Sunday, July 22, 2007

Glaciers and ice caps to dominate sea level rise in this century

Terra Daily: Ice loss from glaciers and ice caps is expected to cause more global sea rise during this century than the massive Greenland and Antarctic ice sheets, according to a new University of Colorado at Boulder study. The researchers concluded that glaciers and ice caps are currently contributing about 60 percent of the world's ice to the oceans and the rate has been markedly accelerating in the past decade, said Emeritus Professor Mark Meier of CU-Boulder's Institute of Arctic and Alpine Research, lead study author.

The contribution is presently about 100 cubic miles of ice annually -- a volume nearly equal to the water in Lake Erie -- and is rising by about three cubic miles per year.

In contrast, the CU-Boulder team estimated Greenland is now contributing about 28 percent of the total global sea rise from ice loss and Antarctica is contributing about 12 percent. Greenland is not expected to catch up to glaciers and ice caps in terms of sea level rise contributions until the end of the century, according to the study.

A paper on the subject appears in the July 19 issue of Science Express, the online edition of Science magazine. Co-authors include CU-Boulder INSTAAR researchers Mark Dyurgerov, Ursula Rick, Shad O'Neel, Tad Pfeffer, Robert Anderson and Suzanne Anderson, as well as Russian Academy of Sciences scientist Andrey Glazovsky.

"One reason for this study is the widely held view that the Greenland and Antarctic ice sheets will be the principal causes of sea-level rise," said Meier, former INSTAAR director and professor in geological sciences. "But we show that it is the glaciers and ice caps, not the two large ice sheets, that will be the big players in sea rise for at least the next few generations."…

…"At the very least, our projections indicate that future sea-level rise may be larger than anticipated, and that the component due to glaciers and ice caps will continue to be substantial," wrote the researchers in Science Express….

…Anderson also said that although the volume of ice locked up in Greenland is equal to roughly 23 feet in sea rise, only a small fraction is likely to be "pulled out" during the next century, most of it through outlet glaciers….

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