Deborah Zabarenko, PlanetArk 28 Aug 08;
WASHINGTON - Arctic sea ice shrank to its second-lowest level ever, US scientists said on Wednesday, with particular melting in the Chukchi Sea, where polar bears were recently seen swimming far off the Alaskan coast.
This year's Arctic ice melt could surpass the extraordinary 2007 record low in the coming weeks. Last year's minimum ice level was reached on Sept. 16, according to the National Snow and Ice Data Center.
Even if no records are broken this year, the downward trend in summer sea ice in the Arctic continues, the Colorado-based center said. Last year's record was blamed squarely on human-spurred climate change.
"No matter where we stand at the end of the melt season it's just reinforcing this notion that Arctic ice is in its death spiral," said Mark Serreze, a scientist at the center. The Arctic could be free of summer ice by 2030, Serreze said by telephone.
This year's data "primarily reflects melt in the Chukchi Sea off the Alaskan coast and the East Siberian Seas off the coast of eastern Russia," the center said.
The Chukchi Sea is home to one of the world's largest polar bear populations and also includes a vast area where the United States sold oil and gas rights worth US$2.66 billion last year.
On Tuesday, Arctic sea ice stretched over 2.03 million square miles (5.26 million sq km), which is less than the 2005 mark of 2.05 million square miles (5.32 million sq km), set on Sept. 21 of that year, the center's analysis found.
The record drop in 2007 left a minimum ice cover of 1.59 million square miles (4.1 million sq km). The fabled Northwest Passage was open for the first time in memory.
Government scientists reported seeing at least nine polar bears swimming in open water over a six-hour period on Aug. 16, including one more than 50 miles (80 km) offshore, World Wildlife Fund officials said.
LONGER SWIMS FOR POLAR BEARS
That represents a huge increase over previous sightings, said Margaret Williams of the fund's Alaska office. A total of 12 polar bears were spotted in open water between 1987 and 2003, Williams said in a telephone interview.
In 2004, she said, four drowned bears were observed.
"Unfortunately it's what we might expect to see if bears are forced to swim longer distances," Williams said. "The Arctic is gigantic. When you have nine bears sighted in one transect (route) ... one can assume that there are likely a lot more bears swimming in open water."
She noted that bears are capable swimmers and rely on sea ice as platforms for hunting seals, their main prey. If relegated to land, bears have little to hunt and sometimes feed on carrion or garbage and can be a threat to humans.
As more Arctic ice melts, bears are forced to swim longer distances to find adequate platforms for hunting. Rescuing bears in distress in open water is problematic, Williams said: tranquilizing the bears sends them into the water to drown.
The US government in May listed polar bears as a threatened species because their icy habitat was disappearing, but offered no plans to address climate change or drilling in the Arctic for fossil fuels that spur the climate-warming greenhouse effect.
Summer ice melt in the Arctic is seen as a strong indicator of climate change, and feeds on itself in what scientists call a positive feedback loop where warming exposes dark sea water, which absorbs more solar radiation than the white ice.
Arctic sea ice is sometimes dubbed Earth's air conditioner for its ability to moderate world climate. In the last decade, this ice has declined by roughly 10 percent. (Editing by Sandra Maler)
Arctic sea ice drops to 2nd lowest level on record
Seth Borenstein and Dan JOling, Associated Press 28 Aug 08;
More ominous signs Wednesday have scientists saying that a global warming "tipping point" in the Arctic seems to be happening before their eyes: Sea ice in the Arctic Ocean is at its second lowest level in about 30 years.
The National Snow and Ice Data Center reported that sea ice in the Arctic now covers about 2.03 million square miles. The lowest point since satellite measurements began in 1979 was 1.65 million square miles set last September.
With about three weeks left in the Arctic summer, this year could wind up breaking that previous record, scientists said.
Arctic ice always melts in summer and refreezes in winter. But over the years, more of the ice is lost to the sea with less of it recovered in winter. While ice reflects the sun's heat, the open ocean absorbs more heat and the melting accelerates warming in other parts of the world.
Sea ice also serves as primary habitat for threatened polar bears.
"We could very well be in that quick slide downward in terms of passing a tipping point," said senior scientist Mark Serreze at the data center in Boulder, Colo. "It's tipping now. We're seeing it happen now."
Within "five to less than 10 years," the Arctic could be free of sea ice in the summer, said NASA ice scientist Jay Zwally.
"It also means that climate warming is also coming larger and faster than the models are predicting and nobody's really taken into account that change yet," he said.
Five climate scientists, four of them specialists on the Arctic, told The Associated Press that it is fair to call what is happening in the Arctic a "tipping point." NASA scientist James Hansen, who sounded the alarm about global warming 20 years ago before Congress, said the sea ice melt "is the best current example" of that.
Last year was an unusual year when wind currents and other weather conditions coincided with global warming to worsen sea ice melt, Serreze said. Scientists wondered if last year was an unusual event or the start of a new and disturbing trend.
This year's results suggest the latter because the ice had recovered a bit more than usual thanks to a somewhat cooler winter, Serreze said. Then this month, when the melting rate usually slows, it sped up instead, he said.
The most recent ice retreat primarily reflects melt in the Chukchi Sea off Alaska's northwest coast and the East Siberian Sea off the coast of eastern Russia, according to the center.
The Chukchi Sea is home to one of two populations of Alaska polar bears.
Federal observers flying for a whale survey on Aug. 16 spotted nine polar bears swimming in open ocean in the Chukchi. The bears were 15 to 65 miles off the Alaska shore. Some were swimming north, apparently trying to reach the polar ice edge, which on that day was 400 miles away.
Polar bears are powerful swimmers and have been recorded on swims of 100 miles but the ordeal can leave them exhausted and susceptible to drowning.
And the melt in sea ice has kicked in another effect, long predicted, called "Arctic amplification," Serreze said.
That's when the warming up north is increased in a feedback mechanism and the effects spill southward starting in autumn, he said. Over the last few years, the bigger melt has meant more warm water that releases more heat into the air during fall cooling, making the atmosphere warmer than normal.
On top of that, researchers were investigating "alarming" reports in the last few days of the release of methane from long frozen Arctic waters, possibly from the warming of the sea, said Greenpeace climate scientist Bill Hare, who was attending a climate conference in Ghana. Giant burps of methane, which is a potent greenhouse gas, is a long feared effect of warming in the Arctic that would accelerate warming even more, according to scientists.
Overall, the picture of what's happening in the Arctic is getting worse, said Bob Corell, who headed a multinational scientific assessment of Arctic conditions a few years ago: "We're moving beyond a point of no return."
Science Writer Seth Borenstein reported from Washington and Dan Joling reported from Anchorage, Alaska. AP writer Arthur Max contributed from Accra, Ghana.
