OSLO (Reuters) - Polar bears are drowning and receding Arctic glaciers have uncovered previously unknown islands in a drastic 2006 summer thaw widely blamed on global warming.

Signs of wrenching changes are apparent around the Arctic region due to unusual warmth — the summer minimum for ice is usually reached between mid-September and early October before the Arctic freeze extends its grip.

"We know about three new islands this year that have been uncovered because the glaciers have retreated," said Rune Bergstrom, environmental adviser to the governor of Svalbard, a Norwegian archipelago about 1,000 km (600 miles) from the North Pole.

The largest is about 300 by 100 meters, he told Reuters.

On a trip this summer "We saw a couple of polar bears in the sea east of Svalbard — one of them looked to be dead and the other one looked to be exhausted," said Julian Dowdeswell, head of the Scott Polar Research Institute in England.

He said that the bears had apparently been stranded at sea by melting ice. The bears generally live around the fringes of the ice where they find it easiest to hunt seals.

NASA projected this week that Arctic sea ice is likely to recede in 2006 close to a low recorded in 2005 as part of a melting trend in recent decades. A stormy August in 2006 had slightly slowed the 2006 melt.

"There are very unusual conditions this year from Svalbard to Alaska," said Samantha Smith, director of the WWF's environmental group's Arctic Programme.

One international study in 2004 projected that summer ice could disappear completely by 2100, undermining the livelihoods of indigenous peoples and driving creatures such as polar bears toward extinction.

WAKE-UP CALL

Smith said the shrinking ice should be a wake-up call for governments to cut emissions of greenhouse gases, mainly from power plants, factories and cars that most scientists say are causing global warming.