Climate and Land Degradation (Environmental Science and Engineering Environmental Science) (Environmental Science and Engineering Environmental Science) PDF
Preview Climate and Land Degradation (Environmental Science and Engineering Environmental Science) (Environmental Science and Engineering Environmental Science)
Environmental Science and Engineering Subseries: Environmental Science Series Editors: R. Allan • U. Förstner • W. Salomons TanzaniaMeteorologicalAgency(TMA) UnitedNationsConventiontoCombatDesertification(UNCCD) WorldMeteorologicalOrganization(WMO) Mannava V.K. Sivakumar · Ndegwa Ndiang’ui (Eds.) Climate and Land Degradation With192Figuresand61Tables 123 Mannava V.K. Sivakumar AgriculturalMeteorologyDivision WorldMeteorologicalOrganization 7bisAvenuedelaPaix P.O.Box2300 1211Geneva2,Switzerland E-mail: [email protected] Ndegwa Ndiang‘ui CommitteeonScienceandTechnology(CST) UnitedNationsConventiontoCombatDesertification Hermann-Ehlers-Str.10 D-53113Bonn Germany e-mail:[email protected] ISSN 1863-5520 ISBN10 3-540-72437-0 SpringerBerlinHeidelbergNewYork ISBN13 978-3-540-72437-7 SpringerBerlinHeidelbergNewYork LibraryofCongressControlNumber: 2007931628 Thisworkissubjecttocopyright.Allrightsarereserved,whetherthewholeorpartofthematerial is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting,reproductiononmicrofilmorinanyotherway,andstorageindatabanks.Duplication ofthispublicationorpartsthereofispermittedonlyundertheprovisionsoftheGermanCopyright LawofSeptember9,1965,initscurrentversion,andpermissionforusemustalwaysbeobtainedfrom Springer-Verlag.ViolationsareliabletoprosecutionundertheGermanCopyrightLaw. SpringerisapartofSpringerScience+BusinessMedia springeronline.com ©Springer-VerlagBerlinHeidelberg2007 The use of general descriptive names, registered names, trademarks, etc. in this publication does notimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevant protectivelawsandregulationsandthereforefreeforgeneraluse. Coverdesign:deblik,Berlin Production:AgataOelschläger Typesetting:Satz-Druck-Service(SDS),Leimen Printedonacid-freepaper 30/2132/AO 543210 Foreword Desertificationisoneofthemostalarmingprocessesofenvironmentaldegrada- tion. It is about land degradation: the loss of the land‘s biological productivity, caused by human-induced factors and climate change, affecting one-third of the Earth‘ssurfaceandoverabillionpeople.Moreover,itcanhavedevastatingconse- quencesintermsofsocialandeconomiccosts. Theimpactsoflanddegradationonglobalfoodsecurityandthequalityofthe environmentareofmajorsignificanceandconcernwhenoneconsidersthatonly about11%ofthegloballandsurfacecanbeconsideredasprimeland,yetthismust feedthe6billionpeopleinhabitingtheWorldtodayandthe8.2billionexpected bytheyear2020.Long-termfoodproductivityisthreatenedbysoildegradation, whichisnowsevereenoughtoreducecropyieldsonapproximately16%oftheag- ricultural land, especially in Africa and Central America, as well as the African pastures.TherateoflanddegradationishighestinSub-SaharanAfrica,whereit isestimatedthatlossesinproductivityofcroppinglandareintheorderof0.5-1% annually,suggestingacumulativelossofatleast20%overthelast40years. Sustainable development of countries affected by drought and desertification canonlycomeaboutthroughconcertedeffortsbasedonasoundunderstanding ofthedifferentfactorsthatcontributetolanddegradationaroundtheWorld.Cli- maticvariationsarerecognizedamongthemajorfactorscontributingtolanddeg- radation,asdefinedintheUnitedNationsConventiontoCombatDesertification (UNCCD),anditisimportanttounderstandtherespectiverolesofthedifferent climatic factors in land degradation. For example, development and adoption of sustainablelandmanagementpracticesareamongthemajorsolutionsadoptedto combatlanddegradationoverdrylands,buttoaccuratelyassesssustainableland managementpractices,theclimateresourcesandtheriskofclimate-relatedorcli- mate-inducednaturaldisastersmustbewellknownforagivenregion. Only when climate resources are paired with potential management or devel- opmentpracticescanthelanddegradationpotentialbeassessedandappropriate mitigationtechnologiesbedeveloped.Theuseofclimateinformationmustbeap- pliedeffectivelyindevelopingsustainablepractices,sinceclimaticvariationisone ofthemajorfactorscontributingtoorevenactingasatriggertolanddegradation. Thereisthereforeaclearneedtoconsidercarefullyhowclimatecaninduceandin- fluencelanddegradation. TheWorldMeteorologicalOrganization(WMO)contributestotheunderstand- ing of the interactions between climate and land degradation through dedicated observationsoftheclimatesystem;improvementsintheapplicationofagrometeo- rologicalmethodsandtheproperassessmentandmanagementofwaterresourc- es;advancesinclimatescienceandprediction;andpromotionofcapacitybuild- ingintheapplicationofmeteorologicalandhydrologicaldataandinformationin VI Foreword droughtpreparednessandmanagement.However,muchmoreneedstodone,such asthepromotionoffurtherinterestandresearchinthistopic. Atits58thordinarysession,theUNGeneralAssemblydeclared2006tobethe International Year of Deserts and Desertification (IYDD). In doing so, the Gen- eralAssemblyunderlineditsdeepconcernfortheexacerbationofdesertification, particularly in Africa,and noted its far-reaching implicationsfor the implemen- tationoftheMillenniumDevelopmentGoals(MDGs),whichmustbemetbythe year2015.Accordingly,theIYDDpresentsagoldenopportunitytogetthemessage across,stronglyandeffectively,thatDesertificationisaglobalproblemthatwecan onlyignoreatourownperil.Italsooffersanimpulsetostrengthenthevisibility andimportanceofthedrylandsissueontheinternationalenvironmentalagenda, whileprovidingatimelyremindertotheinternationalcommunityoftheimmense challengesthatstilllieahead. In recognition of the importance of climatic factors in land degradation, the SeventhSessionoftheConferenceofParties(COP-7)totheUNCCDaccordedpri- oritytoclimateissuesinlanddegradationinthefutureworkoftheCommitteeon ScienceandTechnology(CST)oftheConvention,invitingWMOtoorganizeand find the necessary funding for an International Workshop on Climate and Land Degradationin2006,inthespiritofimplementationoftheInternationalYearof DesertsandDesertification(IYDD)andalsoaskingCSTtoassistWMOinfinding expertsforthisworkshop. ItiswiththisbackgroundthatWMO,theUNCCDSecretariatandtheTanza- niaMeteorologicalAgencyjointlyorganizedinArusha(Tanzania),from11to15 December2006,theInternationalWorkshoponClimateandLandDegradation. Theworkshop,whichwascosponsoredbytheOrganizationofthePetroleumEx- portingCountries(OPEC)FundforInternationalDevelopment(OFID),theUnit- edNationsDevelopmentProgramme(UNDP)andtheUnitedNationsEducation- al,ScientificandCulturalOrganization(UNESCO),focusedthewaythatclimate induces andinfluences land degradation and what measures need to be taken in order to enhancethe applicationsofweather andclimateinformationtocombat landdegradation. Wehopethatthepaperspresentedinthisbookwillserveasasignificantsource ofinformationtotheCSTaswellastoallagenciesandorganizationsinvolvedin designing and implementing appropriate strategies for sustainable land manage- menttoarrestlanddegradation. M. Jarraud Hama Arba Diallo Secretay-General ExecutiveSecretary WorldMeteorologicalOrganization SecretariatoftheConvention toCombatDesertification Preface Landdegradationisathreattonaturalresourceswithconsequencesonfoodsecu- rity,poverty,andenvironmentalandpoliticalstability. Theincreasingoccurrence ofclimateextremes(forexampleheatwaves,droughts,heavyprecipitation)ishav- inganimpactonlanddegradationprocesses,includingfloods,massmovements, soilerosionbywaterandwindandsalinizationinallpartsoftheglobe. Climate variability,climatechangeandlanddegradationareintimatelylinkedandaregen- eratingunexpectedeffects,forexample,anincreasedoccurrenceofweathercon- ditionsthataresuitableforafiretostart,ortopropagateinthewild,inlargeparts of the globe. Sustainable development of countries affected by drought and de- sertificationcanonlycomeaboutthroughconcertedeffortsbasedonasoundun- derstandingofthedifferentfactorsincludingclimaticvariationsthatcontributeto landdegradationaroundtheworld. Toaddressthesekeyissues,expertsfromaroundtheworldwerebroughttogeth- eratanInternationalWorkshoponClimateandLandDegradationwhichwasheld inArusha,UnitedRepublicofTanzaniafrom11to15December2006.Thework- shop focused on how climate induces and influences land degradation and what measuresneedtobetakentoenhancetheapplicationofweatherandclimatein- formationtocombatlanddegradation. TheworkshopwasorganizedbytheWorld MeteorologicalOrganization,theUnitedNationsConventiontoCombatDesert- ification (UNCCD) and the Tanzania Meteorological Agency and was co-spon- sored by the OPEC Fund for International Development (OFID), the United Na- tionsDevelopmentProgramme(UNDP)andtheUnitedNationsEducational,Sci- entificandCulturalOrganization(UNESCO). SpecificobjectivesoftheWorkshopwere: (cid:122) Tosurveythestatusof,andsummarizetheinformationon,trendsinlanddeg- radationatnationalandregionallevels; (cid:122) Toreviewandassesstheextenttowhichweatherandclimatedataandinforma- tionarecurrentlyusedatthenationalandregionallevelsinordertoadequately monitorandassesslanddegradationandtodevelopsustainablelandmanage- mentpracticestocombatlanddegradation; (cid:122) Toproviderecommendationsonappropriatestrategiesforreducinglanddegra- dationthroughmoreeffectiveuseofweatherandclimateinformationandap- plications; (cid:122) To assess the historic loss of terrestrial carbon pool due to land degradation, andestimatethepotentialofcarbonsequestrationinsoil/terrestrialecosystems throughsoilrestorationanddesertificationcontrol; VIII Preface (cid:122) To assess the feasibility of restoring degraded/desertified lands with a view to achievingfoodsecurityintheaffecteddevelopingcountries; (cid:122) To document case studies of successful measures to manage land use, protect landandmitigatelanddegradation; (cid:122) To suggest ways and means of improving the implementation of the National Action Programmes(NAPs)throughtheeffectiveuseofearlywarning. Sixty four participants from 30 countries and 5 UN agencies (WMO, UNCCD, FAO,UNDP,UNEP)presentedstate-of-the-artpapers,realworldapplicationsand innovativetechniquesforcombatinglanddegradation,andofferedrecommenda- tions for effectively using weather and climate information for sustainable land managementpractices. Altogethertherewere9sessions(includingtheopeningandclosingsession)in theworkshopduringwhich34invitedpaperswerepresentedaddressingthediffer- entspecificobjectivesoftheworkshop.Alltheparticipantsintheworkshopwere engagedindiscussionsonthesepapersanddevelopedseveralusefulrecommenda- tionsforallorganizationsinvolvedinpromotingclimatepredictionandapplica- tionsinagriculture,andincombatinglanddegradationparticularlyinthedevel- opingcountries. Thisvolumeincludes33invitedpaperspresentedattheworkshop,theconclu- sions and recommendations that emerged out of the working group discussions and the final workshop statement. As editors of this volume, we would like to thankalltheauthorsfortheireffortsandfortheircooperationinbringingoutthis volumeintime.WearemostgratefultoMr.M.Jarraud,theSecretary-Generalof WMOandMrArbaDiallo,ExecutiveSecretaryoftheUNCCDfortheircontinu- oussupportandencouragement. Mannava V. K. Sivakumar Ndegwa Ndiang’ui Editors Contents 1 The Assessment of Global Trends in Land Degradation Uriel N. Safriel 1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1.1 Landdegradation–whatisitandhowisitassessed . . . . . . . . 2 1.1.2 Theneedforassessmentataglobalscale . . . . . . . . . . . . . . . 3 1.1.3 Assessmentoflanddegradationattheglobalscale . . . . . . . . . 4 1.2 Assessmentofcurrentdegradation. . . . . . . . . . . . . . . . . . . . . . . 5 1.2.1 Globallanddegradationanddrylanddesertification . . . . . . . . 5 1.2.2 Islanddegradationindrylandsdifferentthanthat inthenon-drylands? . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.2.3 Degradationdegreeanddegradationseverity . . . . . . . . . . . . 11 1.2.4 TheSpatialextentofgloballanddegradation . . . . . . . . . . . . 18 1.2.5 Thespatialextentofdrylanddegradation . . . . . . . . . . . . . . 18 1.2.6 Degradationanddegradationvulnerability . . . . . . . . . . . . . 19 1.2.7 Degradationvulnerabilityanddegradationrisk . . . . . . . . . . 20 1.3 Remote-sensingofproductivityforassessingglobaldegradation . . . . . 23 1.3.1 Soilorvegetationassessment? . . . . . . . . . . . . . . . . . . . . . 23 1.3.2 Degradationasapersistentreductioninlandproductivity . . . . 26 1.3.3 Assessingdegradationasdeviationofproductivity fromitspotential . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.4 Assessmentofdegradationtrends . . . . . . . . . . . . . . . . . . . . . . . 30 1.4.1 RainUseEfficiencymethodology . . . . . . . . . . . . . . . . . . . 31 1.4.2 TheResidualTrendsmethodology . . . . . . . . . . . . . . . . . . 34 1.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 2 Status and Trends in Land Degradation in Africa Lamourdia Thiombiano and Ignacio Tourino-Soto 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2.2 EvaluatingthetrendsinlanddegradationinAfrica . . . . . . . . . . . . . 40 2.2.1 DiversityofAgro-ecologicalzones,soilsandlandusesystems . . 40 2.2.2 Methodologicalapproachtoestimatelanddegradationextent inAfrica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
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