Climate change widespread, rapid, and intensifying – IPCC

However, strong and sustained reductions in emissions of carbon dioxide (CO2) and other greenhouse gases would limit climate change. Follow Engage TherearemanywaystoengagewiththeIPCC LearnMore GENEVA,Aug9–ScientistsareobservingchangesintheEarth’sclimateineveryregionandacrossthewholeclimatesystem,accordingtothelatestIntergovernmentalPanelonClimateChange(IPCC)Report,releasedtoday.Manyofthechangesobservedintheclimateareunprecedentedinthousands,ifnothundredsofthousandsofyears,andsomeofthechangesalreadysetinmotion—suchascontinuedsealevelrise—areirreversibleoverhundredstothousandsofyears. However,strongandsustainedreductionsinemissionsofcarbondioxide(CO2)andothergreenhousegaseswouldlimitclimatechange.Whilebenefitsforairqualitywouldcomequickly,itcouldtake20-30yearstoseeglobaltemperaturesstabilize,accordingtotheIPCCWorkingGroupIreport,ClimateChange2021:thePhysicalScienceBasis,approvedonFridayby195membergovernmentsoftheIPCC,throughavirtualapprovalsessionthatwasheldovertwoweeksstartingonJuly26. TheWorkingGroupIreportisthefirstinstalmentoftheIPCC’sSixthAssessmentReport(AR6),whichwillbecompletedin2022. “Thisreportreflectsextraordinaryeffortsunderexceptionalcircumstances,”saidHoesungLee,ChairoftheIPCC.“Theinnovationsinthisreport,andadvancesinclimatesciencethatitreflects,provideaninvaluableinputintoclimatenegotiationsanddecision-making.” Fasterwarming Thereportprovidesnewestimatesofthechancesofcrossingtheglobalwarminglevelof1.5°Cinthenextdecades,andfindsthatunlessthereareimmediate,rapidandlarge-scalereductionsingreenhousegasemissions,limitingwarmingtocloseto1.5°Coreven2°Cwillbebeyondreach. Thereportshowsthatemissionsofgreenhousegasesfromhumanactivitiesareresponsibleforapproximately1.1°Cofwarmingsince1850-1900,andfindsthataveragedoverthenext20years,globaltemperatureisexpectedtoreachorexceed1.5°Cofwarming.Thisassessmentisbasedonimprovedobservationaldatasetstoassesshistoricalwarming,aswellprogressinscientificunderstandingoftheresponseoftheclimatesystemtohuman-causedgreenhousegasemissions. “Thisreportisarealitycheck,”saidIPCCWorkingGroupICo-ChairValérieMasson-Delmotte.“Wenowhaveamuchclearerpictureofthepast,presentandfutureclimate,whichisessentialforunderstandingwhereweareheaded,whatcanbedone,andhowwecanprepare.” Everyregionfacingincreasingchanges Manycharacteristicsofclimatechangedirectlydependonthelevelofglobalwarming,butwhatpeopleexperienceisoftenverydifferenttotheglobalaverage.Forexample,warmingoverlandislargerthantheglobalaverage,anditismorethantwiceashighintheArctic. “ClimatechangeisalreadyaffectingeveryregiononEarth,inmultipleways.Thechangesweexperiencewillincreasewithadditionalwarming,”saidIPCCWorkingGroupICo-ChairPanmaoZhai. Thereportprojectsthatinthecomingdecadesclimatechangeswillincreaseinallregions.For1.5°Cofglobalwarming,therewillbeincreasingheatwaves,longerwarmseasonsandshortercoldseasons.At2°Cofglobalwarming,heatextremeswouldmoreoftenreachcriticaltolerancethresholdsforagricultureandhealth,thereportshows. Butitisnotjustabouttemperature.Climatechangeisbringingmultipledifferentchangesindifferentregions–whichwillallincreasewithfurtherwarming.Theseincludechangestowetnessanddryness,towinds,snowandice,coastalareasandoceans.Forexample: Climatechangeisintensifyingthewatercycle.Thisbringsmoreintenserainfallandassociatedflooding,aswellasmoreintensedroughtinmanyregions. Climatechangeisaffectingrainfallpatterns.Inhighlatitudes,precipitationislikelytoincrease,whileitisprojectedtodecreaseoverlargepartsofthesubtropics.Changestomonsoonprecipitationareexpected,whichwillvarybyregion. Coastalareaswillseecontinuedsealevelrisethroughoutthe21stcentury,contributingtomorefrequentandseverecoastalfloodinginlow-lyingareasandcoastalerosion.Extremesealeveleventsthatpreviouslyoccurredoncein100yearscouldhappeneveryyearbytheendofthiscentury. Furtherwarmingwillamplifypermafrostthawing,andthelossofseasonalsnowcover,meltingofglaciersandicesheets,andlossofsummerArcticseaice. Changestotheocean,includingwarming,morefrequentmarineheatwaves,oceanacidification,andreducedoxygenlevelshavebeenclearlylinkedtohumaninfluence.Thesechangesaffectbothoceanecosystemsandthepeoplethatrelyonthem,andtheywillcontinuethroughoutatleasttherestofthiscentury. Forcities,someaspectsofclimatechangemaybeamplified,includingheat(sinceurbanareasareusuallywarmerthantheirsurroundings),floodingfromheavyprecipitationeventsandsealevelriseincoastalcities. Forthefirsttime,theSixthAssessmentReportprovidesamoredetailedregionalassessmentofclimatechange,includingafocusonusefulinformationthatcaninformriskassessment,adaptation,andotherdecision-making,andanewframeworkthathelpstranslatephysicalchangesintheclimate–heat,cold,rain,drought,snow,wind,coastalfloodingandmore–intowhattheymeanforsocietyandecosystems. ThisregionalinformationcanbeexploredindetailinthenewlydevelopedInteractiveAtlasinteractive-atlas.ipcc.chaswellasregionalfactsheets,thetechnicalsummary,andunderlyingreport. Humaninfluenceonthepastandfutureclimate “IthasbeenclearfordecadesthattheEarth’sclimateischanging,andtheroleofhumaninfluenceontheclimatesystemisundisputed,”saidMasson-Delmotte.Yetthenewreportalsoreflectsmajoradvancesinthescienceofattribution–understandingtheroleofclimatechangeinintensifyingspecificweatherandclimateeventssuchasextremeheatwavesandheavyrainfallevents. Thereportalsoshowsthathumanactionsstillhavethepotentialtodeterminethefuturecourseofclimate.Theevidenceisclearthatcarbondioxide(CO2)isthemaindriverofclimatechange,evenasothergreenhousegasesandairpollutantsalsoaffecttheclimate. “Stabilizingtheclimatewillrequirestrong,rapid,andsustainedreductionsingreenhousegasemissions,andreachingnetzeroCO2emissions.Limitingothergreenhousegasesandairpollutants,especiallymethane,couldhavebenefitsbothforhealthandtheclimate,”saidZhai.   Formoreinformationcontact: [email protected],+41227308120 [email protected] NadaCaud(French)[email protected]   NotesforEditors ClimateChange2021:ThePhysicalScienceBasis.ContributionofWorkingGroupItotheSixthAssessmentReportoftheIntergovernmentalPanelonClimateChange TheWorkingGroupIreportaddressesthemostupdatedphysicalunderstandingoftheclimatesystemandclimatechange,bringingtogetherthelatestadvancesinclimatescience,andcombiningmultiplelinesofevidencefrompaleoclimate,observations,processunderstanding,globalandregionalclimatesimulations.Itshowshowandwhyclimatehaschangedtodate,andtheimprovedunderstandingofhumaninfluenceonawiderrangeofclimatecharacteristics,includingextremeevents.Therewillbeagreaterfocusonregionalinformationthatcanbeusedforclimateriskassessments. TheSummaryforPolicymakersoftheWorkingGroupIcontributiontotheSixthAssessmentReport(AR6)aswellasadditionalmaterialsandinformationareavailableathttps://www.ipcc.ch/report/ar6/wg1/ Note:OriginallyscheduledforreleaseinApril2021,thereportwasdelayedforseveralmonthsbytheCOVID-19pandemic,asworkinthescientificcommunityincludingtheIPCCshiftedonline.ThisisfirsttimethattheIPCChasconductedavirtualapprovalsessionforoneofitsreports. AR6WorkingGroupIinnumbers 234authorsfrom66countries 31–coordinatingauthors 167–leadauthors 36–revieweditors plus 517–contributingauthors Over14,000citedreferences Atotalof78,007expertandgovernmentreviewcomments (FirstOrderDraft23,462;SecondOrderDraft51,387;FinalGovernmentDistribution:3,158) MoreinformationabouttheSixthAssessmentReportcanbefoundhere. AbouttheIPCC TheIntergovernmentalPanelonClimateChange(IPCC)istheUNbodyforassessingthesciencerelatedtoclimatechange.ItwasestablishedbytheUnitedNationsEnvironmentProgramme(UNEP)andtheWorldMeteorologicalOrganization(WMO)in1988toprovidepoliticalleaderswithperiodicscientificassessmentsconcerningclimatechange,itsimplicationsandrisks,aswellastoputforwardadaptationandmitigationstrategies.InthesameyeartheUNGeneralAssemblyendorsedtheactionbytheWMOandUNEPinjointlyestablishingtheIPCC.Ithas195memberstates. ThousandsofpeoplefromallovertheworldcontributetotheworkoftheIPCC.Fortheassessmentreports,IPCCscientistsvolunteertheirtimetoassessthethousandsofscientificpaperspublishedeachyeartoprovideacomprehensivesummaryofwhatisknownaboutthedriversofclimatechange,itsimpactsandfuturerisks,andhowadaptationandmitigationcanreducethoserisks. TheIPCChasthreeworkinggroups:WorkingGroupI,dealingwiththephysicalsciencebasisofclimatechange;WorkingGroupII,dealingwithimpacts,adaptationandvulnerability;andWorkingGroupIII,dealingwiththemitigationofclimatechange.ItalsohasaTaskForceonNationalGreenhouseGasInventoriesthatdevelopsmethodologiesformeasuringemissionsandremovals.AspartoftheIPCC,aTaskGrouponDataSupportforClimateChangeAssessments(TG-Data)providesguidancetotheDataDistributionCentre(DDC)oncuration,traceability,stability,availabilityandtransparencyofdataandscenariosrelatedtothereportsoftheIPCC. IPCCassessmentsprovidegovernments,atalllevels,withscientificinformationthattheycanusetodevelopclimatepolicies.IPCCassessmentsareakeyinputintotheinternationalnegotiationstotackleclimatechange.IPCCreportsaredraftedandreviewedinseveralstages,thusguaranteeingobjectivityandtransparency.AnIPCCassessmentreportconsistsofthecontributionsofthethreeworkinggroupsandaSynthesisReport.TheSynthesisReportintegratesthefindingsofthethreeworkinggroupreportsandofanyspecialreportspreparedinthatassessmentcycle. AbouttheSixthAssessmentCycle Atits41stSessioninFebruary2015,theIPCCdecidedtoproduceaSixthAssessmentReport(AR6).Atits42ndSessioninOctober2015itelectedanewBureauthatwouldoverseetheworkonthisreportandtheSpecialReportstobeproducedintheassessmentcycle. GlobalWarmingof1.5°C,anIPCCspecialreportontheimpactsofglobalwarmingof1.5degreesCelsiusabovepre-industriallevelsandrelatedglobalgreenhousegasemissionpathways,inthecontextofstrengtheningtheglobalresponsetothethreatofclimatechange,sustainabledevelopment,andeffortstoeradicatepovertywaslaunchedinOctober2018. ClimateChangeandLand,anIPCCspecialreportonclimatechange,desertification,landdegradation,sustainablelandmanagement,foodsecurity,andgreenhousegasfluxesinterrestrialecosystemswaslaunchedinAugust2019,andtheSpecialReportontheOceanandCryosphereinaChangingClimatewasreleasedinSeptember2019. InMay2019theIPCCreleasedthe2019Refinementtothe2006IPCCGuidelinesforNationalGreenhouseGasInventories,anupdatetothemethodologyusedbygovernmentstoestimatetheirgreenhousegasemissionsandremovals. TheothertwoWorkingGroupcontributionstotheAR6willbefinalizedin2022andtheAR6SynthesisReportwillbecompletedinthesecondhalfof2022. Formoreinformationgotowww.ipcc.ch ThewebsiteincludesoutreachmaterialsincludingvideosabouttheIPCCandvideorecordingsfromoutreacheventsconductedaswebinarsorlive-streamedevents. MostvideospublishedbytheIPCCcanbefoundonourYouTubeandVimeochannels. Date August9,2021 Downloads Pressrelease(2021/17/PR)inPDF-English Pressrelease(2021/17/PR)inPDF-Arabic Pressrelease(2021/17/PR)inPDF-Chinese Pressrelease(2021/17/PR)inPDF-French Pressrelease(2021/17/PR)inPDF-Russian Pressrelease(2021/17/PR)inPDF-Spanish Shortbiosofthepressconferencespeakers