The Antarctic Peninsula under a 1.5°C global warming scenario What change is it locked into? MARTIN SIEGERT 1 , ANGUS ATKINSON 2 , ALISON BANWELL 3 , MARK BRANDON 4 , PETER CONVEY 5 , BETHAN DAVIES 6 , ROD DOWNIE 7 , TAMSIN EDWARDS 8 , BRYN HUBBARD 9 , GARETH MARSHALL 5 , JOERI ROGELJ 1 , JANE RUMBLE 10 , JULIENNE STROEVE 11 , DAVID VAUGHAN 5 Introduction The UN Paris Agreement seeks to limit global warming to well below 2°C above pre-industrial levels, prompting an assessment of how to achieve a 1.5°C target 1,2 . Here, we bring together information on how a 1.5°C scenario will affect the Antarctic Peninsula, noting it has already experienced rapid change in atmospheric climate, ocean and ice conditions, and the impacts of direct human activities. Antarctic Treaty Parties, as well as other interested parties, are invited to consider the implications of these predictions for the governance of human activities in the Antarctic Peninsula over the coming decades. Grantham Institute Briefing note No 10 April 2019 Highlights • Antarctic Peninsula warming in the late 20th Century was greater than anywhere else in the Southern Hemisphere. • With a further increase in global temperatures of 0.5°C: – Antarctic Peninsula temperatures will increase by 1-2°C in winter and 0.5-1.0°C in summer, with up to 130 days per year above 0°C, leading to increased rain, snow and ice melt, and surface run-off. – Ocean turbulence will increase and deliver heat to the sea surface and coast. – Sea ice extent will be highly variable west of the Antarctic Peninsula. – Retreat of marine glacier margins will accelerate, increasing iceberg production. – Meltwater production will increase on ice shelves, but will likely not lead to further collapses. – Southward shifts in marine life distribution have been observed and will continue. – Ice-free land area will expand, providing habitats for native and non-native plants and invertebrates, with each likely to benefit from warming. • Non-native species are a far greater threat to native biodiversity than the direct impacts of warming under a 1.5°C scenario. 1. Grantham Institute, Imperial College London, Exhibition Road, South Kensington, London SW7 2AZ, UK 2. Plymouth Marine Laboratory, Prospect Place, Plymouth, PL1 3DH, UK 3. Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder 80309 CO, USA. 4. School of Environment, Earth and Ecosystem Sciences, Open University, Milton Keynes, MK7 6AA UK 5. British Antarctic Survey, NERC High Cross, Madingley Road, Cambridge, CB3 0ET, UK 6. Centre for Quaternary Research, Department of Geography, Royal Holloway University of London, Egham, TW20 0EX, UK 7. WWF UK, The Living Planet Centre, Rufford House, Brewery Rd, Woking GU21 4LL, UK 8. Department of Geography, King’s College London, London, WC2R 2LS, UK 9. Department of Geography & Earth Sciences, Aberystwyth University, Aberystwyth, SY23 3DB, UK 10. Polar Regions Department, UK Foreign & Commonwealth Office, W2.80 King Charles Street, London SW1A 2AH, UK 11. Centre for Polar Observation and Modelling, University College London, Gower Street, London, WCE 1BT, UK
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The Antarctic Peninsula under a 1.5°C global warming scenario What change is it locked into? MARTIN SIEGERT1, ANGUS ATKINSON2, ALISON BANWELL3, MARK BRANDON4, PETER CONVEY5, BETHAN DAVIES6, ROD DOWNIE7, TAMSIN EDWARDS8, BRYN HUBBARD9, GARETH MARSHALL5, JOERI ROGELJ1, JANE RUMBLE10, JULIENNE STROEVE11, DAVID VAUGHAN5
How will the Antarctic Peninsula respond in a 1.5°C scenario?
Climate and weather. AntarcticPeninsulatemperatureswillincreasebymorethantheglobalaverageina1.5°Cscenario2.ThislevelofwarminghasalreadybeenexceededinthenorthernPeninsula10,despitetherecentpauseinrisingtemperaturesintheregion11.Regionaltemperaturescouldincreaseby1-2°Cinwinterand0.5-1.0°Cinsummerbeyondcurrentlevels12.Warmingof1°Cfromtodaywillresultina50to150percentincreaseindaysperyearabove0°C,fromarangeof25to80daysinthenorthernAntarcticPeninsulato
Land ice. AntarcticPeninsulaglaciersaresteepandfastflowing,andrespondrapidlytoclimatechange6.Oceanwarmingislikelytocauseacceleratedrecessionofglaciersthatareincontactwiththesea,withslowerrecessiondrivenbyatmosphericchangesforglaciersthatendinland.Thinningandrecessionofglaciersthatextendfromthelandintotheocean,knownasmarine-terminatingglaciers,arethereforeexpectedtoaccelerate,drivenlargelybyincreasedupwellingofwarmCDW.Oncethemarine-terminatingglaciersretreattotheirlandmarginstheywillexperienceslowerthinningandrecession.InsouthernPalmerLand,glaciersaregroundeddeeplybelowsealevelwhichcouldleadtosignificantglacierretreat16.Undera1.5°Cscenario,glaciersonlandwillexperiencemoremeltingthanatpresent16,22,causingincreasedsurfacerun-off.
THE ANTARCTIC PENINSULA UNDERA GLOBAL 1.5°C SCENARIOAn assessment of how atmospheric, oceanographic, glaciologicaland biological processes may be affected if global averagetemperatures are limited to 1.5ºC above pre-industrial levels (i.e.another 0.5ºC increase globally).
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Low
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ANTARCTICAW
SITUATION TODAY AT 1°C of GLOBAL WARMING
Krill and sea-ice dependent food web (e.g. with Antarctic krill, Crabeater- and Weddell seals, Adélie penguins) is still present in the north.
CHANGES EXPECTED UNDER 1.5°C OF GLOBAL WARMING35-130 days per year above 0°Cin the northern Peninsula
Increasing populations of native species, and numbers and impacts of non-native species, on exposed surfaces.
Increased surface melting on glaciers andice shelves. Wholescale ice-shelf instability is not expected
Retreat of marine margins of glaciers.
Krill-dependentfood web
Loss of Larsen Aand B ice shelves.
25-80 days per year above 0°C in the northern Peninsula
Productive new habitat may open up with the reduced ice shelves, glaciers and sea ice.
Krill and sea-ice dependent food web displaced southward down peninsula.
Bottom-dwelling species with limited dispersal capability stressed by impacts from icebergs, changes in surface productivity, warming and ocean acidification.
Terrestrial communities on exposed surfaces.
The sea ice is typically further south on this side of the Peninsula.
Annual presenceof sea ice.
Sea ice limited and variable west of the peninsula.
Species less dependent on krill and sea ice (e.g. fur seals, elephant seals, gentoo penguins) increase around the northern peninsula.
Cold water circulating clockwise around the Weddell Sea approaches the Peninsula.
Relatively warm Circumpolar Deep Water approaches the Peninsula at depth.
Cold water circulating clockwise around the Weddell Sea approaches the Peninsula maintains the sea ice cover.
Circumpolar Deep Water is expected to increase in temperature and ascend closer to the surface.
2. IPCC,2018:SummaryforPolicymakers.In:Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty[Masson-Delmotteetal.(eds.)].World Meteorological Organization, Geneva, Switzerland, 32pp.
16. Gille,S.T.(2014).MeridionaldisplacementoftheAntarcticCircumpolarCurrent.Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences, 372(2019),20130273.
20. Turner,J.,Hosking,J.S.,Bracegirdle,T.J.,Marshall,G.J.,&Phillips,T.(2015).RecentchangesinAntarcticSeaIce.Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 373(2045).
About the authorsProfessor Martin SiegertisCo-DirectoroftheGranthamInstitute,andanAntarcticglaciologist.Hespecialisesinusingairbornegeophysicalmeasurementstounderstandtheflowandformofpolaricesheets.In2013hewasawardedtheMarthaTMusePrizeforAntarcticScienceandPolicybytheTinkerFoundation.
Dr. Angus AtkinsonisaseniorplanktonecologistatPlymouthMarineLaboratory.Hehasmaintainedalong-standinginterestintheresponseofzooplanktontoclimatechange,withfocusonpolarfoodwebsandparticularlyonAntarctickrill.
25. Banwell,A.F.,D.R.MacAyeal,andO.V.Sergienko,Breakup of the Larsen B Ice Shelf triggered by chain reaction drainage of supraglacial lakes.GeophysicalResearchLetters,2013.40(22):p.5872-5876.
26. Bell,R.E.etal.Antarctic ice shelf potentially stabilized by export of meltwater in surface river. Nature544,344–348(2017).
Dr. Alison BanwellisaResearchFellowattheCooperativeInstituteforResearchinEnvironmentalSciences(CIRES)attheUniversityofColoradoBoulder.Sheisaglaciologistwhoisprimarilyinterestedinthepolarregions,andcurrentlyspecialisesinAntarcticice-shelfhydrologyanddynamicsthroughmodelling,remotesensingandfieldwork.
Professor Mark Brandonisanoceanographerwithover25yearsexperience,basedattheOpenUniversity.Hehasatrackrecordofsuccessfullargeprojectsandextensivepublicengagement.
Professor Peter ConveyisapolarterrestrialecologistandhasbeenworkingwiththeBritishAntarcticSurveyinbothpolarregionsforover30years.Hehaswideinterestsinallaspectsofterrestrialecosystems,butparticularlyinbiodiversity,biogeographyandhumanimpactsinthepolarregions.
Dr. Bethan DaviesisaSeniorLecturerinQuaternaryGeologyatRoyalHolloway,UniversityofLondon.Sheisaglacialgeologistinterestedintheinteractionbetweenglaciersandclimateovermultipletimescales.
Dr. Rod DownieistheChiefPolarAdvisoratWWF.RodhasledWWFspolarprogrammeintheUKsince2011,following14yearswiththeBritishAntarcticSurvey.Hehascompleted15fieldseasonsintheAntarctic,totallingmorethantwo-and-a-halfyearslivingandworkingontheice.
Dr. Tamsin EdwardsisaclimatescientistatKing’sCollegeLondon,specialisingintestingandassessinguncertaintiesforclimatemodels,especiallyfortheAntarcticandGreenlandicesheetcontributionstofuturesealevelrise.Sheisalsoanexperiencedcommunicator,involvedinpublicengagementwithscience.
Professor Bryn Hubbardisafieldglaciologist,specializinginborehole-basedinvestigationsofthethree-dimensionalphysicalstructureoficemasses.Thisresearchfocuseson,forexample,firnificationprocesses,englacialicetemperatureanddeformation,andthelinksbetweenglaciermotionandhydrology.
Dr. Gareth Marshall isaseniorclimatologistattheBritishAntarcticsurvey.
Dr Joeri RogeljisaLecturerinClimateChangeattheGranthamInstituteresearchinghowourunderstandingoftheEarthsystemcanaffectclimatepolicy.HeservedasaCoordinatingLeadAuthorontheSpecialReporton
Jane RumblejoinedthePolarRegionsDepartmentintheForeign&CommonwealthOfficein2003,andshehasbeenHeadoftheDepartmentsinceJanuary2007.Inthisrole,JaneleadsonallAntarcticissuesfortheUKGovernmentandoverseestheUK’sengagementwiththeArcticCouncil.JanewasmadeanOBEattheQueen’sBirthdayHonoursinJune2018forservicestoPolarscience,marineconservationanddiplomacy;andwasmadeanhonoraryDoctorofSciencebyLeedsUniversityinJuly2018.
Professor Julienne Stroeveisasea-icescientistatUniversityCollegeLondonwhospecialisesinremotesensingofthepolarregions.ShewasrecentlyawardedaCanada150ResearchExcellenceChairattheUniversityofManitoba.
Professor David VaughanistheDirectorofScienceattheBritishAntarcticSurvey.Hehasadistinguishedcareerinunderstandingicesheetsandthecryosphereandin2017hewasawardedanOBEforservicestoscience.
