New paper finds East Antarctic ice sheet will have negative contribution to sea levels over next 200 years

A paper published today in The Cryosphere studies one of the largest ice shelfs in East Antarctica and predicts increased accumulation of ice on the surface of the ice shelf will have a net contribution of decreasing sea levels over the 21st and 22nd centuries.

According to the authors,

"Overall, the increased accumulation computed by the atmosphere models outweighs ice stream acceleration so that the net contribution to sea level rise is negative."

Furthermore, the authors predict the grounding line of this ice shelf system will have "little grounding line retreat" and thus it very unlikely this ice sheet will break off from the continent. 

Related: New paper finds the majority of East Antarctic glaciers have advanced in size since 1990

The Cryosphere, 8, 1057-1068, 2014 www.the-cryosphere.net/8/1057/2014/ doi:10.5194/tc-8-1057-2014 Modelling the response of the Lambert Glacier–Amery Ice Shelf system, East Antarctica, to uncertain climate forcing over the 21st and 22nd centuries

Y. Gong^1,2, S. L. Cornford³, and A. J. Payne^3
1School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK
²Arctic Center, Lapland University, 96101, Rovaniemi, Finland
³School of Geographical Sciences, University of Bristol, Bristol BS8 1SS, UK
Abstract. The interaction between the climate system and the large polar ice sheet regions is a key process in global environmental change. We carried out dynamic ice simulations of one of the largest drainage systems in East Antarctica: the Lambert Glacier–Amery Ice Shelf system, with an adaptive mesh ice sheet model. The ice sheet model is driven by surface accumulation and basal melt rates computed by the FESOM (Finite-Element Sea-Ice Ocean Model) ocean model and the RACMO2 (Regional Atmospheric Climate Model) and LMDZ4 (Laboratoire de Météorologie Dynamique Zoom) atmosphere models. The change of ice thickness and velocity in the ice shelf is mainly influenced by the basal melt distribution, but, although the ice shelf thins in most of the simulations, there is little grounding line retreat. We find that the Lambert Glacier grounding line can retreat as much as 40 km if there is sufficient thinning of the ice shelf south of Clemence Massif, but the ocean model does not provide sufficiently high melt rates in that region. Overall, the increased accumulation computed by the atmosphere models outweighs ice stream acceleration so that the net contribution to sea level rise is negative.