GLACIERS

GLACIERS

The work was based on 2,000 aerial photos, some taken in the 1940s, and satellite images. The climate in the region has warmed by more than 4.5 degrees Fahrenheit (2.5 Celsius) in the last 50 years, the scientists said.

"The widespread retreat of the glaciers on the Antarctic Peninsula over the last 50 years was largely caused by climate change," said David Vaughan of the British Antarctic Survey in Cambridge. "Are humans responsible? We can't say for sure, but we are one step closer to answering this important question.

A new study of glaciers in a portion of the Antarctic finds 84 percent of them have retreated over the past 50 years in response to a warmer climate

The study, led by the survey's Alison Cook, is detailed in the April 22 issue of the journal Science. Among the most comprehensive surveys ever done, it looked at floating glacier-ice shelves, which are connected to the land-based glacier from which they flowed, and tidewater glaciers that rest on land and break off into the ocean when they reach the water

Glacial retreat is a complex phenomenon that often involves thinning of the glacier, too. As glaciers melt, they sometimes move toward the sea more quickly, exacerbating the melting. Where a glacier meets the sea, an ice shelf can hold it back. When those ice shelves break apart, however, a glacier can become .