"For two decades, uncertainty over whether Antarctica was gaining mass or losing it from melting ice has made it difficult for scientists to predict the level of sea-level rise to be expected from global warming. The data showed, in the view of some scientists, that ice loss in the Arctic was being balanced by a gain in the Antarctic. Now a study published in the Nov. 30 issue of Science shows conclusively from satellite data that East Antarctica is, in fact, gaining ice, but the loss from western Antarctica and the Antarctic peninsula is twice as great as that gain.
In Greenland, the study concludes, ice is now melting at five times the rate it was in the 1990s.
Together with ice lost in Greenland, the melting in Antarctica has, the scientists say, raised sea levels worldwide by 11 mm in those 20 years, several times as much as previous measurements have shown. Combined loss: nearly 5 trillion metric tons of ice."
