Early Last Interglacial ocean warming drove substantial ice mass loss from Antarctica

• Main Authors: Turney, Chris, Fogwill, Christopher, Golledge, Nicholas, McKay, Nicholas, van Sebille, Erik, Jones, Richard, Etheridge, David, Rubino, Mauro, Thornton, David, Davies, Siwan, Bronk Ramsey, Christopher, Thomas, Zoë, Bird, Michael, Munksgaard, Niels, Kohno, Mika, Woodward, John, Winter, Kate, Weyrich, Laura, Rootes, Camilla, Millman, Helen, Albert, Paul, Rivera, Andres, van Ommen, Tas, Curran, Mark, Moy, Andrew, Rahmstorf, Stefan, Kawamura, Kenji, Hillenbrand, Claus-Dieter, Weber, Michael, Manning, Christina, Young, Jennifer, Cooper, Alan
• Format: Text
• Language: unknown
• Published: Open Science Framework 2019
• Subjects: Antarctic; Southern Ocean; The Antarctic; West Antarctic Ice Sheet; Antarc*; Antarctica; Ice Sheet
• Online Access: https://dx.doi.org/10.17605/osf.io/3z69p; https://osf.io/3z69p/

The future response of the Antarctic ice sheets to rising temperatures remains highly uncertain. A valuable analogue for assessing the sensitivity of Antarctica to warming is the Last Interglacial (129-116 kyr), when global sea level peaked 6 to 9 meters above present. Here we report a blue-ice record of ice-sheet and environmental change from the periphery of the marine-based West Antarctic Ice Sheet (WAIS). Constrained by a widespread volcanic horizon and supported by ancient microbial DNA analyses, we provide the first direct evidence for Last Interglacial WAIS collapse, driven by ocean warming and associated with destabilization of sub-glacial hydrates. Ice-sheet modelling supports this interpretation and suggests a 2˚C warming of the Southern Ocean over a millennia could trigger a ~3.2 meter rise in global sea levels. Our data indicate Antarctica is highly vulnerable to projected increases in ocean temperatures and may drive ice-climate feedbacks that further amplify warming.