May 3, 2008

Another Record Arctic Ice Melt Expected This Summer

Scientists warned on Friday that they expect climate change to begin affecting the Antarctic, as the pace of thinning ice in the Arctic continues.

"The long-term prognosis is not very optimistic," Jennifer Francis, an atmospheric scientist with Rutgers University said during a briefing.

In a shift many attribute to climate change, sea ice in the North shrank to a record low last summer.

Although levels of solar radiation and greenhouse gases are similar at each of the planet's poles, the regions have so far responded differently to these events. To date, there has been little change observed in the region of the South pole, remarked James Overland, an oceanographer with the National Oceanic and Atmospheric Administration (NOAA).

Researchers believe the phenomenon is due to the reinforcement of global warming and natural climate cycles in the North, which in the Artic have caused levels of sea ice to become far less than in the past.

"And there is very little chance for the climate to return to the conditions of 20 years ago," Overland told the Associated Press.

On the other hand, he said, the ozone hole above the Antarctic has disguised climate conditions there, maintaining temperatures low in most of the continent with the exception of the peninsula that reaches out toward South America.

"So there is a scientific reason for why we're not seeing large changes in the Antarctic like we're seeing in the Arctic," he said, while warning that as the ozone hole recovers in coming years, global warming will also begin affecting the South Pole.

The new findings were developed at a recent workshop.Overland, formerly skeptical of global climate change, said he found the new data "startling".

There is now agreement between computer climate models, weather observations, and scientific forecasts for what should occur in the future, Francis said, adding that all the evidence points toward human-made changes at both poles. The conclusion "further depletes the arsenals of those who insist that human-caused climate change is nothing to worry about," she said.

Gareth Marshall , a climatologist of the British Antarctic Survey, told the Associated Press that although the term global warming is widespread, at the regional level the issue is actually more complicated.

In the Antarctic, climate change strengthened winds and trapped colder air around the continent. But in the future, he said, that will decrease, allowing warmer conditions to begin.

Marshall added that all studies now show human activities as the drivers of Antarctic climate change.

Overland said it is likely that last year's record low sea ice would be matched again this summer.

"The tea leaves point to a minimal amount of sea ice next September, that would be the same as we had last summer, 40 percent loss compared to 20 years ago," he said, adding that the winter freeze had a late start last fall.



A report about the new findings is scheduled for publication in next week's' edition of EOS, an American Geophysical Union journal.


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