WEST ANTARCTICA WARMING IN TRIPLE TIME

The West Antarctic Ice Sheet is warming at twice the rate previously thought, say scientists who have teased the information from more than 50 years of temperature data at Byrd Station, in the center of the ice. The average temperature at that station has risen 4.3 degrees F (2.4 degrees C) since 1958, which is triple the warming rate of most of the planet and on par with the very fastest warming parts of the world.

Of particular concern is that the warming is partially taking place in the summer months. That's when the already seasonal warmth, plus the new higher average air temperatures, combine and increase the likelihood of major melting events that destabilize the ice shelves. Those shelves hold back a lot of Antarctic glacial ice from reaching the sea, explained Ohio State University's David Bromwich, the lead author on the study, which was published in the latest issue of Nature Geoscience.

“Lots of melting can do lots of damage to the ice shelves,” Bromwich told Discovery News. And that can ramp up Antarctica's contribution to sea level rise worldwide. “We know that these melting events can happen today and we are likely to see more melting events.”

Researchers have already documented accelerating of glaciers along the Amundsen Sea coast, which is dumping more West Antarctic ice into the sea, but warmer sea temperatures had been seen as the primary cause of that. Air temperatures have been harder to pin down, due to large gaps in the records at Byrd Station.

“There are very, very few observations for that part of the world,” said Davis Schneider an Antarctic researcher at the National Center for Atmospheric Research, and not a contributor to the new study. Thinning ice sheets, borehole temperature readings and ice cores all provide indirect evidence of warming, he said, but what's been needed is “ground-truthing” with old fashioned thermometer data.

source:http://news.discovery.com

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