By Juliet Eilperin
The Washington Post.
WASHINGTON — The extent of Arctic sea ice reached a record low Monday, according to the University of Colorado National Snow and Ice Data Center, and is on track to decline further in the next two weeks.
The news that the Arctic sea ice cover had shrunk to 1.58 million square miles on Sunday came two days after Royal Dutch Shell's drill ship, the Noble Discoverer, took advantage of reduced sea ice and started sailing from Alaska's Dutch Harbor to the Chukchi Sea, in anticipation of final federal approval for oil exploration activities there.
The area covered by Arctic summer sea ice usually reaches its low point around Sept. 13, when the region begins to cool. But it has been melting at an unprecedented 38,600 square miles per day, and it is likely to decline even further before the ice begins to re-form. The last minimum sea-ice record of 1.61 million square miles was set in September 2007.
Walt Meier, a research scientist at the National Snow and Ice Data Center, said long-term warming coupled with recent weather conditions account for the new low. He noted that the long-term warming trend has produced more open water, which in turn absorbs more heat and makes the ice thinner.
"The thinner ice cover is then more easily melted during the summer, and more easily broken up by winds and waves from storms, which leads to more melting as well," Meier wrote in an e-mail. "This year we had a pretty strong storm go through the Arctic in early August, and that certainly has been a big factor in the rapid loss during August. But before that storm, we were already tracking along the 2007 trajectory, so a record may have happened even without that storm because of the long-term trend."
Rafe Pomerance, former deputy assistant secretary of state for environment and development under President Bill Clinton, called the record low "a profound moment that will change the debate" over climate change.
"It is very troubling, because the refrigerator of the Northern Hemisphere has been unplugged, so we will keep warming," Pomerance said.
But the new record may not convince some global warming skeptics, who continue to question the general scientific consensus that human-generated greenhouse gas emissions are helping drive climate change. Just last week, a team of British Antarctic Survey researchers published findings in the journal Nature that recent warming in the Antarctic was "unusual" but not unprecedented, since ice core samples showed the continent experienced a warm period several thousand ago, and temperatures had begun to rise again 600 years ago after a relatively cool period.
Further reduction in the extent of summer sea ice, which has declined 40 percent over the past three decades, would have implications far beyond the Arctic. The difference in temperature between the region and temperate zones is what propels the west-to-east speed of the jet stream, which could shift storm tracks as well as lead to more extreme weather.
Diminished sea ice means there will be a smaller expanse of white reflecting sunlight into space, according to researchers, which could accelerate warming in the Arctic and increase sea surface temperatures. If this led to the melting of a major ice sheet, like the one in Greenland, this could raise global sea levels substantially.
This spring, a group of scientists from the Georgia Institute of Technology, the Chinese Academy of Sciences and Columbia University published an article in the Proceedings of the National Academies of Science that found changes in atmospheric circulation brought on by sea-ice melt contributed to recent cold and snowy winters in the Northern Hemisphere.
Northern latitudes in Alaska, Greenland and elsewhere have experienced unusually high temperatures this summer. Barrow, Alaska, had six record-breaking days in a row of temperatures above 48 degrees Fahrenheit between Aug. 14 and 20, including a record high of 66 degrees on Aug. 19.
Between July 11 and 13 the Greenland ice sheet experienced the broadest thaw since 1973, with melt on 97 percent of its surface. Three days later, a chunk of ice twice the size of Manhattan calved off from Greenland's Petermann glacier, a break researchers at the University of Delaware and Canadian Ice Service attributed to warmer ocean temperatures.
While climate change hasn't grabbed the spotlight in congressional debates and the presidential campaign this year, it remains a highly polarized political issue. Environmental activists said they will use the shrinking of sea ice in the Arctic — along with one of the worst U.S. drought and wildfire seasons in decades — to press for a cut in the burning of fossil fuels, whose greenhouse gas emissions are linked to climate change.
Lou Leonard, managing director of climate change at the advocacy group WWF, noted that thousands of walruses are now "huddled on the remaining sea ice in shallow waters off the northern coast of Alaska. "As it melts, he said, the animals will have to swim long distances and haul out on land, which has led in the past to deadly walrus stampedes.
But even as advocates such as Leonard called for a cut in fossil fuels linked to climate change, at the moment Arctic warming is helping to speed oil and gas extraction, not curb it. Marine traffic is accelerating in the region, as both the Northwest Passage and the Northern Sea Route are becoming routinely ice-free in the summer. The Chinese icebreaker Xuelong, or "Snow Dragon," is now exploring a high-latitude route and had reached 81 degrees north latitude Friday.
While thicker-than-usual sea ice in the Chukchi and Beaufort seas, combined with federal permitting concerns, have delayed Shell's offshore exploration plans by nearly a month this summer, the company appears poised to start drilling soon.
Shell spokeswoman Kelly op de Weegh wrote in an e-mail that the Discoverer should arrive in the Chukchi by the end of the week, while another vessel, the Kulluk, is halfway through its two-week journey to Shell's Beaufort Sea leases.
"The departure of both the Kulluk and the Discoverer marks the first time working drilling rigs have charted a course for the Beaufort and Chukchi Seas in more than two decades," she wrote, adding the company will await final permission from the Interior Department before starting exploration."It's one of many operational milestones we expect to achieve in the days that remain in Alaska's open water season."