PerspectiveOcean Science

Ice Sheet Stability and Sea Level

Science  15 May 2009:
Vol. 324, Issue 5929, pp. 888-889
DOI: 10.1126/science.1173958

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Summary

Volume changes in the Antarctic Ice Sheet are poorly understood, despite the importance of the ice sheet to sea-level and climate variability. Over both millennial and shorter time scales, net water influx to the ice sheet (mainly snow accumulation) nearly balances water loss through ice calving and basal ice shelf melting at the ice sheet margins (1). However, there may be times when parts of the West Antarctic Ice Sheet (WAIS) are lost to the oceans, thus raising sea levels. On page 901 of this issue, Bamber et al. (2) calculate the total ice volume lost to the oceans from an unstable retreat of WAIS, which may occur if the part of the ice sheet that overlies submarine basins is ungrounded and moves to a new position down the negative slope (see the figure).