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LONG TERM ADAPTATION SCENARIOSTOGETHER DEVELOPING ADAPTATION RESPONSES FOR FUTURE CLIMATES

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AGRICULTURE AND FORESTRY

315 Pretorius Streetcnr Pretorius & van der Walt StreetsFedsure Forum BuildingNorth Tower2nd Floor (Departmental reception) or1st Floor (Departmental information centre) or6th Floor (Climate Change Branch)Pretoria, 0001

Postal AddressPrivate Bag X447Pretoria0001

Publishing date: October 2013

environmental affairs Environmental Affairs Department:

REPUBLIC OF SOUTH AFRICA

2 1LTAS: CLIMATE CHANGE IMPLICATIONS FOR THE AGRICULTURE AND FORESTRY SECTORS LTAS: CLIMATE CHANGE IMPLICATIONS FOR THE AGRICULTURE AND FORESTRY SECTORS



When making reference to this technical report, please cite as follows: DEA (Department of Environmental Affairs). 2013. Long-Term Adaptation Scenarios Flagship Research Programme (LTAS) for South Africa. Climate Change Implications for the Agriculture and Forestry Sectors in South Africa. Pretoria, South Africa.

CLIMATE CHANGE IMPLICATIONS FOR THE AGRICULTURE AND FORESTRY SECTORS IN SOUTH AFRICALTAS Phase 1, Technical Report (no. 3 of 6)

LONG-TERM ADAPTATION SCENARIOS FLAGSHIP RESEARCH PROGRAMME (LTAS)

The project is part of the International Climate Initiative (ICI), which is supported by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety.


LIST OF AbbREvIATIONS 5

ACKNOWLEDGEMENTS 7

THE LTAS PHASE 1 8

REPORT OvERvIEW 9

ExECUTIvE SUMMARY 10

1. INTRODUCTION 13

1.1 Factorsinfluencingclimatechangevulnerabilityintheagriculturesector 13

1.2 Temperatureandrainfallchangesofimportancetoagriculture 13

2. CLIMATE CHANGE IMPACTS ON THE AGRICULTURE SECTOR 17

2.1 Impactsonirrigationdemand 17

2.2 Impactsonfieldandhorticulturalcropyields 19

2.3 Projectedchangesincropsuitability 20

2.4 Impactsonagriculturalpestspecies 24

2.5 Impactsonpasturecrops–rangelandsandplantedpastures 28

2.6 Impactsonanimalproduction-livestocksector 30

2.7 Impactsonforestry 32

2.8 Impactsonfarmlabour–humandiscomfortindex 32

3. ADAPTATION RESPONSE OPTIONS 41

3.1 Conservationagriculture,climatesmartagriculture,ecosystem-basedadaptation, community-basedadaptationandagroecology 41

3.2 Sustainablewateruseandmanagement 43

3.3 Sustainablefarmingsystems 45

3.4 Forestry 48

3.5 Earlywarningsystems,riskmanagementanddecisionsupporttools 50

3.6 Integratedandsimplifiedpolicyandeffectivegovernancesystems 51

3.7 Awareness,knowledgeandcommunication 52

4. RESEARCH REqUIREMENTS 53

4.1 Climateforecastsandclimatechangeuncertainties 53

4.2 Generalconsiderations 54

5. CONCLUSION 56

REFERENCES 57

TAbLE OF CONTENTS

Figure1.Hybridfrequencydistributions(HFDs)oftheimpactsofUCEandL1Sglobalclimatescenarios 18

Figure2.Medianchangesinnetannualirrigationdemands 18

Figure3.Combinedimpactofchangesinprecipitationandevaporationondrylandcropyields 19

Figure4.Medianchangeincropyieldsforrainfedmaizeandwheatcropsby2050 20

Figure5.Shiftsinoptimumgrowingareasforsorghum 21

Figure6.Differencesbetweenpresentandfuturesorghumyields 21

Figure7.Shiftsinoptimumgrowingareasforsoybean 22

Figure8.Differencesbetweenpresentandfuturesoybeanyields 22

Figure9.Shiftsinoptimumsugarcanegrowingareasbetweenpresent,andfuture 23

Figure10.Differencesbetweenpresent,andfuturesugarcaneyields 23

Figure11.Globalchangeinviticulturesuitability 25

Figure12.Distributionpatternsofchiloforpresentandfuture 26

Figure13.Meanannualnumbersoflifecyclesofcodlingmothforpresentandfuture 27

Figure14.DistributionpatternsofthematingindexofEldanaoverSouthAfricaforpresentandfuture 27

Figure15.ShiftsinoptimumgrowingareasofEragrostis curvula betweenpresentandfuture 28

Figure16.Differencesbetweenpresentandfuture Eragrostis curvulayields 29

LIST OF FIGURES


Figure17.Shiftsinclimaticallyoptimumgrowingareasofkikuyu 29

Figure18.Differencesbetweenpresentandfuturekikuyuyields 30

Figure19.Heattolerancethresholdsforcattle 31

Figure20.Areasexceedingthe30°Cthresholdforatleasttwosummermonths 31

Figure21.TemperaturemeasurementcollarsforDorpersheep,SuidBokkeveld 31

Figure22.ShiftsinclimaticallyoptimumgrowingareasofEucalyptus grandis 34

Figure23.DifferencesbetweenpresentandfuturemeanannualincrementsofEucalyptus grandis 34

Figure24.ShiftsinclimaticallyoptimumgrowingareasofPinus patula 35

Figure25.DifferencesbetweenpresentandfuturemeanannualincrementsofPinus patula 35

Figure26.Shiftsinclimaticallyoptimumgrowingareasof Acacia mearnsii 36

Figure27.DifferencesbetweenpresentandfuturemeanannualincrementsofAcacia mearnsii 36

Figure28.Averagenumbersofcomfortable,partiallycomfortableanduncomfortabledaysperyear 37

Figure29.Averagenumbersofcomfortable,partiallycomfortableanduncomfortabledaysinBallito 38

Figure30.Averagenumberofcomfortabledaysperannum 38

Figure31.Theaveragenumberofuncomfortabledaysperannum 39

Figure32.ChangesinthenumberofcomfortableanduncomfortabledayspermonthatBallito 40

LIST OF AbbREvIATIONS

ACRU AgriculturalCatchmentsResearchUnit

ARC AgriculturalResearchCouncil

CA Conservationagriculture

CbA Community-basedadaptation

CbD ConventiononBiologicalDiversity

CGCM3.1/T47 Coupledglobalclimatemodelversion3.1versionT47 (CanadianCentreforClimateModellingandAnalysis(CCCma))

CNRM–CM3 CentreNationaldeRecherchesMeteorologiquesFrance,coupledglobalclimatemodelversion3

CSA Climate-smartagriculture

CSIR CouncilforScientificandIndustrialResearch

DAFF DepartmentofAgriculture,FisheriesandForestry

DEWFORA DroughtEarlyWarningandForecasting

DMP Drymatterproductivity

DSSAT DecisionSupportSystemforAgrotechnologyTransfer

EbA Ecosystem-basedadaptation

ECHAM5/MPI-OM Coupledglobalclimatemodelversion3.1versionT47(CanadianCentreforClimateModellingandAnalysis(CCCma))CNRM–CM3CentreNationaldeRecherchesMeteorologiquesFrance,coupledglobalclimatemodelversion3

EM Empiricalmodel

GAM Generalisedadditivemodel

GCM Generalcirculationmodels

GHG Greenhousegas

GISS–ER GoddardInstituteforSpaceStudies(GISS),NASA,USA,ModelE-R

HFD Hybridfrequencydistributions

6 LTAS: CLIMATE CHANGE IMPLICATIONS FOR THE AGRICULTURE AND FORESTRY SECTORS

i Mr Matiga Motsepe, DAFF focal person • Tel: +27 (0) 12 309 5828 • email: [email protected] • 20 Steve Biko (Formerly Beatrix) Street, Arcadia, Pretoria 0002

ii Mr Shonisani Munzhedzi, Department of Environmental Affairs, Climate Change Branch, Chief Directorate Adaptation • Tel: +27 (0) 12 395 1730 • Cell: +27 (0) 76 400 0637 • email: SMunzhedzi@environment

7LTAS:CLIMATECHANGEIMPLICATIONSFORTHEAGRICULTUREANDFORESTRYSECTORS

IPCC IntergovernmentalPanelonClimateChange

IPSL-CM4 InstitutPierreSimonLaPlace,Paris,France,climatesystemmodelversion4

L1S Level1stabilisation

LSU/ha Livestockstandardunitperhectare

MAI Meanannualincrement

MAP Meanannualprecipitation

MIT MassachusettsInstituteofTechnology

MM Mechanisticmodel

NPC NationalPlanningCommission

NPP Netprimaryproductivity

PCU Positivechillunits

qnCD QuinaryCatchmentsDatabase

RCM Regionalcirculationmodel

RHmin Minimumrelativehumidity

SAWS SouthAfricanWeatherService

SRES SpecialReportonEmissionsScenarios

START Globalchangesystemforanalysis,research&training

THI Temperature-heatindex

Tmxd Maximumdailytemperature

UCE UnconstrainedEmissions

WNCT Waterandnutrientconservationtechnologies

ACKNOWLEDGEMENTS

ThefirstphaseoftheLongTermAdaptationScenarioFlagshipResearchProgramme(LTAS)involvednumerouspeopleandorganisations,andwascharacterisedbyaspiritofcollaborationandcooperationacrossorganisationalanddisciplinaryboundaries.TheDepartmentofEnvironmentalAffairs(DEA)andtheSouthAfricanNationalBiodiversityInstitute (SANBI)would like to thank theDeutscheGesellschaftfürInternationaleZusammenarbeit(GIZ)fortechnicalandfinancialassistance,underthesupervisionofDrMichaelaBraunandMrZaneAbdul,whoalsoservedontheProjectManagementTeam.

DEAandSANBIwould like tothankDepartmentofAgriculture,ForestryandFisheries (DAFF) for theirpartnership in thisworkand inparticularMrMatigaMotsepeiwhoservedas the focalpoint fromDAFF.Specif ically, we would like to thank the groups,organisations and individuals who participated andprovidedtechnicalexpertiseandkeyinputstotheClimateChangeImplicationsfortheAgricultureSectortechnicalreport,namelyProf.RolandSchulze(UKZN),DrEmmaArcher(CSIR),DrJohanMalherbeandDrTonyPalmer(ARC),MsBettinaKoelleandMsDonnaKotze(IndigoDevelopmentandChange),DrRobynHetem(UniversityofWitwatersrand),MrGabrielLekalakala (LimpopoDepartmentofAgriculture),MrKonstantinMakrelovandMrYogeshNarsing(theNationalTreasuryandNationalPlanningCommission),DrJamesCullis,AliceChangeandJacqueTaljaard(Aurecon),GeralddeJagerandJonathanSchroeder(AECOM),DrAdamSchlosserandDrKennethStrzepek(MassachusettsInstituteofTechnology[MIT]),LTASTechnicalWorkingGroupmembers,andmembersoftheClimateandImpactstaskteams.

DEAandSANBIwouldalsoliketoacknowledgeothermembersoftheProjectManagementTeamwhocontributedtheirtimeandenergytothedevelopmentofthistechnicalreport,namelyMrShonisaniMunzhedziiiandMrVhalinavhoKhavhagaliwhoprovidedkeyguidanceonbehalfoftheDEA,Prof.GuyMidgley(SANBI),MsSarshenScorgieandMsPetradeAbreu(ConservationSouthAfrica)whowerekeyeditorsofthetechnicalreport.MsGigiLaidlerservedastheSANBIprojectadministratorwithassistancefromMsFaslonaMartin,MrNkoniseniRamavhonawhoservedasDEAprojectadministratorandMsGwendolinAschmannfromGIZwhoprovidedadditionalprojectmanagementsupport.MsJaquiStephenson(EnvironmentalResourcesManagement)andMrDickCloete(MediaDirections)providedpreliminaryandfinaleditingofphase1productsrespectively,andStudio112conductedthelayout.

9LTAS: CLIMATE CHANGE IMPLICATIONS FOR THE AGRICULTURE AND FORESTRY SECTORS

TheLong-TermAdaptationScenarios(LTAS)FlagshipResearchProgramme(2012–2014) isamulti-sectoralresearchprogramme,mandatedbytheSouthAfricanNational Climate Change Response White Paper(NCCRP,para8.8).TheLTASaimstodevelopnationalandsub-nationaladaptationscenariosforSouthAfricaunderplausible futureclimateconditions anddevelopmentpathways.DuringitsfirstPhase(completedinJune2013),fundamentalclimatemodellingandrelatedsector-basedimpactsandadaptationscopingwereconductedandsynthesised.ThisincludedananalysisofclimatechangetrendsandprojectionsforSouthAfricathatwascomparedwithmodelprojectionsforthesametimeperiod,andthedevelopmentofaconsensusviewofscenariosforthreetimeperiods(short-,medium-andlong-term).Scopingofimpacts,adaptationoptionsandfutureresearchneeds,identifiedintheWhitePaperandguidedbystakeholderengagement,wasconductedforprimarysectorsnamelywater,agriculture and forestry,humanhealth,marinefisheries,andbiodiversity.Thismodellingandscopingwillprovideabasis forcross-sectoralandeconomicassessmentworkneededtodevelopplausibleadaptationscenariosduringPhase2(scheduledforcompletioninApril 2014).

Six individual technicalreportshavebeendevelopedtosummarisethefindingsfromPhase1,includingonetechnicalreportonclimatetrendsandscenarios forSouthAfricaandfivesummarisingtheclimatechangeimplicationsforprimarysectors,water,agriculture and forestry,humanhealth,marinefisheries,andbiodiversity.AdescriptionofthekeymessagesemergingfromtheLTASPhase1hasbeendevelopedintoasummaryforpolicy-makers,aswellasintosevenfactsheetsconstitutingtheLTASClimateandImpactsFactsheetSeries.

ThistechnicalreportpresentstheLTASPhase1findingsfortheagricultureandforestrysectors.ItreferencesexistingSouthAfricanresearchcombinedwithinsightsfromglobalprojectionstodevelopapreliminarypictureofthepotentialeffectsofclimatechangeonkeyagriculturalandforestryactivities.Specifically,itsummarisesclimatechangeimpactsaswellasadaptationresponseoptionsandfutureresearchneedsfortheagricultureandforestrysectors,basedontheresultsofrelevantpastandcurrentresearch, includingtheClimate Change Adaptation and Mitigation Plan for the South African Agricultural and Forestry Sectors(DAFF,2013);theDepartmentofAgriculture,FisheriesandForestry(DAFF)fundedAtlas of Climate Change and the South African Agricultural Sector(Schulze,2010);andnewsimulationsfromrecentmodellingworkfromtheTreasuryandtheNationalPlanningCommissionstudy(TreasuryandNPC,2013).

To illustrate thepotential impactsofclimatechangeon the SouthAfrican agricultural sector it presentschangesinyieldsandclimaticallyoptimumgrowthareasforselectedcrops,pasturegrassesandcommerciallygrowntreespecies,aswellaschangesinthelifecyclesofselectedpestsandinirrigationrequirements.Additionalworkdoneontheclimatechangeimplicationsforfarmlabourthroughahumandiscomfortindexapproachisdescribed.ForthepurposesoftheLTASPhase1work,in addition to reviewing previous work on climatechangeimpactsoncropproductionandoptimalgrowingareas,initialimpactsassessmentshavebeenconductedonkeycrops(maize,wheat,sunflowerandsugarcane)usingafullrangeofpotentialfutureclimatescenariosunderanunconstrainedemissions(UCE)scenarioanda

THE LTAS PHASE 1 REPORT OvERvIEW

450ppmstabilisation,level1stabilisation(L1S),emissionsscenario.Wherepossible,asynthesisofpreviousworkonimpactsispresentedinrelationtooneofthefourbroadclimatescenariosdefinedintheLTASClimateTrendsandScenariosreport,namelywarmer/wetter;warmer/drier;hotter/wetter,hotter/drier.Forexample,thegeneralcirculationmodels(GCMs)usedinSchulze(2010)areconsideredbyclimatologiststoproducerainfalloutputsomewhatonthewettersideofthespectrum(Hewitson,2010;pers.comm.).Abriefdescriptionofeachchapterofthetechnicalreportfollows.

Chapter 1 (Introduction) describes the factorsinfluencingclimatechangevulnerabilityinSouthAfricaaswellastheclimaticvariablesofimportancetotheagricultureandforestrysectors.

Chapter 2 (Climatechangeimpactsontheagricultureandforestrysector)describestheclimatechangeimpactsonirrigationdemand,fieldandhorticulturalcropyields,cropsuitability,agriculturalpestspecies,pasturecrops,animalproduction,majorforestrygenera,andfarmlabour.

Chapter 3 (Climatechangeadaptationresponseoptions)providesanoverviewofadaptationresponseoptionsforSouthAfrica.

Chapter 4 (Researchrequirements)highlightsresearchgapsrelatedtoclimate forecastsandclimatechangeuncertainties as well as general considerations forresearch priorities for the sector.

Chapter 5 (Conclusion) concludes the reporthighlightingthescopeofPhase2inassessingadaptationresponse options.

8 LTAS:CLIMATECHANGEIMPLICATIONSFORTHEAGRICULTUREANDFORESTRYSECTORS

10 11LTAS:CLIMATECHANGEIMPLICATIONSFORTHEAGRICULTUREANDFORESTRYSECTORS LTAS:CLIMATECHANGEIMPLICATIONSFORTHEAGRICULTUREANDFORESTRYSECTORS

ExECUTIvE SUMMARY

TheSouthAfricanagriculturalsectorishighlydiverseintermsofitsactivitiesandsocio-economiccontext.Only 14% of the country is currently consideredpotentiallyarable,withonlyonefifthofthislandhavinghigh agricultural potential. Climate limitations areimportantindeterminingpotentialagriculturalactivitiesandsuitabilityacrossthecountry,especiallyinsmall-holdingandhomesteadsettings.However, irrigationandconservationtillagepracticescanovercomerainfallconstraints, especially in thehigh-value commercialagriculturalsector.Irrigationforagriculturalproductionis estimated to consume inexcessof 60%of SouthAfrica’ssurfacewaterresources,andasignificantfractionofextractedgroundwater.ThismakesthesectortheprimarywateruserinSouthAfrica,andthereforeakeyfocusindevelopingadaptationresponsesthatinvolvewater and consider food security and other socio-economicimplications.

Thisreportsummarisespotentialimpactsundertwobroadsetsofglobal fossil fuelemissionsscenarios.These are outlined in more detail in the climatetechnicalreport,butbrieflyrefertounconstrainedemissions(typifiedbyIPCCSRESA2andIPCCAR58.5W.m -2RCP)andconstrainedemissions(typifiedby IPCC SRESB1 and IPCCAR5 4.5W.m -2 RCP). Theseemissionsscenarios,combinedwithuncertaintyrelatingtoclimateprojections,leadtoawiderangeofpotentialclimatescenariosovertheshort,mediumandlongtermthatcanbegroupedintooneoffourgeneraloutcomesnationally,namelywarmer/wetter;warmer/drier;hotter/wetter;hotter/drier,withthethresholdbetweenwarmer and hotter scenarios defined byanaveragewarmingnationallyabovethe1950–2010averageof3°C.

Basedontheresultsofawiderangeofimpactsmodellingefforts, climate change impacts are projected tobegenerallyadverseforawiderangeofagriculturalactivitiesoverthenextfewdecades.

• Irrigation demandinSouthAfricaisprojectedtoincreaseoverthenextfewdecadesunderbothunconstrainedandconstrainedemissionsscenarios.Increasesintherangeof15–30%areplausibleunderahotter/drierfutureclimatescenarioandwouldpresentsubstantialriskforThesector.

• Some spatial shifts intheoptimumgrowingregionsaswellasimpacts on yieldsformanykeyagriculturalandforestryspeciesarelikelytooccurbymid-century,especiallyunderhotterscenarios.Thisincludesfieldcropssuchasmaize,wheat,sorghum,soybeansandsugarcane;pasture/rangelandgrassessuchasEragrostis curvulaandkikuyu(Pennisetum clandestinum);horticulturalcropssuchasapplesandpears;viticulturecropsandmajorcommercialforestrytreessuchasEucalyptus, Pinus,andAcacia.Climatechange-inducedeffectsonplant and animal diseases and insect distributioncouldadverselyaffectbothcropandlivestockproduction,andanimalhealth.– Arangeofimpactsarepossibleonyields

ofrain-fedcropsincludinga-25%to+10%changeinmaizeyield.GlobalmitigationeffortstoachieveCO2stabilisationat450ppmwouldreducethisrangeofimpacttoa-10%to+5%changeinyields.Similarresultsareobtainedforothercropssuchaswheatandsunflowers.

– Maizeproductionareastowardsthewestwouldbecomelesssuitableformaizeproduction.

– OptimalareasforviticultureinthewesternandsouthernCapecouldbesubstantiallyreducedormovetohigheraltitudesandcurrentlycooler,moresoutherlylocations.

– ProjectedreducedrunoffinareasimportantforthedeciduousfruitindustryintheWesternCapewillnegativelyaffecttheproductionofhorticulturalcrops.

– ThetotalareasuitableforcommercialforestryplantationsinKwaZulu-Natal,MpumalangaandtheEasternCapeProvinceswouldincreaseovertheeasternseaboardandadjacentareas.

– Tropicalcrops,suchassugarcane,mayincreaseinyieldgiventhewarmer/wetterprojections in the tropical north-east. However,theywouldbemoreexposedtopestssuchaseldana–oneofthemostserioussugarcanepestsinSouthAfrica–whichwouldincreasethroughouttheclimaticallysuitableareaforsugarcaneby~10%to>30%.

– Theareasubjecttodamagebychilo–akeypestofmajortropicalcropsandsugarcane–andcodlingmoth–akeypestofseveralhighvaluetemperatefruittypes,includingapples,pears,walnutsandquince–wouldincreasesubstantially,andthesepestscouldbecomemoredamagingduetohigherreproductiverates.

• Climatechangeimpactsonlivestockhavebeenlessstudiedthanthoseonkeycrops.However,studiesdoindicatealikelyincreaseinheatstressasaresultofclimatechange.Discomforttolivestockasaresultofheatstresshasknowneffectssuchasreducingmilkyieldsindairycattle,andinfluencingconceptionratesacrossvirtuallyallbreedsoflivestock.Furthermore,projecteddecreasesinrainfallandhenceherbageyieldswouldresultinnegativehealthimpactsforlivestock.

• Increasesinhumanthermaldiscomfortonmoredaysoftheyear,andespeciallyinsummermonths,havebeenprojectedoverSouthAfricaunderfutureclimatescenarios.Thiswillhaveseriousimplicationsfortheproductivityofagricultural labour,specificallyforthoseengagedinoperationswithsummerandwithmulti-yearcrops.

Itisprojectedthatwitheffectiveinternationalmitigationresponses(i.e.underaconstrained/mitigatedemissionsscenario) as well as with the implementation ofappropriateadaptationresponsesadverseimpactscouldbesignificantlyreduced–withlargeavoideddamages.Potentialadaptationresponsesintheagriculturesectorrange from national level strategies that relate, forexample, to capacity building in key research areas,inextension,andtoconsiderationofwaterresourceallocation,allthewaythroughtothelocallevelwhereresponsesmaybespecifictoproductionmethodsandlocalconditions.

Adaptingagriculturaland forestrypractices inSouthAfricarequiresanintegratedapproachthataddressesmultiplestressors,andcombinesindigenousknowledge/experienceswiththelatestspecialistinsightsfromthescientificcommunity.Promotionofsustainablealternativelivelihoods–especiallyforsmallholderandsubsistencehouseholds–willbebeneficialasclimatechange,andtheresultantinabilitytofarm,couldpromptindividualstofindothersourcesofincome.Forlarge-scalecommercialfarmersadaptationneedstofocusonoptimisingpracticesforclimaticconditionsinordertomaximiseoutputina sustainablemanner and tomaintain a competitiveedge.Asanoveralladaptationstrategy,benefitswouldbegainedfrompracticesbasedonbestmanagementandonclimate-resilientprinciples;thesearecharacteristicofconceptssuchasclimatesmartagriculture,conservationagriculture,ecosystem-basedadaptation,community-basedadaptationandagroecology.

Itwouldbevaluablefortheagriculturesectortoconductaholisticassessmentoffutureresearchneedsrelatingto climate change impacts and adaptation. Such anassessmentcoulddistinguishneedsatarangeofscalesof implementationand identify adaptationneeds forspecificagriculturalactivitiesatlocalscale.Thefeasibilityofanapproachforassessingactivity-specificadaptationoptionsneedstobeexplored.Thisshouldincludedefiningtheappropriate levelof interventionandprioritising


agriculturesub-sectorsforimplementation.Scientificsupport isneededto improveanswersonthewhen,where,howmuch,whatimpact,andhowtoadapttoclimatechange,includingreducinguncertaintiesonrainfallvariabilityanditsimpactonagriculturalproductionandagriculturallivelihoods.

Irrigatedagricultureisthelargestsinglesurfacewateruserinthecountry.Dependenceonwaterrepresentsa signif icant current vulnerability for almost allagriculturalactivities.Thereisevidencethatsmallholderandsubsistencedrylandfarmersaremorevulnerabletoclimatechangethancommercialfarmers,whilelarge-scaleirrigatedproductionisprobablyleastvulnerabletoclimatechange,conditionaluponsufficientwatersupplyforirrigationbeingavailable.Adaptationplanswouldbenefit by consideringwater curtailments toirrigatorsintimesofdrought,inthelightoffoodsecurityandconditionaluponirrigatorsusingwaterefficiently.Thesocio-economicimplicationsofwaterusetrade-offscenariosunderplausiblefutureclimatesneedtobeinvestigatedtoinformkeydecisionsondevelopmentandadaptationplanninginordertoreduceimpactsonthemostvulnerablecommunitiesandgroups.TheLTASPhase2processhasthepotentialtoassesslargescaleadaptationresponsesrelating, forexample,towaterallocation; however, it will not address finer scaleadaptationresponseoptions.

The SouthAfrican agricultural and forestry sectorsexperiencearangeofvulnerabilities.Thisisduebothtothediverseagriculturalnaturalcapitalthatsupportsatwo-tiered,agriculturalsystem(commercialversus smallholderandsubsistencefarmers),andawidevarietyandhighvariabilityof climatic conditionsacross thecountry.Approximately90%ofthecountryissub-arid,semi-arid,orsub-humid,whileabout10%isconsideredhyper-arid(Schulze,2008).Only14%ofthecountryisconsideredpotentiallyarable,withonefifthofthislandhavinghighagriculturalpotential(DEA,2011).

1.1 Factorsinfluencingclimatechangevulnerability in the agriculture sector

1.1.1 Climatic factors – rainfall

Rainfallis,toalargeextent,themostimportantfactorindeterminingpotentialagriculturalactivitiesandsuitabilityacross thecountry.Rainfall variability introduces aninherently high risk to climate change atmany timescales,especiallyintransitionalzonesofwidelydifferingseasonalityandamountofrainfall.Thesetransitionalzones seem particularly sensitive and vulnerable togeographicalshiftsinclimate.

1.1.2 Climatic factors – evaporative losses

The exceedingly high atmospheric demand, i.e. thepotentialevaporation,inSouthAfricaat1400–3000mm/yearcoupledwithunreliablerainfalloftenresultsinsemi-aridconditionsdue tohighevaporationratesalone,despiteoftenadequaterainfall.

1.1.3 Dependence on water

Dependenceonwaterrepresentsasignificant,currentvulnerabilityforalmostallagriculturalactivities.Irrigated

agriculture is the largest single surface water userconsuming~60%oftotalavailablewater,andwithallagriculturerelatedactivitiesconsuming~65%.

1.1.4 Soil properties

Agriculture’svulnerabilityisexacerbatedbysoilpropertiesandtopographicalconstraintsthatlimitintensivecropproduction.SouthAfrica’ssoilmantleiscomplex,diverse,oftenthinandsusceptibletodegradation.Soilorganicmatter isvulnerableto increasingtemperaturesthatadverselyaffectsoilbiological,chemical,andphysicalproperties resulting inmoreacid soils, soil nutrientdepletion,adeclineinmicrobiologicaldiversity,weakenedsoilstructure,lowerwater-holdingcapacity,increasedrunoffandsoildegradation.

1.1.5 Land degradation related issues

Increasingpopulationpressure,unsustainablelanduseandincreasingcompetitionforagriculturalland,resultinginlandusechangeandpooreconomicdecisions,areleadingtolanddegradation,aggravatedbybushencroachmentandinvasivealienplants.

1.2 Temperature and rainfall changes of importance to agriculture2

Temperature affects a wide range of processes inagricultureandisusedasanindexoftheenergystatusoftheenvironment.Itistheoneclimaticvariableforwhichthereisahighdegreeofcertaintythatitwillincreasewithglobalwarming.

1.2.1 Annual temperatures and variability

Intothe intermediate futureannual temperaturesareprojected to increase by 1.5–2.5°C along the coast(illustratingthemoderatinginfluenceoftheoceans)to

1. INTRODUCTION1

1 FactorslistedanddescriptionshavebeenextractedfromDAFF(2013)andwerederivedfromarangeofsourcesintheliteratureincludingBarnardetal.,2000;Reidetal.,2005;BenhinandHassan2006;Schulze2006,2007,2009,2010;theDepartmentofAgriculture2007;Blignautetal.,2009andDEA2011.


1.Introduction

3.0–3.5°Cinthefarinterior.However,bytheendofthecenturyanacceleratingincreaseintemperaturesbecomesevidentwithprojectedincreasesbetween3.0–5.0°Calongthecoastandupto6.0°Candmoreintheinterior.Year-to-yearvariabilityofannualtemperaturestendstoincreaseinthenorthernhalfofthecountryanddecreaseinthesouth.

1.2.1.1 Heat waves

Inregardtoheat waves (i.e.maximumdailytemperaturesTmxd >30°Con3ormoreconsecutivedays)andextreme heat waves (Tmxd≥35°Con3ormoreconsecutivedays),themediannumberofheat wavesperannumfromthefiveGCMsusedintheSchulze(2011)studyisprojectedtoincreasebyanythingfrom30%tomorethandoublefromthepresent inboththe intermediateandmoredistantfutures.Inthecaseofextreme heat waves, the mediannumberisprojectedtomorethandoubleintotheintermediatefuture,withthemostaffectedareasbeingthosethatarealreadyhot,namely,theeasternandnorthernbordersofSouthAfricaandtheNorthernCape.

1.2.1.2 Heat units

Heatunits,sovitalforcropgrowthbutalsoforpestlifecycles,areprojectedtoincreaseintotheintermediate

futurebyanaverageof~10%annuallyalongthecoast(where temperatures are moderated by oceanicinfluences)to>30%intheinterior.Projectedincreasesinthesummerseasonaremoremoderate,butrelativelyhigh in ecologically sensitive mountainous areas,whereasincreasesinthewinterseasonaremarkedlyhigherat>30%overmostofSouthAfricaandmorethandoublinginplacesintheMalutiandDrakensbergmountainranges.

1.2.1.3 Cold spells

While the numbers of cold spells (i.e. ≥3 or moreconsecutivedayswithminimumtemperatures<2.5°C) and severe cold spells (≥3ormore consecutive dayswithminima<0°C)areshownnottochangealongthecoastofSouthAfricaintothefuture,whileinthemorecontinentalinteriorareductionto<70%ofpresentcoldspellsisprojected.

1.2.1.4 Positive chill units

Certainbiennialplantsrequireaperiodofwinterchillingto complete their dormant season to produce highqualityfruit.Thischillingisestimatedbypositivechillunits(PCUs),derivedfromhourlytemperaturesaboveor

2 SeeSchulzeetal.(2010)fordetailedinformationontheGlobalCirculationModels(GCMs)anddownscalingmethodologyfromwhichtheinformationandprojectionsbelowwerederived.Ingeneral,fiveGCMswereused,viz.CGCM3.1(T47),CNRM–CM3,ECHAM5/MPI-OM,GISS-ERandIPSL-CM4.Furthermore,inmanycasesresultsarederivedfromcomputationsusingdownscaleddailyclimateoutputfromasingleemissionscenariofromasingleGCM–ECHAM5/MPI-OMGCM(indicatedinfigurecaptionsbelowwhererelevant).Climaticand/orhydrologicaland/oragriculturaloutputinSchulze(2010)andDAFF(2013)wassimulatedforeachofthe5838hydrologicallyinterlinkedquinarycatchmentsthatmakeupSouthAfrica,LesothoandSwaziland,usinginformationfromtheQuinaryCatchmentsDatabase,(QnCD)(SchulzeandHoran,2010;Chapter2.2).TheQnCDhasbeenpopulatedwith50years(1950–1999)ofdailyrainfall,temperatureandpotentialevaporationdata,aswellaswithhydrologicallyrelevantsoilsandlandcoverinformationforeachquinarycatchment.Inordertosimulatehydrological/agriculturalattributesfortheintermediate(2046–2065)andmoredistant(2081–2100)futureclimatescenarios,thedownscaleddailyrainfallandtemperaturevaluesfromthefiveGCMsareinputintotheAgriculturalCatchmentsResearchUnit(ACRU)and/orothermodels,whilstkeepingeachquinary’ssoilsandlandcoverinformationconstant(Schulzeetal.,2010).TheGCMsusedinSchulze(2010)areconsideredbyclimatologiststoproducerainfalloutputsomewhatonthewettersideofthespectrum(Hewitson,2010,pers.com.),andthishastobeborneinmindininterpretinganyimpactsinwhichrainfallisaninputvariable.Furthermore,theuseofasingleprojection–thelimitationsofwhicharewellappreciatedanddocumented(Hewitsonetal.,2005b;IPCC,2007;Schulzeetal.,2007)–obviouslyfailstocapturetherangeofpossiblefuturesprojectedbythe>20GCMs,forthevariousSRESscenarios,usedintheIPCC’sFourthAssessmentReport(IPCC,2007).ECHAM5/MPI-OMGCM,however,wasselectedforthisreason,asitisconsideredbythesouthernAfricanclimatemodellingspecialists,viz.TheClimateSystemsAnalysisGroup(CSAG)(2008),torepresenta“middleoftheroad”projectionoffutureclimatesforSouthAfrica(Schulzeetal.,2010).

belowcriticalthresholds.Fromsensitivitystudies,a2°CtemperatureincreaseresultsinPCUreductionsrangingfrom14% to>60% in SouthAfrica,with reductionscommonlyaround40%.Similarly,medianreductionsinratiosofPCUscomputedfrommultipleGCMsaregenerally>30%intotheintermediatefuture,withhighconfidenceintheseprojections.

1.2.1.5 Reference crop evaporation

Theaccurateestimationofevaporationfromagriculturalcropsisvital,foritisthedrivingforceofthetotalamountofwaterwhichcanbe“consumed”byaplantsystemthroughtheevaporationandtranspirationprocesses.The reference for estimating crop evaporationwasthePenman-Monteithequation,whichhasbecomethedefactostandardmethodinternationally.Asensitivityanalysis shows that in January (summer) a 2°Ctemperatureincreaseissimulatedtoincreasereferencecropevaporationby~3.5%(2.9–3.8%),whileinwinter(July)thepercentageincreasesareevenhigherthaninsummer.UsingoutputsfrommultipleGCMs,anincreaseincropevaporationbytheintermediatefutureofaround5–10% is projected,with the increase higher in theinteriorofthecountry.Inthemoredistantfuturetheprojectedincreasesrangefrom15–20%,againwiththehigherincreasesintheinteriorfrom~100kminland.The implicationsofthese increasesarehigherwatersurfaceevaporationfromdamsandamorerapiddryingoutofsoils.

1.2.2 Rainfall and its importance in agriculture

In agriculture, limitations in water availability arearestrictingfactorinplantdevelopment,sincewaterisessential for themaintenanceofphysiological andchemicalprocesses in theplant, actingasanenergyexchangerandcarrierofnutrientfoodsupplyinsolution.Inanyregionalstudyofagriculturalproduction,rainfall,asabasicdrivingforceinmanyagriculturalprocesses,isthereforeoffundamentalimportance.Focusisinvariably

onpatternsofrainfallintimeandspace,byenquiringhowmuchitrains,whereitrains,whenitrains,howfrequentlyitrains,andwhatthedurationandintensityofrainfalleventsare.

1.2.2.1 Annual rainfall and its variability

Asapointofdeparture it is noted that evenundercurrentclimaticconditions,SouthAfricaisregardedasasemi-aridcountrywith~20%receiving<200mmperannum,47%<400mmandonly~9%withmeanannualprecipitation(MAP)>800mm.Inter-annualvariabilityishigh.ProjectedmediansofchangesinMAPfromtheensembleofGCMsusedshowrelativelylittlechangeintotheintermediatefuture,withaslightwettingintheeast,particularlyinthemoremountainousareas.Bythemoredistantfuture,changesinMAPbecomemoreevident,withareasofdecreaseinthewestandsomeincreasesalongtheeasternescarpmentandinmountainousareasproducingrunoff.Theperiodofsignificantchange inthewestappearstobeinthelatterhalfofthecentury.Theinter-annualvariabilitiesofrainfallshowstandarddeviationstobeintensifyingintotheintermediatefutureandmoresointothemoredistantfuture,especiallyintheeast,butwithdecreasesinvariabilityinthewest.Theoverallincreaseinrainfallvariabilityislikelytohavesevererepercussionsonyear-on-yearconsistencyofagriculturalproductionandonthemanagementofwaterresourcesforirrigationthroughtheoperationsofmajorreservoirsandsmallerfarmdams.

1.2.2.2 Monthly rainfall

Projectionsofmonthlyandseasonalchangesinrainfall distributionpatternsoverSouthAfricaare not uniform, butcanvarymarkedlyindirection,inintensity,aswellasvaryingspatiallywithinSouthAfricainagivenmonth,betweendifferentmonthsoftheyearforthesamestatistic,and between the intermediate future and themoredistantfutureforthesamestatistic,withthislast-nameddifferencesuggestinganintensificationandaccelerationof


1.Introduction

impactsofclimatechangeovertime.Arecurringfeatureisaslightwetting trendofvaryingintensityanddistributionin the east, atrendwhichingeneralcouldbebeneficialtoSouthAfrica’sagriculturalproductionandtowateravailabilityforagriculture,butcouldbedetrimentalduetoflooddamage.Thereis,however,adrying trendevidentin the west,mainlytowardstheendoftherainyseason,andalsoadryingtrendin northernareas.Combinedwithincreasesintemperature,repercussionsonagriculturalproduction,irrigationdemandandwaterresourcescouldthusbesevereinthewest.Thetransitionalareabetweenthesummerandwinterrainfall areasfrequentlydisplaysmarkedchangesinrainfall.

Fortheperioduptotheintermediatefutureinthemid-2050s,summerandautumnmonthsdisplayanarrowstripofdecreasedrainfallvariabilityalongthecoastintothefuture,butwithageneralincreaseovertheinteriorwhichintensifiesintoautumn.Bymid-wintervirtuallytheentireSouthAfricadisplayssignificantincreasesintheinter-annualvariabilityofrainfall.Overmuchofthecountrythishaslittleimpactonagricultureandwaterresourcesasmid-wintercoincideswiththedryseason,butinthewinterrainfallregionofthesouthwestitdoeshaveanimpact.ByOctober,thestartoftherainyseasonformuchofthecountry,theeasternhalfofSouthAfricaandthesouthwestshowreductionsinvariability,withonlythesemi-aridcentralinteriordisplayingaveragedincreasesinvariability.

1.2.2.3 Rainfall concentration

Therainfallconcentrationstatisticindicateswhethertherainfallseasonisconcentratedoverashortperiodoftheyearorspreadoveralongerperiod.Medianchangesin ratios of intermediate future to present rainfallconcentrationindicateaslightlymoreevenspreadoftherainyseasonsovermuchofthecountrybymid-century,accordingtotheGCMsused(i.eCGCM3.1(T47),CNRM-CM3,ECHAM5/MPI-OM,GISS-ERandIPSL-CM4),butintheallyearrainfallbelt,aswellasthetransitionalarea

betweenwinterandsummerrainfallregions,therainyseasonisprojectedtobecomemoreconcentratedthanat present.

1.2.2.4 Rainfall seasonality

LargetractsofthecurrentwinterandsummerrainfallregionsareprojectedbytheGCMsusedbySchulze(2011)toremainastheyarenow.However,themodelsdifferintheirprojectionsofchangesoffutureseasonalityinthetransitionalareasbetweenthewinterandsummerregionsinthewest,andinthefuturelocationoftheallyearrainfallregion.

1.2.2.5 Soil water content

Information on soil water content is vital since itdetermineswhenplantwaterstresssetsin(andwiththatareduction intranspiration losses),theneedtoirrigateandwhetherornotrunoffwillbegenerated,andhowmuch,fromagivenamountofrainfall.ChangesinsoilwaterstressunderprojectedfutureclimateswerederivedfromtheoutputofthemultipleGCMsusedasinput to theAgriculturalCatchmentsResearchUnit(ACRU)agro-hydrologicalmodel(Schulze,1995).

Forconditionsofno soil water stress,themajorityofSouthAfricaisprojectedtoexperiencemoresuchdaysintotheintermediatefuture,exceptinthesouthwestwheredesiccationisprojectedtoresultinplantsexperiencingmoredayswithstress.Formild stress conditionsdecreasesintotheintermediatefutureareshownalongthecoastandespeciallyintheEasternCapeandLesotho,withtheremainderofthecountrydisplayingmoredayswithmildstress.Similarly,basedontheGCMprojectionsused,dayswithsevere soil water stressshowageneralreduction intothe intermediate future,exceptalongthewestcoastwheremorestressdaysareprojected.Stress due to waterloggingisprojectedtoincreaseintotheintermediatefuture,exceptalongthewestcoastwherefewerwaterloggeddaysareprojected.Thesepatternsintensifyintothemoredistantfuture.

Different emission scenarios, climate models anddownscalingtechniquescomplicatetheprojectionofclimatechangeimpactsonagricultureinSouthAfrica,makingitextremelychallengingtoextractkeymessagesthat allow an assessment of, for example, the localeconomicbenefitsofglobalmitigationefforts.Projectionsof impacts have used different emissions scenarios,different climatemodels, and different downscalingtechniques.MostofthefocushasbeenontheSRESA2scenarios,equatingtoCO2equivalentlevelsofabove500ppmby2050,andthereforerepresentingtheimpactsof largelyunmitigatedclimatechange.Theworkthathasbeendonesuggeststhatevenrelativelysmallmeantemperatureandrainfallchangesmaybeamplifiedbyspecificcropsensitivities.Forexample,aslittleasa2°Cincreaseindailytemperaturewouldleadtoa10–35%annual increase in biologically important heat units,a40–60%reductioninpositivechillunits,anda5–13%increaseinpotentialevapotranspiration(Schulze,2010).However,thisknowledgehasnotyetbeentranslatedintousableinformationontheeconomicimpactsofclimatechangeontheagriculturalsector.Itisonlyrecently,withtheworkoftheTreasuryandNPCmodellingeffort,thatithasbecomepossibletobegintoassessthepotentialeconomic impactof globalmitigationeffortson theagriculturalsector.

2.1 Impacts on irrigation demandAsimplecropwaterdeficitmodelhasbeenappliedtodeterminetheimpactsofthefullrangeofclimatechangescenarioson irrigationdemandsacrossSouthAfrica.Theanalysisisbasedonestimatesofthecurrentcropareasandcurrentcropmixesandasetofmonthlycropcoefficients.ThisallowstheestimatedimpactofUCE(unconstrainedemissions)and450ppmL1S(constrainedemissions)scenariosontheaverageannual irrigation

demandforthecountryby~2050(Figure1)(TreasuryandNationalPlanningCommission,2013).

Under both scenarios irrigation demand is certainto increase in the future due primarily to increasesin temperature and evaporation.The unconstrainedemissions scenario results in a verywide spread ofpossible impactswith somemodels showing a>10%increase.Themedian increase for theunconstrainedemissionsscenarioisapproximately5%whilethemedianimpactfortheconstrainedemissionsscenarioisonly2.5%withamuchnarrowerrangeofpossibleimpacts.Noneofthemodelspredictmorethana5%increaseinirrigationdemandunderthe450ppmstabilisationscenario(TreasuryandNationalPlanningCommission,2013).

Theimpactsofclimatechangeonirrigationdemanddovaryacrossthecountry.Formostpartsofthecountry,there is an increase in the average annual irrigationdemandofbetween4%and6%asaresultofarelativelyconsistent increase in evaporationof 5%across thewholecountry.Forthecatchmentsalongtheeasternseaboardtheincreaseinevaporativedemandisoffsetbytheincreaseinprecipitation,resultinginnochangein irrigationdemand, evenunder theunconstrainedemissions scenario (Treasury andNational PlanningCommission,2013).

Whileitispossiblethatprojectedminorincreasesinirrigationdemandwouldnotbelikelytohavesignificantimplicationsfortheagriculturalsector,underwarmer/drierscenariosincreasesofbetweenand15and30%areplausible, indicatingasubstantialrisk forgreaterwaterlimitationinthissectorandstrongcross-sectoralimplicationsgiventhecurrenthighallocationofsurfacewatertothissector(TreasuryandNationalPlanningCommission,2013).

2. CLIMATE CHANGE IMPACTS ON THE AGRICULTURE SECTOR


2.ClimateChangeImpactsontheAgricultureSector

Figure1.Preliminaryresultsforhybridfrequencydistributions(HFDs)oftheimpactsoftheUnconstrainedEmissions(UCE)and450ppmstabilisation(L1S,constrainedemissionsscenario)globalclimatescenariosontheaverageannualirrigationdemandsforallcatchmentsfortheperiod2040–2050relativetothebasescenariobasedonthecurrentcropmixandestimateoftotalirrigatedareaineachquaternarycatchment(Treasury&NationalPlanningCommission,2013).

For example, Schulze (1995 andupdates)3 simulatedchanges in net irrigation demand for a fully growncropunderawarmer/wetterclimatescenario forallmonthsoftheyearwiththeACRUmodel.WithmeanannualnetirrigationdemandsoverSouthAfricaalreadyhighat~800mminthewettereasternandsouthernregionsandupto1600mminthearidnorthwest,thecompositeresultsofthemultipleGCMsusedinthestudybySchulze(2010)showareductioninirrigationwaterrequirementsof~10%inthecentraleasternareasintotheintermediatefuture,indicatingthatinthoseareasthe increaseddemand throughhigher temperatures,andhenceenhancedevaporativedemands,ismorethanoffsetbycorrespondingprojectedincreasesinrainfall.Bycontrast,inthedrierwesternhalfandinthenorthernquarterofthecountry irrigationwaterdemandsareprojectedtoincreaseby~10%.Bythemoredistantfuture(morerepresentativeofahotter/wetterscenario)twodifferencesemerge,namely,thattheareaofreducedirrigationdemandhasshrunkandthatin~90%ofSouthAfricairrigationdemandsincreaseby10–20%andinpartsofthesouth-westernCapeevenbecoming>20%.

Theimplicationsofthesefindingsarefirst,thatinthealreadydrierpartsofSouthAfricawhereagriculturalproductionlargelydependsonsupplementingrainfallwithirrigation,evenmoreadditionalwaterwouldbeneededthanatpresenttomaintaincurrentproduction,second,thatthiswaterwouldpotentiallyneedtobetransferredfromremotesourcesandthird,thatwithrisingtemperaturesaconversiontomoreheatanddroughttolerantcropsislikelytobeneeded(Figure2)(Schulze,2010).

Figure2.Medianchangesinratiosofintermediatefuturetopresent(top,representingawarmer/wetterfuturescenario),aswellasofmoredistantfuturetopresent(bottom,representingahotter/wetterfuturescenario)netannualirrigationdemands,computedwiththeACRUmodelfromtheoutputofmultipleGCMs(Schulze&Kunz,2010h)

3 Usingdemandirrigationscheduling,bywhichirrigationwaterisappliedtotheplantjustbeforethesoilhasdriedtoalevelwherecropwaterstresssetsin,andthenrechargingthesoilprofiletoitsdrainedupperlimit.

2.2 Impactsonfieldandhorticulturalcrop yields

ForthepurposesoftheLTASPhase1work,inadditiontoreviewingpreviousworkonclimatechangeimpactsoncropproductionandonoptimalgrowingareas,wehaveconductedinitialimpactsassessmentsonkeycropsusingafullrangeofpotentialunconstrainedandconstrainedemissionsscenarios,asdescribedabove,forexploringimpactsonirrigationdemand.Theseimpactsofclimatechangeonfieldcropyieldshavebeendeterminedbasedonrelationshipsbetweenannualwateravailabilityandcropyieldsforthemajorfieldcropscurrentlycultivatedin SouthAfrica. These aremaize, sorghum,wheat,sunflowers,groundnuts,soybean,lucerne,sugarcaneandcotton.Thefrequencydistributionofthepotentialimpactsontheyieldsformaize,wheat,sugarcaneandsunflowersthroughacombinationofchangesinprecipitationand

evaporationaregivenbelow(Figure3)(TreasuryandNationalPlanningCommission,2013).

Theresultsshowaverywiderangeofpossibleimpactsontheaverageannualyieldofnon-irrigatedcropsby2050undertheUCEscenario.Overall,drylandcropyieldsamplifyrainfallchangessubstantially.Theimpactonmaizeandwheatyields,forexample,rangesfromareductioninthetotalnationalyieldof25%toapotentialincreaseof 10%under an unconstrained emissions scenario.Mitigationtoachieve450ppmstabilisationreducesthisrangeofimpacttobetweenalessthan10%reductionanda5%increase.Similarresultsareobtainedforothercropswiththeexceptionofsugarcane(TreasuryandNationalPlanningCommission,2013),whichisoneofthefewcropsthattendstoshowastrongpotentialforincreasedproductionevenunderhotter/drier futurescenariostypicalofanunconstrainedfutureemissionstrajectory.

Figure3.Preliminaryresultsforcombinedimpactofchangesinprecipitationandevaporationondrylandcropyields(t/ha)forSouthAfricafortheperiod2040–2050relativetothebaselinescenarioformaize,wheat,sunflowerandsugarcane(Treasury&NationalPlanningCommission,2013).Climate scenarios: UCE = unconstrained emissions; L1S = 450 ppm stabilisation (constrained emissions scenario).



These results are in line with previous studies.Forexample,asSouthAfrica’sstaplefoodcrop,maizehas been under the spotlight since the late 1990sin vulnerability research (Du Toit et al., 2002) andwithregardtoproductivity(Schulzeetal.,1995),andsubsequentlyfromasustainabilityperspective(Walker&Schulze,2006;2008).YieldshavebeensimulatedtobesensitivetobothclimateandCO2fertilisation,withdoubledCO2offsettingmuchofthereducedprofitabilityassociatedwitha2°Ctemperaturerise,especiallyincoreareasofmaizeproduction(WalkerandSchulze,2008).

2.3 Projected changes in crop suitabilityOne approach to assessing impacts on agriculturalactivities isviamappingareasofsuitability,andtheirpotentialspatialshifts.Arecentstudy(Estesetal. inpress)usedtwoindependentimpactmodellingmethodstoprojectclimatechangeimpactsonwheatandmaizeyields,andsuitablecroppingareasinSouthAfrica(Figure4).Thisstudypointsoutthatcrop-modelspecificbiasesareakeyuncertaintyaffectingtheunderstandingofclimatechangeimpactsonagriculture,andthustheyusedbothanempiricalmodel(EM)andamechanisticmodel(MM).TheEM’smedianprojectedmaizeandwheatyieldchangeswere-3.6%and6.2%,forSRESemissionsscenariosA1andB2respectively,comparedto6.5%and15.2%fortheMM.TheEMprojecteda10%reductioninthepotentialmaizegrowingarea,whiletheMMprojecteda9%gain.Bothmodelsprojectedincreasesinthepotentialspringwheatproductionregion(EM=48%,MM=20%).Whiletheseresultsappeartoindicatepositiveprospectsforincreasingyields,mostoftheseyieldincreaseswereprojectedinmarginalareas,andyieldreductionsofupto10%areprojectedincoreproductionregionsespeciallyforwheat.Onlyinthecaseofmaizewerenotableincreasesinyieldprojectedinsomecurrentlyhighyieldareas.TheMMapproachmayprovideamoreusefuloutput,giventhattheapproachisabletoaccountforthedirecteffectsofrisingCO2onproductivity.

Maize

Wheat

Figure4.Medianchangeincropyieldsforrainfedmaize(top)andwheatcrops(bottom)by2050underaB1SRESemissionscenario.Twoindependentmodellingmethodsarepresented,DSSAT=mechanisticmodel,andGAM=empiricalmodellingapproach(Estesetal.in press).

AdescriptionofspecificimpactsforkeySouthAfricanfieldcropsispresentedbelow(Schulze,2010;DAFF,2013):

2.3.1. Wheat and barley

These are generallywinter rainfall crops.Dry spellsoccurnaturallyduring thegrowing season inwinter,and the projected decrease inwinter rainfallwouldpotentiallyaccentuatethisnaturaleffect.Incaseswhereareasarealreadyclosetothresholdvaluesformaximumtemperature,afurthertemperatureincreasecanhavedevastatingeffectsonproductionpotential(ERC,2007).AstudybySchulzeandDavis(2012)usingtheSmith(2006)wheatyieldmodelshowswinterwheatyieldstoincreaseslightlyby0.5to1.5t/ha/seasonintotheintermediate

futureinthemainwheatgrowingSwartlandandRûens

regionsoftheWesternCape,withsimilarincreasesinthe

easternFreeStatewheatbelt,whileintothemoredistant

futuremostoftheWesternCape’swheatbeltisprojected

toshowdecreasedyieldsof0.5–1.0t/hafromthepresent,

butwiththeFreeStatecontinuingtodisplayincreases.

2.3.2 Sorghum

Sorghum(Sorghum bicolour)isarelativelydroughtresistant

cropwhichcantolerateerraticrainfall.Areasforsorghum

suitableunderpresentclimaticconditionsareprojected

tobecomeunsuitablebytheintermediatefuturealongthe

easternborderwhileconsiderablenewareas,presently

climaticallyunsuitableforsorghum,areprojectedtobe

gainedintheFreeStateandEasternCape(Schulze2010)

(Figure5).Sorghumyieldsareprojectedtopotentially

increaseby2–4t/haintotheintermediatefutureinparts

ofwesternKwaZulu-Natal,theinlandareasoftheEastern

CapeandtheeasternFreeState,withsomeareasinthe

northregisteringlossescomparedwithpresentclimatic

conditions.This translates toprojected increases in

excessof30%inthecentralgrowingareas,withsome

yielddecreasesalongtheeasternperiphery(Figure6).

2.3.3 Soybeans

Forsoybeanstheareaslosttopotentialproductionin

boththeintermediateandmoredistantfuturearein

theeast,withanexpansionofclimaticallysuitableareas

inlandtowardsthewestintothefuture,andwithareas

gainedandlostbeingmoresensitivetochangesinrainfall

thanincreasesintemperatures(Schulze,2010).Projected

changesof soybeanyieldsbetweenthe intermediate

Figure5.Shiftsinoptimumgrowingareasforsorghumbetweenintermediatefutureandpresent(top,representingawarmer/wetterclimatescenario),andbetweenmoredistantfutureandpresentclimatescenarios(bottom,representingahotter/wetterclimatescenario),derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010c)

Figure 6.Differences between intermediate future and present (top,representing awarmer/wetter climate scenario), and betweenmoredistantfutureandpresent(bottom,representingahotter/wetterclimatescenario)sorghumyields,derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010c)



futureandpresentclimatescenariosdisplayanarc of yield decreasesfortheclimaticallysuitablegrowthareassurroundingaconsiderablylargercore area of median yield increases(generallyby>30%)(Figure7).Bythemoredistant futureboththeareasshowingdecreasesandincreaseshavebecomeamplified.Theimplicationisthatwhilemajorexpansionofclimaticallysuitableareasforsoybeanproductionmightoccur,thereisalsoalikelihoodthattheareaofactualproductionmaybecomemoreconcentrated(Figure8).

2.3.4 Sugarcane

If future climates change in accordance with theprojectionsfortemperatureandrainfallusedinSchulze(2010)thensomemajorinlandshiftsintheclimatically

optimumgrowthareasforsugarcanemaybeexpected(Figure 9). The harvest-to-harvest cycle, or ratoontime,couldreduceby3–5months(i.e.by20–30%)bytheintermediatefutureandby>5months(i.e.>30%)inthemoredistantfuture,whileyieldsperratoonareprojectedtoincreaseby5–15t/haalongthecoastandbyupto20–30t/haintheinlandgrowingareasbymid-century,withmajorimplicationsforthesugarindustry(Schulze,2010)(Figure10).Whenatemperatureincreaseof2°Cisassociatedwithsimultaneouschangesinrainfall,yieldsweremodelledtodecreasebyabout 7%fora10%reductioninrainfall,andtoincreasebyasimilarpercentagefora10%increaseinrainfall.Medianchangesinratiosofcaneyieldsperratoonareprojectedtoincreasebytheintermediatefutureby<10%inmanypartsofthe

Figure7.Shiftsinoptimumgrowingareasforsoybeanbetweenintermediatefutureandpresent(top,representingawarmer/wetterclimatescenario),andbetweenmoredistantfutureandpresentclimatescenarios(bottom,representingahotter/wetterclimatescenario),derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010d).

Figure 8.Differences between intermediate future and present (top,representing awarmer/wetter climate scenario), and betweenmoredistantfutureandpresent(bottom,representingahotter/wetterclimatescenario),soybeanyields,derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010d)

presentcanegrowingareas,butbyupto30%andmore

inpotentiallynewgrowthareasfurtherinland.Allthe

aboveprojectedchangesaresignificantenoughforthe

sugarindustrytoconsidermorein-depthstudiesofits

entirevaluechainfromproductionthroughtransportand

millingtoexport(Schulze,2010;DAFF,2013).

Adescriptionof specific impacts for selectedSouth

Africanhorticulturalandalternativecropsispresented

below(Schulze,2010;DAFF,2013):

2.3.5 Apples

Futuretemperatureincreasesareprojectedtocausea28%

reductionoftheareasuitableforappleproductionbyas

earlyas2020,withsuitableappleproducingclimateslimited

tothehigh-lyingareasoftheKoueBokkeveldandCeresby2050(Cartwright,2002).Thisprojectionisconsistentwithobservedtrendsofreducedexportapplevolumespartlyascribedtoadverseclimaticconditions.Appleshavestringentchillingrequirementsevenundercurrentclimateconditions;thisabsoluteneedforcoolingfacilitiesandtheirhighsensitivitytoheatstressresultinapplesbeingvulnerabletoincreasesintemperatureandhumidity.

2.3.6 Pears

Pears have similar climatic requirements to apples,butwithlessstringentchillingrequirementsandlowersensitivitytoheatstress.Overall,therisksassociatedwithproducingexport-qualitypearsarerelatedtocultivar-specificsensitivities,withsomecultivarsatmoreriskthan

Figure9.Shiftsinoptimumsugarcanegrowingareasbetweenthepresentandintermediatefuture(top,representingawarmer/wetterclimatescenario),andbetweenthepresentandmoredistantfuture(bottom,representingahotter/wetterclimatescenario),derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010e)

Figure10.Differencesbetween intermediate futureandpresent (top,representingawarmer/wetterclimatescenario),andbetweenmoredistantfutureandpresent(bottom,representingahotter/wetterclimatescenario),inmeanannualisedsugarcaneyields,derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010e)



others.Itisverylikelythatoverthenext30yearsmostcommercialpearproducersshouldbeabletomaketheadjustmentsneededtoremainprofitable.

2.3.7 Rooibos tea

Rooibosteaproductionisvulnerabletoreducedrainfallandlackofrainfallatcriticaltimes,withyieldsprojectedtodecrease40%duringadroughtyear(Oettle,2006).Numerousadaptationstrategiesare,however,usedorknownbyfarmers,includingchangesingroundpreparationand tea harvesting times, wind erosion preventionmeasuresandwaterconservationmeasures.Notallthesemeasuresareimplemented,oftenduetolackoffinances.

2.3.8 Viticulture

Themarketislikelytodictateimpactsandadaptations(ERC,2007)withglobaltrendsinsupplyanddemand,andresultingpricevolatility,beingbyfarthemostimportantfactorsindeterminingfutureprofitability.Impactsandvulnerabilitieswilldifferdependingonscale(industry-wideversus farmlevel).Theindustryasawholemayshrink,butsuccessfulproducersincoreareascouldcapitaliseonopportunitiessuchaschangingmarketdemandduetoadverseclimateimpactsoninternationalcompetitors.Waterforirrigationorrainfallinnon-irrigatedvineyardswillbeamuchgreaterissuethantemperature.Marginalnon-irrigatedvineyardscouldbecomeuneconomicalandtotalproductionareacoulddecreasebyupto30%underprojectedchangesby2050,butincreasingyieldsarepossibleinirrigated,well-managedvineyardsingoodareas(Schulze,2010;DAFF,2013).

Shiftingtheindustrytootherregionswouldbedifficultand expensive, not somuch due to the planting ofvineyardsastothere-developmentof infrastructure(suchascellars).ThemountainousregionsoftheeasternOverbergoffernewopportunitiesonoldlandsprovidedthereissufficientwater.Theindustrycouldusefullyre-evaluateitscultivarmixandpossiblymakemoreuseofearly-seasoncultivarstoavoiddamagingeffectsofheat

wavesinmid-summer.Evenwithincultivars,thestyleofwinewilllikelychange.Therearenewopportunitiestoacquirecultivars(orbreedlocally)withpest/diseaseresistancewithoutforfeitinghighqualityandyield.Ittakesabout tenyearstosource,quarantine,register,andcertifyanewcultivarforrelease(Schulze,2010;DAFF,2013).

Hannahet al. (2013) indicate thatoptimal areas forviticultureinthewesternandsouthernCapecouldbesubstantiallyreducedandfocusonhigheraltitudeandcurrentlycoolerlocations(southerlylocationsinSouthAfrica).Thistrendistrueofallmajorwinegrowingregionsoftheworld,andSouthAfrica’sprojectedlossof50%ofsurfaceareasuitableforwinegrowingliesinthemedianlossrangeforMediterranean-typeregions(Chileshowsalowerprojectedloss,Europe,CaliforniaandAustraliashowmuchgreaterprojectedlosses)(Figure11).

2.4 Impacts on agricultural pest speciesStagesinthedevelopment,orduration,ofentirelifecyclesofagriculturalpestsanddiseasesarecloselyrelatedtotemperaturethresholds,andarethusaffectedbyglobalwarming.Climatechangeactstoacceleratecriticallifestagesof thesepests, thuspotentially increasing thepotentialforcropdamageandincreasingthecostsofvarious formsofcontrol.Examplesof some impactsfollow(Schulze,2010).

Chiloisakeypestofamajortropicalcrop,sugarcane,andcodlingmothisakeypestofseveralhighvaluetemperatefruittypes,includingapples,pears,walnutsandquince.Resultsindicatethatwarmingalonehasthepotentialtosignificantlyincreasetheareasubjecttobothchilo(Figure12)andcodlingmothdamageinSouthAfrica(Figure13),thusexposingmanyhighvalueregionsforbothsugarcaneandfruitcropstoincreasesincostsanddamages.

Forcodlingmoth,theloweranduppertemperature(°C)thresholdsandaccumulateddegreedaysforonelifecycleare,respectively,11.1°C,34.4°Cand603degreedays.Undercurrentclimaticconditionsthenumberoflife

cyclesperannumofcodlingmothrangesfrom<2inthecoolermountainousareasofSouthAfricato>6alongitsnorthernandeasternborders(Schulze,2010).Using output from the ensemble ofGCMs used inSchulze(2010),thenumberoflifecyclesperannumof

thecodlingmothbytheintermediatefutureisinexcessof30%greaterthanthepresentoverthecentralareasofSouthAfrica,20–30%alongtheperipheryofthecountryand10–20%alongthecoastofKwaZulu-Natalandpatcheselsewhere.

Figure11.GlobalchangeinviticulturesuitabilityundertheRCP8.5scenario.Changeinviticulturesuitabilityisshownbetweencurrent(1961–2000)and2050(2041–2060)timeperiods,showingagreementamonga17GCMensemble.Areaswithcurrentsuitabilitythatdecreasesbymid-centuryareindicatedinred(>50%GCMagreement).Areaswithcurrentsuitabilitythatisretainedareindicatedinlightgreen(>50%GCMagreement)anddarkgreen(>90%GCMagreement),whereasareasnotcurrentlysuitablebutsuitableinthefutureareshowninlightblue(>50%GCMagreement)anddarkblue(>90%GCMagreement).Insets:Greaterdetailformajorwine-growingregions:California/westernNorthAmerica(A),Chile(B),CapeofSouthAfrica(C),NewZealand(D),andAustralia(E)(takenfromHannahetal.,2013).



Figure12.DistributionpatternsofthematingindexofchilooverSouthAfricaforpresentclimaticconditions,foratemperatureincreaseof2°Candthedifferencebetweenpresentandfuture.

TheAfrican sugarcane stalk borerEldana saccharina isoneof themost serious sugarcanepests inSouthAfrica,causingsubstantial losses inyields.Crucialtoeldanainfestationsarethenumberofmatinghoursperannum.Thesedependonhourlynight-timetemperaturethresholdsbeingexceeded,withmeanannualnumberofeldanamatinghoursrangingfrom<200hoursinthecoolerinlandregionsofSouthAfricato>1000hoursinthehottereasternpartsoftheregion,withtheso-called‘sugarbelt’cominginat>800hoursperannum(Schulze,2010).WhentheannualmatingindexofeldanaisassessedinregardtoprojectedchangesintoawarmerfuturebytheGCMsusedinSchulze(2010),theseincreasethroughouttheclimaticallysuitableareaforsugarcaneby~10%alongtheeastcoastto>30%furtherinland.Thisindicatesthatcomparedwithpresent conditions the “new” inlandclimaticallysuitableareasforcanearerelativelymorevulnerabletoeldanainfestation(Figure14).

Inthecaseoftheorientalfruitmoth(Grapholita molesta), whichaffectsapples,theloweranduppertemperature(°C)thresholdsandaccumulateddegreedaysforonelifecycleare,respectively,7.7°C,32.2°Cand535degreedays.Undercurrentclimaticconditionsthenumberoflifecyclesperannumoftheorientalfruitmothrangesfrom<3inthecoolermountainousareasoftheRSAandLesothoto>9andeven10alongthenorthernandeasternbordersofthecountry(Schulze,2010).Projectionsofclimatescenariosintothe intermediate future indicate increases in thenumberoflifecyclesperannumoftheorientalfruitmothby<1.2inthesouthwestto~1.5lifecyclesalongtheeastcoastandalmostparalleltothecoastinthecentralnorthincreasingto>2additionallifecycles,withhighconfidenceintheseprojections(Schulze,2010;DAFF,2013).

Figure13.MeanannualnumbersoflifecyclesofcodlingmothoverSouthAfricaforpresentclimaticconditionsandfortemperatureincreasesof1°C,2°Cand3°C.

Figure14.DistributionpatternsofthematingindexofEldanaoverSouthAfricaforpresentclimaticconditions,foratemperatureincrease2°Candthedifferencebetweenpresentandfuture.



2.5 Impacts on pasture crops – rangelands and planted pastures

Climatechange(includingeffectsofincreasedatmosphericcarbon)maycomplicatetheexistingproblemsofbushencroachmentandinvasivealienspeciesinrangelands.RisingatmosphericCO2levelsmayincreasethecoverofshrubsandtreesingrasslandandsavannah,withmixedeffectsonbiodiversityandpossiblepositiveimplicationsforcarbonsequestration(Bondetal.,2003).Increasedtemperaturesare likelytoprovideamoreconduciveniche foravarietyofpestsandpathogenscritical toagricultural and livestock activities, including thoseundertakeninrangelands.Increasedtemperaturesandincreasedevaporationmayincreasetheincidenceofheatstressaswellaslivestockwaterrequirementsinextensiverangelandlivestockproduction.

Eragrostis curvula is one of the economically mostimportantandhighlyproductivepasturegrassesinSouthAfrica,yielding>12t/ha/seasoninthecoolerwetterareasbuttaperingoffto<4t/hatowardsthewesternpartsofitsgrowtharea(Schulze2010).Inboththeintermediateandmoredistantfuture,areaslosttopotentialE. curvula productionarefoundintheeast,butwithsignificantareasbecomingclimaticallysuitablemainlyinthewest(Figure15).FrommultipleGCManalyses,E. curvulayieldsintotheintermediatefutureareprojectedtodecreaseby~10%inanarcfromnorthtosoutheastaroundthecoreclimaticallysuitablegrowtharea,buttoincreasebyupto4–5t/ha/season,inthecorearea(Figure16).One implicationmaybethatwhile major expansion of climatically suitable areas for E. curvula might occur, there is also a possibility that the area of actual production may decrease (Schulze,2010).

Kikuyu(Pennisetum clandestinum)hasbecomeanimportantpasture grass in South Africa because it providespalatableandhighlynutritiousmaterial,withyieldsintotheintermediatefutureprojectedtodecreaseinanarc

Figure15Shifts inoptimumgrowingareasofEragrostis curvula betweenintermediatefutureandpresent(top,representingawarmer/wetterclimatescenario),andbetweenmoredistantfutureandpresentclimatescenarios(bttom,representingahotter/wetterclimatescenario),derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010b).

fromthenorthwestthroughthenorthtothesoutheastaroundthecoreclimaticallysuitablegrowtharea,buttoincreasebyupto3–5t/ha/seasoninthecorearea.Intothemoredistantfuturetheclimaticallysuitableareaforkikuyubecomesspatiallymorecompact(Schulze,2010)(Figures17and18).Kikuyuyieldchangesarerelativelymoresensitivetosimultaneouschangesinrainfallandtemperaturethantotemperaturealone.Aswas thecasewithE. curvula,majorexpansionof climaticallysuitableareasforkikuyuisprojectedtooccurintotheintermediatefuture,butthereisalsoapossibilitythattheareaofactualproductionmaydecrease(Schulze,2010).

Figure16.Differencesbetween intermediate futureandpresent (top,representingawarmer/wetterclimatescenario),andbetweenmoredistantfutureandpresent(bottom,representingahotter/wetterclimatescenario),Eragrostis curvula yields,derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010b).

Figure17.Shiftsinclimaticallyoptimumgrowingareasofkikuyubetweenintermediatefutureandpresent(top,representingawarmer/wetterclimatescenario),aswellasbetweenmoredistantfutureandpresentclimatescenarios(bottom,representingahotter/wetterclimatescenario),derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010i).



2.6 Impacts on animal production – livestock sector

SouthAfrica’slivestocksectoriscriticaltotheagriculturaleconomy,yethastraditionallyreceivedlessattentionthancropsinconsideringtheimpactsofclimatechange.InSouth Africa’s Second National Communication under the United Nations Framework Convention on Climate Change (DEA, 2011), forexample,staplecropsreceivefarmoreattentionthandoeslivestock,despiteitssignificance,particularlyinthearidandsemi-aridpartsofthecountry.Selectedrecentfindingsofrelevance,aswellasworkinprogressaredescribedbelow.

Toestimatetheeffectsofclimatechangeonthelivestocksector,severalapproachesandsimulationshavebeenusedinSouthAfricatodevelopheatstressandhumidityindicesfor livestock.Loweranduppercritical temperaturesdeterminethethermallycomfortablezoneperlivestocktypetoensureoptimumdevelopmentandproductivity.

Inthecaseofheatstress,Nesamvunietal.(2012)andArcher vanGarderen (2011) show that heat stressprobabilitiesarelikelytoincreaseinthefuture.ArchervanGarderen(2011)usestworegionalcirculationmodels(RCM) for southernAfrica toshowareasexceedingthe30°Ctemperaturethreshold,usingfindings fromliterature(Figure19).Figure20belowshowsareasthatnewlyexceedthe30°Ctemperaturethresholdforalloratleasttwoofthesummermonthsconsideredgiventheprojections (downscalingofbothRCMs is takenintoaccount).TheNorthernCapeProvinceofSouthAfrica,borderingonNamibiaandBotswana,isanareaofparticularconcern,newlyexceeding30°Cinallofthesummerseasons,asdoestheeasterninteriorofKenya(althoughitisrecognisedthatthelattercannotstrictlybeconsideredasbeingrestrictedto‘summer’months).

Figure18.Differencesbetween intermediate futureandpresent (top,representingawarmer/wetterclimatescenario),aswellasbetweenmoredistantfutureandpresent(bottom,representingahotter/wetterclimatescenario)kikuyuyields,derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010i).

Cattle

72THI(22°C@100%humidity)

ComfortthresholdforUSHolsteinsheatstress(Sanshezetal 2009,Ravagnoloetal2000,Freitaset al 2006)

72THI(22°C@100%humidity)

comfortthresholdforhighproducingdairycows(Hernandezelat2002,Amstrong1994)HigherforBos Indicusbreeds(highlyadaptedtoheatstress)

27°C

UpperlimitofcomfortzoneformaximummilkprodutioninIndia-2°Chigherthanfortemperatecountries(Sichi&Michaelowa2007)

28°Candhighhumidity

Heatstressbeginsinmostbreeds(AgricultureInformationCentre,GovermentofAlberta)

30°Cambienttemparature

“seemstobethecriticalpointatwhichbothBosTaurusandBosIndicusbegintodifferinabilitytomaintainnearnormalrectaltemperaturesandrespiratoryrates.”(Hermandezetal2002)

32°C Acceptedcomfortthresholdformostcattlebreeds

72THI Criticallimitforeverykindoflivestock

Figure19.Heattolerancethresholdsforcattlederivedfromliterature(ArchervanGarderen,2011).

Figure20.Areasexceedingthe30°Cthresholdforatleasttwosummermonths(ArchervanGarderen,2011).

Nesamvunietal.(2012)usetheTemperature-HeatIndex(THI);incorporatingclimatechangeprojectionstoshowthatdairycattlearelikelytoexperiencemoresevereheatstressevents in the future.Under theDroughtEarlyWarningandForecasting(DEWFORA)project(Winsemiusetal.,inpreparation),THIisagainusedforthresholdingtoshowthelikelihoodofheatstressoverasingleseasonwithaviewtotailoredforecastsforthelivestocksector.

Forsheepandgoats,theUniversityoftheWitwatersrand,IndigoDevelopmentandChangeandtheCouncil forScientific and IndustrialResearch (CSIR)havebeguna collaborative initiative, funded in part by START,to understand climate change implications for smallstock,usingparticipatoryresearchmethods.ThestudyobjectivesaretobetterunderstandheatstressreactionsandpossiblethresholdsforgoatsandsheepintheSuidBokkeveldarea,aswellaspossibleimplicationsforfuturelivestockfarmingunderclimatechange(Figure21).

Figure 21.Temperaturemeasurement collars forDorper sheep, SuidBokkeveld,May2013.



Inthecaseofforage,theAgriculturalResearchCouncil(ARC)currentlyleadsacollaborativeinitiativetoupdatefindingsonclimateimplicationsforforageusingboththeseasonalandthelongertermclimatechangeprojectiontimescale.Usingdrymatterproductivity(DMP)calculatedfromnetprimaryproductivity(NPP)bestpredictorsforDMParecurrentlybeingisolated;afterwhichpredictivemodellingwill be undertaken.DMP is subsequentlyconvertedtolivestockstandardunitperhectare(LSU/ha).Outstandingtasksincludeaccountingfortreedensityinbaselinecarryingcapacitycalculation,afurthertaskforthecollaboration,andfieldassessment.

Experimental results fromother heat and humiditysimulationmodelssuggestthefollowing(DAFF,2013):

2.6.1 Broilers

Researchhasshownthat,withaheatstressincreaseof10%,despitea10%increaseinenergyconsumptionforadditionalventilation,eachcropofbroilers tookaday longertoreachthetargetweight.Consideringanexpected2.5–3°Criseintemperature,substantialmortalitycanbeexpected.Optionstobeconsideredbyfarmerswouldbereducingstockingdensityby12%,therebyreducingthefrequencyofheatstresstobaselinelevels,orimprovingventilation,whichimpliesacapitalinvestment(DEA,2011;DAFF,2013).

2.6.2 Pigs

Increasedheat stresswas found to result in a smallreductioningrowthratebecauseofreducedfoodintake,withpigletstakingonedaylongertoreachtargetweight.Solutionstocounteractheatstressincludeareductioninstockingratesperhousingunit,sothatthelevelofgrossstressisreducedsignificantly,ortoimproveventilation,whichwouldrequirecapital investmentandelevatedrunningcost(DEA,2011;DAFF,2013).

2.6.3 Feedlot cattle

Feedlotcattleareadverselyaffectedbyhightemperatures,relativehumidity,solarradiation,andlowwindspeeds.TolerancethresholdshavebeenreachedintheNorthWest,NorthernCapeandFreeStateduringthesummermonthsof 1980–1999. It is projected, using climatescenarios,thatthresholdscanbeexpectedtobeexceededintheseprovincestowardstheendofthecentury(DEA,2011) (DAFF, 2013).

2.6.4 Dairy cattle

Thepresentclimatescenario(1980–1999) indicatesthat the north-eastern parts of the Northern Cape are experiencingmoderatetosevereheatstress,whilethiswaslesssevereinMpumalanga,northernFreeStateandmuch of KwaZulu-Natal. Projected scenariosindicate that stress levels could increase to mildstresslevelswithaminimaleffectonmilkproduction.Tocounterbalanceharmfuleffectswithoutjeopardisingmilkproduction,highmilk-producingexoticbreedshavebeencross-bredwithheat-tolerant indigenousbreeds(DAFF,2013).

2.7 Impacts on forestry4

Commercialplantations,woodlands,naturalandurbanforests are complex ecosystems providing a rangeof economic, social andenvironmental benefits andecosystem services to awide rangeof people, andcontributing significantly to national and provincialeconomies and employment (CCSPAFF, 2013).MostcommercialplantationsinSouthAfricaaregrowninKwaZulu-Natal,MpumalangaandtheEasternCapeprovinceswith the threemajor genera being Pinus, EucalyptusandAcacia(wattle).SouthAfrica’scommercialproduction forests arevulnerable as a resultof thefollowing(DAFF,2010):

4.DAFF,2013;Schulze,2010.

• Geographicallyproductionforestsextendoverawidebutfragmentedarea,withonly~1.5%ofthecountryclimaticallysuitablefortreecrops.

• Individualtreespecieshaveclimaticallyoptimumgrowthareasdependentonacombinationofrainfallandtemperatureconditionswithsub-optimumconditionstheresultofeitherdroughtconditions,snow/frostdamageorpest/diseaseprevalence.Timberfarmersandcompaniesareoftenvulnerableduetonotmatchingsiteandspeciesandthussubjectingthemselvestolossesandreductionsinprofitmargins.

• Associatedwiththetimberindustryarefixedcapitalinvestmentssuchassawmillsandpulpmillswhichneedtobelocatedoptimally.

• Thetimberindustryisvulnerabletocompetitionfrom,andconversionsto,morelucrativeusesfortheland,e.g.residentialandindustrialdevelopment,orsugarcaneorsub-tropicalfruitcultivation.

• Vulnerabilityandrisksarelikelytobehigheroncommercialplantationsthaninnaturalforests,particularlywhenoneconsiderslandavailability,waterdemand,environmentalsustainabilityandsocio-economicfactors.

• Plantationsare,furthermore,vulnerabletolightningorarsoninducedfires,moresoinsomeregionsthaninothers,withvulnerabilityalsostronglydependentonthedegreetowhichpro-activefuelloadreductionstrategiesareimplemented.

• Climatically,forestplantationsarealsoatriskoffrost,snowandhaildamage.

• Climateinfluencesthesurvivalandspreadofinsectsandpathogensdirectly,aswellasthesusceptibilityoftheirforestecosystems,withinter-andintra-annualvariationsintemperatureandprecipitationaffectingpestreproduction,dispersalanddistribution.

• Indirectconsequencesofdisturbancefrompestsandpathogensincludetheimpactsofclimateon

competitorsandnaturalenemiesthatregulatetheirabundance.

• Withforestryplantationsgenerallyusingmorewaterthanthenativevegetationtheyreplace,theycansignificantlyreducetheflowinrivers,thusmakingthemvulnerableasacompetitorforscarcewaterresources.

• Inaddition,plantationsreducegroundwaterrechargewhererootsareabletotapintothegroundwatertable,withforestplantationshavingbeenshowntosignificantlydepresslowflows.

Positive climate change impacts on forests includeincreasesinatmosphericCO2concentrationsenhancingphotosynthesisandrootgrowth.However,thepositiveeffectsofenhancedCO2couldbecounteredbyincreasedrespiration,carbonpartitioningtorootsandlowerlevelsofavailablesoilwaterorhighvapourpressuredeficits.Changesinphotosyntheticefficiencymay,inaddition,becappedbysoilfertilityandnutrientsupply,assoilwateravailabilityaffectsnutrientuptake.UnderelevatedCO2 levels,nitrogen(N)levelsofforestfoliage,andlevelsinthelitterlayerdecreaseresultinginhigherqualitylitter.TheeffectofelevatedCO2onnutrientmineralisationandlitterdecomposition,however,remainsuncertain.

Changesintemperatureandrainfallregimesarelikelytohaveamarkedimpactontheextentandlocationoflandclimaticallysuitableforspecificgenotypes.Areaselectionwillbeexacerbatedbypossiblebioticandabioticrisks,includingatmosphericpollutants(DEA,2011).Anumberofstudies(e.g.Warburton&Schulze,2008;Schulze&Kunz,2010a,f,g)haveattemptedtosimulatepotentialfutureimpactsofclimatechangeontheextentandproductivityofplantationforestryinSouthAfricausingsimplerule-basedmodelswithannualrainfallandtemperaturetomapareaspotentiallysuitableforafforestationwithparticularspecies.Thestudieshaveconcludedthat,inthemediumandlongerterm,thetotalareaofpotentialafforestedlandisprojectedtoincreaseduetothewettingtrendovertheeasternseaboardandadjacentareas.



2.7.1 Impacts on major forestry trees

2.7.1.1 Eucalyptus grandis

Eucalypts,grownasshortrotationhardwoods(6–10years)forpulpwoodoraslongrotationhardwoods(20–25years)assawlogs,makeup~40%oftheareaundercommercialforestsinSouthAfrica,withmeanannualincrements(MAIs)from14–30t/ha/annum.Withprojectedperturbationsoftemperatureandrainfall,majorclimaticallysuitableareascouldbeaddedinlandbytheintermediatefuture,withpossibleMAIgainsof4–12t/ha/season,whilevirtuallynopresentlysuitableareasforE. grandisarelost(Figures22and23)(Schulze,2010).

2.7.1.2 Pinus patula

Pinusspecies,makingup~49%ofSouthAfrica’scommercialforests,aregrowneitherasshortrotationsoftwoodforpulpwood(harvestedat~15years)oraslongrotationsoftwoodforsawlogs(harvestedat25–30years),withareasclimaticallysuitableforP. patulaoccurringinastripfromtheEasternCapetoLimpopoandwithMAIsinanarrowrangeof16–20t/ha/annum.BytheintermediatefuturenewclimaticallysuitableareasforP. patula areininlandareasoftheEasternCapeandsouthernMpumalanga,withyieldsprojectedtoincreaseby~3t/ha/annum,whileareaswhicharesuitableunderpresentconditions,butareprojectedtobecomeunsuitablewithinthenextfourdecadesorso

Figure22.ShiftsinclimaticallyoptimumgrowingareasofEucalyptus grandis betweentheintermediatefutureandpresent(top,representingawarmer/wetterclimatescenario),andbetweenmoredistantfutureandpresentclimatescenarios(bottom,representingahotter/wetterclimatescenario),derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010f).

Figure23.Differencesbetween intermediate futureandpresent (top,representingawarmer/wetterclimatescenario),andbetweenmoredistantfutureandpresent(bottom,representingahotter/wetterclimatescenario),MAIs of Eucalyptus grandis,derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010f).

includethecoastalareasoftheEasternCapeandpartsofeasternMpumalangaandLimpopo.AcomparisonofresultsbetweenP. patulaandE. grandisshowsP. patula tobelesssensitivetoclimateperturbations,butwithyieldincreasesalsomuchmoremuted(Figures24and25)(Schulze,2010).

2.7.1.3 Acacia mearnsii

Acacia mearnsii(blackwattle)hasprovedtobethemostdroughtresistantofthecommercialhardwoodsgrowninSouthAfrica.Witharotationcycleaveraging10yearsandaMAIof~10–11t/ha/annum,A. mearnsiiisstrippedforits

barkinadditiontobeingusedforitstimber.Majorshiftsin

theareasclimaticallysuitableforA. mearnsii areexpected,

withareaswhicharepresentlyclimaticallysuitablebeing

lostinanarcintheeast,initiallyalongthecoastandthen

curvinginland,whilenewclimaticallysuitableareasare

gainedinthewest,withmanyareaspresentlysuitable

nolongerclimaticallysuitableunderprojectedfuture

climates(Figure26).Bytheintermediatefutureinthe

climaticallysuitablegrowthareasofA. mearnsii MAIs are

projectedtodecreaseby1–2t/ha/annumintheeastand

increaseby2–3t/ha/annuminthenewlysuitableareas

inland(Figure27)(Schulze,2010).

Figure24.ShiftsinclimaticallyoptimumgrowingareasofPinus patulabetweentheintermediatefutureandpresent(top,representingawarmer/wetterclimatescenario),andbetweenmoredistantfutureandpresentclimatescenarios(bottom,representingahotter/wetterclimatescenario),derivedwith theSmithmodelusingoutput fromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010g).

Figure25.Differencesbetween intermediate futureandpresent (top,representingawarmer/wetterclimatescenario),andbetweenmoredistantfutureandpresent(bottom,representingahotter/wetterclimatescenario)MAIs of Pinus patula,derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010g).



2.8 Impacts on farm labour – human discomfort index

2.8.1 The concept of human discomfort

Inordertobecomfortableandfunctioneffectively,thehumanbodymustattainastableheatbalancewithitssurroundings.Theconceptofthermalcomfortmaybedefinedinseveraldifferentways(e.g.Moustrisetal.,2010).Alldefinitionsarebasedoncriteriaofanenergybalancebetweenthehumanbodyanditsenvironment.Thermalcomfortisachievedwhentheheatproductionfromthehumanorganismcounterbalanceswiththeexchangeofheatfromtheenvironment,aimingatthemaintenanceofconstantbodytemperaturebetween36.5°Cand37°C,

sinceincreasesordecreasesinthebody’stemperatureproducediscomfort.Forexample,ifthebody’stemperatureexceeds 40°C blood circulation problems appear,andabove41–42°C,comaortotalcollapsecanoccur(Gomezetal.,2004).Duringthehotperiodoftheyearorhottimesofadaythehumanbodydevelopsdefensivemechanismssuchasperspirationinordertomaintainitstemperatureatnormal-bearablelevels.However,highlevelsofhumidityintheenvironment–whencombinedwithlowwindspeedandhightemperature–mayresultinthesuspensionofsuchdefensivemechanismsofthehumanbody(e.g.Moustrisetal.,2010).Thisthencausesthermaldiscomfortandmayeventuallyleadtoheatstroke(Beckeretal.,2003;Contietal.,2005).

Figure26.ShiftsinclimaticallyoptimumgrowingareasofAcaciamearnsiibetweentheintermediatefutureandpresent(top,representingawarmer/wetterclimatescenario),andbetweenmoredistantfutureandpresentclimatescenarios(bottom,representingahotter/wetterclimatescenario),derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010a).

Figure27.Differencesbetween intermediate futureandpresent (top,representingawarmer/wetterclimatescenario),andbetweenmoredistantfutureandpresent(bottom,representingahotter/wetterclimatescenario)MAIs of Acacia mearnsii,derivedwiththeSmithmodelusingoutputfromtheECHAM5/MPI-OMGCM(Schulze&Kunz,2010a).

A considerable amountof literature has highlightedtheinfluenceofclimateonhumancomfort,andevenmortality.Resultsshowahighincreaseinmortalityinsummermonthsduring“heatwave”periodswithveryhightemperatureandhumiditylevels.Thisrelationshipwith climate seems to be stronger thanwith otherenvironmental factors,suchasatmosphericpollution(ZauliSajanietal.,2002)

2.8.2 Comfortable and uncomfortable days per year in South Africa

Figure28(topleft)showsthatfordaytimeconditionswhentemperaturesareatmaximumandrelativehumidityatminimum,thenumberofcomfortabledaysperannumovermostofSouthAfricaaveragedbetween50and100for thehistoricalperiod1950–1999.Theexceptionsareinnorth-easternKwaZulu-Natal,easternLimpopoandMpumalangawhereonlyabout20daysperyearareclassedascomfortable.Thedistributionofpartially comfortabledaysperannumdisplaysadifferentpattern,withthenorthernhalfoftheregiontogetherwiththeeasternperipheryat200–300days,reducingto100–200partiallycomfortabledaysinthesouthernhalf(Figure28,topright).

Ofprimeconcernisthedistributionofthenumberofdaysperannumwhich,onaverageforthehistoricalrecord,are uncomfortableonaccountofbeingtoohotandhumidaroundmiddayaccordingtoThom’sdiscomfortindexusingdailymaximumtemperaturesandminimumhumidityasinputs.Figure28(bottom)highlightsthenorthwestaswellasthenorthernandeasternbordersofSouthAfricaashavingthemostnumberofuncomfortabledaysperyearat50–100,withthisnumbertaperingofftofewerthan10uncomfortabledaysinthecoolerinterior.

Figure28.Averagenumbersofcomfortable(top),partiallycomfortable(middle)anduncomfortable(bottom)daysperyearoverSouthAfricaforthehistoricaltimeperiod1950–1999,accordingtoThom’s(1959)humandiscomfortindexforthemiddayconditions.



OnashorterthanannualtimestepFigure29showsthatmidday thermaldiscomfort is clearly a summerphenomenon, as illustratedby themonth-by-monthanalysisatBallito(~29°40’S)–abeachholidaydestinationinthesugarcanegrowingbeltalongthecoastofKwaZulu-Natal – where the number of uncomfortable dayspermonthpeak fromDecember toMarch.Partiallycomfortabledaysdominatethroughouttheyear,withmiddle-of-the-daythermalconditionsatthissub-humidlocationonlyreallycomfortableinthemildwintermonthsJunetoAugust.

Figure29.Averagenumbersofdayspermonth,definedbytheThom’sdiscomfortindex,aseitherbeingcomfortable,partiallycomfortableoruncomfortablearoundmiddayatBallitoalongthecoastofKwaZulu-Natalforeachmonthoftheyearunderhistoricalclimateconditions.

2.8.3 Projected changes to comfortable and uncomfortable days per year over South Africa

Inordertoassessimpactsofprojectedclimatechangeonindicatorsofhumanthermalcomfort/discomfort,thenumberofcomfortabledaysperannumand then thenumberofuncomfortabledaysweremappedforThom’scriteriausingdailyTmaxandRHminvaluesgeneratedfromtheGCMoutputsforthe20yeartimeslicesmakingupthepresent(1971–1990)climatescenariosaswellastheintermediatefuture(2046–2065)andmoredistantfuture(2081–2100)climatescenarios.OnthepremisethatnoonesingleGCM’soutputofTmaxandRHminwasperfect,themeansofcomfortableanduncomfortabledaysperyearderivedfromtheensembleofthe5GCMsusedinthisstudy

weremappedatthespatialresolutionofthe5838QuinarycatchmentsmakinguptheRSA,LesothoandSwaziland.

Figure30showsthatprojectionsofthenumberofcomfortable daysperannumdecreasesdistinctlyinthe75yearsfrom

Figure30.Theaverageof thenumberofcomfortabledaysperannumaccordingtoThom’shumandiscomfortindex,derivedfromdailyclimateoutputof5GCMsforpresent(1971–1990),intermediatefuture(2046–2065)andmoredistantfuture(2081–2100)climatescenarios

thepresenttimeslicetothatoftheintermediatefuture,andevenmoremarkedlyinthe35yeargapbetweentheintermediate futureandthemoredistant future,withdecreasesmainlyinthenorthernhalfofSouthAfrica.

However, amore significantvisual change isevidentinFigure31whichcomparesdistributionpatternsofuncomfortable daysperannumaccordingtoThom’shumandiscomfort indexbetweenthepresent, intermediatefutureandmoredistantfutureclimatescenariosderivedfromthemultipleGCMsusedinthisstudy.Itmaybeseenthatthedarkerredshadedareasdepictingmorethan50uncomfortabledaysperyearexpandconsiderablyfromthepresentintotheintermediatefuturearound40yearsfromnow(2013)andintothemoredistantfuturearoundthe2090sbywhichtimeoutputfromtheGCMsusedinthisstudyprojectthatmostofSouthAfrica–exceptthesouthandhighlyinghighveldandmountainousareas–couldexperienceover50,andinmanyplaces,over100thermallyuncomfortabledays.

An assessment of the distribution within a year ofcomfortableversusuncomfortabledaysisagainillustratedforBallitoonthecoastofKwaZulu-Natal.Figure32showsthatfromoutputofthe5GCMsusedinthisstudytheaveragenumberofdaysthatarecomfortablearoundmiddaybyThom’scriteriareducefrom8permonthforJunetoAugustunderthepresentclimatescenariosto3intheintermediatefutureandonly2inthemoredistantfuture.Morecriticalinthecontextofthispaper,however,isthatthenumberofuncomfortabledaysdisplaysamarkedincreasefromaround5permonthforthehotsummerperiodJanuaryandFebruaryunderpresentconditionstoaround15intotheintermediatefutureandover20dayspermonthforfourmonthsoftheyearintothemoredistantfuture.

2.8.4 Implications of increased human discomfort under future climate conditions

Inthispaperhumanthermalcomfort/discomfortformiddayconditionswasassessedbyapplyingThom’sdiscomfortindexbasedondailymaximumtemperaturesincombination

Figure31.TheaverageofthenumberofuncomfortabledaysperannumaccordingtoThom’shumandiscomfortindex,derivedfromdailyclimateoutputof5GCMsforpresent(1971–1990),intermediatefuture(2046–2065)andmoredistantfuture(2081–2100)climatescenarios.



withdailyminimumrelative humidity.The studywasundertakenatthespatialresolutionofthe5838quinarycatchmentscoveringtheRSA,LesothoandSwazilandwithThom’sdiscomfortindexcomputedforhistoricalclimaticconditionsaswellas forprojectionsof futureclimatescenariosusingoutputaveragedfrom5GCMsforcedwiththeA2emissionsscenario.Resultsshowedaconsiderablereduction in comfortable daysintotheintermediatefutureinmid-century,withaccelerationofthisreductiontowardstheendofthecentury.Morecritically,resultsgeneratedwithprojectedfutureclimatescenariosoverSouthAfricadisplayed amarked increase in uncomfortable days per annumandpersummermonthwiththeindexofdaytimetemperaturemaximaincombinationwithhumiditybeingabovethethresholdofcomfort,againwithanaccelerationofuncomfortabledaysintothemoredistantfuture.

Whileconstrainedbyoutputfromonly5GCMsbasedontheA2greenhousegasemissionsscenarioshavingbeenused,theresultspresentedneverthelesshavemajorimplicationsforadaptingtoprojectedclimatechangeimpacts.Examplesincludethefollowing:

• Thermaldiscomfortonmoredaysoftheyear,andespeciallyinsummermonths,impliesapossiblereductioninproductivityofagriculturallabourers,specificallythoseengagedinoperationswithsummerandwithmulti-yearcrops.Thismaybeoffsetbyanearlierstarttotheworkdayorworkintwodistinctsessionswithalongermiddaybreakbetweensessions.

• Althoughthethresholdvaluesdifferslightly,humandiscomfortequallyimpliesdiscomforttolivestockwhichhastheknowneffects,forexample,ofreducingmilkyieldsindairycattleandinfluencingconceptionratesacrossvirtuallyallbreedsoflivestock.Animalshadingandothermeansofartificialcooling(e.g.sprayingwithwater)arepossibleadaptationoptions.

• Increasedhumandiscomforthasmajorimplicationsfortheagri-tourismindustry,forexample,onwheretogoandwhentogoandhowthesedecisionsmaychangeinfuture.

• Mapsofdiscomfortindiceswouldbevaluableforhousingneeds,buildingmaterialandheating/coolingrequirements.

• Coolingrequirements,e.g.forfruitinpackhousesandforfoodstorage,willnecessitateincreasedoperationofairconditioners(longerperiodsintheyearand/ormorehoursperday)andtheneedforcoolingfacilitiesandabilitieswithcorrespondingincreasesinelectricitycosts.Itwillbepossibletooffsetthisthrough,forexample,conversionto“green”buildings.

• Similarly,medicalgeographyshouldtakecognisanceofpossiblechangesinhumandiscomfortinregardtoarangeofdiseases.

Figure32.Changesinthenumberofcomfortable(top)anduncomfortable(bottom)dayspermonthatBallitofromthepresentthroughtheintermediatefuturetothemoredistantfuture,computedusingThom’sHumanDiscomfortIndexandbasedonaveragesfrommultipleGCMs.

Ithastobeemphasisedthatclimateandclimatechangeissuesaresuperimposeduponthemultipleotherchallenges,problemsandstressorsthattheSouthAfricanagriculturesector already faces (e.g. globalisation, urbanisation,environmentaldegradation,diseaseoutbreaks,marketuncertainties,higherfuelandmachinerycosts,policiesconcerningwater,veldburning,overgrazingand landredistribution,andslowresponses fromauthorities).Togethertheseaffectfutureplanningstrategies.However,uptoapoint,farmingcommunitiesalreadycopewith,andadapt to,avariableclimate.Thekey toenablingcommunitiestodealwithanuncertainfutureclimateistounderstandwhatmakesthemvulnerableandtoworktowardsreducingthosefactors(Anderssonetal.,2009).

AdaptingtoprojectedclimatechangeinSouthAfrica’sagriculturesectorwillbeaboutlarge-scalecommercialfarmersoptimisingclimaticconditionstomaximiseoutputinasustainablemannerandtomaintainacompetitiveedge.Attherurallivelihoodscale,ontheotherhand,adaptationneedstofocusonthemostvulnerablegroupsandareassothatlivelihoodsarenoterodedbyclimateevents,butratherthattheaffectedcommunitiesbecomemore resilient to the expected changes in climate.Forboth setsof farmers, adaptationwill require anintegratedapproachthataddressesmultiplestressors,andwillhavetocombinethe indigenousknowledge/experiencesofvulnerablegroupswiththelatestspecialistinsightsfromthescientificcommunity.

Most agricultural programmes and information areinitiated at high levels in government for regionalimplementationandarenot always adapted to localconditions.Allagriculturalprogrammesandplanningstrategiesinregardtoclimatechangewillneedtofocusonlocalconditions,asclimatechangewillhaveverylocalrepercussions(Schulze,2010).

Asanoverall adaptationstrategy,benefitswouldbegainedfrompracticesbasedonbestmanagementandclimate-resilientprinciples,whicharecharacteristicofconceptssuchasclimatesmartagriculture,conservationagriculture,ecosystem-basedadaptation,community-basedadaptationandagroecology.Thisincludespracticessuchasrestorationandrehabilitationofecosystemstailoredforoptimisingclimaticconditions,aswellasminimisingsoildisturbance,maintainingsoilcover,multi-croppingandintegratedcrop/livestockproductionforoptimisingyields,sequesteringcarbonandminimisingemissions. Below is a summary of the findings onadaptationoptions for theSouthAfricanagriculturesectorpresentedintheDAFFClimateChangeAdaptationandMitigationPlan(DAFF,2013).

3.1 Conservation agriculture, climate smart agriculture, ecosystem-based adaptation, community-based adaptation and agroecology

Conservation agriculture (CA) is a concept for resource-savingagriculturalcropproductionthatstrivestoachieveacceptableprofits togetherwithhighandsustainedproductionlevelswhileconcurrentlyconservingtheenvironment.Itconsistsofthreeprinciples:

• practicingminimummechanicalsoildisturbance,whichisessentialformaintainingmineralswithinthesoil,stoppingerosion,andpreventingwaterloss

• managingtopsoiltocreateapermanentorganicsoilcoverforgrowthoforganismswithinthesoilstructure

• croprotationwithmorethantwospecies(FAO 2007).

CAisanintegratedapproachaddressingmultiplesectors,includingin-fieldrainwaterharvesting,collectingroofandroadrunoffwatertosupplementirrigation,andorganic

5.Schulze,2010;DAFF,2013.

3. ADAPTATION RESPONSE OPTIONS5


3.AdaptationResponseOptions

and precision farmingwith a focus onminimumorno tillage,maintaining soil cover and crop rotation.ThebenefitsofCAarewellestablishedatsmallscales,andarecurrentlybeingquantifiedatcommercialfarmlevelandcomparedtoconventionalproductionmethods(Smithetal.,2010).AdoptionofCApracticesbythecommercial and household food security sectors iscomparativelylow,astheadoptionprocessisintricateandason-farmexperimentation/demonstrationsarelimited.However,thosewhohaveadoptedandexpandedthesepracticesarereportingbenefitssuchasincreasedcropyieldsevenduringperiodsofdrought,productivesoils,minimuminputcostsandthuslargerprofitmargins,lesssoildegradation,bettersoilwater-holdingcapacity,andall-year-roundhouseholdfoodsecurity.

Climate-Smart Agriculture(CSA)asdefinedandpresentedby theFAOat theHagueConferenceonAgriculture,FoodSecurityandClimateChangein2010,contributestotheachievementofsustainabledevelopmentgoals.Itintegratesthethreedimensionsofsustainabledevelopment(economic,socialandenvironmental)byjointlyaddressingfoodsecurityandclimatechallenges.Itiscomposedofthreemainpillars:

• sustainablyincreasingagriculturalproductivityandincomes

• adaptingandbuildingresiliencetoclimatechange• reducingand/orremovinggreenhousegases

emissions,wherepossible.

TheCSAapproachisdesignedtoidentifyandoperationalisesustainableagriculturaldevelopmentwithintheexplicitparametersofclimatechange(FAO,2013).

Ecosystem-based adaptation(EBA)asdefinedbytheConventiononBiologicalDiversity(CBD),“usesbiodiversityandecosystemservicesinanoveralladaptationstrategy. It includes the sustainable management,conservationandrestorationofecosystemstoprovideservicesthathelppeopleadapttotheadverseeffectsof

climatechange.EBAaimstomaintainandincreasetheresilienceandreducethevulnerabilityofecosystemsandpeopleinthefaceoftheadverseeffectsofclimatechange(CBD,2009).”Themaintenanceofgeneticdiversityisparticularlyimportanttotheagriculturesector.EBAcutsacrossmultipleeconomicsectors,includingagriculture,water,energy,tourism,forestryandnaturalresources.There are several existing EBA related projects inSouthAfrica, includingsustainablemanagementand/orrestorationofuplandwetlandsandfloodplainsformaintainingwaterflowandquality;conservationandrestorationofforeststostabiliseslopesandregulatewaterflows;andestablishingwind-breakstoincreaseresilienceofrangelands.

Community-based adaptation (CBA) works toempower people to plan for and copewith climatechangeimpactsbyfocusingoncommunityledprocessesgrounded in the priorities, needs, knowledge andcapacities of communities (Chesterman &Hope inMidgleyetal;2011).CBAisanimportantcomponentofthelargerscopeofadaptationtoclimatechangeimpactsandpressuresbylocalpeople.Itprovidesinformationandconcreteexamplesofpotentialclimatechangeimpactsandadaptationmeasuresthatarelocationspecificandcommunitymanaged.CBAalsoprovidesinformationthatcanbesharedandreplicatedinanappropriateformatandmanneracceptabletocommunities.TheneedforinformationonadaptationthatincorporatesandbuildsonexistingcopingstrategiesofcommunitiesshouldbearticulatedanddemonstratedthroughCBAprojects(GEF, 2011).

Agroecology approachesincluderecyclingnutrientsandenergyonthefarm,ratherthanintroducingexternalinputs; integrating crop and livestock managementpractices;diversifying species andgenetic resourcesinagroecosystemsovertimeandspace;andfocusingoninteractionsbetweenproductioncomponentsandproductivityacrosstheagriculturalsystem.

3.2 Sustainable water use and management

DuringthenextdecadesSouthAfricanpeoplewillfacechangesinrainfallpatternsthatwillcontributetoseverefreshwatershortagesorfloodingresultinginnegativeimpactsonagriculturalproduction.Enhancingwateravailability throughadaptationoptions thatconsidersustainablewateruseandmanagementisakeystrategyforincreasingagriculturalproductivityandsecuringfoodsecurityinSouthAfrica.Itisimportantthatboththerisksandopportunitiesofclimatechangearetakenintoconsiderationwhenplanningadaptationoptions.

• Impoundments: Incertainareasmorewatermighthavetobeimpoundedasanadaptationstrategyinordertocopewithincreasedflowvariabilityandhigherirrigationdemands.Thiswillbeconditionaluponrequiredenvironmentalflowreleasesbeingmadeandimpoundmentsnotbeingamaladaptivepracticefordownstreamwaterusers.

• Damre-evaluationand/ormodification:Existingdamsweredimensionedforsizeandsafetyonhistoricalhydrologicalrecords.Theywillnotnecessarilybeabletodealwithfutureclimateconditionsinregardtoprojectedincreasesinfloodsorlowerinflows.Climatechangethereforeneedstobeincludedasafactorwhenassessingthesafetyofcurrentdamsandinthedesignofnewstructures.

• Maintaining ecological corridors: Naturalvegetationbuffersalongriversystemsonfarmsarecriticaltosupportwateryieldandforfloodattenuationaswellastomaintainnaturalbiodiversity.

• Water and nutrient conservation technologies (WNCT): AsanadaptationstrategyWNCTshavethepotentialtomakebetteruseofprecipitationandcontributesubstantiallytoreducingfoodinsecurityand

povertybyreducingvulnerabilitytoriskanduncertainty.Examplesincludetechnologiestopromotewateruseefficiency,especiallyirrigationefficiency;reductioninreticulationlosses;sociallyacceptablewaterrecycling;rainwaterharvesting;adaptationssuchaschangesinplantingdates;selectingcropswithshortergrowingperiods;hightechnology-intensivesolutionssuchastheincreaseduseofmodernmachinerytotakeadvantageofshorterplantingperiods;andgroundwatermanagementsystems,notablytheartificialrechargeofaquifers.

• In-situ rainwater harvesting: Thisincludestillagepracticesconducivetosoilwaterconservationandwaterharvestinginitsmanyforms.

• Wetland conservation: Wetlandsneedtobeconservedasanadaptationmeasureastheynotonlyperformvitalecosystemsfunctionssuchaswaterstorage,floodprotection,erosioncontrolandgroundwaterrecharge/discharge,buttheyalsoprovideawiderangeofagriculturallyrelatedgoodsandservicesinsupportinglivelihoodsinmanycommunities,includingprovisionofhydrologicalbuffersandprovidingfood,livestockgrazing,domesticwater,constructionmaterialandothernaturalproducts(Kotze&Silima,2003;Mondi,2009).

• Distribution of water: In the interests of futurenationalfoodsecurityconsiderationhastobegiventoagriculturereceivinganequitableshareofwaterinrelationtourbandemandsandtheenvironmentalreserve.Theextenttowhichwaterforagricultureisreallocatedtoothersectorsduringadroughtwillhavetobeplannedcarefully,dependingonthevalueofdifferentcropsasstaplefoodsorforeignexchangeearnersandtheirphysiologicalresponsetoreducedwater,e.g.deciduousfruittreesmaysufferforuptofiveyearsafteraseveredrought.



• Flood management:WithfloodmagnitudesprojectedtoincreaseovermanypartsofSouthAfrica,theprotectionofagriculturallandswillbecomeanimportantcomponentofadaptation.

• Groundwater management: Manyfarmersdependonboreholewaterwhichisdrawnfromwidelyvaryingdepths,andwillbeimpacteduponindifferentwaysunderfutureclimaticconditions.Farmerswillneedtoadapttorevisedgroundwaterrechargeratesforboreholestoremainsustainable.

• Reduction of high salinity levels: Wheresalinitylevelsarealreadyhighthesewillneedtobereduced,elsewhereirrigationpracticeswillneedtoadapttopreventsalinisation,especiallywherefutureclimaticconditionswillresultinwidespreadrainswhichwillmobilisesalts.

• Sewage management: Sewageworksbecomingoverloaded,nolongerfunctioningproperlyanddischargingsewageintoriversshouldbedeemedanunacceptablepracticeunderfutureclimaticconditions.

• Increasing the area under irrigation: Whereclimatescenariosprojectlowerrainfall,increasingtheareaunderirrigationisanadaptationoption,butonlysubjecttowaterandsuitablesoilsbeingavailable,farmingpracticesbeingefficientandexpansionnotleadingtomaladaptiverepercussionsdownstream(e.g.regardingenvironmentalflowsorreductionstootherusers).

• Integrated water use planning: This is an essentialadaptationstrategy,whichfocusesondevelopingcomprehensiveplansthatguideallinitiativesandinfrastructuredevelopmentwithinthewatersector,takesintoaccountthewater

• Water curtailments: Adaptationplanswillneedtoconsidercarefullywatercurtailmentstoirrigatorsintimesofdroughtinlightoffoodsecurityandconditionaluponirrigatorsusingwaterefficiently.

• Water price increase trade-offs: Waterhasbecomeexpensivetoirrigatorsandpriceincreaseswill,withclimatechange,havetobeweighedcarefullyagainsttheissuesofnationalfoodsecurity,exportvalueandforeignearningspotentialofcrops.ThelatterisparticularlypertinenttothedeciduousfruitindustryoftheWesternCape,anareaprojectedtoexperiencereducedrunoff.

3.3 Sustainable farming systemsCertaincropsgrowninSouthAfricaaremoreresilienttoclimatechange,whileothersaremoresensitive.Similarly,climatechangeimpactsforsomecropscanbeprojectedwithmoreconfidencethanforothers.Additionally,thereisevidencethatfoodproduction/securityisatriskespeciallyduetofutureprojectedwatersupplyconstraints,declinesinwaterquality,andcompetitionforwaterfromothersectors.Thereisevidencethatsmallholder,subsistenceandurbanhomesteaddrylandfarmersaremostvulnerable,whilecommercialirrigatedproductionisleastvulnerabletoclimatechange–givensufficientwater supply forirrigation.Intensivelivestockproductionsystemsneedtoreducetheirwateruse,containtheirGHGemissionsandensureimprovedgrazingservices.

Overgrazing,desertification,naturalclimatevariabilityandbushencroachmentareamongthemostseriousproblems facing rangelands (DEA, 2011). Externalstressorssuchasclimatechange,economicchangeand

shifts inagricultural landusesmayfurthernegativelyimpacttheproductivityoftheseregionsanddeepenpre-existingvulnerability.Adaptationinterventionswouldbenefitfromanintegratedapproachthatincorporatesboth ecological and socio-economic dimensions ofrangelanduse.Apurelysectoralapproach,whethertargetingclimatechange,desertification,oraddressingbothphenomena, is likely tobe limited in itsabilitytoaddress theresilienceofkeyprocessesandtheirrelatedsocio-economicbenefits(e.g.Theprotectionand restorationof ecosystem services). Past policyshiftsrelatingtoadvisedandlegislatedstockingrates(asinformedbyestimatedcarryingcapacity)haveproveneffective in reversing degradation trends in certainclimaticandsocio-economicsettings.Thesemechanismswouldbenefitfromscience-basedinsights(i.e.ongoingobservationsandprojections)relatingtocurrentandfuturecarryingcapacities(astheymaybe influencedbyclimatechangeandvariability),andfromeffortstounderstandthefactorsthatdetermineobservanceofsuchadviceandlegislation(DEA,2011).

Asanoveralladaptationstrategy,concertedpromotionof bestmanagement practices is required basedontheprinciplesof the least possible soil disturbance,permanent soil cover,multi-cropping and integratedcropandlivestockproductioninordertooptimiseyields,sequestercarbonandminimisemethaneandnitrousoxideemissions.Examplesinclude:

• Shifts in optimum growing areas: Changesintheoptimumgeographiclocationsforcropsandcultivarswillneedtobeidentified,withheat/droughttoleranceandwateruseefficiencybeingparamountconsiderationsinneworalternativecropselection,suchas

needsofallusersandidentifiestheappropriateinterventionstoensurereliablewatersupplyinthemostefficient,sustainableandsociallybeneficialmanner.

• Drip irrigation: Conversiontodripirrigation(fromoverheadorfloodmethods)isanobviousadaptationstrategybecauseofitshighwateruseefficiency.However,itentailsexpensivecapitaloutlaysininfrastructureandinstallationandgovernmentsubsidiesshouldbeconsideredtoassisttheuptakeofdripirrigation.Dripirrigationdoeshavedisadvantagesinthatitcannotbeusedforcooling(unlikesprinklers),norcanitbeusedeffectivelyonsandysoils.Furthermore,itcanworkwellforcertaincrops(e.g.vines),butnotforothers.Thisismainlydeterminedbytherootstructureofparticularcrops.

• Localandcropspecificirrigationscheduling: Thisshouldbepractisedtoavoidexcessivelossofphosphatesfromirrigatedfieldsduetosurfacerunoffandofnitratesthroughdeeppercolation.

• Mulching/crop residue: Thiscansaveupto20%ofirrigationwaterrequirements.

• Viticulturespecific:Theindustrycouldusefullyre-evaluateitscultivarmixandpossiblymakemoreuseofearly-seasoncultivarstoavoidthedamagingeffectsofheatwavesinmid-summer.Evenwithincultivars,thestyleofwinewilllikelychange.Therearenewopportunitiestoacquirecultivars(orbreedlocally)withpest/diseaseresistancewithoutforfeitinghighqualityandyield.However,ittakes~10yearstosource,quarantine,register,andcertifyanewcultivarforrelease (DEA, 2011).



changingtoyellowmaizeorlatematuringfruittreesorrelocatingtoclimaticallysuitableareas.Progresshasbeenmadewiththedevelopmentofgeneticallymodifiedcropswithregardtoheatresistance,droughttolerance,andwateruseefficiency(DEA,2011).Theseincludepotatoes,sweetpotatoes,soybeans,indigenousvegetables,maizeandwheat.Othernotabledevelopmentsincludelow-costalternativestochemicalsfororganicproduction,areductioninwaterconsumptionbyvegetables,theproductionofindigenousandothervegetablescropsunderlowinput-costconditionsandhydroponics.

• Climatically marginal land: These areas willbemorepronetoreducedyieldsandevencompletecropfailuresinthelightofprojectedincreasesinclimatevariability.Suchareasshouldbeidentifiedandcropsselectedwithaviewtomaintainingsoilproductivityandpreventinglanddegradation.

• Climate-specificfarms:Asanadaptationstrategy,farmersmayneedtoprocure“climatespecific”farmsforspecificcrops,aswellaslookingtootherAfricancountriestoproducetheir crops.

• Growing indigenous species:Indigenousspeciessuitableforlocalconditionsshouldbeencouragedaswellasthemaintenanceofnaturalcorridorsandbufferswherepossiblewithincultivatedlandandalongriversystems.

• Farming indigenous and locally adapted breedswhichareheatanddroughttolerant(e.g.Bonsmara,Nguni,Huguenot,andBoergoats).

• Stocking densities: Veldcoverandcompositionarelikelytochangeinfutureclimaticregimes,andfarmerswillneedtoadapttheirlivestock(andgame)densitiestochanginggrassveldcarryingcapacities.Thiswillincludereducingstockingdensities,providingsupplementalfeedandwaterand/orshiftinglivestocktolandwithhighercarryingcapacityandimplementingrotationalgrazingthatincludesrestperiodsforrangelands.

• Losses of herbage yields: Thesemaybeduetoovergrazing,whichwillneedtobeminimisedasanadaptationstrategy,aswilllossesduetoincreasederosionthroughmoresurfacerunoff,wherethatisprojected.

• Alien invasive grasses: ThesearelargelyunpalatableandtendtorespondmorefavourablytoelevatedCO2 availabilitythanindigenousspecies.Theywillneedtobekepttoaminimumastheyarelikelytobecomeamajorthreattoindigenousspecies,withhugepotential(andpartiallyunavoidable)lossesinbiodiversitywithclimatechange.

• Weed infestations in grasslands: Severeweedinfestationsneedtobeminimised.Weedsaremostlypioneerspeciesandtendtodegradeecosystemsandadaptmorerapidlytoenvironmentalchangesthanindigenousflora.

• Fodder storage/banking: Inareasofprojectedrainfalldecreasesandhencedecreasesinherbageyields,therewillbeincreasedneedtostorefodderforlivestockortousealternativessuchasmaizestalks.

• Animal health: Adaptationwillneedtofactorinanimalhealth,aschangesinrainfallandtemperaturewillimpactonthedistribution,

• Altering planting and harvesting times: Thisisanotheradaptationstrategythatwillhavetobeconsideredonayear-to-yearbasistakingintoaccountseasonalclimateforecasts.Indrierregionsharvestinglessfrequentlyshouldbepromotedtopreventnutrientdepletion.

• Diversifying crops:Introducingnewcultivatedspeciesandimprovedvarietiesofcropswillenhanceplantproductivity,quality,healthandnutritionalvalueincludingbuildingcropresiliencetodiseases,pestsandenvironmentalstresses.Thiscanincludetheadditionofnewcropsorcroppingsystemstoagriculturalproductiontakingintoaccountdifferentreturnsfromvalue-addedcropsandmarketopportunities.

• Minimum or no-till practices:Practisingminimumand/orno-tillasasoilconservationmeasureandfollowingconservationlawsandpolicesisalreadyacceptedbyprogressivefarmers.However,manysmallholderandsubsistencefarmershavelimitedresourcesandpressingneedsandprioritiesthatlimittheiroptionsandmotivationwhenitcomestoputtingeffortintosoilconservationpractisesasanadaptationmeasure.

• Water harvesting:Initsmanyformswaterharvestingshouldbepromotedtocaptureadditionalrainfallforcroputilisation.

• Cover crops: Theseshouldbeencouragedinthecaseofcropsgrowninwidelyspacedrows(e.g.vines)toreducesoilwaterevaporation.

• Decreasing wind erosion: Decreasingwinderosion(e.g.bymulchstripsorshelterbeltsofnaturalvegetation)shouldbecomestandardpractice.

competenceandabundanceofvectorsandparasites.Furthermore,dependenceonriverflowsforwatermaybecomeanimportantadaptationissueunderfutureclimaticconditions.Domesticanimals(andwildlife)willbecomestressedorevendieiftheydependonriverflowsandiftheseprovideinsufficientwater.

Anumberofadaptationstrategiescanbeimplementedto protect intensive livestock production. Majorinfrastructureinvestment(e.g.Tominimisetheeffectsofheatstressandenhancewaterprovision),couldaddsubstantiallytothealready-highinputcostofintensiveanimalproductionsystemsandfurtheraffectprofitabilityofalreadyfinanciallyburdenedfarmers.Bestmanagementtechnologies should be promoted by assessing thevulnerabilityofsmallholderlivestockfarmersinmarginalareas,andfacilitatingearlyadaptationtotheeffectsofclimatechange.Programmescouldbeestablishedtobreedheat-tolerantanimals.

Diversificationof theagriculturesector isespeciallyimportant inareasofprojecteddecreases inrainfall,includingincreasingtheamountofirrigatedland(subjecttowateravailabilityandnotleadingtomaladaptation),findingnewlocationswhichareclimaticallysuitableforcrops,growingindigenousspecies,harvestinglessoftentopreventnutrientdepletion,using local techniquestodecreasewinderosion(e.g.mulchstripsforshelterbeltsofnaturalvegetation),andplantingdrought-resistantmaizevarieties,alternativecropsorlate-maturingfruittrees.Climatechangeandtheresultantinabilitytofarmasbeforemaypromptespeciallysubsistencehouseholdstofindothersourcesofincome,throughmigratingforwork(e.g.tourbanareas)orthroughotheractivitiessuchasmakingbricks,sewing,sellingfirewood.



3.4 ForestryShort-term adaptation options for the forestrysectorinclude:

• Community-based climate-resilient forestry6 anddiversificationoflivelihoodskills(linkedtocommunity-basedadaptationasdescribedabove):Thiswillassistinthesustainabilityofecosystemsanddependentcommunities.

• Extreme event preparedness and early response: Benefitsarederivedfrompreparationforbothextremeeventsandchangesinthecurrentaverageresourceavailabletoamelioratepredictedclimatechangeimpactssuchashigherincidencesofdrought,hail,fire,anddisease.Inlightofthis,forestmanagementparadigmsmayrequirerevision.Furthermore,theimpactsofextremeeventsshouldbeassessedusingcurrentlyavailabledata.

• Fire mitigation: Reducinglossesduetofireandrapidresponsetoforestfiresareimperativesintheforestrysector.Present-dayinitiativestolimitwildfiredamageinforestsincludegovernmentsupport(theWorkingonFireprogramme),aswellasanintegratedfiremanagementapproachbyseveralindustrialforestrycompanies.Thisinvolvesthecombinationofproactivefuelreductionstrategiesinstrategicallycreatedbufferstripsinthelandscapecombinedwithreactivefirefightingattheselocations,whichhasgreatpotentialtocounter(tosomeextent)thepotentialincreasesinfireriskandseverity.Intensivelymanagedforestlandscapesmaythusplayasignificantroleinlandscapefire

6 Community forestryisanevolvingbranchofforestryinwhichlocalcommunitiesplayasignificantroleinforestmanagementandlandusedecisionmakingandactaschangeagentswithgovernmentsupportandfacilitation.

Enhancedeffortstooptimisesite-speciesmatchingarelikelytoprovidebenefits.Empiricalandmechanisticmodellingtechniqueshavetobeappliedtopredictsitesuitabilityonanationalscaleandmatchitwithavailablespecies,hybrids,orclones.FirstapproachesinSouthAfricaarepromising(Fairbanks&Scholes,1999;Warburton&Schulze,2008),butstilllackmanyimportantcriteriatomeetallthechallengesofclimatechange.Anintegratedmulti-criteriadecisionsupportsystemcouldbedevelopedtoadaptsite-speciesmatchingiterativelytothelatestupdatesofclimatepredictions.

• Potential relocation: Thecommercialforestrysectorhastodealwithlongharvesttoharvestcyclesof10to25yearsaswellashightransportationcostsandhighcostsofrelocatingtimbermills/plantswhenadaptationstoclimatechangeareassessed.

• Climate resilient tree selection and breeding: Sincetreespeciesandprovenancesdifferintheirabilitytoadapttoclimaticchangeandtheirvulnerabilitytohazards,selectionandbreedingshouldbeundertakeninlightofclimateprojections,withhybridisationandclonalselectionprovidingthepotentialtoadapttoenvironmentalchanges.Despiteaprojectedincreaseofprecipitationinsomepartsofthetreegrowingarea,thecriteriafortheselectionofspecies,hybrids,andcloneswillhavetofocusmoreonwaterefficiency,droughtandfiretolerance,aswellasdiseaseresistance,asfutureprecipitationmaybemoreerratic.

regimesinfuture.However,thenecessaryhigherinvestmentsinfiremanagementwillundoubtedlyimpacteconomicallyoncommercialforestry.

Short,mergingtolongertermadaptationoptionsfortheforestrysectorinclude:

• Integrating climate change into forestry curricula:Thisshouldbedoneatbothschoolandpost-schoollevels.

• Ecosystems based adaptation (EbA):Thiswouldenhancebiodiversityconservation,waterconservationandoverallenvironmentalsustainability.

• Multi-objective landscape level planning and implementation: Thisshouldbeundertakenincollaborationwithothersectorssuchasbiodiversity.

• Quantifiedbaselines:Forplanningintothefuture,long-termmonitoringplots/datasetsneedtobemaintained.

• Long term research funding: Suchfundingshouldbesoughtforthesectorasawhole,butmorespecificallyformitigationandadaptationresearch.

• Diversify species production systems: Introducingnewtreespeciesandimprovedvarietieswillenhanceproductivity,quality,healthandtimbervalue,whilealsobuildingtreeresiliencetodiseases,pestsandenvironmentalstresses.

• Shift geographical location of key species to match areas of optimum potential:

51LTAS: CLIMATE CHANGE IMPLICATIONS FOR THE AGRICULTURE AND FORESTRY SECTORS

50 LTAS:CLIMATECHANGEIMPLICATIONSFORTHEAGRICULTUREANDFORESTRYSECTORS


3.5 Early warning systems, risk management and decision support tools

Earlywarningsystems,suchasseasonalandshorter-termforecastsofclimate,andinparticularofextremeevents,canbeeffectiveinenablinglandmanagerstotakeappropriateactiontominimisetheadverseimpactsofnegativeevents,whilebenefittingfrompositiveevents(DEA,2011).Climateinformationonaday-to-daybasisisvitalforfarmingoperationssuchasirrigationscheduling,timingoffertiliserapplications,in-fieldtrafficcontrol,cultivar andvariety selection, timingofplanting andharvesting, and response farming.Amajor concernis timelyearlywarningsof adverseweatherand thepossibilityofrelatedpestanddiseaseoccurrences.Timelyinformation isofparticular importance to themostvulnerablefarmersinremoteareas,oftenwithoutaccesstotheelectronicmediausedtoissueearlywarnings.BoththeSouthAfricanWeatherService(SAWS)andARC,whichmaintainstheagriculturalweatherstationsnetwork,areprovidingsuchwarningsbymeansofcellphones.Manyfoodproducersinremoteareas,farmingonmarginalland,arepronetoreducedyieldsandtheimpactsofclimatechangesuchascropfailureduetotheincreasedfrequencyofdrought,floods,andflashfloods,aswellasdiminishingsoilproductivityandlanddegradation,willaddadditionalstress(DEA,2011).

Decisionsupporttoolsshouldbedevelopedandpromotedto inform farmers in timeof climate risks includingextremetemperatures,droughtsandfloods,andtoassistfarmerswithdecisionmakingregardingcurrentandfutureagriculturaloperationsinthefaceofchangingclimate.Riskassessmentswillbeneededtoinformthedevelopmentofearlywarningsystemsandrelateddecisionsupporttools.

3.6 Integratedandsimplifiedpolicyandeffective governance systems

As a point of departure it needs emphasising thatagriculture inmanyareasofSouthAfrica is theonly primaryproducer(e.g.intheWesternCapewheretherearenomines)andthereforeinoverallstrategiestoadapttoclimatechangetheentireagriculturesector,andnotonlypartsofit,requirespecialattentionfrom:

• Integrated planning: Inadaptationstudiesthiscannotbestressedtoomuch,withjointplanningforagriculture,miningandmunicipalitiesneededformanagingwaterquantityandqualityrequirements.

• Simplifiedandunambiguouslegislation: Complexandcumbersomelegislationexists,forexample,ontaxes,minimumwages,municipalratesandAgriBEE,andpolicydecisionsareoftennotcleartofarmers,orareperceivedtobeinconsistentandevenconflicting.Tomakeadaptationtoanadditionalstressorsuchasclimatechangeeasierpolicies,legislationandregulationswillneedtobesimplifiedandunambiguousforallfarmers.

• Policy awareness: Foreasieradaptation,smallholderandsubsistencefarmersneedtobeawareofpoliciesconcerning,forexample,veldburning,overgrazing,orcontourploughing,astheydonotalwaysprioritisethembecausetheytendtochooseshorttermbenefitsoverlong-termsustainability.

• Expanded extension services: Inordertoexpediteadaptationtotheaddeduncertainties

ofclimatechangesubsistence,smallholderandcommercialfarmersneedefficientandinformativeagriculturalextensionservicestoprovideadviceandstate-of-the-artknowledgeonhowtoadaptforclimatevariabilityandchange.Theseservicesneedtobestrengthenedinnumberandcapacity.

• Expanded research services: Research on climatechangeaswellasintegratingclimatechangeintoagriculturalschoolsanduniversity/collegecurriculaisnecessary.

• Financing: Findingmeanstofinanceandtousecurrentandnewtechnologyandpractices,especiallytargetedtowardssmallscalefarmers,willbecomeimportantinstrumentsofadaptation.

• Climate sensitive land claims and land redistribution: Adaptationtoclimatechangeimpliesanexperienced,receptive,productiveandadaptivefarmingcommunity.Landreformandlandredistributionwillneedtoincorporatetheseattributestobeeffectiveunderconditionsofclimateuncertaintyinordertocurtaillossofproductionanddegradationofproductiveagriculturalareas.

• Sustainable urban expansion: Urbanexpansionisusingupvaluablehighpotentialagriculturallandwhichcanneverberecovered,inadditiontoenhancingfloodingandreducingreturnflows.Urbanexpansionshouldbesustainablymanagedbyauthoritiesinordertoaddressnationalfoodsecurityissueswithgreaterconfidenceinthefaceofrapidpopulationgrowthunderfutureclimaticconditions.



3.7 Awareness, knowledge and communication

Awarenessandknowledgeof the impactsofclimatechangeareessentialtomaketheagriculturesectorlessvulnerable,toencouragethesectortoadapttoclimatechangeand,mostimportantly,adoptasoilprotectionethosandconservationagriculturepracticesconducivetosoilandwaterconservation,minimumgreenhousegasemissions,andcarbonsequestration.Manywithinthefarmingcommunityareeithernotawareofclimatechangeanditsimpacts,orregardclimatechangeasnormalclimatevariability.Ameansofadaptation,targetedespeciallytowardssmallholderandsubsistencefarmers,wouldbetodisseminateknowledgeonandmakefinanceavailabletousealreadyestablishedpractices(e.g.soilsampling,conservationtillage),toembracenewtechnologiesandtopurchaseappropriateequipment.

There is a dire need for scientists to createmoreawarenessonpotentialclimatechange impactsnow,andtogetthemessageofthelatestavailablescienceacrosstogovernment,agri-business(e.g.seedcompanies),extensionservicesandfarmersrelatedtotheonsetofrains,numberof raindays,persistenceof raindays,enhancedrainfallvariability,theimpactsofdroughtsonlongandshortcyclecrops,andtheuncertaintiesthatremainaboutclimatechange.Ashighlightedabove,thedevelopmentandpromotionofdecisionmakingtoolsareessentialforinformingdecisionmakingintheagriculturesectoragainstthebackdropofachangingclimate.

Experienceshowsthatfarmersnotabletocopewithdisastersinthepastaretheonesleastlikelytobeabletocopewith,andadaptto,thevagariesoffutureclimates.Aclearcommunicationstrategyisthereforerequiredfor climate issues.Commercial farmers shouldhaveorganisedandoperationalnetworksofcommunication

7 Schulze, 2010; DAFF, 2013.

andinformation-sharingwithoneanother(andextensionservices)onclimaterelatedissues(e.g.duringthedrymonthstofollowoutbreaksandspreadingoffires)inordertohelponeanotherandsmallholderfarmersinsurroundingareaswhorequirementoring.Anincreaseincommunicationandtrustshouldbebuiltupbetweenauthorities and all farming sectors (commercial,smallholderandsubsistence)todisseminateasmuchrelevantknowledgeaspossibleonclimatechangeinordertoimplementadaptationstrategies.Forthis,humanandeconomicresourcesneedtobemadeavailable.

SouthAfricanfarmerswithexportcropsneedtoknowmoreabouttheircompetitors(e.g.AustraliaandSouthAmericainthecaseofdeciduousfruit;Brazilinthecaseof sugarcane)andhowglobalwarmingmightchangetheircompetitiveedge.Thereis,therefore,aneedformarketprojectionsintothefutureinordertoadapt.Agriculturalsubsidiesindevelopedcountriesimplythatitisoftencheapertoimportthantoproducelocally.Thepotentialrepercussionsofchangingclimatemightpromptgovernmenttoreconsiderwaysofsubsidisingkeyagriculturalcommoditiesasanadaptationmeasure.Where the market is changing (e.g. from dairy tosugarcane),theimpactsofprojectedclimatechangeneedtobeconsideredintheinterestsofindividualfarmersandthenation.

beingobserved;numberofraindaysandfuturechangestotheminthegrowingseason;andwhethertherainyseasonwillstartearlierorlaterandhowlongitwilllast.

4.1.1 CO2 fertilisation effect

AbetterunderstandingoftheCo2 fertilisation effect is required,withitsanticipatedeffectofenhancinggrowththroughincreasedphotosynthesisasaresultofhigheratmospheric CO2 concentrations and reductions intranspiration,howthesechangeswillinteractwithcropcoverandplantwaterstress,andtheacclimationeffectsforannualversusperennialcrops.

4.1.2 Changing population dynamics of grazing lands

This is pertinent especially for natural vegetationandwhereentireecosystemsmaysufferdegradationor collapse.

4.1.3 C3/C4 grassland dynamics

C3andC4grassspeciesgenerallyoccurwithinthesameareaandsharethesameresources.However,C4grassphotosyntheticratesfavourwarmerregionscomparedtoC3grasses.Furthermorethetallandhorizontalgrowthfrom theC4 grassesholds a competitive expansion/invasiveadvantageovertheshorter,slowergrowthC3 grassesinregardtolight.C3andC4grasslanddynamicsneedtobebetterunderstoodintermsoftheirimpactonthecarryingcapacityofgrasslandsforlivestockandgame.

4.1.4 Grassland/woody species dynamics

Improved understanding is required on grasslandsbecoming woodier with further atmospheric CO2 enrichment, andon fires favouring theexpansionofgrasslands(bothC3andC4).Morescientificunderstanding

4. RESEARCH REqUIREMENTS7

Itiscriticalfortheagriculturesectortoconductaholisticassessmentoffutureresearchneedsonclimatechangeimpactsandadaptation.Suchanassessmentcouldusefullydistinguishneedsacrossarangeofscalesofimplementation(i.e.fromnationalandregionalgovernanceissuesthroughtolocalneeds)forspecificagriculturalactivitiesconductedinavarietyofcommercialandnon-commercialcontexts.Withoutsuchanassessmentitisnotcurrentlypossibletodevelopapracticalandprioritisedlistofresearchneedsforthissector.Intheabsenceofthisassessment,specificscience-relatedresearchneedsandgeneralconsiderationsarepresentedbelow.

4.1 Climate forecasts and climate change uncertainties

Ifclimatevariabilityincreasesasprojected,itwillbevitalforfarmerstouseandtrustclimateforecasts(dailytoseasonal)tomakeadaptationplanstocounterclimatevariability.Thefactthatpoorerfarmerscurrentlyderivefewbenefitsfromforecastsmaybeattributedtotheirnothavingenoughresourcestoactontheforecastsandthiswillneedtoberectified.

Forfarmerstomakeandimplementadaptationplans,thereisaneedforscientificinsightstobecombinedwithindigenousknowledgeandexperiencestocontinuallyimproveanswersonthewhen,where,howmuch,whatimpact,andhowtoadapttoclimatechange,includingreducinguncertaintieson,interalia,enhancedrainfallvariabilityanditsimpactsoncropproduction;multipleyeardroughtsand longcyclecropswithplantcyclesof10–30years(suchascommercialtimberspeciesordeciduousfruittrees)wheresuccessivedroughtsyearsarecriticaltothesurvivalofthetrees;persistenceofraindaysinregardtochangesinwet/wet,wet/dry,dry/dryordry/wetsequences,orthefewerlongduration,multipledaygentlerainsinthewinterrainfallregionwhichare


4.ResearchRequirements

isalsoneededon,forexample,alieninvasivegrassspecies,weedinfestationsingrassland,andC3/C4 grasslandsandfiredynamics.

4.1.5 Livestock animal health

This isan issuewherescienceneedstoaddresshowchangesinrainfallandtemperaturewillimpactonanimalhealthwithchangesinthedistribution,competenceandabundanceofvectorsandectoparasites.Atpresent,theresearchintotheeffectsofclimatechangeonthespreadandboundariesofparticularanimaldiseasesandparasitesislimitedtobasicestimations.Thisisdespitethepotentially largeeffectsoncosts(protectionandtreatmentcosts)andmanagement.

4.1.6 Changing pest/disease distributions

Improved science includes better understanding ofthe likelihood ofmore pest attackswith significantrepercussions;likelychangesinthedistributionofplantandanimaldiseasesand insects,andthedynamicsofinsectpestsanddiseasecomplexes;thepossibilityofnewpestspossiblyemergingandofotherpestsexpandingtheirrangesorincreasingtheintensityofoutbreaks;andbiologicalcontrolagents/predatorscurrentlyeffectiveincontrollingagriculturalpestswhichmaylosetheirefficacy.

4.1.7 Weed control

Furtherunderstandingisrequiredonweedsashosts,i.e.wheredifferentcrop/grassspecieshostdifferentinsects,pestsanddiseases;andthepossibilityofincreasedcostsofweedcontrolduetoalieninvasiveplants.Indigenousweeds are expected to rapidly adapt to changingclimateconditions.

4.1.8 Plant breeding

Geneticistsneedtobreedmoredrought/heatresistantvarietiesof,forexampledeciduousfruits,withmorerapidlyrespondingphenologiesandrequiringlowerpositivechillunits.Developmentandbreedingofnewvarietiesshouldbedonenowbecausedeciduousfruitspecies,forexample,havelongresponsetimes.

4.1.9 Plant needs

Waterrequirements,pHandfertiliserrequirementsofplantsamongotherthingsneedtobere-examined.

4.1.10 Sizing and safety of dams

Existingdamsweredimensionedforsizeandsafetyonhistoricalhydrologicalrecords.Theywillnotnecessarilybeabletodealwithfutureclimaticconditions(e.g.increasedfloods;orlesswater).Climatechangeneedstobetakenintoaccountwhenassessingthesafetyofcurrentdamsandinthedesignofnewstructures.

4.2 General considerationsTheinteractionbetweenresearchandpolicyneedstobestrengthenedintheagriculturesector(DAFF,2010)throughsignificantcapacitybuilding.Thiswill facilitateeffectiveadaptation planning and implementation. Agriculturalresilienceisaboutretainingorimprovingthecapacityofagriculturalsystemstoprovideagriculturalgoodsandservicesdespiteclimaterisks.Byimplicationitincludesthefollowing:

• Promotingclimate-resilientruraldevelopmentplanningtoaddressjobcreation,foodsecurity,sustainablelivelihoodsandtocontributetobiodiversity.

• Usingtheresultsofvulnerabilityandriskstudiestodevelopshort-,medium-andlong-termadaptationscenariostoidentifyclimate-resilientlanduses.

• Investinginandimprovingresearchintowater,nutrientandsoilconservationtechnologiesandtechniques;post-harvesttechnologies;coolingtechnologiesinthefruitindustryandforfoodstorage;climate-resistantcrops,livestock,pasturesandplantationsincludingsuitablecrossbreedingprogrammestosupportadaptation(heatstress,droughttolerance,diseaseresistance);agriculturalproduction;ownershipandfinancingmodelstopromotethedevelopmentof“climate-smartagriculture”thatlowersagriculturalemissions,ismoreresilienttoclimatechanges,andboostsagriculturalyields.

• Usingearlywarningsystemstogivetimelywarningsofadverseweatherandpossiblerelatedpestsanddiseaseoccurrence.

• Developingandpromotingdecisionsupporttoolstoassistfarmersinmakingappropriatedecisionsonfarmingoperationsandadaptationoptionsunderachangingclimateandtoinformfarmersofactionsneededtorespondtoclimaterisks.

• Investingineducationandawarenessprogrammesinruralareasandlinkingthesetoagriculturalextensionactivities.

Futureagricultureadaptationisallaboutbeingprogressiveandactingtooptimisechangingclimaticconditionsinordertomaximiseoutputinasustainablemannerandmaintainacompetitiveedge.AdaptingtoclimatechangeattherurallivelihoodscalewillbecriticallyimportantintheSouthAfricancontext,withafocusonthemostvulnerablegroups,andthemostvulnerableareasnecessarytoensurethatlivelihoodsarenoterodedbyclimateeventsandaffectedcommunitiesbecomemoreresilienttoprojectedchanges.Thisrequiresanintegratedapproachaddressingmultiplesectors,combining indigenousknowledgeofvulnerablegroupswiththelatestscientificinsights.

Most agricultural programmes are initiated at highlevels ingovernmentandarenotalwaysadapted tolocal conditions.All agricultural planning strategiesneedtofocusonlocalconditions,especiallyinregardtoclimatechangewhichcanhaveveryspecific localrepercussions. In order to adapt to local climaticconditionssoilsuitabilitystudiesneedtobeundertakenpriortofuturelandusechangeandlandusedecisions.Soilswillthenneedtobeusedinaccordancewithlocalpropertiesandinconjunctionwithprojectedclimaticregimes,e.g.shallowsoilsresultinginhighsurfacerunoffwillneedprotection.Soilanalysesshouldbelinkedtoadaptationdecisionsupportsystemstoassistfarmerstoincreasetheresilienceofagriculturaloperationsunderachangingclimate.

Climatechangeadaptationmeasuresintheagriculturesectorshouldconsiderimpactsonothersectorsandensurethatanyoftheactionsoutlinedabovedonothavenegativeimplicationsforthesustainabilityofothersectors.Thereareissuesincludingpotentialbiodiversitylossand/orsocial implicationsthatneedtobetakenintoconsiderationbeforeadaptationmeasurescanbeimplemented(DAFF,2010).Forexample,beforenewafforestationtakesplace, itshouldbeborne inmindthat forestsgenerallyuserelatively largeamountsofwater inacatchmentandundertheNationalWaterAct,No.36of1998plantationforestsarea“streamflowreductionactivity”andneedtobelicensedgiventhatmanySouthAfricancatchmentsarealreadywaterstressed.Furthermore,beforeanynewafforestationtakesplace,considerationhastobegiventocompetitionforsuitablelandfromother,eithermoreprofitableorsociallydesirable,landusessuchascropping,bearinginmindthatnationalandhouseholdfoodsecurityisapriorityinSouthAfrica.


5.Conclusion

5. CONCLUSION

Impacts of climate change on food production,agriculturallivelihoodsandfoodsecurityinSouthAfricaaresignificantnationalpolicyconcerns,andarealsolikelytohaveimplicationsbeyondthecountry’sborders.Overall,manyagriculturalsub-sectorsaresensitivetoprojectedclimatechange.CertaincropsinSouthAfricaaremoreresilienttoclimatechange,whileothersaremoresensitive.Similarly,climatechange impacts forsomecropsareprojectedwithmoreconfidencethanforothers.Additionally,muchofthefoodproductionandfoodsecuritywhichmaybeatriskislinkedtofutureprojectedwatersupplyconstraints,declinesinwaterqualityandcompetitionfromnon-agriculturalsectors.There is evidence that smallholder and subsistencedrylandfarmersaremorevulnerabletoclimatechangethancommercial farmers,while large-scale irrigatedproductionisprobablyleastvulnerabletoclimatechange,conditionaluponsufficientwatersupplyforirrigationbeingavailable(Schulze,2010;DAFF,2013).

Potential adaptation responses in the agriculturesectorrangefromnationallevelstrategiesthatincludecapacitybuildinginkeyresearchareas,extension,andconsiderationofwaterresourceallocation,allthewayto the local levelwhere responsesmay be specificto productionmethods and local conditions. Localadaptationoptionsthemselveswillbeuniquetotheverywidevarietyofagriculturalpracticesinlargescalecommercial,smallholderandsubsistenceagriculture.

These,however,needtobeeffectivelycommunicatedtofarmersandinmostcasestrainingandextensionservicesarerequired.Expandedresearchservicesonclimatechangeaswellasintegratingclimatechangeadaptationintoschool,collegeanduniversitycurriculawillassistin this process.

Irrigation agriculture is the largest single surfacewateruserinthecountry.Thisdependenceonwaterrepresentsasignificantcurrentvulnerabilityforalmostallagriculturalactivities.Adaptationplanswouldbenefitbyconsideringwatercurtailmentstoirrigatorsintimesofdrought,inthelightoffoodsecurityandconditionaluponirrigatorsusingwaterefficiently.Waterpricingincentiveswouldneedconsiderationinthecontextofissuesofnationalfoodsecurity,andtheexportvalueandforeignearningspotentialofcrops.Thesocio-economicimplicationsoftrade-offscenariosunderplausiblefutureclimatesneedtobeinvestigatedtoinformkeydecisionsin development and adaptation planning to reduceimpactsonthemostvulnerablecommunitiesandgroups.The LTAS Phase 2 process has the potential to assess largescaleadaptationresponsesrelating,forexample,towaterallocation,however,itwillnotaddressfinerscaleadaptationresponseoptions.Thereisthereforeaneedtoexplorethe feasibilityofanapproachthatwouldassessactivity-specificoptions,thelevelatwhichthiscouldbeproductivelytackled,andforwhichagriculturalsub-sectors.

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Notes

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Notes

When making reference to this technical report, please cite as follows: DEA (Department of Environmental Affairs). 2013. Long-Term Adaptation Scenarios Flagship Research Programme (LTAS) for South Africa. Climate Change Implications for the Agriculture and Forestry Sectors in South Africa. Pretoria, South Africa.

NOTES

66 LTAS: CLIMATE CHANGE IMPLICATIONS FOR THE AGRICULTURE AND FORESTRY SECTORS

LONG TERM ADAPTATION SCENARIOSTOGETHER DEVELOPING ADAPTATION RESPONSES FOR FUTURE CLIMATES

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