Arctic is warmest in 2 millennia

"The Arctic is experiencing its warmest temperatures in 2,000 years, even though it should be cooling because of changes in the Earth's orbit that cause the region to get less direct sunlight

If it hadn't been for the increase in human-produced greenhouse gases, summer temperatures in the Arctic should have cooled gradually over the last century," says Bette Otto-Bliesner of National Center for Atmospheric, USA and co-author of a study of Arctic temperatures published in the journal Science.
The most recent 10-year interval, 1999-2008, was the warmest of the last 2,000 years in the Arctic, according to the researchers led by Darrell S. Kaufman, a professor of geology and environmental science at Northern Arizona University, USA.
Summer temperatures in the Arctic averaged 2.5 degrees Fahrenheit (1.4 degrees Celsius) warmer than would have been expected if the cooling had continued, the researchers says.
It is the latest in a drumbeat of reports on warming conditions in the Arctic, including:
—A marine scientist reports that Alaskan waters are turning acidic from absorbing greenhouse gases faster than tropical waters, potentially endangering the state's 4.6 billion dollars fishing industry.
—NASA satellite measurements show that sea ice in the Arctic is more than just shrinking in area; it is thinning dramatically. The volume of older crucial sea ice in the Arctic has shrunk by 57 percent from the winter of 2004 to 2008.
—Global warming effects in Alaska also include shrinking glaciers, coastal erosion and the march north of destructive forest beetles formerly held in check by cold winters.
And as land-based ice melts, such as the massive Greenland ice cap, sea levels could rise across the world, to threaten millions who live in coastal cities.
In addition as the Arctic warms there is less snow and ice to reflect solar energy back into space and the newly exposed dark soil and dark ocean surfaces absorb solar energy and warm further, accelerating the warming process.
The Arctic cooling had been the result of a 21,000-year cycle in the Earth's movement that caused the far north to get progressively less summertime energy from the sun for the last 8,000 years. That process will not be reversed for another several thousand years.