The most comprehensive survey yet completed of glaciers in the Antarctic has discovered widespread movement, especially in the past five years. The findings, published today in the journal Science, indicate that the rate of sea-level rise could increase if ice shelves in the area continue their retreat.

Scientists with the British Antarctic Survey (BAS) analyzed data collected from studies of 244 marine glaciers on the Antarctic Peninsula over the past 50 years. More than 2,000 aerial photos and 1,000 satellite images helped the researchers reconstruct the behavior of glacier-ice shelves and tidewater glaciers. They found that 87 percent of the glaciers have retreated over the study period by about 600 meters, on average. Over the same time period, the atmospheric temperatures in the region increased by 2.5 degrees Celsius. Such dramatic and localized warming is certainly playing a role in the changes, says the study's lead author Alison Cook of the BAS, but it is not the only factor that caused the changes. "It's a complex picture," she notes.

The retreat has occurred at a discontinuous rate over the past half century. According to the report, the past five years have seen the quickest recoil, with glaciers moving back about 50 meters annually, faster than any other time period since 1955. There were some exceptions, however, as 32 glaciers showed modest advancements. Says study co-author David Vaughan of BAS, "this is the kind of exploration of Antarctica you could never do on site."