Antarctica Not Immune to Warming

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USA Today

Antarctica Not Immune to Warming

by
Doyle Rice

A 65-foot high ice cliff forming the edge of the Wilkins Ice shelf on the Antarctic Peninsula is seen from a plane January 18, 2009. The huge Antarctic ice shelf is on the brink of collapse with just a sliver of ice holding it in place, the latest victim of global warming that is altering maps of the frozen continent. (By Alister Doyle, Reuters)

WASHINGTON - The Earth's lone holdout to climate change, Antarctica, is actually warming, says a new study in today's edition of the journal Nature.

Scientists had long thought that while some isolated parts of Antarctica had been warming, much of the continent had been cooling over the past 50 years. But the new analysis found that since 1957, when measured as a whole, the continent's temperature has risen about 1 degree Fahrenheit .

"The thing you hear all the time is that Antarctica is cooling - and that's not the case," says study lead author Eric Steig, a University of Washington professor of Earth and space sciences. "If anything, it's the reverse, but it's more complex than that. Antarctica isn't warming at the same rate everywhere."

Perhaps most troubling is that "a fairly large part of West Antarctica is warming more than we realized," says study co-author Michael Mann, a climatologist at Pennsylvania State University.Scientists say West Antarctica is the ice sheet most susceptible to a possible collapse in the future due to warming global temperatures. If the ice sheet collapsed, it would cause cataclysmic sea-level rise around the world.

Technique questioned

Researchers in this study developed a new technique that combined data from satellites and automated weather stations in Antarctica to make what they say is the best estimate of the continent's temperature so far. However, there are very few weather stations on Antarctica, and the satellite data have been available for only the past 25 years.

This troubles some scientists.

"One must be very cautious with such results because they have no real way to be validated," says atmospheric scientist John Christy of the University of Alabama-Huntsville, who was not part of the study. "In other words, we will never know what the temperature was over the very large missing areas that this technique attempts to fill in so that it can be tested back through time."

Researchers had thought Antarctica was getting cooler in part because of the ozone hole over the South Pole. This break in the protective ozone layer brings cooling weather patterns across parts of Antarctica. Steig agrees that the ozone hole has contributed to cooling in East Antarctica.

"However, it seems to have been assumed that the ozone hole was affecting the entire continent, when there wasn't any evidence to support that idea, or even any theory to support it," he adds.

Contributing: Associated Press

 

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