Global warming causing record Arctic ice melts

Scientists say new U.S. and Canadian satellite images have tracked a stunning reduction in Arctic Sea ice following the northern summer. The shrinkage is far more extensive than normal for the fourth consecutive year. The researchers say the current rate of decline could mean that the Arctic would be free of ice well before the end of the century.

Since 2002, U.S. satellite data have revealed unusual springtime melting in areas north of Siberia and Alaska. Now, the National Snow and Ice Data Center at the University of Colorado says the trend expanded this year to include the entire Arctic ice pack.

"What it's telling us is that the pace of retreat of ice in summer is accelerating," said snow and ice data center researcher Ted Scambos.

He says the record Arctic ice sheet reductions each summer are feeding on themselves, making each subsequent year worse.

"It's sort of a vicious circle. What happens is if you start to melt the sea ice up in the Arctic, it actually starts to get darker. Dry, white snow reflects 85 percent of the sunlight that falls on it. If you start to melt it, though, that brightness goes down to about 60 percent, and so it starts to absorb more energy. Once it gets a little more darker, it starts absorbing more heat, leading to further melting," he added.

Mr. Scambos says the shrinking summer Arctic ice cap means less and less expansion each winter, with less thickness. The new report shows that last winter's recovery was the smallest in a quarter century of satellite monitoring, reports VOA.

According to Globe, the U.S.-based National Snow and Ice Data Center presented data showing that the dramatic decay has continued for the fourth consecutive year, with 2005 being a record year for sea-ice shrinkage.

The researchers, who used satellite images and were assisted by NASA and the University of Washington, also predicted that if the current rates of decline in sea ice continue, the summertime Arctic could be ice-free before the end of this century.

A thawed Arctic region would have massive implications for Canada's economy and sovereignty claims.

Mark Serreze, a researcher at the Colorado-based centre, said it's been so warm in the region this year that the legendary Northwest Passage was largely open during the summer.

"It's certainly a rare event. . . . It's becoming easier to get through," he said. "Could this become one of the positive impacts of global warming? It all depends on your perspective."

In recent years, some have predicted that the treacherous waterway, which is normally clogged with ice, could become the much sought-after shortened trade link between Europe and Asia.

Mr. Serreze said he is worried that the decline of sea ice can never be reversed.

He said that historically, the ice cap recuperates during the winter, but that isn't happening any more.

P.T.