Jan. 16 (Bloomberg) -- Climate change led to accelerated melting of Greenland's ice sheet during the past half-century, scientists said in a study that adds to evidence suggesting sea levels will rise faster than expected.

Global warming has led to a ``significant increase'' in Greenland summer warmth and ice sheet melt and runoff since 1990, according to the study, published yesterday in the Journal of Climate. In a review of ice thaw from 1958 to 2006, scientists determined that the five biggest melts have occurred since 1995.

The largest thaw -- 453 cubic kilometers of ice (109 cubic miles) -- was in 1998, followed by 2003, 2006, 1995 and 2002, respectively, according to the report. The ice thaw in Greenland supports what scientists are finding in Antarctica and Alaska, said Konrad Steffen, a co-author of the study and professor of geography at the University of Colorado in Boulder.

``They all give the same story: ice is moving faster into the ocean, and that will add to the sea-level rise,'' Konrad said in an interview yesterday. He said that preliminary data suggests Greenland had its largest melt last year.

Ice melt in Antarctica has accelerated almost 60 percent in the past decade, according a study published this week in Nature Geoscience. Researchers estimated that West Antarctica lost 132 billion tons of ice in 2006, from 83 billion tons shed in 1996.

IPCC Estimates

The United Nations Intergovernmental Panel on Climate Change estimated that the ice sheets of Greenland and Antarctica hold enough water to raise sea levels by about 70 meters (230 feet) if they melted completely.

Changes have also been reported in Alaska's Kennicott Glacier, where warming has caused an increasing amount of water to get inside and under the ice, causing the glacier to move and melt more quickly, according to a separate Nature Geoscience study published this week.

``All the major ice masses are responding to the current warming,'' Konrad said.

Ice melt in Greenland and Antarctica could lead sea levels to rise more than the 18 to 59 centimeters (7 to 23 inches) by 2100 forecast by the United Nations Intergovernmental Panel on Climate Change, according to Eric Rignot, the lead author of the Antarctica study.

To contact the reporter on this story: Adam Satariano in San Francisco at asatariano1@bloomberg.net

Last Updated: January 16, 2008 00:19 EST