Traveling on top of the world: melting of arctic sea ice due to global warming may open legendary northwest passage.

• Author: Orr, Vanessa
• Position: CLIMATE CHANGE

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You can't turn on the news today without hearing some reference to global warming and the effect it is having on the earth. Temperatures are rising, glaciers are retreating and birds are beginning to return north earlier than expected. Arctic ice is taking longer to form, and the ice that does form is not as thick as in previous years.

While this might sound like a disaster movie in the making, the fact is, some of the changes that are taking place might actually provide benefits, especially to those who make a living in the frozen north. As sea ice retreats, ships have access to open water routes for a longer time, and the possibility of developing a trade route between Alaska and Europe across the Arctic Ocean comes closer to reality.

"Depending on your perspective, the retreat of the sea ice can be good or bad," explained John Walsh, Presidents Professor of Global Change, University of Alaska Fairbanks. "If you're a polar bear or a walrus dependent on the ice cover for survival, things aren't that good. But if you're a shipping company looking for a shortcut, or a company that develops oil and gas resources offshore, it might be to your advantage."

BREAKING THE ICE

Scientists who document the retreat of sea ice have seen some notable changes in the last eight years. "Since 2000, we've seen four new record minima of summer ice extent, including last summer, when the record was broken by 20 percent," said Walsh. "We've also seen a change in the thickness of the ice in the Arctic Ocean, as well as in the Beaufort, Chukchi and Bering seas."

According to Walsh, the average thickness of ice found in the Arctic Ocean, which used to be 3 to 4 meters, is now just 2 to 2 1/2 meters (6.56 to 8.2 feet). "This 25 percent to 40 percent reduction is due largely to the older, thicker ice being driven by the wind out of the Arctic into the North Atlantic," he explained.

"Older ice, which might be 10 years old, is replaced by first-year ice, which doesn't get as thick," he continued. "It takes five to 10 years for the thickness of ice to reach 3 or 4 meters (9.84 to 13.12 feet)."

According to NASA researchers, though perennial, or older ice, used to cover 50 percent to 60 percent of the Arctic, it covered less than 30 percent this year. Ice that is six or more years old comprised 6 percent of the Arctic area, down from more than 20 percent in the mid- to late-80s.

This current retreat of sea ice may change the future of shipping...