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In the Arctic, shrinking sea ice sets early winter record

Doug O'Harra

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The Big Chill hasn't been working -- at least for the eastern Arctic of Canada and Greenland.

Overall, Arctic sea ice covered the smallest area ever recorded by satellite for the month of December -- largely due to record decreases near Hudson Bay, Baffin Island and Greenland, according to the National Snow and Ice Data Center in Boulder, Colo.

But in what demonstrates the complexity of the Arctic climate system, and the influence of short-term weather patterns, new ice has spread across more ocean on Alaska's west coast than usual.

"In contrast to the Atlantic side of the Arctic, sea ice extent in the Pacific region -- i.e., the Bering Sea off the coast of Alaska -- is higher than normal," NSIDC research scientist Walt Meier told Dispatch in an e-mail. "In recent years, there has often been more ice than normal in the region."

Part of a decades-long trend toward an ever-shrinking ice cap across the seasons, the Far North's frozen sea averaged about 4.63 million square miles in extent during the month -- 521,000 square miles smaller than the 30-year average and about 110,000 square miles below the previous minimum December record set in 2006, the NSIDC reported.

It's the winter footnote to one of the most dramatic signals of global climate change. Summer sea ice cover has thinned and melted back across the Arctic, in effect seasonally wiping out vast tracts of habitat necessary for the health of species like polar bears, ringed seals and walruses. The loss of summer ice cover also feeds and accelerates regional climate warming: ice reflects solar energy back into space, while darker open water absorbs heat.

The 2010 ice minimum -- recorded during every year during September -- flirted with record territory. On Sept. 19, the Arctic's frozen pack shrank to the third-smallest extent seen since 1979 -- about 1.78 million square miles, the NSIDC reported.

To put that statistic in perspective, the polar ice of summer 2010 was about 815,000 square miles smaller than the 30-year average; an area larger than Alaska had transformed into slush.

The approach of dark, frigid winter is supposed to rebuild this ice habitat by quickly refreezing the ocean. While that happened near Alaska, the eastern Arctic met a different fate.

"Arctic sea ice grew more slowly than average in November, leading to the second-lowest ice extent for the month," the NSIDC reported on Dec. 6. "At the end of November, Hudson Bay was still nearly ice-free."

The heat wave has continued, impeding freeze-up in Hudson and Davis straits as well. How big is the loss so far? It's as though the average December ice cover has disappeared from an area as large as California, Washington, Oregon, Nevada and Idaho combined.

'South Baffin swelters in heat wave'

The remaining open water has startled residents of Nunavut, the Inuit territory of far Northeastern Canada, a place where people depend on solid sea ice for travel and hunting.

"Normally, these areas are completely frozen over by late November," reported the NSIDC. "In the middle of December, ice extent stopped increasing for about a week, an unusual but not unique event. "

In Iqaluit, the capital of Nunavut, it was raining on Monday with temperatures hovering near the freezing point, according to CBC News. Normal temperatures for the date dip into double digits below zero.

"In a rare sight for this time of year, Frobisher Bay has not yet frozen over entirely. Likewise, there is a lack of sea ice in parts of Hudson Bay, Davis Strait and other Arctic waterways," the CBC reported this week.

"A bag of ice cubes left on New Year's Eve near an Iqaluit apartment's front door was melting Jan. 4, as temperatures around South Baffin reached record highs as much as (40 degrees Fahrenheit) above normal," Chris Windeyer wrote Tuesday in a story posted on Nunatsiaq Online.

The Canadian weather service was still issuing marine forecasts for boaters in Hudson Strait, he reported, while the City of Iqaluit shut down non-emergency functions on Monday with its graders sliding into ditches and streets clumping up with frozen road sand.

Windeyer's headline? "South Baffin swelters in winter heat wave -- ‘It doesn't show any signs of abating'"

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Simon Donner, a geography professor at the University of British Columbia, posted on the Energy Collective blog that he was amazed when a Iqaluit couple told him at a holiday gathering about the open water in Frobisher Bay at mid-month.

"I almost coughed up my food," Donner wrote. "The Bay is normally frozen a month or two, or more, before Christmas, allowing people to head out on the ice for hunting, celebrating, etc."

In an interview with CBC News, NSIDC director Mark Serreze blamed the open water on a lingering pattern of high-pressure -- put in place by an atmospheric phenomenon known as the Arctic Oscillation.

"Now you've got all this open water where you usually don't have it, and that pumps heat into the atmosphere," he told CBC News here. "So it's kind of a double whammy you've got working on there right now. ... You may be seeing a little bit of a hint of what the future holds in store for you."

So what's the Arctic Oscillation -- and how will it ruin my seal hunt?

The Arctic Oscillation is a hemispheric shift in atmospheric pressure that alters storm tracks and drives unexpected weather. Over decades, it morphs from one state to another, something like the behavior of El Nino and La Nina of the tropical Pacific. It's the same phenomenon that helped reduce ice cover in 2009-10.

This year, the old AO (as nicknamed by some of those technical types) has clicked into what scientists call a "negative phase" -- with high pressure over the North Pole and low pressure at mid-latitudes (the Lower 48 states.)  Once it's in place, it sort of feeds on itself.

"The warm temperatures in December came from two sources: unfrozen areas of the ocean continued to release heat to the atmosphere, and an unusual circulation pattern brought warm air into the Arctic from the south," the NSIDC explained in its monthly release. "Although the air temperatures were still below freezing on average, the additional ocean and atmospheric heat slowed ice growth."

What does this mean for Alaska?

"I think the recent data indicate how the sea ice responds over the short (days, weeks, months) to weather and short-term climate," Meier explained.

Winter variations in ice cover are more directly controlled by weather and climate patterns -- like the Arctic Oscillation - than by atmospheric warming due to greenhouse gases, Meier added.

A few weeks ago, a team of scientists argued in the journal Nature that there was no irrevocable "tipping point" to Arctic ice loss -- that people could still halt the decline of summer ice and save species like the polar bear from extinction by reducing greenhouse gas emissions.

The winter ice extent doesn't say much about that issue, Meier said.

"Where we expect to see a long-term warming signal is in the amount of summer ice remaining and the thickness of that ice," he said. "In winter, temperatures are still cold, below freezing, most everywhere in the Arctic, so there is still ice growth -- it's just a matter of where, when, and exactly how much. Thus winter conditions don't tell us a lot about any tipping point."

Doug O'Harra is an Anchorage writer.