University of Alaska scientist Rick Steiner (L) and National Oceanic and Atmospheric Administration oceanographer Jim Overland pose in front of a U.S. Coast Guard C130 in Barrow,Alaska during refueling stopover for their flight over the Arctic Ocean September 30, 2009. REUTERS / Yereth RosenBy Yereth Rosen

ON BOARD COAST GUARD FLIGHT ABOVE BEAUFORT SEA, Oct 2 (Reuters) – Out in the Arctic Ocean, about 200 miles (322 km ) north of the nearest human settlement, the future of the world’s climate is written in the patterns of ice patches on the water’s surface. Old, “multiyear” ice — the glue that holds the polar ice cap together and forms the Arctic’s defense against encroaching warming — is slowly disintegrating, a process that is plain to see from the air. Thick ice floes used to be kilometers (miles) wide just over a decade ago, said Jim Overland, a sea-ice expert with the U.S. National Oceanic and Atmospheric Administration, who has been surveying the site since the 1990s. Now the narrow floes — with bright-white tops and a blue underwater glow — are just meters (yards) wide, observed Overland as he studied the patterns from the window of a U.S. Coast Guard C-130 aircraft. The dense, high-quality ice is not coming back, Overland said. “That’s a one-way street,” he said “We have the same amount of multiyear ice this year as last year, even though we have a little more ice overall.” Overland said while there was broad awareness of the harmful effect of sea-ice loss on polar bears and other Arctic animals, its impact on weather elsewhere in the northern hemisphere and the rest of the world was potentially more critical. A warmed Arctic Ocean emits heat into the atmosphere that drastically alters weather patterns, he said. “That’s the big question: Who cares about the Arctic? Well, it’s going to change the whole heat engine of the planet,” he said. …

Vanishing Arctic ice shows no sign of returning