Seth Borenstein in Dallas News.com via the AP: Antarctica's
massive ice shelves are shrinking because they are being eaten away from below
by warm water, a new study finds. That suggests that future sea levels could
rise faster than many scientists have been predicting.
The western chunk of Antarctica is losing 23 feet of its
floating ice sheet each year. Until now, scientists weren't exactly sure how it
was happening and whether or how man-made global warming might be a factor. The
answer, according to a study published Wednesday in the journal Nature, is that
climate change plays an indirect role - but one that has larger repercussions
than if Antarctic ice were merely melting from warmer air.
Hamish Pritchard, a glaciologist at the British Antarctic
Survey, said research using an ice-gazing NASA satellite showed that warmer air
alone couldn't explain what was happening to Antarctica. A more detailed
examination found a chain of events that explained the shrinking ice shelves.
Twenty ice shelves showed signs that they were melting from
warm water below. Changes in wind currents pushed that relatively warmer water
closer to and beneath the floating ice shelves. The wind change is likely
caused by a combination of factors, including natural weather variation, the
ozone hole and man-made greenhouse gases, Pritchard said in a phone interview....
Photo of an Antarctic iceberg by Georges Nijs, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license
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