Desertification, and climate change the case for greater convergence

GREATERCONVERGENCE

ALANGRAINGER1,∗,MARKSTAFFORDSMITH2,VICTORR.SQUIRES3and

EDWARDP.GLENN4

2CSIRONationalRangelandsProgramme,POBox2111,AliceSprings,NT0871,Australia

3DrylandManagementConsultant,POBox31,Magill,SA5072,Australia

4EnvironmentalResearchLaboratory,UniversityofArizona,Tucson,AZ85706-6985,USA

(∗Authorforcorrespondence)

1SchoolofGeography,UniversityofLeeds,LeedsLS29JT,UK

(Received7February2000;acceptedinfinalform5September2000)

Abstract.PoorknowledgeoflinksbetweendesertificationandglobalclimatechangeislimitingfundingfromtheGlobalEnvironmentFacilityforanti-desertificationprojectsandrealizationofsynergiesbetweentheConventiontoCombatDesertification(CCD)andtheFrameworkConventiononClimateChange(FCCC).Greaterconvergencebetweenresearchinthetwofieldscouldovercometheselimitations,improveourknowledgeofdesertification,andbenefitfourareasofglobalclimatechangestudies:mitigationassessment;accountingforlandcoverchangeinthecarbonbudget;landsurface-atmosphereinteractions;andclimatechangeimpactforecasting.Convergencewouldbeas-sistedifdesertificationweretreatedmoreasaspecialcaseindryareasoftheglobalprocessoflanddegradation,andstimulatedby:(a)closercooperationbetweentheFCCCandCCD;(b)betterinformalnetworkingbetweendesertificationandglobalclimatechangescientists,e.g.withintheframeworkoftheIntergovernmentalPanelonClimateChange(IPCC).BothstrategieswouldbefacilitatediftheFCCCandCCDrequestedtheIPCCtoprovideascientificframeworkforrealizingthesynergiesbetweenthem.

Keywords:carbonbudget,climatechange,desertification,internationalenvironmentalinstitutions,landdegradation,researchconvergence,sciencepolicy

1.Introduction

Desertification,theprocessoflanddegradationindryareas,isthe‘Cinderella’ofglobalenvironmentalchange.Itpotentiallyaffects40%oftheEarth’ssurfaceand32%ofthehumanpopulation(UNEP1997)and,likeglobalclimatechange,isthesubjectofaninternationalframeworkconvention.Yetwhilethelatterhasbeenthefocusofanunprecedentedandcontinuinginternationalresearcheffort(Watsonetal.1996)onlyarelativelysmallamountofeffortandfundshavebeendevotedtodesertificationresearch.Consequently,ourunderstandingofthephenomenon,anddataonitsextentandrateofchange,arebothlimited.Thisisparticularlyunfortu-nateastheimpressiveprogrammeofresearchcommissionedbytheUnitedNationsEnvironmentProgramme(UNEP)priortotheUNConferenceonDesertification(UNCOD)in1977setabenchmarkfortheroleofscienceinUNconferences.

MitigationandAdaptationStrategiesforGlobalChange5:361–377,2000.©2000KluwerAcademicPublishers.PrintedintheNetherlands.

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Thechroniclackofdataondesertificationhasevencausedsometoderideitasamyth(Binns1990),andpoorknowledgeofitslinkswithglobalclimatechangehasbecomeamajorobstacletoexploitingsynergiesbetweentheFrameworkCon-ventiononClimateChangeandtheConventiontoCombatDesertification(SCCD1999a).Inthispaperwearguethatgreaterconvergencebetweenresearchintodesertificationandglobalclimatechangewouldovercomethisobstacleandleadtobetterknowledgeofdesertificationaswell.Thepaperhastwomainparts.Partonedefinesdesertificationandsuggestshowitcouldbeincorporatedintotheoverallframeworkofglobalclimatechangeresearch,byviewingitaspartofthewiderphenomenonoflanddegradation.Parttwoassessestheprospectsforpromotingresearchconvergence.

2.DesertificationasDegradation

DesertificationwasdefinedinthepreambletotheConventiontoCombatDeser-tification(CCD)(UNEP1995)as‘landdegradationinarid,semi-aridanddrysub-humidareasresultingfromvariousfactors,includingclimaticvariationsandhumanactivities’.Ithastwomaincomponents,vegetationdegradationandsoildegradation,causedbyovercultivation,overgrazing,reductionintreecover,andpoorirrigationmanagement.Itvariesindegreefromslighttosevere,isgenerallyreversibleuntillandiseventuallyturnedintodesert,andcanoccuranywhereindryareasandnotjustondesertfringes(Grainger1990a).

Onereasonwhydesertificationhasbecomemarginalizedisdisagreementoverhowitis,orshouldbe,defined.UNCODspecificallyrefutedtheideathatdeserti-ficationprincipallyinvolvesthespreadingofdeserts,thoughsomepeoplestilldonotacceptthisandsoquestionitsexistencewhenevidenceofadvancingdesertsisnotfound(Pearce1994).Othersjustdisliketheterm‘desertification’andwanttorestrictittodescribinganirreversibletransformationoflandintodesert(Nelson1988;WarrenandAgnew1987;Mainguet1991).Alternativetermshavebeenusedtodescribethisorsimilarphenomenainthepast(Verstraete1986),butdesertifica-tionhasnowbecometheestablishedtermbyvirtueofitsbeingincludedinthetitleofaninternationalconvention.

Vegetationandsoilaredegradedallovertheworld,andifdesertificationwereregardedmoreasaspecialcaseindryareasoftheglobalprocessoflanddegrad-ation,andlessinisolationfromotheraspectsofglobalenvironmentalchange,thismightassuagethescepticsandprovideastrongerscientificframeworkfordesertificationresearch.Vegetationdegradationinvolvesatemporaryorpermanentreductioninthedensity,structure,speciescompositionorproductivityofvegeta-tioncover(Grainger1996a),andaffectscroplandandrangelandaswellasforests.Thus,incontrasttothetotalclearanceofforestwhichconstitutesdeforestation,forestcouldbedegradedbyreducingthenumberoftreesinanareaortheaver-agebiomassdensitypertreeetc.Soilisdegradedbywatererosion,winderosion,

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compaction,waterlogging,salinizationandotherformsofchemicalandphysicaldeterioration.Bothtypesofdegradationappearattheirmostextremeindryareas,wheretheyarecloselylinkedtogether.

DesertificationhasbeenrecognizedsinceUNCODasalong-termtrendinlanddegradationbut,incommonwithdegradationinotherpartsoftheworld,identify-ingthistrendismadedifficultbyshort-termfluctuations.Degradingimpactsareoftenoffsetbysubsequentregeneration,thoughwhetherthisfullycompensatesfortheinitiallossdependsontheintensityandlengthoftheimpact.Vegetationgrowthgenerallydeclinesduringaperiodofdrought,whichisusuallyarelativelyshort-termfallinprecipitationfromthelong-termaverage,andnormallyrecoverswhenthedroughtends.Butsincehumanbeingsoftenrespondtothelowervegetationgrowthbyoverusingtheland,droughtcanbecomeacontributingcauseofdeser-tificationbyacceleratingthelong-termtrendindegradationcausedbypreviousoveruse(Grainger1990a).

3.IntegratingDesertificationintoClimateChangeResearch

Desertificationcouldbeincorporatedintofourmajorcategoriesofglobalclimatechangeresearch:mitigationassessment;accountingforlandcoverchangeinthecarbonbudget;landsurface-atmosphereinteractions;andclimatechangeimpactforecasting.3.1.SUITABILITY

OFDEGRADEDLANDFORCLIMATECHANGEMITIGATION

Desertificationisalreadyintegraltoassessmentsofthepotentialformitigatingglobalclimatechangebyrestoringdegradedlandstosequestersurpluscarbonfromtheatmosphere(Watsonetal.1996).TheFrameworkConventiononCli-mateChangeprovidedforapilotphaseofJointImplementationforestryprojectsindevelopingcountriesfundedbydevelopedcountries,andtherearenewinitiat-ivestoextendthisaspartoftheCleanDevelopmentMechanismincludedintheKyotoProtocol(e.g.WorldBank1998),thoughtheirimplementationislikelytobeaffectedbypoliticalcontroversy(TrexlerandKosloff1998).

Overhalfthedegradedtropicallandsarepotentiallyindryareas(Grainger1990b).AccordingtoaUNEPworkshopabout1.0GtCyr−1couldbesequesteredbyrestoringthem,atacostof$10-$20t−1C(Anon1995;Squiresetal.1997).Laletal.(1999)gaveahighermeanfigureof1.4GtCyr−1,ormorethan40%ofthetotalannualriseinatmosphericcarbondioxideconcentration(TableI).Besidestheadditionalcarbonsequesteredinthevegetationandsoilthisalsoallowedforthereductionsincarbonemissionsfromsoilerosionandtheuseoffossilfuels(sub-stitutedbybiomassfuels).Bothestimateswerestatedtobeveryapproximate,notleastbecausetheyreliedonhighlyinaccurateestimatesoftheextentandseverityofdesertification(Squires1998).

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TABLEI

Potentialofdesertificationcontrolandlandrestorationtosequestercarbon(GtCyr−1).Process

Emissionreductionthrougherosioncontrol

RestorationoferodedlandsRestorationofphysically

andchemicallydegradedsoilsReclamationofsalt-affectedsoilsAgriculturalintensificationonundegradedsoils

FossilfuelCoffsetthroughbiofuelproduction

SequestrationassecondarycarbonatesTotal

Source:Laletal.(1999).

TABLEII

Distributionofdesertifiedlands(ha.106).

Landsaffectedbysoildegradation

AfricaAsiaAustraliaEurope

NorthandCentralAmericaSouthAmericaTotal

319.3370.487.699.579.379.11035.2

Rangelandswithdegradedvegetation

nananananana2559

Range0.2–0.30.2–0.3<0.010.2–0.40.01–0.020.3–0.50.01–0.40.9–1.9

Mean0.250.25<0.010.30.0150.40.21.4

%oftotalpotential

1818–21–2914100

Source:UNEP(1997).NB.Datanotavailable.

Theshortageofreliablenationalandglobaldataontheextentandrateofchangeofdesertificationhasbeenapersistentproblemsincethe1970s(Dregne1985).Itresultsfrombothalimitedmonitoringeffortandinadequatemonitoringprocedures,andcontrastswiththewealthoflocalizedevidenceofwidespreadandsubstantialdrylanddegradation,e.g.inEastAfrica(Mung’ong’o1991;Stahl1993),Australia(StateofEnvironmentAdvisoryCouncil1996),China(Sheehy

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1992),andtheUSA(CommitteeonRangelandClassification1994).UNEP’smostrecentglobalestimateoftheareaofsusceptibledrylandsufferingfromdesertific-ation,includedinthesecondeditionofitsWorldAtlasofDesertification,is3.6billionha.Thisincludes1billionhaofdrylandsufferingfromsoildegradation,mainlycausedbyovergrazing,overcroppinganddeforestation,andanother2.6billionhaofrangelandwithdegradedvegetation(TableII)(UNEP1997),andisessentiallythesameastheestimateinthefirsteditionoftheAtlas(UNEP1992).Anexternalreviewclaimedthattheaccuracyofthelatterwaslimitedby(a)con-siderablesubjectivity,whichmeantthatobservationswerenotrepeatable;(b)lackofresolution,whichmadecomparisonsovertimeimpossible;and(c)theuseofsampledataunrepresentativeoflargerareas(UNEP1994).Giventhisinaccuracy,estimatesoftheannualrateofdesertification,whichhadpreviouslybeenashighas27.0millionhayr−1(UNEP1987),arenotverymeaningfulandnonewereincludedintheAtlas.

Thesubjectivityofestimatesreflectsageneralreadinessintheearlystagesofglobalchangeresearchtoacceptthatdatacollectionneednotmeetthesamehighstandardsrequiredforotherbranchesofscience(Simonet19).Fortunately,thesituationisnowchanging(BauliesandSzejwach1998).Forwantofanythingbetter,UNEPtraditionallybaseditsdesertificationestimatesonsubjectiveassess-mentsbyasmallgroupofexperts,insteadofremotesensingandgrounddata.ThisremainedthecasewiththeestimatesofsoildegradationincludedinUNEP(1997),thoughtheapproachwasmorestructuredthanbeforeandinvolvedmoreexperts(Thomas1993).ThesameusedtobetrueofUNestimatesoftropicalforestareasanddeforestationrates,thoughdeforestationiseasiertomonitorbyremotesensingtechniquesandtheirusehasgraduallyincreased(Grainger1996b).ASwedishAgencyforResearchCooperationwithDevelopingCountriesworkshopatOrenasin1990concludedthatdesertificationdatawouldnotimproveunlessexpertas-sessmentswerereplacedbyaglobalmonitoringsystemthatcollectedprimarydata(Helldén1991).Thiswould,ofcourse,requiretheuseofsampling.Althoughthereiscontinualinnovationintheanalysisofsatelliteimagesofdryareas(e.g.Kumaretal.1997),certainfundamentalproblemsremain,e.g.thoserelatedtotherespectivereflectancesofsoilandthesparsevegetationcover(Tueller1987).

Nomonitoringsystemwillbeeffectiveifitsresolutionisinappropriatetothephenomenonbeingobserved.Theresolutionofsatelliteremotesensingtechniqueshassofarbeentoolowtomonitordesertificationeffectivelyonalargescale.Deser-tificationisaspatiallycomplex,fine-grainedphenomenonthatmainlyconsistsofdispersed,patch-likedegradation,notthefrontierexpansionofdesertfringesofpopularimagination.AUNEPexpertpanelhascalledfortheuseofhighresolutionremotesensingdatatoproduce‘geographicallyexplicitandpreciseassessmentsofdrylandresources’(UNEP1994).

Thesedifficultiesareexacerbatedbythelackofanagreedsetofdesertificationindicators.Someexpertsarguethatphysicalindicatorsofsoilandvegetationde-gradationaresufficient;othersgofurtherandclaimthatonlysoildegradationcan

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showalongtermdeclineinpotentiallandproductivity,asvegetationdegradationiseasilyreversed(ThomasandMiddleton1994).ThiswasthegeneralapproachtakenbyUNEP(1997),whichwasalmostexclusivelyconcernedwithsoildegradation.Ithasalsobeensuggestedthatphysicalindicatorsshouldbecomplementedbysocio-economicandagriculturalindicators,butthiscouldleadtodifficulties,e.g.studiesinSudanfoundthatonly10–15%ofthefallincropyieldsinadrought-proneareawasduetolanddegradation,withtherestexplainedbyclimaticvariation(Olsson1993).Thefirstsetsofdesertificationindicatorswereproposedovertwentyyearsago(BerryandFord1977;Reining1978).Othershavebeenputforwardsincethen(Mabbutt1986),butUNEPstillhadtodecideonwhichsettousebythetimetheCCDcameintoforce(Cardy1995).In1999theCCD’sCommitteeonScienceandTechnologycirculatedadraftsetofindicatorsandbenchmarkstogovernmentssotheycouldassessitsfeasibilityforuseinpreparingnationalreports(SCCD1999b).Ofcourse,onceaproperglobalmonitoringsystemwasinplace,apragmaticdecisiononthechoiceofindicatorswouldhavetobetakentomakethesystemoperational.3.2.THE

ROLEOFLANDDEGRADATIONINTHECARBONBUDGET

Incontrasttoitskeeninterestintheareaofdesertifiedlandsuitableforcarbonsequestration,theclimatechangecommunityhasbeenmuchlessconcernedwiththeactualdegradationoftheselandsandthecontributionthismakestogreenhousegasemissions.Thisreflectsageneralneglectoflanddegradationasawhole.Grossannualcarbonemissionsfromdeforestationandotherlandusechange(1.6±0.8GtCyr−1)arecurrentlyonlyaquarterofthosefromfossilfuelcombustionandcementproduction(6.3±0.6GtCyr−1).Yetthebiotaandsoilarealsoimportantsinksandthereisanassumednetterrestrialuptakeof2.3GtCyr−1(IPCC2000a).However,thesizesofspecificterrestrialfluxesarestilluncertain,andpoorknow-ledgeofthecomplexbalancebetweencarbonemissionsanduptakeondegradedlandscontributestothis.

Theneedtoaccountforthecontributionoflanddegradationtogreenhousegasemissionshasbeenrecognizedforsometime(Grahametal.1990;Grainger1991),butsofarithasreceivedlessscientificattentionthandeforestationinlandcoverchangestudies,andintheKyotoProtocoltoo.Deforestation,afforestationandreforestationtogetherdoprovideagoodapproximationtothelandcoverchangeprocessesinmostdevelopedcountries(withthenotableexceptionofAustralia).Butthesituationismorecomplicatedindevelopingcountries,wheretheerrorinvolvedinignoringlanddegradationisalsomoreimportantbecausecarbonemis-sionsfromlandcoverchangeaccountforamuchhigherproportionoftotalcarbonemissions(WorldResourcesInstitute1996).Sogivingmoreattentiontodegrad-ationincarbonaccountingisjustifiedbytheneedforcomprehensivenessandpoliticalinclusivity.

TABLEIII

Comparisonofdeforestationandforestdegradation,shownbyachangematrixfor31sampleareasinAfrica1980–1990(ha.103)

Statein1980Classesin1990Classes

Area

ClosedOpenLongFrag-ShortShrubs

OtherWater

Plant-Forest

Forest

Fallow

mentedFallowLandations

ForestCoverClosedForest18319.316781382.182.6291.8524.39.5247.5––OpenForest11021.823.61004948.3371.2117.812.7397.30.11.4LongFallow665.47.714.6556.81.651.74.428.5––Fragmented8461.124.140.01.08088.85.87.7293.5––Forest

ShortFallow2338.67.610.99.62.122.8–53.30.4–Shrubs

4055.10.810.8–1.1–3877.91.30.1–Otherlandcover26752.816.938.211.063.134.386.625251.2–Water

3045.90.5––0.53.20.181.52960.1–Plantations5.3––––0.4–0.4–4.6Areain199074665.2

18863

106

709.2

8820.2

2992.4

3999.0

27718

3011.9

6.0

Source:FAO(1993).

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ALANGRAINGERETAL.

Themagnitudeofdegradationintropicalforestsgenerallyisindicatedbyachangematrixbasedon31samplesinSub-SaharanAfrica(TableIII),thoughthisonlyprovidesdataonareasandnotbiomass(FAO1993).Between1980and19907.0%ofallclosedforestwasconvertedtosomeformofdegradedforest,comparedwithonly1.4%deforestedandconvertedtoanothertypeoflandcover.Openforest(orsavannawoodland)isthemoretypicalforestcoverindryareasandaccountsfor69%ofAfrica’stotalforestarea(Lanly1981).Some5.0%ofopenforestinthestudywasdegraded,comparedwiththe3.6%convertedtoanothertypeoflandcover.Ifthiswasarepresentativesamplethentheerrorinvolvedinbasingestimatesofcarbonemissionsfromlandcoverchangeinforestedareasondeforestationes-timatesalonecouldbeconsiderable.Althoughindirectmethodshavebeendevisedtocompensateforthelackofdataonforestdegradation(BrownandGaston1995),theyarenosubstituteforaproperprogrammetomonitorthecontributionofallvegetationdegradationtoglobalclimatechange.Newtechniquesandactivitiestomonitordesertificationcouldbedevelopedaspartofsuchaprogramme.

Vegetationchangeinthedrytropicsmakesamuchlowercontributiontooverallcarbonemissionsthanitdoesinthehumidtropics.Estimatesareveryinaccurate,butcarbonemissionsfromdeforestationinthedrytropicsin1980(therewerenodataonthedegradationofforestandothervegetation)wereestimatedatonly0.10GtCyr−1,comparedwithupto0.70GtCyr−1forclosedforestsinthehumidtropics(Grainger1990c).Monitoringismadedifficultbythemaskingoflong-termtrendsbyshort-termvariations.AsdesertificationdataweresparseatthetimeofUNCOD,UNEPpublicizedtheresultsofanaerialandgroundsurvey(Lamprey1975)thatseemedtogiveevidenceofanadvancingdesertfrontinSudan’sKordo-fanprovince.ThiswaslaterchallengedbyHelldén(1991),whoseremote-sensingstudiesoftheareafoundnoevidenceofchangesinvegetationcoverthatcouldnotbeexplainedbyshort-termclimaticvariation.WhenlowresolutionAdvancedHighResolutionRadiometer(AVHRR)satelliteimageryoftheentireSahelshowedalarge-scalecyclicalspatialvariationinbiomassproductioninthe1980sthatcouldbelinkedtochangesingrowingseasonrainfall(TuckerandChoudhury1987;Tuckeretal.1991),scepticsconcludedthatwhathadbeenregardedasdeserti-ficationwasjustpartofashort-termfluctuation(albeitaratherextendedoneinthiscase).Butremotesensingstudiesneedgoodsupportfromground-truthdata,andmisleadingconclusionscanbedrawnifsuchdataareobtainedusingapoorsamplingdesign(Pickup19).Ironically,questionsaboutgroundtruthdataandthechoiceofchangedetectionperiodlaterputHelldén’sownfindingsindoubt(Stiles1995).Separatinglong-termtrendsfromshort-termvariationinremote-sensingstudiesofdryareasisdifficultbutpossible(Bastinetal.1993,1995)andwouldundoubtedlyshowlong-termhuman-inducedchangesinsomeregions.Indryareassoildegradationistheleadingsourceofcarbonemissionsfromlandcoverchange,andcouldbeashighas0.227–0.292GtCyr−1(TableIV)(Laletal.1999).Drylandsoilscontainlargerstocksofcarbonthanthevegetationwhichcoversthem:inhyper-arid,aridandsemi-aridzonesthemeanratiobetweencarbon

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TABLEIV

Carbonemissionsfromsoildegradationindryareas.Degreeofdegradation

Totalareaaffectedbywindandwatererosion

(ha.106)

372.3423.997.06.6–

Cemissionstoatmosphere(GtC.yr−1)0.08–0.100.11–0.140.015–0.020.0015–0.0020.02–0.03

SlightModerateStrongExtremeExposureofCalciferousHorizonTotal

Source:Laletal.(1999).

0.227–0.292

TABLEV

Globalcarbonstocksinvegetationandsoilcarbonpoolsdowntoadepthof1m.Biome-Type

Area(ha.109)1.761.041.372.251.2.550.950.351.615.12

Carbonstocks(GtC)VegetationSoilTotal212

598866986153466

21610047122951911212251282011

4281595593303041991272401312477

Carbondensities(tC/ha)VegetationSoil121

5729723231

12396344117232127380133

TropicalforestsTemperateforestsBorealforestsTropicalsavannasTemperategrasslandsDesertsandsemi-desertsTundraWetlandsCroplandsTotal

Source:IPCC(2000a).

stocksinsoilandthoseinvegetationisabout20/1,comparedwith1/1intropicalmoistforests(TableV)(IPCC2000a).Theratioislowerinsub-humidsavannas,whicharealsoaffectedbydesertification.3.3.LAND

SURFACE-ATMOSPHEREINTERACTIONS

Studiesofdesertificationcouldalsoimproveourknowledgeoflandsurface-at-mosphereinteractions,theimportanceofwhichhasbeenappreciatedforsome

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time(Verstraete19).Althoughtheroleofdroughtincatalyzingdesertificationiswellunderstood(Grainger1990a)muchmoreneedstobelearnedaboutotherpossiblelinksbetweendesertificationandclimate(WilliamsandBalling1996).Desertificationisknowntochangethermalprocesses,e.g.byaffectingthealbedo(Lyonsetal.1993),andoneexplanationproposedfortheprolongeddroughtintheSahelinthe1970sand1980swasbiogeophysicalfeedback,inwhichdroughtledtoreducedvegetationcover,promptingoverexploitationbyhumansandanim-als,whichfedbackthroughalbedochangestoreducerainfall,leadinginturntoincreasedexploitationetc.(Charneyetal.1975).However,therewasnoconclus-iveproofofthis,norofothersuggestionsthatthedroughtwascausedbyglobalclimatechange,andvariationinsea-surfacetemperaturesseemedtoofferamoreconvincingexplanation(Hulme1992).Thepresentconsensus,basedonempiricalandmodellingstudies,isthatthemainimpactsofdesertificationonclimateareatlocalandregionallevels(WilliamsandBalling1996).3.4.IMPACTS

OFGLOBALCLIMATECHANGE

Despitecontinuingadvancesintheabilityofglobalclimatemodelstosimulatepossiblefutureclimatechangesitisdifficulttopredicttheimpactsthesemighthaveontheterrestrialenvironment,owingtothebehaviouralresponsesofhumanbeingsasclimatezonesshift.AsimilarsituationcouldarisetothatseeninAfricainthe1970sand1980swhenhumanbeingsrespondedtotheprolongeddroughtbyoverusingtheland,andcausingdesertificationtoaccelerate.Somoreempiricalresearchintodesertificationcouldhelptoimproveglobalclimatechangeimpactmodelsandtheformulationofmitigationandadaptationpolicies.

4.CapitalizingonSynergiesBetweentheRioConventions

Inprinciple,therefore,greaterconvergencebetweenresearchintodesertificationandglobalclimatechangewouldenhanceourunderstandingofbothfields.Thekeyquestionishowtostimulatethis.OneapproachwouldbetoassumethatitwouldoccurasanaturalconsequenceofgrowingcooperationbetweenthethreeenvironmentalregimesthatemergedfromtheUNConferenceonEnvironmentandDevelopment(UNCED)inRiodeJaneiroin1992.BoththeFrameworkConven-tiononClimateChange(FCCC)andtheConventiononBiodiversity(CBD)men-tiontheimportanceofdesertification.ThevalueofcooperationtorealizesynergiesbetweenthethreeregimeswasalsostressedintheAgenda21actionplanagreedatUNCED,andrestatedbytheSpecialSessionoftheUNGeneralAssemblyinJune1997thatreviewedprogressintheinterveningfiveyears.

Followinganexpertmeetingtoexploresynergiesbetweenthethreeconven-tions,heldinIsraelin1997,thesecretariatsoftheCCDandtheCBDestablishedformalbilaterallinksin1998byexchangingamemorandumofunderstanding

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(SCCD1998).NegotiationsonsimilarlinkswiththeFCCCarestillcontinuing.Intheshort-term,informalcooperativeeffortsarefocusingoncapacitybuild-ing,informationmanagement,andcommunity-levelpilotprojectsthatcanachievecomplementaryimplementationoftheFCCC,CBDandCCD(SCCD1998).

TheforgingofstrongertiesbetweentheCCDandtheFCCCisbeingobstructedbypoorscientificknowledgeofthelinkagesbetweendesertificationandglobalcli-matechange(SCCD1999a).Thisisnotforwantofmeetings:UNEPconvenedtwoexpertpanelsonthesubjectinthe1990s(WilliamsandBalling1996;Squiresetal.1997),anddesertificationwasoneofthe‘adverseeffects’ofglobalclimatechangediscussedataworkshopconvenedbytheFCCCSubsidiaryBodyforScientificandTechnologicalAdviceinBonninSeptember1999(SFCCC1999).Therehavealsobeen‘initialcommunications’betweentheCCDCommitteeonScienceandTechnology(CST),theIntergovernmentalPanelonClimateChange,theFCCCSubsidiaryBodyonScientificandTechnologicalAdvice,andtheCBDSubsidiaryBodyonScientific,TechnicalandTechnologicalAdvice(SCCD1998).Butastale-matesituationseemstohavedeveloped,andpresentlinksbetweentheCCDandtheFCCCmaynotbestrongenoughtopromotetheresearchneededtoovercomeit.

Allocationofmultilateralfundsforanti-desertificationprojectsisalsocon-strainedbylackofknowledge.TheCCDdiffersfromtheothertworegimesinhavingnospecificmultilateralfundforitsimplementation.Instead,ithasaGlobalMechanism,coordinatedbytheInternationalFundforAgriculturalDevelopment(IFAD),basedinRome,toimprovethemanagementofexistingfunds.FundscanalsobechannelledthroughtheGlobalEnvironmentFacility(GEF)but,aspresentlyconstituted,thishasonlyfourmainfocalareas:climatechange,biodiversity,ozonedepletionandinternationalwaters.IthasrecognizedthegenericimportanceoflanddegradationbydevisingaframeworkthatincludesbothdesertificationanddeforestationandincorporatingthisintoitsOperationalStrategy(GEF1996),butisonlyallowedtoonlyfundprojectshavingaglobalimpactononeofitsfourfocalareas.Localandregionalimpactsofdesertificationonclimatechange(whichareallthatarecurrentlyrecognized)aretakenintoaccountbutarenotbythem-selvessufficient.Atpresent,sincetheimpactsofdesertificationonbiodiversityaremoreclearlyidentifieditismainlythroughthislinkthatfinanceisreques-tedfordesertification-relatedprojects.Butgovernmentsstillfindithardtoobtainfunding,owingtodifficultiesinclearlydefiningandinterpretingGEFcriteriaforlinksbetweendesertificationanditsfourfocalareas,valuingtheglobalbenefitsofprojects,andestimatingtheincrementalcostsofrealizingthelatter.ThefirstGEFAssembly,heldinNewDelhiinApril1998,calledforactiontoresolvetheuncertaintyaboutlinksbetweendesertificationandclimatechange,andtheGEFCouncilreviewedalltheproblemsatitsmeetinginDecember1999.SolutionstothevaluationdifficultieswereproposedataGEFworkshopinLondoninMarch1999(GEF/IIED1999),butsomeproceduralmattersstillremaintobeclarified.

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AunilateralinitiativeforbasicresearchfromorgansoftheCCDseemsunlikelyatthemoment.ItsCSTplanstoestablishanetworkofresearchinstitutionstosup-portimplementationoftheCCD,asprovidedforinArticle25.Buttheimmediatepriorityofthenetworkistosupportfieldprojects,sotheCSThasfocusedinitiallyonpromotingtheuseofearlywarningsystems,identifyingtraditionalknowledgeofmethodstocombatdesertification,andproducingbenchmarksandindicators(SCCD1999b).Itrecognizestheneedformorebasicresearchintothelinkagesbetweendesertification,globalclimatechangeandbiodiversitydegradation,butasyethasnospecificplanstoexpandthenetworkalongthoselines,eventhoughfundingforprojectswouldappeartodependongainingbetterknowledgeoftheselinkages.

5.ExtendingScientificCooperation

Analternativestrategyforachievingconvergencewouldbetoimproveinformalnetworkingbetweendesertificationandglobalclimatechangeresearchers.OnewaytodothiswouldbethroughthesupportiveinstitutionalframeworkprovidedbytheIntergovernmentalPanelonClimateChange(IPCC).Thisindirectlyhelpstosetresearchagendasandfacilitateresearchcooperationbythewayitstructuresitsreg-ularassessmentsandselectsthetopicsforoccasionalworkshops.However,whiledesertificationwasmentionedinIPCC’sSecondAssessmentReport(Houghtonetal.1996;Watsonetal.1996),itislikelyonpresentevidencetobelessprominentintheThirdAssessmentReport.Ofthefourmainresearchcategoriesdiscussedabove,mitigationstudiesofferthegreatestscopeforputtingmoreemphasisondesertification,atleastintheshortterm.Ontheotherhand,theflexibilitytoaddresstheroleoflanddegradationintheglobalcarbonbudgetappearstobelimitedbytheKyotoProtocol.Article3.3restrictstheaccountingofchangesincarbonstocksinAnnexI(industrialized)countriestothoseduetoafforestation,reforestationanddeforestation.Thiswouldappeartoexcludeforestdegradation,whichplaysanimportantroleinthereductionoftreecover(andvegetationcovergenerally)indryareas.However,Article3.4covers‘additionalhuman-inducedactivities’whichcouldencompasscroplandandrangelanddegradation.

ArecentreportbytheIPCC(2000a),speciallycommissionedtoprovidesci-entificadviceonproceduresforincludinglanduse,landusechangeandforestryintheKyotoProtocol,recognizestheimportanceofforestdegradation,drylanddegradationandopenwoodlandsintheglobalcarbonbudgetandtheadvantagesofallowingforthemintheKyotoProtocol.Italsoofferspolicymakerstheoptionofrelaxingtheaboveconstraints.Insteadofdefiningdeforestationintermsofachangeoflanduseandlandcoverfromforesttonon-forest,itsuggests(IPCC,2000b)that:

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Analternativedefinitionofdeforestationmightbebasedonadecreaseinthecanopycoverorcarbondensitybyagivenamountorcrossingoneofasequenceofthresholds.

Inotherwords,theterm‘deforestation’couldbeusedtorefertotheprocessof‘forestdegradation’asunderstoodinthispaper.Sincedeforestation,asconven-tionallydefined,ismerelyanextremecaseofforestdegradationthiswouldallowamoreinclusivetreatmentoflandcoverchange,andafforestationandreforesta-tioncouldbedefinedasthereverseofthisprocess.IPCC(2000b)recognizesthatproblemscouldarisewithrespecttothesizeofthethresholdcanopycoverchosentodistinguishforestfromnon-forest:

Ifahighthreshold...(e.g.70%)...isused...,thenmanyareasofsparseforestandwoodlandcouldbeclearedorcouldincreaseincoverwithoutthelossesorgainsincarbonbeingcountedunderArticle3.3.Ifalowthresholdisset(e.g.10%)thendenseforestcouldbeheavilydegradedandsignificantamountsofcarbonreleased,withouttheactionsbeingdesignatedasdeforest-ation.

Theformerisparticularlyrelevanttotheopenwoodlandscharacteristicofdryareas.Thereportacknowledgesthedifficulties,referredtoabove,ofaccountingforchangesincarbonstocksresultingfromthe‘regenerationoftreesimmediatelyafterdisturbanceorharvestingwherenolandusechangeoccurs’.Italsorecognizesthatpreventingthedegradationofagriculturallandscouldbeincludedin‘additionalhuman-inducedactivities’(IPCC2000a).

ItisuptotheConferenceofthePartiesoftheFCCCtodecideonwhichdefinitionofdeforestationitprefers,andontheextenttowhichlanddegradationgenerallyisincorporatedintheKyotoProtocol.AsArticles3.3and3.4donotapplytodevelopingcountriesatthemomentthereisnoreasoninprinciplewhyfutureIPCCassessmentsshouldnotputgreateremphasisonvegetationandsoildegradationinthosecountries,andhenceondesertification.AmodeststartcouldbemadeintheThirdAssessment,forexample,byidentifyingasetofresearchpri-oritiesonthelinksbetweenlanddegradationandglobalclimatechange.Giventhestrengthoffeelingindevelopingcountriesaboutdesertification,theIPCCmightbenefitfromretainingflexibilityinthisareawhilethedevelopedanddevelopingcountriescontinuetonegotiatetheircommitmentstomitigatingglobalclimatechange.DevelopingcountriesmightinsistonlanddegradationbeingreferredtoinanelaboratedKyotoProtocolinreturnforagreeingtoparticipateinit.

6.Conclusions

Greaterconvergencebetweenresearchintodesertificationandglobalclimatechangewouldbenefitbothfieldsofresearch.Desertificationrequiresavastincreaseinresearchactivity,andatleastfourareasofglobalclimatechangeresearchwouldbenefitfromtheinformationthatthisresearchwouldgenerate.Ifdesertification

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weretreatedmoreasaspecialcaseofthegenericprocessoflanddegradation,insteadoftheratherisolatedfieldofstudywhichitisatthemoment,thenthiscouldprovideitwithamoresubstantialscientificframeworkandimproveitsstandingwithinthescientificcommunity.

Twopossiblestrategiesforstimulatingconvergencehavebeendiscussed.ThefirstwouldrelyonthefruitsofgrowingcooperationbetweentheFrameworkCon-ventiononClimateChange(FCCC)andtheConventiontoCombatDesertific-ation(CCD).Yetthisiscurrentlylimitedbyalackofscientificknowledgeonthelinksbetweenthetwophenomenawhichsuchresearchwouldhelptoremedy.Thesecondwouldimproveinformalnetworkingbetweendesertificationandglobalclimatechangescientists,e.g.withintheframeworkoftheIntergovernmentalPanelonClimateChange(IPCC).However,desertificationhasalowprofileintheIPCCatthemomentandthiscouldbefurtherreducedbyrestrictionsimposedbytheKyotoProtocol.

Ifpoorscientificknowledgeofthelinksbetweendesertificationandglobalcli-matechangecontinuestoinhibitthestrengtheningoftiesbetweentheCCDandtheFCCC,andsupportiveactionbytheGlobalEnvironmentFacility,thenonewaytobreakthedeadlockmightbefortheCCDandFCCCtoasktheIPCCtoprepareaspecialreportonthesubject,toprovideaconstructiveframeworkforcontinuednegotiation.ThiswouldalsohelptoraisetheprofileofdesertificationwithintheIPCCaswell.

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