Assessment of East Antarctic Ice Sheet sensitivity to warming and its potential for contributions to sea level rise

Scientific question and rationale for study

The primary question driving this program is the sensitivity of the East Antarctic Ice Sheet (EAIS) to warming and its potential contribution to sea level rise in the future. Despite intense study of the West Antarctic Ice Sheet (WAIS), little is known about the inherent dynamics of the ice contained within the marine-based Aurora and Wilkes Subglacial basins (ASB, WSB respectively). Totten Glacier, the main outlet from the ASB, is estimated to contribute 3.8 m sea level equivalent (SLE) (all estimates from Rignot et al., 2019), while the WSB is estimated to have a SLE contribution of 2.5 m, contributions that together are similar to that of the estimated WAIS contribution of 5.3 m SLE. Direct observations and sampling at the interface between the ice sheet and subglacial materials can provide the first ever assessment of past ice-sheet history and the current conditions governing glacial flow and instability. The recovery of Pliocene marine sediments from interior sectors of these subglacial basins would provide direct evidence for past large-scale retreat in these sectors during the most recent time Earth experienced modern CO2 levels. These data will provide critical constraints to improve modeling skill regarding vulnerability for future ice margin retreat and sea level rise. This document outlines the scientific rationale for a comprehensive and collaborative study of East Antarctica that addresses these first-order problems.