Antarctic ice sheet discharge driven by atmosphere-ocean feedbacks at the Last Glacial Termination

Fogwill, C.J., Turney, C.S.M., Golledge, N.R., Etheridge, D.M., Rubino, M., Thornton, D.P., Baker, A., Woodward, J., Winter, K., Van Ommen, T.D., Moy, A.D., Curran, M.A.J., Davies, S.M., Weber, M.E., Bird, M.I., Munksgaard, N.C., Menviel, L., Rootes, C.M., 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.

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Abstract

Reconstructing 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.

Item ID: 52291
Item Type: Article (Refereed Research - C1)
Additional Information:

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ISSN: 2045-2322
Funders: Australian Research Council (ARC), Royal Society of New Zealand, Natural Environment Research Council (NERC), UK, Coleg Cymraeg Cenedlaethol, European Research Council (ERC)
Projects and Grants: ARC LP120200724, NERC NE/I027576/1, ERC 25923, ARC DE150100107
Date Deposited: 26 Feb 2018 22:48
FoR Codes: 04 EARTH SCIENCES > 0499 Other Earth Sciences > 049999 Earth Sciences not elsewhere classified @ 50%
04 EARTH SCIENCES > 0405 Oceanography > 040599 Oceanography not elsewhere classified @ 50%
SEO Codes: 96 ENVIRONMENT > 9603 Climate and Climate Change > 960303 Climate Change Models @ 50%
96 ENVIRONMENT > 9603 Climate and Climate Change > 960306 Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts) @ 50%
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