In spite of the rising temperatures everywhere else, the Antarctic has cooled during the past 35. However, some Antarctic ?hotspot? have gotten warmer over the past few decades.
The research was done by Dr. Peter Doran, of the University of illinois, at the American National Science Foundation?s long-term ecological research site in Antarctica?s Dry Valleys, a snow-free mountainous area on McMurdo Sound.
Doran says long-term data from weather stations across the continent, coupled with a separate set of measurements from the Dry Valleys, shows a cooling trend. ?Our 14-year continuous weather station record from the shore of Lake Hoare reveals that seasonally averaged surface air temperature has decreased by 0.7C per decade,? he says. ?The temperature decrease is most pronounced in summer and autumn. Continental cooling, especially the seasonality of cooling, poses challenges to models of climate and ecosystem change.?
A drop in Antarctic temperatures is puzzling because most climate models suggest that polar regions should respond first and most rapidly to worldwide temperature changes.Previous claims that the Antarctic is warming may have been mistaken because the measurements were taken largely on the Antarctic Peninsula, which extends toward South America and is warming five times more quickly than the rest of the world.?Averaging the temperature readings from the more numerous stations on the Peninsula has led to the misleading conclusion that there is a net warming continent-wide,? says Doran. ?Our approach shows that if you remove the Peninsula from the dataset, and look at the spatial trend, the majority of the continent is cooling.?
But Dr. David Vaughan, of the British Antarctic Survey, says temperature records going back 50 years show that the continent has actually been getting warmer over the longer term. ?There are regional differences in climate change,? he says. ?If we are going to predict climate change for the next 100 years . . . we need to know what is going to happen to the Antarctic Peninsula, to the Falkland Islands, or to Hampshire. That is the scale that impacts people.?
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