Glaciers in Antarctica in retreat

Researchers find that 87 percent of 244 glaciers have retreated during the past half century. Giant iceberg strikes Antarctica

Glaciers in the Antarctic are retreating rapidly due in part to increased temperatures, another sign that the Earth's environment is indeed changing.

Studying photos dating back to 1940 and satellite images dating back to 1960, researchers from the British Antarctic Survey and the United States Geological Survey have determined that 87 percent of the 244 glaciers studied in the region have retreated during the past 50 years. On average, the glaciers retreated 164 feet, or 50 meters, every year for the last five years, faster than in earlier years.

That's a reversal of the situation 60 years ago when many glaciers were expanding. Still, 32 glaciers of those studied have made minor advances.

"This region has shown dramatic and localized warming--(an increase of) around 2 degrees Celsius (3.6 degrees Fahrenheit) in the last 50 years," lead author of the study, Alison Cook, said in a statement. "Fifty years ago, most of the glaciers we looked at were slowly growing in length, but since then this pattern has reversed. In the last five years, the majority were actually shrinking rapidly."

Cook said warming is likely the primary cause, but there are others. Further study will be required to determine to what extent the warming is caused by human activity, the researchers said.

Global warming is taking its toll in the Northern Hemisphere as well, with ice around the North Pole retreating. During the next 10 years, the ice will likely retreat to a point where a sea lane will exist above Siberia that will allow ships to run from Tokyo to Halifax, said University of Colorado scientist Mark Serreze.

Meanwhile, scientists at the National Center for Atmospheric Research published a study earlier this year stating that ocean levels will likely rise by 25 to 30 centimeters, or nearly a foot, by 2100. If no actions are taken to curb greenhouse gases, ocean levels could rise by a meter by 2400.

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