Articles | Volume 10, issue 5
Research article
30 Sep 2016
Research article |  | 30 Sep 2016

Impacts of marine instability across the East Antarctic Ice Sheet on Southern Ocean dynamics

Steven J. Phipps, Christopher J. Fogwill, and Christian S. M. Turney

Abstract. Recent observations and modelling studies have demonstrated the potential for rapid and substantial retreat of large sectors of the East Antarctic Ice Sheet (EAIS). This has major implications for ocean circulation and global sea level. Here we examine the effects of increasing meltwater from the Wilkes Basin, one of the major marine-based sectors of the EAIS, on Southern Ocean dynamics. Climate model simulations reveal that the meltwater flux rapidly stratifies surface waters, leading to a dramatic decrease in the rate of Antarctic Bottom Water (AABW) formation. The surface ocean cools but, critically, the Southern Ocean warms by more than 1 °C at depth. This warming is accompanied by a Southern Ocean-wide “domino effect”, whereby the warming signal propagates westward with depth. Our results suggest that melting of one sector of the EAIS could result in accelerated warming across other sectors, including the Weddell Sea sector of the West Antarctic Ice Sheet. Thus, localised melting of the EAIS could potentially destabilise the wider Antarctic Ice Sheet.

Short summary
We explore the effects of melting of the East Antarctic Ice Sheet on the Southern Ocean. Using a climate model, we find that melting changes the ocean circulation and causes warming of more than 1 °C at depth. We also discover the potential existence of a "domino effect", whereby the initial warming spreads westwards around the Antarctic continent. Melting of just one sector could therefore destabilise the wider Antarctic Ice Sheet, leading to substantial increases in global sea level.