Antarctic ice sheet discharge driven by atmosphere-ocean fee

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TitleAntarctic ice sheet discharge driven by atmosphere-ocean feedbacks at the Last Glacial TerminationAbstractReconstructing the dynamic response of the Antarctic ice sheets to warming during the Last Glacial Termination (LGT; 18,000-11,650 yrs ago) allows us to disentangle ice-climate feedbacks that are key to improving future projections. Whilst the sequence of events during this period is reasonably well-known, relatively poor chronological control has precluded precise alignment of ice, atmospheric and marine records, making it difficult to assess relationships between Antarctic ice-sheet (AIS) dynamics, climate change and sea level. Here we present results from a highly-resolved 'horizontal ice core' from the Weddell Sea Embayment, which records millennial-scale AIS dynamics across this extensive region. Counterintuitively, we find AIS mass-loss across the full duration of the Antarctic Cold Reversal (ACR; 14,600-12,700 yrs ago), with stabilisation during the subsequent millennia of atmospheric warming. Earth-system and ice-sheet modelling suggests these contrasting trends were likely Antarctic-wide, sustained by feedbacks amplified by the delivery of Circumpolar Deep Water onto the continental shelf. Given the anti-phase relationship between inter-hemispheric climate trends across the LGT our findings demonstrate that Southern Ocean-AIS feedbacks were controlled by global atmospheric teleconnections. With increasing stratification of the Southern Ocean and intensification of mid-latitude westerly winds today, such teleconnections could amplify AIS mass loss and accelerate global sea-level rise. Copyright The Author(s) 2017.AcknowledgementsC.J.F., C.S.M.T. and N.R.G. are supported by their respective Australian Research Council (ARC) and Royal Society of N.Z. fellowships. Fieldwork was undertaken under ARC Linkage Project (LP120200724), supported by Linkage Partner Antarctic Logistics and Expeditions. J.W. and K.W. undertook GPR survey of the Patriot Hills record under NERC grant NE/I027576/1 with logistical field support from the British Antarctic Survey. We thank Dr Chris Hayward for electron microprobe assistance, Dr Nelia Dunbar for providing the Siple Dome data and Kathryn Lacey and Gareth James for help with preparing the tephra samples, CSIRO GASLAB personnel for support of gas analysis, and Prof. Bill Sturges and Dr Sam Allin of the Centre for Ocean and Atmospheric Sciences, University of East Anglia for performing the SF6 analyses. CSIROÅ› contribution was supported in part by the Australian Climate Change Science Program (ACCSP), an Australian Government Initiative. SMD acknowledges nancial support from Coleg Cymraeg Cenedlaethol and the European Research Council (ERC grant agreement no. 25923), LM acknowledges funding from the ARC (DE150100107). We thank A/Prof. Andrew Mackintosh for detailed discussions over the implications of our data and acknowledge the efforts of two anonymous reviewers whose detailed reviews strengthened the manuscript. The data reported in this paper are archived on the NOAA Paleoclimatology website. The author(s) wish to acknowledge use of the Ferret program for analysis and graphics of the LOVECLIM outputs presented in this paper. Ferret is a product of NOAA's Pacific Marine Environmental Laboratory. (Information is available at http://ferret.pmel.noaa.gov/Ferret/).Funding Details25923, ERC, European Research Council; DE150100107, ARC, Australian Research Council; NE/I027576/1, NERC, Natural Environment Research Council

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1st AuthorFogwill, C.AuthorFogwill, C.Turney, C.Golledge, N.Etheridge, D.Rubino, M.Thornton, D.Baker, A.Woodward, J.Winter, K.Van Ommen, T.Moy, A.Curran, M.Davies, S.Weber, M.Bird, M.Munksgaard, N.Menviel, L.Rootes, C.Ellis, B.Millman, H.Vohra, J.Rivera, A.Cooper, A.Year2017JournalScientific ReportsVolume7DOI10.1038/srep39979URLhttps://www.scopus.com/inward/recor.....5bbb2db222e20e205540a059c

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TypeArticleCitationFogwill, C., Turney, C., Golledge, N., Etheridge, D., Rubino, M., Thornton, D., Baker, A., Woodward, J., Winter, K., Van Ommen, T., Moy, A., Curran, M., Davies, S., Weber, M., Bird, M., Munksgaard, N., Menviel, L., Rootes, C., Ellis, B., Millman, H., Vohra, J., Rivera, A. and Cooper, A. (2017). Antarctic ice sheet discharge driven by atmosphere-ocean feedbacks at the Last Glacial Termination. Scientific Reports, 7 IdentifierFogwill2017Antarctica NZ supported?NoNZARI?No