The multi-millennial Antarctic commitment to future sea-leve

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TitleThe multi-millennial Antarctic commitment to future sea-level riseAbstractAtmospheric warming is projected to increase global mean surface temperatures by 0.3 to 4.8 degrees Celsius above pre-industrial values by the end of this century. If anthropogenic emissions continue unchecked, the warming increase may reach 8-10 degrees Celsius by 2300 (ref. 2). The contribution that large ice sheets will make to sea-level rise under such warming scenarios is difficult to quantify because the equilibrium-response timescale of ice sheets is longer than those of the atmosphere or ocean. Here we use a coupled ice-sheet/ice-shelf model to show that if atmospheric warming exceeds 1.5 to 2 degrees Celsius above present, collapse of the major Antarctic ice shelves triggers a centennial- to millennial-scale response of the Antarctic ice sheet in which enhanced viscous flow produces a long-term commitment (an unstoppable contribution) to sea-level rise. Our simulations represent the response of the present-day Antarctic ice-sheet system to the oceanic and climatic changes of four representative concentration pathways (RCPs) from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We find that substantial Antarctic ice loss can be prevented only by limiting greenhouse gas emissions to RCP 2.6 levels. Higher-emissions scenarios lead to ice loss from Antarctic that will raise sea level by 0.6-3 metres by the year 2300. Our results imply that greenhouse gas emissions in the next few decades will strongly influence the long-term contribution of the Antarctic ice sheet to global sea level. Copyright 2015 Macmillan Publishers Limited. All rights reserved.AcknowledgementsWe thank the CMIP community for making their data openly available, and J. Lenaerts for providing present-day surface mass balance data. We are also grateful to K. Buckley (Victoria University high-performance computing cluster), C. Khroulev, T. Albrecht and the Parallel Ice Sheet Model groups at the University of Alaska, Fairbanks, and the Potsdam Institute for Climate Impact Research. This work was funded by contract VUW1203 of the Royal Society of New ZealandÅ› Marsden Fund, with support from the Antarctic Research Centre, Victoria University of Wellington, ANDRILL, GNS Science (NZ Ministry of Business Innovation and Employment contract C05X1001), National Science Foundation grant ANT-1043712, and the Australian Research Council (ARC). J. Renwick and D. Zwartz provided comments that improved the manuscript.Funding DetailsAustralian Research Council; ARC, Australian Research Council; ANT-1043712, NSF, Australian Research Council

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1st AuthorGolledge, N.AuthorGolledge, N.Kowalewski, D.Naish, T.Levy, R.Fogwill, C.Gasson, E.Year2015JournalNatureVolume526Number7573Pages421-425DOI10.1038/nature15706URLhttps://www.scopus.com/inward/recor.....f2610816348ea347e4cb556fcKeywordsanthropogenic effectemission inventoryglobal warminggreenhouse gasice sheetIntergovernmental Panel on Climate Changelong-term changesea level changesurface temperaturetimescaleviscoelastic fluid, air temperatureAntarcticaArticleatmospherecarbon footprintclimate changeice sheetice shelfpriority journalseasea levelsea level risesea surface temperaturetime series analysischemistrycomputer simulationfreezinggreenhouse effectheathuman activitiesice coverprevention and controlstatistics and numerical datatheoretical modeltime factoruncertainty, Antarctica, sea water, Antarctic RegionsAtmosphereComputer SimulationFreezingGlobal WarmingGreenhouse EffectHot TemperatureHuman ActivitiesIce CoverModels, TheoreticalOceans and SeasSeawaterTime FactorsUncertainty, rank3

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TypeArticleCitationGolledge, N., Kowalewski, D., Naish, T., Levy, R., Fogwill, C. and Gasson, E. (2015). The multi-millennial Antarctic commitment to future sea-level rise. Nature, 526(7573): 421-425