Arctic Ice Retreat May Be Harbinger of Climate Change (Update1)

by Alex Morales

Sept. 16, 2008 (Bloomberg) -- The shrinking of Arctic sea ice to its second-smallest size on record signals greater changes in the Earth's climate as it opens previously frozen shipping routes.

The polar ice, which melts from March to September each year and expands again as winter approaches, was only smaller in 2007, according to satellite data collected since 1979 and released today by the U.S. National Snow and Ice Data Center. The trend of reduced ice dates to even before 1979, according to measurements from aircraft and ships.

"We certainly haven't seen conditions like this for hundreds of years,'' said Walt Meier, a scientist at the Boulder, Colorado, based center, who blames the retreat largely on emissions of greenhouse gases such as carbon dioxide. Receding ice is "the most visible and largest indicator of climate change that we see.''

Reduced ice poses a risk to the northern region's indigenous people and wildlife and has repercussions for global climate. It's also opened new shipping channels between Canada and Siberia and is easing access to natural resources such as oil and gas under the seabed.

The NSIDC figures are released annually at the lowest level the sea ice reaches before cooling resumes. This year's lowest point was Sept. 12, when 4.52 million square kilometers (1.74 million square miles) of the Arctic Ocean was covered by sea ice. That compares with last year's record low of 4.13 million square kilometers and the average low for 1979 to 2000 of 6.74 million square kilometers.

Tipping Point

The melting has already passed a tipping point, meaning that ice-free summers in the Arctic are inevitable, U.S. scientist Jim Hansen said before the release. Hansen, head of the National Aeronautics and Space Administration's Goddard Institute for Space Studies in New York, has warned publicly about global warming since 1981.

"We are going to lose all the Arctic sea ice in summer,'' Hansen said in an interview in London. "The planet is out of energy balance and there's no way for us to restore it in a timescale of less than a few decades,'' he predicted.

Without reflective ice, a darker ocean is exposed that will absorb more solar energy, exacerbating global warming, said Meier and Martin Sommerkorn, adviser to the environmental group WWF, also known as the World Wildlife Fund.

Arctic Waters

Warmer Arctic waters may release from the seabed methane locked up in compounds called clathrates, Sommerkorn said in a telephone interview from Oslo, where the WWF Arctic program is based. On land, the extra heat will help release carbon dioxide and methane, both greenhouse gases, from the soil, he said.

"The loss of Arctic sea ice does not only have Arctic implications,'' Sommerkorn said. "It has the potential to seriously amplify global climate change.''

Warmer local temperatures may also increase the melting of the Greenland ice sheet, with the potential to raise sea levels, according to Sommerkorn and Hansen.

Rising temperatures due to manmade greenhouse gas emissions threaten to increase flooding and droughts in different parts of the world, put millions of homes at risk and endanger up to 30 percent of species, the United Nations Intergovernmental Panel on Climate Change warned last year.

Wildlife Impact

Arctic species that may suffer include the polar bear, which depends on the surface for hunting. Two-thirds of the world's polar bears could be lost within 50 years as a result of retreating sea ice, the U.S. Geological Survey said last year. In 2006, the animal was classified as a threatened species on the World Conservation Union's Red List.

Indigenous people are already adapting to changing landscapes, taking kayaks to hunt when once they used sled dogs, Meier said. The loss of ice opens up the coast to erosion from waves, endangering settlements, he said.

The seasonal melt is also opening up potential trade routes between the Atlantic and Pacific and making undersea resources more accessible, said Cleo Paskal, a geopolitical analyst at Chatham House, a policy adviser in London.

"The situation is changing very quickly because of climate change,'' Paskal said. 'There's unquestionably going to be dramatically increased traffic through the Arctic.''

The Northwest Passage, a long-sought sea route linking the Atlantic and Pacific, opened up the last three years, Meier said. Last year, the Parry Channel -- deep enough for large ships to pass -- opened for the first time, he said.

New Shipping Routes

"It's advantageous for shipping and in a military-conflict situation,'' Paskal said. 'It needs to be managed very carefully for it not to be another destabilizing factor in geopolitical affairs.''

The U.S., Denmark, Canada, Norway and Russia all claim part of the Arctic and its billions of dollars of resources. Russia last year planted a flag on the seabed at the North Pole, claiming an area that the government estimates holds 10 billion tons of oil- equivalent as well as gold, nickel and diamonds.

Of the northern nations, Russia has a "big advantage in strategic control over the Arctic'' because it has ports on the permafrost and a fleet of icebreaker ships, Paskal said.

While Arctic sea ice is declining, on the other side of the world, Antarctic ice in March covered more ocean than at the end of any previous summer melt season, according to the NSIDC. That's partly due to circling winds that keep sea ice in and tend to isolate the southern continent from the rest of the world's climate, said Ted Scambos, a scientist at the center.

"The Antarctic is a system where year-to-year variability still outweighs any effect of climate change,'' he said in an e-mail. Still, models forecast the southern continent will also eventually begin to warm, he said.

In 2000, scientists were predicting the Arctic could be free of sea ice in summers by 2100, said Meier. Now, trends indicate ice-free summers are likely by 2030, he said.

"It's a harbinger of what we'll see through the rest of the world in coming years,'' Meier said. "It's like we've opened up the refrigerator door all of a sudden.''

To contact the reporter on this story: Alex Morales in London at amorales2@bloomberg.net.

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