Increased Warm Water Intrusions Could Cause Mass Loss in East Antarctica During the Next 200 Years

The East Antarctic Ice Sheet (EAIS) is currently surrounded by relatively cool water, but climatic shifts have the potential to increase basal melting via intrusions of warm modified Circumpolar Deep Water (mCDW) onto the continental shelf. Here we use an ice sheet model to show that under the current ocean regime, with only limited intrusions of mCDW, the EAIS will likely gain mass over the next 200 years due to the increased precipitation from a warming atmosphere outweighing increased ice discharge due to ice-shelf melting. However, if the ocean regime were to become dominated by greater mCDW intrusions, the EAIS would have a negative mass balance, contributing up to 48 mm of SLE over this time period. Our modelling finds George V Land to be particularly at risk to increased ocean induced melting. With warmer oceans, we also find that a mid range RCP4.5 emissions scenario is likely to result in a more negative mass balance than a high RCP8.5 emissions scenario, as the relative difference between increased precipitation due to a warming atmosphere and increased ice discharge due to a warming ocean is more negative in the mid range RCP4.5 emission scenario.