While most of the planet has been warming for decades, part of Antartica, the East Antarctic Ice Sheet -- has actually been getting colder. At least that was the general consensus. A major study by Pennsylvania State University; NASA's Goddard Space Flight Center in Greenbelt, Md.; and NASA's Goddard Institute for Space Studies in New York City shows this may not be the case at all. The work was supported by grants from the National Science Foundation.

The West Antarctic Ice Sheet, with an average elevation of about 6,000 feet above sea level, is substantially lower than East Antarctica, which has an average elevation of more than 10,000 feet. While the entire continent is essentially a desert, West Antarctica is subject to relatively warm, moist storms and receives much greater snowfall than East Antarctica.

The researchers devised a statistical technique that uses data from satellites and from Antarctic weather stations to make a new estimate of temperature trends.

"People were calculating with their heads instead of actually doing the math," Steig said. "What we did is interpolate carefully instead of just using the back of an envelope. While other interpolations had been done previously, no one had really taken advantage of the satellite data, which provide crucial information about spatial patterns of temperature change."

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.

The illustration depicts the warming that scientists have determined has occurred in West Antarctica during the last 50 years, with the dark red showing the area that has warmed the most.