New study finds Antarctica warming over last 50 years

Antarctica, the only place that had oddly seemed immune from climate change, is warming after all, according to a new study. For years, Antarctica was an enigma to scientists who track the effects of global warming. Temperatures on much of the continent at the bottom of the world were staying the same or slightly cooling, previous research indicated.

The new study went back further than earlier work and filled in a massive gap in data with satellite information to find that Antarctica too is getting warmer, like the Earth's other six continents.

The scientists stop short of claiming with certainty that wind-borne greenhouse gases from global industries on other continents are responsible for Antarctica's warming, but they say their evidence makes them "almost certain" that human activity carries at least some of the blame.

In a report published today in the journal Nature, climatologists Eric Geist of the University of Washington and Drew Shindell of NASA's Goddard Institute for Space Studies say that for the first time they combined satellite observations over the entire continent with evidence from more than 100 manned and unmanned weather stations both inland and along the continent's coasts to determine climate trends for the past 50 years.

During Wednesday's teleconference, Shindell said wind patterns across Antarctica make it difficult to pin down the role of greenhouse gases in warming the continent, but human activity in the world's other continents should be added in as an influence pushing Antarctic temperatures up.

"We're almost certain that increases in greenhouse gases on other continents are contributing to this warming in Antarctica," Shindell said.

During an hour-long teleconference Wednesday, the scientists said their data clearly shows that on average the entire Antarctic continent has been gradually warming at least since 1957. "Contrarians have sometime grabbed on to this idea that the entire continent of Antarctica is cooling, so how could we be talking about global warming," said study co-author Michael Mann, director of the Earth System Science Center at Penn State University. "Now we can say: no, it's not true ... It is not bucking the trend."

The research found that since 1957, the annual temperature for the entire continent of Antarctica has warmed by about 1 degree Fahrenheit, but still is 50 degrees below zero. West Antarctica, which is about 20 degrees warmer than the east, has warmed nearly twice as fast, said study lead author Geist. East Antarctica, which scientists had long thought to be cooling, is warming slightly when yearly averages are looked at over the past 50 years, said Geist.

While the numbers are complicated, the team's evidence indicates that over the entire Antarctic continent - where year-round temperatures average nearly 50 degrees below zero - the average temperature increase for the past 50 years has been half a degree Celsius, or just under one full degree Fahrenheit, Geist said.

One degree may not seem like much, but a two-degree global increase - universally forecast before the end of this century - would pose major threats to world stability. Scientists predict that food crops would die in some regions and increase in others, and rising sea levels, caused by melting ice, would drown many low-lying coasts and islands, particularly in developing nations where poverty is already endemic.