October 16, 2008
Scientists Release Updated Arctic Report Card
Arctic temperatures this season are at an all-time high. Sea ice is melting rapidly, causing the Arctic Ocean to become warmer and less salty, researchers said Thursday.
Additionally, the new report, compiled by 46 scientists from 10 countries, finds that populations of reindeer appear to be on the decline.
"Obviously, the planet is interconnected, so what happens in the Arctic does matter" to the rest of the world, Jackie Richter-Menge of the Cold Regions Research and Engineering Laboratory in Hanover, N.H., said in releasing the third annual Arctic Report Card.
Researchers expect the area to be among the first to indicate the early signs of global warming caused largely in part by human activities adding carbon dioxide and other gases to the atmosphere.
Autumn air temperatures in the Arctic are at a record 9 degrees Fahrenheit (5 Celsius) above normal.
"Changes in the Arctic show a domino effect from multiple causes more clearly than in other regions," said James Overland, an oceanographer at the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle. "It's a sensitive system and often reflects changes in relatively fast and dramatic ways."
In 2007, researchers witnessed the largest loss of sea ice on record. This year's sea ice will be the second largest only to 2007's loss.
The study also noted a warming trend on Arctic land and increase in greenness as shrubs move north into areas that were formerly permafrost.
While the warming continues, the rate in this century is less than in the 1990s due to natural variability, the researchers said.
In addition to global warming there are natural cycles of warming and cooling, and a warm cycle in the 1990s added to the temperature rise. Now with a cooler cycles in some areas the rise in temperatures has slowed, but Overland said he expects that it will speed up again when the next natural warming cycle comes around.
Asked if an increase in radiation from the sun was having an effect on the Earth's climate, Jason Box of the Byrd Polar Research Center in Columbus, Ohio, said while it's important, increased solar output only accounts for about 10 percent of global warming.
"You can't use solar to say that greenhouse gases are not a major factor," Overland added.
The report also noted that the rate of sea level rise is nearly 0.1 inch per year as temperatures in the Arctic Ocean continue to rise.
Warming has continued around Greenland in 2007 resulting in a record amount of ice melt. The Greenland ice sheet lost 24 cubic miles of ice, making it the largest single contributor to global sea level rise.
What's more, reindeer herds had been increasing since the 1970s are now showing signs of leveling off or beginning to decline. Meanwhile, goose populations are increasing as they expand their range within the Arctic, researchers said.
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