PARIS (Agence France-Presse) — Parts of Antarctica have cooled sharply in recent years, a finding that counters doomsday perceptions that the frozen continent faces imminent meltdown from global warming, according to a study published yesterday.
Measurements taken by weather stations in the McMurdo Dry Valleys, the largest ice-free area in Antarctica, show that on average this region cooled by .125 Fahrenheit per year between 1986 and 2000, it said.
The cooling was especially strong during the autumn and summer seasons, and had a destructive effect on the fragile local ecosystem, it said.
The research, published online by Nature, the British weekly science journal, was led by Peter Doran of the department of Earth and Environmental Sciences at the University of Illinois at Chicago.
In a phone interview, Mr. Doran said the findings did not conflict with the mounting evidence that the world's overall average surface temperature is rising steadily as a result of burning fossil fuels.
"However, what people have not pointed out before is that Antarctica is the only continent on earth that by and large is cooling, whereas the other continents are warming," he said.
Antarctica could be the exception because of the complex interplay between ocean currents, he suggested.
Changes to the ocean convection system — through global warming — may be cooling the Southern Ocean, the chilly sea that circulates around Antarctica and is a major factor in the continent's frigid climate, he said.
The image of a cooler Antarctica contrasts with the popular fear that the continent's ice cap faces imminent destruction from man-made climate change.
Substantially higher temperatures would indeed cause the cap to crack up and melt, a scenario that would reverberate around the planet's climate system and cause sea levels to rise dramatically.
But that perception, suggested Mr. Doran, is a distorted one, likely generated because most weather monitoring stations are based in the Antarctic Peninsula — the tongue of land projecting northward from the continent toward South America and not indicative of conditions on the entire continent.
"Because the peninsula is so easily accessible, a lot of countries have stations there and are measuring the weather there. And it is warming there; it is warming dramatically," he said.
That measurement put together with the continental data gives people a skewed understanding.
According to Mr. Doran, "You average it all out, people say, 'Oh, the continental average is warming,' but it's being affected by that strong peninsula warming detected by the many monitoring stations there."