animportantstepistoinvestresourcesintheoverallhealthandrelatedinfrastructuredevelopmentinAfricancountries.
2 The complete set of recommendations are available online (http://portal.iri.columbia.edu/portal/server.pt/gateway/PTARGS_0_2_7668_0_0_18/Final%2010%20Years%20On%20Recommendations_April%206.11.pdf) and the report of the meeting is also available on-line with an elaboration of related presentations and discussions (http://portal.iri.columbia.edu/portal/server.pt/gateway/PTARGS_0_4972_7730_0_0_18/TR11-01_10YearsOn_WorkshopReport.pdf).
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ManyofAfrica’scurrenthealthproblemsarearesultoffrequentcontactwithcontaminatedwaterandopensewerage(UNFCCC,2007,p.18;IPCC,2007,p.399,416;Labonte,2004).ImprovedinfrastructurecouldreducethedamageandhealthdangersassociatedwithEWEs.
ComprehensivedrugtherapyandothermitigativeorpreventativemeasuresareusefulsothatthehealthsectorinAfricacancombatthemostprominent,andoftenclimate‐sensitive,infectiousdiseases,forexamplemalariaandmeningitis,plustheNTDs,etc.Medicationandotherparaphernalia(i.e.mosquitonets,condoms,sterilizationtabletsandsanitizers)forcuringorpreventingAfrica’scommoninfectiousdiseasesarerequiredinordertobuildtheoverallhealthstatusofAfrica’spopulation.Thesemeasuresalone,however,wouldnotsuffice.
Anincreasedpresenceofclinicsandhealthprofessionals,providingsupport,explainingoptionsandgivingdirectionsontheuseofdrugsandpreventativeparaphernaliaarealsorequiredtoimprovetheeffectivenessofthesemeasures.Ahealthierpopulaceiscriticaltodevelopmentandinturnadequatelevelsofdevelopmentareneededtoimprovetheoverallhealthstatusofthepopulace.TheGlobalStrategicPlanforRollBackMalaria,2005–2015,agrees,havingasserted"sixoutofeightMillenniumDevelopmentGoalscanonlybereachedwitheffectivemalariacontrolinplace"(Kopec‐Groverwtal.,2006,p.1;Connoretal.,2006,p.21).
Thereisaneedtotackletheproblemoffoodsecurityandmalnutritioninthecontextofclimatechange.Therearemanywaysofdoingthis,aswellasmanycomplications.Healthoutcomesmightbenefitfrominvestmentinagriculturalproductionsystems,improvedlandpolicyandinvestmentinirrigationsystemsforexample.Thereareanumberoforganizationsresearchingsuchissuesinthefieldandatthepolicylevel.Itisimportantthattheoutcomesofsuchresearchcontinuetobeusedtoinformgovernmentpoliciesandinterventions,coupledwithbuildingclimateresilienceintheagriculturesector.
AcrossAfricathereissignificantdevelopmentpotential,andassuchthereistheopportunitytoensureakeyelementofdevelopment,infrastructure,isclimateresilientbytakingclimatechangeintoaccountwhenplanninganddesigninginfrastructure.AchievingthisrequiressignificantincreaseintheawarenessofclimatechangeamongdevelopmentplannersandministriesinAfricancountries.Infrastructureisimportantbothforthedeliveryof,andaccessto,healthservices.
Africangovernmentscanincreasetheeffectivenessofaddressingthehealthimpactsofclimatechangethroughthecreationofknowledgemanagementplatformsforsharinginformation,skills,andtechnologybetweenandwithingovernments,privateinvestors,localandinternationalagencies,andacademicgroupsworking.Akeyissueforconsiderationistheneedforincreasedresearch.Itisimportanttoensurethatresponses,actionsandpoliciesarebasedonthebestavailableresearch.Itisalsoimportant,asstatedbytheWHO(2009)toimproveunderstandingofcurrentclimate‐relatedhealthrisksbeforetryingtounderstandfutureorlong‐termhealthrisks.Robustresearchisalsoneededtoidentifyrelativelyhiddenorunclearclimate‐healthlinks,ensureproperprioritizationofresponsemeasuresandidentifythemostcost‐effectiveinterventionsmeasures.
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Asclimatechangeisnotacompletelynewphenomenon,itwouldbeveryinsightfultolearnhowindigenouscommunitieshavedealtwithchangesoverpreviousgenerationsandhowthesecouldbeadaptedforscaled‐upeffectiveresponsestoclimatechange.
Thereisneedforimprovedregionalandlocalmodellingofclimatechangetoallowformorereliablepredictionsofthepotentialimpactsonhumanhealth.Improveddataandresearchcapacityisimportant.TherearealreadycollaborativeprogrammesinvolvingresearchorganisationswithtechnicalandcomputingcapacityworkinginpartnershipwithNationalHydrologicalandMeteorologicalOrganisationstoimprovingnationalcapacitiesandimprovemodellinganddownscalingoftheeffectsofclimatechangeonallsectorsincludinghealth.Suchinitiativescanbescaledupandwhencoupledwithhealthandothersocialandeconomicinformation,canbeutilisedintheformulationofpolicy.
Duetotheirlifesavingpotential,governmentsshouldworkhardtomakehydrometeorologicaldatasetseasilyaccessibleandusethemtoinformplanninganddevelopment.Further,thisinformationcanbeimprovedandtheapplicationanddevelopmentofearlywarningsystemspromoted.ExamplesofsuchtechnologyappliedacrossAfrica,butnotaspervasivelyasneeded,includemalariaandfamineearlywarningsystems.
ManyofthecurrentlimitationsonadaptationandmitigationresponsestoclimatechangerelatedhealthconcernsforAfricaareduetolimitedaccesstofinanceandbudgetarylimitations.Strategicallocationofclimatefinancewiththeaimofmitigatingclimate‐relatedhealthrisks,includingthosethatarealreadyveryprevalent,couldbecrucialtoimprovingAfrica’soverallhealthstatusinawarmingworld.
Ashighlightedinthisworkingpaper,climatechangeandhealthisacomplexissue,andaddressingclimatechangeandhealthrequiresintegratedanalysisofsocial,economicaswellasenvironmentalandclimaticdimensionsofdevelopmentandhealth.Thelistofoptionsaboveisnotexhaustiveandeachrequiressuchanintegratedanalysesandfurtherinvestigation.AssuchanyfeedbackonthecontentofthisworkingpaperandtheoptionspresentedwillbegreatlyappreciatedandwarmlyreceivedbytheACPC([email protected]).
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