Antarctic ice sheet shrinking at faster rate

The East Antarctic Ice and the West Antarctic Ice contain a huge amount of water – enough to raise ocean levels by 60 meters, according to this story in the Globe and Mail (Toronto): One of the biggest worries about global warming has been its potential to affect the stability of the Antarctic ice sheet, a vast storehouse of frozen water that would inundate the world's coastal regions if it were to melt because of a warming climate.

The huge implications posed by the health of the ice sheet have prompted major scientific interest into whether it is growing, shrinking, or stable, with no clear consensus among researchers about its overall trend.

But a new study released today, based on some of the most extensive measurements to date of the continent's ice mass, presents a worrisome development: Antarctica's ice sheet is shrinking, at a rate that increased dramatically from 1996 to 2006. A new study says the Antarctic ice sheet is melting at an even-faster rate than scientists expected. The results of the research project, led by Dr. Eric Rignot, principal scientist for the Radar Science and Engineering Section at NASA's Jet Propulsion Laboratory's in Pasadena, Calif., appear in the current issue of Nature Geoscience.

… Some experts have even speculated that global warming might lead to increases in ice accumulation in Antarctic's interior due to more snowfall. However, many experts say that this effect is unlikely to offset Antarctica's contribution to sea level rise because of the rapid melting of coastal glaciers. "The concept that global warming will increase precipitation in Antarctica and mitigate sea level rise is a lullaby," Dr. Rignot said.

"Our story shows that the main driver for the mass balance is the rate of glacier flow to the sea, not the precipitation rate because other studies already showed recently that the precipitation rate has not changed significantly."…