Man-made climate change seen in Antarctica, Arctic

By Alister Doyle, Environment Correspondent

OSLO (Reuters) - Both Antarctica and the Arctic are getting less icy because of global warming, scientists said on Thursday in a study that extends evidence of man-made climate change to every continent.

Detection of a human cause of warming at both ends of the earth also strengthens a need to understand ice sheets on Antarctica and Greenland that would raise world sea levels by about 70 metres if they all melted, they said.

"We're able for the first time to directly attribute warming in both the Arctic and the Antarctic to human influences," said Nathan Gillett of England's University of East Anglia of a study he led with colleagues in the United States, Britain and Japan.

The Arctic has warmed sharply in recent years and sea ice shrank in 2007 to a record low. But Antarctic trends have been confusing -- some winter sea ice has expanded in recent decades, leaving doubts for some about whether warming was global.

The U.N. Climate Panel, which draws on work by 2,500 experts, said last year that the human fingerprint on climate "has been detected in every continent except Antarctica", which has insufficient observational coverage to make an assessment.

The scientists, writing in the journal Nature Geoscience, said the new findings filled that gap.

The study, comparing temperature records and four computer climate models, found a warming in both polar regions that could be best explained by a buildup of greenhouse gases, mainly from burning fossil fuels, rather than natural shifts.