Much of Antarctica is warming more than previously thought

Science Daily: Scientists studying climate change have long believed that while most of the rest of the globe has been getting steadily warmer, a large part of Antarctica – the East Antarctic Ice Sheet – has actually been getting colder.

But new research shows that for the last 50 years, much of Antarctica has been warming at a rate comparable to the rest of the world. In fact, the warming in West Antarctica is greater than the cooling in East Antarctica, meaning that on average the continent has gotten warmer, said Eric Steig, a University of Washington professor of Earth and space sciences and director of the Quaternary Research Center at the UW.

…For years it was believed that a relatively small area known as the Antarctic Peninsula was getting warmer, but that the rest of the continent – including West Antarctica, the ice sheet most susceptible to potential future collapse – was cooling.…The study found that warming in West Antarctica exceeded one-tenth of a degree Celsius per decade for the last 50 years and more than offset the cooling in East Antarctica.

…"Simple explanations don't capture the complexity of climate," Steig said. "The thing you hear all the time is that Antarctica is cooling and that's not the case. If anything it's the reverse, but it's more complex than that. Antarctica isn't warming at the same rate everywhere, and while some areas have been cooling for a long time the evidence shows the continent as a whole is getting warmer."

A major reason most of Antarctica was thought to be cooling is because of a hole in the Earth's protective ozone layer that appears during the spring months in the Southern Hemisphere's polar region. Steig noted that it is well established 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 said.

"In any case, efforts to repair the ozone layer eventually will begin taking effect and the hole could be eliminated by the middle of this century. If that happens, all of Antarctica could begin warming on a par with the rest of the world."

This illustration depicts the warming in West Antarctica during the last 50 years, with the dark red showing the area that has warmed the most. (Credit: Image courtesy of University of Washington)