Climate Science

Whither Antarctic Ice?

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Science  18 Jan 2008:
Vol. 319, Issue 5861, pp. 259
DOI: 10.1126/science.319.5861.259d

Determining how much the Antararctic ice sheet may contribute to sea-level rise through global warming depends on an accurate and precise understanding of the mass balance of two broadly defined regions: the coast and the interior. Essentially, the coasts appear to be losing mass while the interior is closer to being in balance, but considerable uncertainty remains in current estimates of mass change for the ice sheet as a whole. In order to better constrain the coastal element of the problem, Rignot et al. have analyzed satellite interferometric synthetic-aperture radar observations of Antarctica's coastline from 1992 to 2006 to estimate ice flux to the oceans. These measurements, which cover 85% of the coast, show that although East Antarctica probably is not losing mass, widespread losses in West Antarctica totaling 132 ± 60 Gt occurred in 2006, and that ice losses that year at the northern tip of the Antarctic Peninsula amounted to 60 ± 46 Gt. Ice mass loss from the coasts increased by 75% over the period of the study. These results highlight the importance of changes in glacier dynamics, which are so poorly understood that the Intergovernmental Panel on Climate Change could not include them in projections of sea-level rise in its 2007 report. — HJS

Nat. Geosci. 1, 10.1038/ngeo102 (2008).

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