Arctic's First Ice-Free Summer Possible Even This Year

June 27, 2008 — -- The distinct possibility that this summer -- for the first time in recorded history -- the North pole could be free of sea ice, is now a common subject of discussion among the world's climate experts.

The Arctic's thick, resilient multiyear sea ice (frozen sea surface), which accumulates and usually lasts through the annual melting season, has started to give way to thinner, vulnerable first-year ice.

Satellite data gathered by the University of Colorado's National Snow and Ice Data Center showed that young sea ice, which is no more than about 60 inches deep and much more susceptible to melting away, now makes up 72 percent of the Arctic ice sheet. Using that estimate, scientists at the center see a 50 percent chance that ice at the Earth's highest point will melt by the summer's end.

Andy Mahoney, a center researcher, has pinpointed this year in particular as having the "greatest chance" of being ice-free.

"It will probably come down to how cloudy it is this summer," Mahoney says. "If there's clear skies and if atmospheric patterns resemble last year's, you're going to see a lot more melt."

The increasing rates of Arctic melt have altered the region in unprecedented ways. Last September, Arctic sea ice dwindled to a record low, clearing a route through the fabled Northwest Passage that runs from Greenland to Alaska. Opening of the path has provided ships a shorter, more direct route between Asia and Europe.

"It's got a shock level for people because there's always ice at the North Pole, but there are also real implications," Mahoney said. "If the North Pole melted out, the shipping industry would be paying very close attention to that."

Wieslaw Maslowski, who conducts Arctic ice research from his base at the Naval Postgraduate School in Monterey, Calif., told ABC News last summer that there was a chance that the Arctic's entire ice sheet could vanish for the first time in just four or five years.

The statement was considered a daring projection at the time, given that earlier climate prediction models estimated that it would take at least another 40 or 50 years before such a scenario is likely to occur.