There goes Santa's workshop. Researchers at the Norwegian Polar Institute report that Arctic sea ice is becoming increasingly thinner and more at risk. The scientists, who monitor the annual summer thaw, say floating ice levels are at their lowest since monitoring began more than 30 years ago. And since the annual melt usually ends around mid-September, there's still a week or so left before temperatures once more drop below freezing. "It's a greater change than we could imagine 20 years ago, even 10 years ago," said Kim Holmén, the director of the institute.