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Arctic Ice Reaches Least Extent Since 2007 Summer Season

September 20, 2012
Map shows summer 2012 Arctic sea ice extent compared with the average minimum extent over the past 30 years, in yellow. Credit: NASA

Lawrence LeBlond for redOrbit.com – Your Universe Online

The Arctic sea ice has stopped receding this year, but not before reaching its smallest extent, breaking the previous record set in the summer of 2007, by 18 percent. The new low sets the summertime ice area extent to about 2.1 million square miles, according to estimates from the US National Snow and Ice Data Center (NSIDC) in Colorado.

This year´s unprecedented ice melt in the Arctic is the clearest sign yet of global climate change and has set off new warnings from scientists and environmental groups about the role climate change has on the planet´s delicate environment.

The new record minimum measures about 300,000 square miles less sea ice than 2007´s record of 1.61 million square miles. For comparison, this year´s extra loss is a little more than the size of Texas, or about half the size of Alaska.

NSIDC cautioned, however, that although the annual minimum has seemed to reach its peak, there is still the possibility for winds to change, compacting the ice floes and reducing sea ice extent even more. A complete analysis of the 2012 ice melt season will be released next month by both NSIDC and NASA.

Claire Parkinson, climate specialist at NASA´s Goddard Space Flight Center, said: “Climate models have predicted a retreat of the Arctic sea ice; but the actual retreat has proven to be much more rapid than the predictions“¦There continues to be considerable inter-annual variability in the sea ice cover, but the long-term retreat is quite apparent.”

But not only is the extent of the ice getting smaller, the thickness of the ice is also in decline.

“The core of the ice cap is the perennial ice, which normally survived the summer because it was so thick,” Joey Comiso, senior scientist at Goddard. “But because it’s been thinning year after year, it has now become vulnerable to melt.”

As the older ice disappears, it gets replaced in winter with seasonal thinner ice that usually melts completely in the summer.

A powerful cyclone that formed off the coast of Alaska in August moved toward the center of the Arctic Ocean, churning the waters and weakening the ice cover over a period of several days. The storm cut off a large section of sea ice north of the Chukchi Sea and pushed it south into warmer waters.

“The storm definitely seems to have played a role in this year’s unusually large retreat of the ice,” Parkinson said. “But that exact same storm, had it occurred decades ago when the ice was thicker and more extensive, likely wouldn’t have had as prominent an impact, because the ice wasn’t as vulnerable then as it is now.”

“The Arctic is the earth´s air-conditioner,” Walt Meier, a research scientist at NSIDC, told NY Times℠ Justin Gillis. “We´re losing that. It´s not just that polar bears might go extinct, or that native communities might have to adapt, which we´re already seeing – there are larger climate effects.”

Meier´s agency waited a few days before announcing the melt-off to be sure refreezing was beginning to re-occur, as it usually does this time of year, when wintry conditions begin to take hold once again in the high Arctic. A relatively thin sheen of ice will cover much of the Arctic Ocean in the coming months.

Julienne Stroece, an NSIDC researcher who has been monitoring the ice aboard the Greenpeace ship Arctic Sunrise, said that data suggest the sea ice collapse will be a predictor of more extreme weather to come.

“We can expect more summers like 2012 as the ice cover continues to thin. The loss of summer sea ice has led to unusual warming of the Arctic atmosphere, that in turn impacts weather patterns in the northern hemisphere, that can result in persistent extreme weather such as droughts, heatwaves and flooding,” Stroece told The Guardian.

A complete collapse of the Arctic sea ice has been predicted by some leading scientists to occur within four years. Professor Peter Wadhams, of Cambridge University, said this collapse is “happening now” and by 2015-16 a total collapse will occur.

Arctic sea ice has been a key indicator of global climate change due to its sensitivity to warming and its role in amplifying climate change. NSIDC has stated the warming of Arctic areas is now increasing at around 10 percent per decade.

Environment groups speaking at a Greenpeace conference in New York last night (Sept. 19) interpreted the collapse of the sea ice as a sign of long-term climate warming caused by man, particularly due to the increased reliance on fossil fuels.

“With the speed of change we are now witnessing in the Arctic, the UK government must show national and global leadership in the urgent transition away from fossil fuels to a low carbon economy,” said Rod Downie, polar expert at WWF-UK.

Sea ice plays a critical role in regulating climate, acting as a giant mirror that reflects much of the sun´s energy, helping to regulate the Earth´s temperature, keeping it relatively cool. But the dramatic overall decline seen over the past 30 years, has weakened the planet´s natural heat shield, which in turn brings unprecedented global warming.

Speaking at the Greenpeace event, James E. Hansen, a prominent NASA climate expert, said the ice melt should serve as a warning to the public of the risks that society is running by failing to limit emissions.

“We have a planetary emergency,” Hansen said. “It´s hard for the public to recognize this because they stick their head out the window and don´t see that much going on.”

But soon we could be faced with dramatically increased rises in the level of the world´s oceans. While the sea ice itself does not contribute to the problem directly, its loss does however mean that the planet has less reflective surface area, replaced with darker oceans, contributing to warming, which in turn means more land ice loss.

At one point this summer, surface melt was occurring across 97 percent of Greenland´s ice sheet, a development not seen since satellite measurements began in 1979. However, geological research suggests it has happened in the past.

Because of global warming and Arctic sea ice loss, the world´s oceans are rising at a rate of about one foot per century. Hansen expects this rate to increase as the planet continues to warm, which will put millions of people living along coastal villages at risk.

Another likely result of sea ice loss is the release of large amounts of methane, a greenhouse gas trapped in the permafrost under Greenland´s ice cap since the last Ice Age.

Methane is 25 times more efficient at trapping solar heat than carbon dioxide, and the released gases could in turn add to global warming, freeing up more locked-in carbon, further contributing to ice loss and rising seas.

“The implications are enormous and also mysterious,” said environmentalist Bill McKibben, co-founder of 350.org, a global non-governmental organization focused on solving the climate crisis.

Peter Schlosser, an expert with the Earth Institute at Columbia University, said the impact of the polar ice cap melt is hard to determine because “the Arctic is likely to respond rapidly and more severely than other part of the Earth“¦The effects of human induced global change are more and more visible and larger impacts are expected for the future.”

While the loss of summer sea ice has dire implications for the environment, some see it as a lucrative business opportunity–drilling for oil and gas in a largely pristine and untapped region, and also opening a shipping route shortening the distance between ports, saving time and fuel.

The Arctic Circle can potentially supply the world with 13 percent of oil reserves and 30 percent of natural gas, according to US Geological Survey data. The potential bounty has encouraged energy groups such as Royal Dutch Shell Co. to invest heavily in the region.

Greenpeace International head Kumi Naidoo said that large oil companies have persuaded governments to not cut back on greenhouse gas emissions. “Why our governments don’t take action? Because they have been captured by the same interests of the energy industry.”

Anne Siders, a postdoctoral researcher at Columbia University’s Center for Climate Change Law, warned against the “temptation” of sending ships through the area.

Using these waters as shipping lanes is a dangerous move because there are plenty of ice floes and little infrastructure available in case of an accident, she cautioned.

And drilling poses a similar, very dangerous scenario. In the event of a tragedy–like the Gulf of Mexico Deepwater Horizon oil disaster in April 2010, for example–the consequences would be nothing less than devastating, both economically and environmentally.

“It is completely irresponsible to drill for oil in such a fragile environment; there are simply too many unmanageable risks.” said WWF-UK´s Downie.


Source: Lawrence LeBlond for redOrbit.com - Your Universe Online



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