Scientists solve enigma of Antarctic 'cooling'
Research 'kills off' climate sceptic argument by showing average temperature across the continent has risen over the last 50 years
* Damian Carrington
* guardian.co.uk, Friday 23 January 2009 18.00 GMT
Scientists have solved the enigma of the Antarctic apparently getting cooler, while the rest of the world heats up.
New research shows that while some parts of the frozen continent have been getting slightly colder over the last few decades, the average temperature across the continent has been rising for at least the last 50 years.
In the remote and inaccessible West Antarctic region the new research, based on ground measurements and satellite data, show that the region has warmed rapidly, by 0.17C each decade since 1957. "We had no idea what was happening there," said Professor Eric Steig, at the University of Washington, Seattle, and who led the research published in Nature.
This outweighs the cooling seen in East Antarctica, so that, overall, the continent has warmed by 0.12C each decade over the same period. This matches the warming of the southern hemisphere as a whole and removes the apparent contradiction.
The issue, which had been highlighted by global warming sceptics, was an annoyance, said Steig, despite the science having been reasonably well understood. "But it has now been killed off," he said.
Gareth Marshall, climatologist at British Antarctic Survey, commented: "This work allows us to look at the continent as a whole, which we have not been able to do before with confidence. It fills a big hole in the data in West Antarctica – it is the final piece in the jigsaw."
The rapid warming now revealed in the west concerns some scientists. The new analysis suggests the West Antarctic ice sheet, like that in Greenland, is precariously balanced, said Professor Barry Brook at the University of Adelaide. "Even losing a fraction of both would cause a few metres of sea level rise this century, with disastrous consequences," he said.