assessment of the earth’s energy and sea level...

JohnA.Church1,Ma0hewD.Palmer2andSusanWijffels11CSIROOceansandAtmosphere,Hobart,Australia2MetOfficeHadleyCentre,Exeter,UnitedKingdomOCEANSANDATMOSPHERENATIONALRESEARCHFLAGSHIP

AssessmentoftheEarth’sEnergyandSeaLevelChanges

vonSchuckmannetal[2016]

Earth’senergyimbalance:thedriverofglobalclimatechange

PalmerandMcNeall[2014]vonSchuckmannetal[2016]

SurfacetemperatureisaweakindicatorofEarth’senergyimbalanceondecadalJmescales

PalmerandMcNeall[2014]vonSchuckmannetal[2016]

OceanheatcontentchangeisareliableonEarth’senergyimbalanceondecadalJmescales

Oceansabsorbed>90%oftheenergystorageandaccountforathirdofradiaJveforcing

5IPCCWGICh3&13

TheArgoArrayprovideshigh-quality,globalcoverageto2000m,fromabout2006• Mapoceanheatcontentandstericsealevel•  Qualitycontrolofdataimportant.Bewareofbiasesfromhistoricaldatabases.

•  Coveragenotcompletepriorto2006

6

ArgoheatcontentesJmatestolate2015SteadyheaJngofocean,parJcularlySouthernOceanandfrom300mto2000m

7|

Wijffelsetal.2016

DeepOceanWarming• Sincethe1990s,whensufficientdeep-oceanobservaUonshavebecomeavailabletoallowanassessment,thedeepoceanbelow3000mdepthhaslikelywarmed.

SPM-4andChapter3.2:DeepOceanWarming

Fig3.3Meanwarmingratesbelow4000mcenteredon1992–2005.SUppledareasnotsignificantat95%.Thickblacklines-RepeatoceanographictransectsusedtoesUmatewarmingrates.DatafromPurkeyandJohnson(2010).

Totalenergystorageconsistentwithclimatemodelensemble(butsignificantvariabilitybetweenmodels)

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• Upper2000mofoceansampledbyArgo=0.5-0.65Wm-2

• Fulloceanarea&deepocean=0.65-0.8Wm-2

• 0.7–0.86Wm-2incllithosphere,cryosphere,atmosphere

ModelresultsfromChurchetal.2013,IPCCWGIAR5Ch13

Rateofheatstoragehasincreased,withsignificantstorageindeepocean

Gleckleretal[2016]

Progresstowardsadeepoceanobservingsystem–needtomaintainGO-SHIPandextendArgotofulldepth

GO-SHIPnowprovidesobservaUonsinthedeepocean(>2000m)

Straw-planfor5x5degreeDeepArgofloatarray0-4000mand0-6000mfloatsarecurrentlybeingdeployedinpilotstudies

Globalsealevelandenergybudgetslinked

RelaUvesealevelisalsoaffectedbyoceandensityandcirculaUon,landmovement,anddistribuUonofmassontheEarth

Fig13.1

Warming(cooling)oftheocean(thermalexpansion/contracUon)

Changeinmassofglaciersandicesheets(BarystaUc)

Changesinliquidwaterstorageonland(BarystaUc)

SealevelisconJnuingtoriseatafasterratethantheaverageduringthe20thcentury

Timeofemergenceforregionalsea-levelchange13|

Thetrendisnotuniformglobally

Timeofemergenceforregionalsea-levelchange14|

ThestrongElNiñohasresultedinhighsealevelanomaliesintheeasternPacificattheendof2015

AswellasthermalexpansionandglaciercontribuJons,theGreenlandandAntarcJcIceSheetsarelosingmass

Timeofemergenceforregionalsea-levelchange16| Velicognaetal.2014

PastclimatevariaJonsimportantforsealevelrisepriorto1950–Anthropogenicforcingdominatesa`er1970

Slangenetal.,inreview

Conclusions• OceanheatcontentcriUcalelementofkeepingtrackofclimatechangeandunderstandingtheEarth’sradiaUonandsealevelbudgets.

• ArgoallowsmuchimprovedesUmatesofupper(<2km)oceanheatcontent-needtoextendtofulldepthandfulloceancoverage,complementedbyrepeatsecUons.

• Unequivocalwarmingoverdecades–EsUmatesconsistentwithCMIP5modelesUmatesofoceanheatcontent.

• SealevelconUnuingtorise;StrongElNiñoinlate2015resultedinhighersealevelsintheeasternPacific.

• ContribuUonsfromthermalexpansionandtheaddiUonofmassfromglaciersandicesheets.

• Anthropogenicclimatechangedominatesrecentrise.• HeatcontentandsealevelarecriUcalmeasuresofefficacyofmiUgaUon.

• Longtermcommitment!18|

InsitudatasuggestsreprocessedalJmeterdatahassmallertrendandaposiJve(notsignificant)acceleraJon(ratherthanadeceleraJon)

Watson et al. 2015

• ObservaUon-basedesUmateNocreatedbyaveragingsatelliteandAMIPsimulaUons

• Goodagreement(r=0.82)withensemblemeanofCMIP5coupledmodels

• VariaUonsdominatedbyvolcanicerupUons(Agung1963,ElChichon1982andPinatubo1991)

• AbsolutevaluesofNfordifferentperiodsinreasonableagreementwithCMIP5andIPCC

Smithetal.2014

Improvedunderstandingof20thcenturysealevelchangeObservedcontribuUonsexplainobservedGMSLR1993-2010

DatafromTable13.1

Figure13.7

Anthropogenicinfluence

Measureoceanmassanditscomponents–significantuncertainJesremainCompareoceanicandgravitaJonalesJmateofregionaloceanmasschange

Diengetal.2015Purkeyetal.2014

CanwebackouticesheetandlandwatercontribuUons?(e.g.Reageretal.2016)

AlJmeterandstericsealeveltrends2006to2014

Timeofemergenceforregionalsea-levelchange23|

DifferencesbetweenAlJmeterandsteric(0-2000m)trends–meanremoved

Timeofemergenceforregionalsea-levelchange24|

PalmerandMcNeall[2014]vonSchuckmannetal[2016]

TheglobaloceandominatestheenergybudgetonJmescales>1year

RadiaJveforcing,climatefeedbacksandstorageofenergywithintheclimatesystemareconsistentwiththelikelyrange

ofclimatesensiJvity

Box13.1,Figure1IPCCAR5,Box13.1Fig1,Churchetal.2013