UNEP：邁向藍碳未來：確保海帶森林的可持續(xù)未來（執(zhí)行摘要）

INTOTHEBLUE

SecuringaSustainableFuture

forKelpForests

?UniversidaddeLosLagos,Chile/AlejandroH.Buschmann

2IntotheBlue

Executivesummary

Theterm“kelp”iscommonlyusedtorefertojustover100speciesoflargebrownseaweedsthatrepresentsome

ofthemostproductiveanddiversehabitatsonEarth.

Kelpdominateapproximatelyonequarteroftheworld’s

coastlines,throughoutpolarandtemperateregions,makingthemthemostextensivemarinevegetatedecosystem

intheworld.Kelpcreatecomplexandthree-dimensional

underwaterforestsrichinbiodiversity.Theseuniquecoastalenvironmentsprovidenurseryhabitat,shelterandforaginggroundsforawiderangeofmarineorganisms,includingfishspeciesofcommercialimportance,suchascodandpollack,andotherspeciessuchascrab,octopusandlobster.Kelp

forestscanmitigatecarbonemissionsbystoringcarboninstandingbiomassandbyfacilitatingthelong-termremovalofcarbondioxide(CO2)throughtheexportandburialofkelpcarboninthedeepsea.Indigenousandcoastalpeoplehaveusedkelpasmedicine,foodandmaterialforgenerations,

withkelpformingpartoftheiridentitiesandfosteringthedevelopmentofasenseofplaceandconnectednesswithnature.

However,kelphavebeendeclininggloballyoverthepast

50years.Ascool-waterspecies,kelparestressedby

oceanwarming,marineheatwavesandotherclimate-

relatedextremes,withextensivelossesrecordedattheir

warmrange-edges.Overfishing,reducedwaterquality

fromexcessnutrients,pollutionandsedimentation,and

unregulatedandunsustainablekelpharvestingalsopose

majorthreatstokelpforests.Thisglobalsynthesisreportisthemostcomprehensiveknowledgereviewonkelptodate,revealingthestateofscienceontheworld’skelpforestsandprovidingrecommendedactionstobuildtherecoveryof

theworld’skelpforeststhroughincreasedpublicawarenessandinstitutionalsupportforadvancingconservation,

managementandrestoration.Thereportalsoprovidesa

rangeofpolicyandmanagementinterventionsandoptions

thatcanbeusedtomaintaintheseremarkableecosystemsnowandinthefutureandtosupportthepeopleand

economiesthathavedependedonthemforgenerations.

Thestateofkelpforests,theirvaluesandkeychallenges

Kelpisthemostextensivemarinevegetatedecosystem

intheworld.Kelparepredominantlycool-waterspeciesoflargebrownseaweedsthatarefoundgrowingonrockyreefsthroughouttemperate,Arcticandsub-Antarcticregions,

along25–30percentoftheworld’scoastlines.Theycover1.5–2millionkm2,anareauptofivetimesgreaterthanthatofcoralreefs.

Kelpforestsarethreatenedbybothlocalandglobal

stressors.Kelphavesufferedwidespreadlossesacrossmuchoftheirrange,ataglobalrateofdeclineof1.8per

centperyear.Thetrajectoriesofchangeacrossregions

arevariable,reflectingthevarietyoffactorsaffectingkelp

ecosystems.Overthepast50years,40–60percentofkelpforestshavebeendegraded,withclimatechange,poor

waterqualityandoverfishingbeingtheprominentcauses.Inseverecases,thesestressorscancausefull-scaleshiftstoecosystemsthataredifficulttoreverse,turningkelpforestsfromcomplexhabitatstostructurallysimpleturf-dominatedreefsorseaurchinbarrens.

Climatechangeisamajorthreattokelpforestsand

requiresurgentaction.Projectionsforclimatechange

impactsonkelpforestsrevealextensivelossesintemperateregions.Akeystrategyforclimatechangeadaptationwouldincludeaddressingallotherstressorsthatcanbemanagedlocallyorregionally,suchasbyimprovingwaterqualityandcontrollingoverfishing,inordertoreducemultiplepressuresactingsimultaneouslyandcumulativelyandincreasekelp

resilience.

Kelpforestsareamongthemostdiverseandproductive

ecosystemsintheworldandprovidemanyvaluable

ecosystemservices.Theseecosystemservicesinclude

supportingcoastalfisheries,providingfood,medicineand

materials,mitigatingclimatechange,protectingbiodiversity,bufferingoceanacidification,improvingwaterqualityand

providingarangeofculturalservicessuchasrecreationandsupportfortraditionalidentities.

Kelpcanprovideimportantnature-basedsolutions

totackleclimatechange.Kelpforestsareessential

contributorstothecarboncycle;theycantakeupCO2andconvertitintoorganicbiomassforshort-termstorage.Kelpcarbonthatisnotgrazed,consumedordecomposedcan

beburiedinseafloorsedimentsortransportedtothedeepocean,thusfacilitatinglong-termcarbonremoval.

Kelpprovideserviceswitheconomicandexistencevalues.

Economicframeworks,suchasthetotaleconomicvalueorcost–benefitanalysis,canbeappliedtorevealthedifferenttypesofeconomicvaluesthatkelpprovideandtosupportmanagementdecisions.Althoughtheseeconomictools

areuseful,manyserviceslinkedtotraditionaluses,spiritualpractices,supportforidentitiesandbroaderecological

functioncannoteasilybemonetized.Economictoolsshouldthereforebecoupledwithgeneralbiophysicaldataon

ecologicalfunctionandsocioculturalknowledgeinordertoacknowledgethefullbreadthofvaluesassociatedwithkelpecosystems.

Kelpforestscanhelpcountriesachieveseveralglobal

goalsintermsofclimate,biodiversityandsustainable

development.TheseforestsareatthecoreofdeliveringSustainableDevelopmentGoal(SDG)14LifebelowWater,

IntotheBlue

3

whiletheconservationandsustainableuseofkelpforests

alignwithmanyotherSDGs,includingSDG1NoPoverty,

SDG2ZeroHunger,SDG6CleanWaterandSanitation,SDG8DecentWorkandEconomicGrowth,SDG12ResponsibleConsumptionandProductionandSDG13ClimateAction.

Kelphavereceivedlittleattentioninoceangovernance.

Todate,nogloballegalorpolicyinstrumentshavefocusedexplicitlyonkelp.Thislackofattentionhasperhapsresultedinlimitedprotectionofkelpforests,andviceversa,withanapproximatefirst-orderestimateoflessthanonethirdof

knowndistributionfallingwithinmarineprotectedareas.

Thereare,however,manyinternationalframeworksand

nationallawsandpoliciesinplacethatcould,inprinciple,

supporttheconservationandeffectivemanagementofkelp.

Demandforkelpforhumanconsumptionandforindustryisgrowing.Inrecentdecades,demandforkelpforhuman

consumption,alginateproduction,aquaculturefeedand

potentiallybiofuelhasincreased,andwillalmostcertainly

continuetogrow.Growingdemandforkelpgloballyhas

mainlybeenmetbycultivation,whichnowdelivers27timesmorethanharvestingofwildkelp.Kelpandseaweedfarminghasbecomethefastest-growingaquacultureindustry

globally,withanincreaseof6.2percentperyearoverthelasttwodecades.

Opportunitiesandrecommendations

Knowledgeanddatageneration

Investinmappingandsystematicandlong-term

monitoringoftheworld’skelpforests.Themost

comprehensivestudyofhistoricaltrendsinkelpabundancecoversonlyaboutonethirdoftheworld’sregionswherekelpforestsexist,asdatawithintheseregionsarespatiallyand

temporallysparse.Assessingthetrendsandconditionofkelpforests–especiallyinthemanyunmonitoredregions–iskeytoevaluatingtheneedformanagementactions.

Supportthedevelopmentofacoordinatednetworkof

globalkelpobservationsandadata-sharingplatform.

Improvedinformationon,andunderstandingof,kelpforests

mayinturnsupportthedevelopmentoftransformativepolicies,whichareoftenaprerequisitetoeffective

managementandinvestment.

Investinfurtherunderstandingandpredictionof

individualstressorsandtheircombinedeffectsonkelp

abundanceanddistribution.Extremeevents(including

marineheatwavesandstorms),overfishingleadingto

outbreaksofgrazers,eutrophication,coastaldarkeningandinvasivespeciescanallaffectmultiplelife-historystages

ofkelpandinteracttoreducetheirgrowthandsurvival.Itiscriticaltounderstandhowthesedriversinteractinordertopredictfuturekelpabundanceanddistributionandmakeinformedmanagementdecisions.

4IntotheBlue

Quantifytheecosystemfunctionsandservicesprovidedbykelp,andunderstandhowthesewillbeaffectedby

climatechangeandhumanactivities.Mostdataon

ecosystemservices–boththebiophysicalmeasuresand

theirvalue–arelimitedtoafewwell-studiedregionsand

direct-usebenefits,buteverykelphabitatcanfunction

differently.Itisthereforecriticaltohavespecificknowledgefordifferentecosystems.

Incentivizekelpprotectionandrestorationthroughtheircarbonvalue.Onepromisingtooltoprotectandrestorekelpcouldbetheuseofkelpforest“bluecarbon”credits.However,operationalizingsuchcreditswouldrequire

improvedscientificestimatesandtoolstomeasurekelp

carbonsequestration,aswellaschangestocarbonmarketpoliciesandframeworks.

Developatoolboxofmanagementinterventions.

Bycompilingexamplesofbestpractice,atoolboxof

managementinterventionsandtheireffectiveness(e.g.the2022GlobalKelpRestorationGuidebook)couldbedeveloped,whichcouldthenbetailoredtotheneedsofindividualnationsandlocalscales.

Managementandpolicyresponses

Takeimmediateandglobalactiontoaddressclimate

change.Increasinglywarmwatershavedriven,bothdirectlyandindirectly,themajorityofrecentkelploss.Thelong-termprovisionofservicesandbenefitsbykelpforestsdependsonoceanwarmingbeingheldincheck.Globalactiontotackle

climatechangeisthereforeneededtomitigatetheeffectsofoceanwarmingonkelpforestsandensuretheirresilienceinthecomingdecades.

Followanecosystem-basedapproachtosustainably

managekelpforests.Ecosystem-basedmanagement

canactasan“umbrella”framework,wherebyanumber

ofdifferentmanagementapproachesareappliedand

integrated,includinginitiativesforaddressingindividual

pressures,area-basedmanagementsuchasmarinespatialplanningandmarineprotectedareas,andsustainable

managementofharvestingofkelpandassociatedspecies.

Ensureanexplicitfocusonkelpwhendesignating

managementmeasuresandsettingtargets.Askelpcan

beaffectedbybothland-basedandsea-basedhuman

activities,managingforthecumulativeimpactsfromvarioususesanduserscallsforaholisticapproach,wherebykelpisregisteredasan“ecosysteminfocus”,andforstrategicplanstoaddresscurrentandfuturestressorsthroughappropriateregulations.

Ensurecapacity-buildingandsustainedinvestment

forkelpmanagementatnationalandlocalscales.

Well-intentionedinitiativesmaynotbeeffectiveiftheirimplementationremainsunderfundedandinadequatelymanaged.Formanagementplanstobeeffectiveandfor

kelp-specificgoalsandtargetstobeachieved,continuousfundingandsufficienttechnicalexpertiseandhuman

resourcesareneededforimplementationandmonitoringofactivities.

Assessharvestingpracticesregularlyandadaptas

needed.Inmanycountries,kelpharvestingismanaged

throughacombinationofdomesticandregionalized

approaches.Toensureregrowthofkelpandkelpecosystemresilience,obtainingregularandaccurateinformationon

kelpstandingstock,monitoringharvestlevelsandassessingharvestimpactsarecriticaltomitigatingimpactson

kelppopulationsandassociatedcommunities.Inlightof

significantuncertaintyaroundimpactsonkelpforestsand

associatedecosystemrecovery(e.g.thelackofasystematicevaluationoftheeffectivenessofapproachestomanage

kelpharvesting),itisnecessarytoapplyanadaptiveandlearningapproach.

Combinesocioculturalknowledgewitheconomic

valuationstostrengthenthecasefordevoting

resourcestotheconservation,sustainable

managementandrestorationofkelp.Economic

frameworksareimportanttoidentifywhichkelp

conservationorrestorationprojectsarelikelytodeliverbenefitsoverallandhowthosebenefitsaredistributed.

Decision-makingshouldalsoconsidersociocultural

frameworksthattakeintoaccountwhetherthedistributionofresourcesisfairandequitable,particularlywhenminoritygroupsareidentifiedasbeingnegativelyimpactedbykelpmanagementpractices.

Useexistingglobalframeworksmoreeffectively.Existing

internationallawcouldbemorewidelyutilizedto

recognizekelpforestsandaddressthreatstothem.Kelpcouldalsobebetteracknowledgedandrecognizedwithin

WorldHeritageSites,theRamsarConvention,theSendai

FrameworkforDisasterRiskReduction,theConvention

onBiologicalDiversity,nationalbiodiversitystrategiesand

nationalactionplans.WithintheframeworkoftheParis

Agreementandnationallydeterminedcontributions,thereisalsopotentialtocatalysetheprotectionandrestorationofkelpforestsinthecontextofbluecarbonandnature-basedsolutionstoclimatechangemiti