Antarctic Ice Sheet Discharge Driven by Atmosphere-Ocean Feedbacks Across the Last Glacial Termination

• Published in: Scientific Reports
• Main Authors: Fogwill, C, Menviel, Laurie, Turney, Chris, Millman, Helen, VOHRA, Juee, Golledge, Nicholas
• Format: Conference Object
• Language: unknown
• Published: Springer Nature 2016
• Subjects: 13 Climate Action; Antarctic; The Antarctic; Weddell; Weddell Sea; Antarc*; Antarctica; ice core; Ice Sheet
• Online Access: http://hdl.handle.net/1959.4/unsworks_46066; https://unsworks.unsw.edu.au/bitstreams/c384f804-9e86-433f-b71b-f91d98ccf99a/download; https://doi.org/10.1038/srep39979

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 identify ice-climate feedbacks that could improve future projections1,2. Whilst the sequence of events during this period are reasonably well-known, relatively poor chronological control has precluded precise alignment of ice, atmospheric and marine records2, making it difficult to assess relationships between Antarctic ice-sheet dynamics, climate change and sea-level rise3-5. Here we present results from a highly-resolved ‘horizontal ice core’6,7 from the Weddell Sea Embayment, which records millennial-scale ice-sheet dynamics across this extensive sector of Antarctica. Counterintuitively, we find ice-sheet surface drawdown of 600 m across the Antarctic Cold Reversal (ACR; 14,600-12,700 yrs ago)5, with stabilisation during the subsequent millennia of atmospheric warming. Earth system and ice-sheet modelling highlights that this response was likely sustained by strong ocean-ice feedbacks4,8; however, the drivers remain uncertain. Given the coincidence of the ice-sheet changes recorded with marked shifts in atmospheric circulation9,10,11we suggest that millennial-scale Antarctic ice-sheet behaviour was initiated and sustained by global atmospheric teleconnections across the LGT. This has important ramifications ice-sheet stability under contemporary climate change, with changing atmospheric and oceanic circulation patterns.