January 21, 2009
Study Claims Antarctica Is Losing Its Cool
A new study suggests that Antarctica is rising in temperature, despite previous claims it was the only continent not suffering from global warming.
Research in the past indicated that temperatures on much of Antarctica were staying the same or even cooling.
But a review of satellite and weather records for the continent, which contains 90 percent of the world's ice and would raise world sea levels if it thaws, proves that freezing temperatures had risen by about 0.8 Fahrenheit since the 1950s.
Michael Mann, director of the Earth System Science Center at Penn State University, and the study's co-author, said contrarians have grabbed on to this idea that the entire continent of Antarctica is cooling, so "how could we be talking about global warming."
"Now we can say: no, it's not true ... It is not bucking the trend."
Until now, the general scientific consensus was that warming had been restricted to the Antarctic Peninsula beneath South America.
The authors wrote in Thursday's issue of the journal Nature that the Antarctic warming is difficult to explain without linking it to manmade emissions of greenhouse gases, mainly from burning fossil fuels.
The researchers used satellite data and mathematical formulas to fill in missing information about the continents warming report, making some outside scientists question the team's large conclusions with such sparse information.
Kevin Trenberth, climate analysis chief at the National Center for Atmospheric Research, told the Associated Press that it looks like a pretty good analysis, but he remains somewhat skeptical over the resulting announcement.
"It is hard to make data where none exist," he said.
Global warming skeptics said that the new study didn't match their measurements from satellites and that there appears to be no warming in Antarctica since 1980.
Roger Pielke Sr., a senior research scientist at the University of Colorado, said the team's research overstates what they have obtained from their analysis.
But Mann's team wrote that the area of warming is much larger than the region of the Antarctic Peninsula and it extended across the whole of West Antarctica to the south.
The study said rising temperatures in the west were partly offset by an autumn cooling in East Antarctica.
Since Antarctica's ice contains enough frozen water to raise world sea levels by 187 ft, even a tiny amount of melting could threaten Pacific island states or coastal cities from Beijing to London, the report warned.
Drew Shindell, of the NASA Goddard Institute for Space Studies, who was one of the authors, said West Antarctica would eventually melt if warming like this continues.
"A 5.4 Fahrenheit rise could trigger a wide melt of West Antarctica," he told AP. "Greenland is also vulnerable. Together, Greenland and West Antarctica hold enough ice to raise sea levels by over 45 feet."
Barry Brook, director of climate change research at the University of Adelaide in Australia, said even losing a fraction of both would cause a few feet this century, with disastrous consequences.
Opposing scientists also said the study did not fully account for shifts such as a thinning of ice sheets in West Antarctica.
"This warming is not enough to explain these changes," said David Vaughan, a glaciologist for the British Antarctic Survey at Rothera. He suggests thinning is probably linked to shifts in the oceans.
On the Net:
- Earth System Science Center at Penn State University
- National Center for Atmospheric Research
- University of Colorado
- NASA Goddard Institute for Space Studies
- University of Adelaide
- British Antarctic Survey