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This page intentionally left blank GeomorphologyandGlobalEnvironmentalChange Howwillglobalenvironmentalchangeaffectourlandscapeand Columbia.HeisaFormerPresidentoftheCanadianAssociation thewayweinteractwithit?Thenext50yearswilldeterminethe ofGeographersandtheInternationalAssociationof futureoftheenvironmentinwhichwelive,whethercatastropheor Geomorphologists,andaLintonMedallist.Hehasheldvisiting reorganisation.Globalclimatechangewillpotentiallyhavea professorshipsattheuniversitiesofVienna,Canterbury,Oslo, profoundeffectonourlandscape,butthereareotherimportant SouthernIllinois,Taiwan,andNanjing.Hehasauthored120 driversoflandscapechange,includingrelief,hydroclimateand refereedjournalarticlesandauthoredandedited20books.Heisa runoff,sealevelchangeandhumanactivity.Thisvolume Co-Editor-in-ChiefofCatenaandmemberofnineinternational summarisesthestateoftheartconcerningthelandscape-scale editorialboards. geomorphicimplicationsofglobalenvironmentalchange. Itanalysesthepotentialeffectsofenvironmentalchangeona THOMASSPENCERisUniversitySeniorLecturerinthe rangeoflandscapes,includingmountains,lakes,rivers,coasts, DepartmentofGeography,DirectoroftheCambridgeCoastal reefs,rainforests,savannas,deserts,permafrost,andicesheetsand ResearchUnit,UniversityofCambridge,andOfficialFellow, icecaps. MagdaleneCollege,Cambridge.Hisresearchinterestsinwetland GeomorphologyandGlobalEnvironmentalChangeprovidesa hydrodynamicsandsedimentation,coralreefgeomorphology,sea benchmarkstatementfromsomeoftheworld’sleading levelriseandcoastalmanagementhavetakenhimtotheCaribbean geomorphologistsonthestateoftheenvironmentanditslikely Sea,thePacificandIndianoceans,Veniceanditslagoonandthe near-futurechange.Itisinvaluableasrequiredreadingingraduate coastlineofeasternEngland.Hehasauthoredandco-edited advancedcoursesongeomorphologyandenvironmentalscience, numerousbooksoncoastalproblems,environmentalchallenges andasareferenceforresearchscientists.Itishighly andglobalenvironmentalchange. interdisciplinaryinscope,withaprimaryaudienceofearthand environmentalscientists,geographers,geomorphologistsand CHRISTINEEMBLETON-HAMANNisaProfessorinthe ecologists,bothpractitionersandprofessionals.Itwillalsohavea DepartmentofGeographyandRegionalResearchattheUniversityof widerreachtothoseconcernedwiththesocial,economicand Vienna.Hermaininterestisinalpineenvironments.Withinthisfield politicalissuesraisedbyglobalenvironmentalchangeandbeof shefocussesonthehistoryofideasconcerningtheevolutionofalpine valuetopolicy-makersandenvironmentalmanagers. environments,genesisanddevelopmentofspecificlandformsand humanimpactonalpineenvironments,andhaswrittenextensivelyon OLAVSLAYMAKERisProfessorEmeritusintheDepartmentof geomorphologicalhazardsandrisksandtheassessmentofscenic Geography,UniversityofBritishColumbia.HeisaSenior qualityofalpinelandscapes.SheisPastPresidentoftheAustrian AssociateofthePeterWallInstituteforAdvancedStudiesand CommissiononGeomorphologyandSecretary-Generalofthe SeniorFellowofStJohn’sCollege,UniversityofBritish InternationalAssociationofGeomorphologistsWorkingGroup. PraiseforGeomorphologyandGlobalEnvironmentalChange: ‘Globalchange,whetherduetoglobalwarmingorotherhuman ‘AccordingtotheWorldResourcesInstitute,21metrictonsof impacts,isoneofthegreatissuesoftheday.Inthisvolumesomeof material,includingmaterialsnotactuallyusedinproduction(soil theworld’smostdistinguishedgeomorphologistsgiveanexpert erosion,over-burden,constructiondebris,etc.)areprocessedand andwide-ranginganalysisofitssignificanceforthemovement.’ dischargedaswasteeveryyeartoprovidetheaverageJapanese ANDREWGOUDIE,UniversityofOxfordandPresidentof withgoodsandservices.ThefigurefortheUSisanastonishing theInternationalAssociationofGeomorphologists 86tonnespercapita.TheOECDsaysthatin2002,50billion tonnesofresourceswereextractedfromtheecospheretosatisfy ‘GeomorphologyandGlobalEnvironmentalChange,with humanneedsandthenumberisheadedtoward80billiontonnes chaptersbyatrulyglobalgroupofdistinguished peryearby2020.Mostofthisisassociatedwithconsumptionby geomorphologists,redressestheimbalancethathasseenan justtherichest20%ofhumanitywhotakehome76%ofglobal overemphasisonclimateastheprimedriveroflandscapechange. income,sothehumanroleinglobalmassmovementandlandscape Thiscomprehensivebooksummarisesthedeepeningcomplexity alterationmayonlybebeginning.Thesedatashowunequivocally ofmultipledriversofchange,recognisingtherolethatreliefplays thatthehumanenterpriseinanintegralandgrowingcomponentof ininfluencinghydrologicalprocesses,thatsealevelexertson theecosphereandoneofthegreatestgeologicalforcesaffecting coastalenvironments,andthefar-reachingimpactsofhuman thefaceoftheearth.Remarkably,however,techno-industrial activityinallthemajorbiomes,inadditiontoclimate.Thelagsand societystillthinksofitselfasseparatefrom“theenvironment”. thresholds,thechangingsupplytothesedimentcascade,andthe Certainlygeomorphologistshavehistoricallyconsideredhuman influenceoffireonvegetationensurethatuncertainnear-future activitiesasexternaltogeosystems.Thisisabouttochange.In processregimeswillresultinunforeseenlandscaperesponses.The GeomorphologyandGlobalEnvironmentalChange,Slaymaker, potentialcollapseandreorganisationoflandscapesprovidefertile SpencerandEmbleton-Hamannprovideacomprehensive researchfieldsforanewgenerationofgeomorphologistsandthis treatmentoflandscapedegradationingeosystemsrangingfrom bookprovidesanauthoritativesynthesisofwherewearetodayand coralreefstoicecapsthatconsidershumansasamajorendogenous abasisforembarkingonamorerisk-basedefforttoforecasthow forcingmechanism.Thislong-overdueintegrationof thelandformsaroundusarelikelytochangeinthefuture.’ geomorphologyandhumanecologygreatlyenrichestheglobal COLON D. WOODROFFE,UniversityofWollongong changedebate.Itshouldbeaprimaryreferenceforallserious studentsofcontemporarygeomorphologyandthefullrangeof ‘Arobustfutureforgeomorphologywillinevitablyhavetobe environmentalsciences.’ foundedongreaterconsiderationofhumanimpactsonthe WILLIAM E. REES,UniversityofBritishColumbia; landscape.Anintellectualframeworkforthiswillnecessarilyhave co-authorofOurEcologicalFootprint;FoundingFellowofthe environmentalchangeasacentralcomponent.Thisvolume OneEarthInitiative representsanimportantstartingpoint.Coverageiscomprehensive, andasetofauthoritativevoicesprovideindividualchaptersserving asbothbenchmarksandsignpostsforcriticaldisciplinarytopics.’ COLIN E. THORN,UniversityofIllinoisat Urbana-Champaign Geomorphology and Global Environmental Change EDITED BY Olav Slaymaker TheUniversityofBritishColumbia Thomas Spencer UniversityofCambridge Christine Embleton-Hamann UniversitätWien CAMBRIDGEUNIVERSITYPRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo, Delhi, Dubai, Tokyo Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521878128 © Cambridge University Press 2009 This publication is in copyright. Subject to statutory exception and to the provision of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published in print format 2009 ISBN-13 978-0-511-59520-2 eBook (EBL) ISBN-13 978-0-521-87812-8 Hardback Cambridge University Press has no responsibility for the persistence or accuracy of urls for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. Contents List of contributors page x Preface xiii Acknowledgements xiv Listofacronymsandabbreviations xv 1 Landscapeandlandscape-scaleprocessesasthe unfillednicheintheglobalenvironmentalchange debate:anintroduction 1 OLAV SLAYMAKER, THOMAS SPENCER AND SIMON DADSON 1.1 Thecontext 1 1.2 Climaticgeomorphology 4 1.3 Processgeomorphology 5 1.4 Identificationofdisturbanceregimes 6 1.5 Landscapechange 8 1.6 Systemicdriversofglobalenvironmentalchange(I):hydroclimateand runoff 10 1.7 Systemicdriversofglobalenvironmentalchange(II):sealevel 14 1.8 Cumulativedriversofglobalenvironmentalchange(I):topographic relief 17 1.9 Cumulativedriversofglobalenvironmentalchange(II):human activity 19 1.10 Broaderissuesforgeomorphologyintheglobalenvironmentalchange debate 22 1.11 Landscapechangemodelsingeomorphology 25 1.12 Organisationofthebook 28 2 Mountains 37 OLAV SLAYMAKER ANDCHRISTINE EMBLETON-HAMANN 2.1 Introduction 37 2.2 DirectdriverI:relief 42 2.3 DirectdriverII:hydroclimateandrunoff 44 2.4 DirectdriverIII:humanactivity,populationandlanduse 45 2.5 Twenty-first-centurymountainlandscapesundertheinfluenceof hydroclimatechange 49 vi Contents 2.6 Twenty-first-centurymountainlandscapesundertheinfluenceofland useandlandcoverchange 55 2.7 Vulnerabilityofmountainlandscapesandrelationtoadaptive capacity 61 3Lakesandlakecatchments 71 KENJI KASHIWAYA, OLAV SLAYMAKER ANDMICHAEL CHURCH 3.1 Introduction 71 3.2 Lakesandwetlands 72 3.3 Thelakecatchmentasgeomorphicsystem 74 3.4 Internallakeprocesses 78 3.5 Hydroclimatechangesandproxydata 80 3.6 Effectsofhumanactivity 86 3.7 Scenariosoffuturewetlandandlakecatchmentchange 92 4Rivers 98 MICHAEL CHURCH, TIM P. BURT, VICTORJ. GALAYAND G. MATHIAS KONDOLF 4.1 Introduction 98 4.2 Landsurface:runoffproduction 98 4.3 Riverchannels:functionandmanagement 103 4.4 Fluvialsedimenttransportandsedimentation 109 4.5 Watercontrol:damsanddiversions 114 4.6 Riverrestorationinthecontextofglobalchange 121 4.7 Conclusions 125 5Estuaries,coastalmarshes,tidalflatsandcoastal dunes 130 DENISEJ.REED,ROBINDAVIDSON-ARNOTTANDGERARDO M.E. PERILLO 5.1 Introduction 130 5.2 Estuaries 133 5.3 Coastalmarshesandtidalflats 136 5.4 Coastalsanddunesystems 142 5.5 Managingcoastalgeomorphicsystemsforthe twenty-firstcentury 150 6Beaches,cliffsanddeltas 158 MARCEL J.F. STIVE, PETERJ. COWELL AND ROBERT J. NICHOLLS 6.1 Introduction 158 6.2 Coastalclassification 159 6.3 Thecoastal-tractcascade 162 6.4 Applicationsofthequantitativecoastaltract 167 6.5 Risk-basedpredictionandadaptation 174 6.6 Conclusions 176 Contents vii 7Coralreefs 180 PAUL KENCH, CHRIS PERRY ANDTHOMAS SPENCER 7.1 Introduction 180 7.2 Carbonateproductionincoralreefenvironments:thereefcarbonate factory 182 7.3 Coralreeflandforms:reefandreefflatgeomorphology 188 7.4 Reefsedimentarylandforms 195 7.5 Anthropogeniceffectsonsedimentarylandforms 202 7.6 Synthesis 205 8Tropicalrainforests 214 RORYP.D. WALSHAND WILL H.BLAKE 8.1 Thetropicalrainforestecologicalandmorphoclimaticzone 214 8.2 Geomorphologicalcharacteristicsoftherainforestzone:asynthesis 217 8.3 Recentclimatechangeintherainforestzone 231 8.4 Approachesandmethodsforpredictinggeomorphologicalchange: physicalmodelsversusconceptual/empiricalapproaches 234 8.5 Potentialecological,hydrologicalandgeomorphologicalresponsesto predictedfutureclimatechangeinrainforestareas 235 8.6 Researchgapsandprioritiesforimprovementtogeomorphological predictionsinthehumidtropics 243 8.7 Summaryandconclusions 243 9Tropicalsavannas 248 MICHAEL E.MEADOWS ANDDAVIDS.G. THOMAS 9.1 Introduction 248 9.2 Keylandformsandprocesses 255 9.3 Landscapesensitivity,thresholdsand‘hotspots’ 262 9.4 Acasestudyingeomorphicimpactsofclimatechange:theKalahariof southernAfrica 265 9.5 Concludingremarks 269 10Deserts 276 NICHOLAS LANCASTER 10.1 Introduction 276 10.2 Driversofchangeandvariabilityindesertgeomorphicsystems 278 10.3 Fluvialgeomorphicsystemsindeserts 283 10.4 Aeoliansystems 286 10.5 Discussion 291 11Mediterraneanlandscapes 297 MARIASALA 11.1 Introduction 297 11.2 Geology,topographyandsoils 297 11.3 Climate,hydrology,vegetationandgeomorphologicalprocesses 299 11.4 Long-term environmental change in Mediterranean landscapes 303 viii Contents 11.5 TraditionalhumanimpactsinMediterraneanlandscapesand nineteenth-andtwentiethcenturychange 307 11.6 Contemporaryandexpectednear-futurelandusechanges 310 11.7 GlobalenvironmentalchangeinMediterraneanenvironmentsandits interactionwithlandusechange 312 11.8 Concludingremarks 315 12Temperateforestsandrangelands 321 ROY C. SIDLE ANDTIM P.BURT 12.1 Introduction 321 12.2 Globaldistributionofmid-latitudetemperateforestsandrangelands 323 12.3 Potentialclimatechangescenariosandgeomorphicconsequences 325 12.4 Types,trajectoriesandvulnerabilitiesassociatedwithanticipatedmass wastingresponsestoclimatechange 325 12.5 Anthropogeniceffectsongeomorphicprocesses 328 12.6 Techniquesforassessingeffectsofanthropogenicandclimate-induced masswasting 334 12.7 Summaryandconclusions 337 13Tundraandpermafrost-dominatedtaiga 344 MARIE-FRANÇOISE ANDRÉ AND OLEGANISIMOV 13.1 Permafrostregions:aglobalchange‘hotspot’ 344 13.2 Permafrostindicators:currenttrendsandprojections 348 13.3 Permafrostthawasadrivingforceoflandscapechangeintundra/taiga areas 350 13.4 Impactoflandscapechangeongreenhousegasrelease 354 13.5 Socioeconomicimpactandhazardimplicationsofthermokarstactivity 356 13.6 Vulnerabilityofarcticcoastalregionsexposedtoacceleratederosion 358 13.7 Discriminatingtheclimate,sealevelandlandusecomponentsof globalchange 360 13.8 Lessonsfromthepast 361 13.9 Geomorphologicalservicesandrecommendationsforfuture managementofpermafrostregions 362 14Icesheetsandicecaps 368 DAVID SUGDEN 14.1 Introduction 368 14.2 Distributionoficesheetsandicecaps 369 14.3 Icesheetandicecaplandscapes 374 14.4 Icesheetsandicecaps:massbalance 378 14.5 Iceflowandicetemperature 380 14.6 Externalcontrolsandfeedbacks 381 14.7 Landscapesofglacialerosionanddeposition 384 14.8 Howwillicesheetsandicecapsrespondtoglobalwarming? 389 14.9 Conclusionandsummary 399