Large variations in Arctic sea ice

[OKIsItJustMe]

http://news.ku.dk/all_news/2011/2010.8/arctic_sea_ice/

2011-08-02

Large variations in Arctic sea ice

Climate

For the last 10,000 years, summer sea ice in the Arctic Ocean has been far from constant. For several thousand years, there was much less sea ice in the Arctic Ocean – probably less than half of current amounts. This is indicated by new findings by The Centre for Geogenetics at the University of Copenhagen. The results of the study will be published in the journal Science.

…

Less ice than today

Team leader Svend Funder, and two other team members and co-authors of the Science article, Eske Willerslev and Kurt Kjær, are all associated with the Danish Research Foundation at the University of Copenhagen.

…

“Our studies show that there have been large fluctuations in the amount of summer sea ice during the last 10,000 years. During the so-called Holocene Climate Optimum, from approximately 8000 to 5000 years ago, when the temperatures were somewhat warmer than today, there was significantly less sea ice in the Arctic Ocean, probably less than 50% of the summer 2007 coverage, which is absolutely lowest on record. Our studies also show that when the ice disappears in one area, it may accumulate in another. We have discovered this by comparing our results with observations from northern Canada. While the amount of sea ice decreased in northern Greenland, it increased in Canada. This is probably due to changes in the prevailing wind systems. This factor has not been sufficiently taken into account when forecasting the imminent disappearance of sea ice in the Arctic Ocean.”

Driftwood unlocks mystery

In order to reach their surprising conclusions, Funder and the rest of the team organised several expeditions to Peary Land in northern Greenland. Named after American Polar explorer Robert E. Peary, the region is an inhospitable and rarely visited area, where summer blizzards are not uncommon.

…

Point of no return

“Our studies show that there are great natural variations in the amount of Arctic sea ice. The bad news is that there is a clear connection between temperature and the amount of sea ice. And there is no doubt that continued global warming will lead to a reduction in the amount of summer sea ice in the Arctic Ocean. The good news is that even with a reduction to less than 50% of the current amount of sea ice the ice will not reach a point of no return: a level where the ice no longer can regenerate itself even if the climate was to return to cooler temperatures. Finally, our studies show that the changes to a large degree are caused by the effect that temperature has on the prevailing wind systems. This has not been sufficiently taken into account when forecasting the imminent disappearance of the ice, as often portrayed in the media,” Funder says.

…

http://dx.doi.org/10.1126/science.1202760

[xchrom]

1. also in the bbc...

http://www.bbc.co.uk/news/science-environment-14408930

Arctic 'tipping point' may not be reached

Scientists say current concerns over a tipping point in the disappearance of Arctic sea ice may be misplaced.

Danish researchers analysed ancient pieces of driftwood in north Greenland which they say is an accurate way to measure the extent of ancient ice loss.

Writing in the journal Science, the team found evidence that ice levels were about 50% lower 5,000 years ago.

They say changes to wind systems can slow down the rate of melting.


...it'll be interesting to watch what happens to this conversation.
i'm guessing not all scientists will agree. but what do i know?