Increased warm water intrusions would cause mass loss in East Antarctica within 200 years

Increased warm water intrusions would cause mass loss in East Antarctica within 200 years

The East Antarctic Ice Sheet (EAIS) is the single largest potential contributor to future global mean sea level rise, containing 52.2 m of sea level equivalent. Current observations put the mass balance of the EAIS to be approximately stable (albeit with some margin of error), although future climatic conditions have the potential to change this. A warming climate is expected to have both a positive effect on ice sheet mass balance via increased precipitation and a negative effect via increased ice discharge over the grounding line, a process enhanced by ocean driven melting of floating ice reducing the buttressing effect of ice shelves. In addition to a general increase in the ocean temperature surrounding the EAIS there is the potential that future climatic shifts may increase the incidence of intrusions of warm Circumpolar Deep Water (CDW) onto the continental shelf, further increasing basal melting.

Here we show, by using a numerical ice-sheet model, simulations of the future EAIS under different  future climate scenarios, both with and without increased CDW intrusions. We find that without increased CDW intrusions the EAIS will have a negative contribution to sea level rise, with increased precipitation more than compensating increased ice discharge. If melting becomes predominately driven by CDW, however, our simulations find the EAIS to have a positive contribution to sea level rise. All simulations, both those with increased CDW forcing and those without, show an overall reduction in floating ice as well as a reduction in grounded ice area.