SHISHMAREF - Mean temperatures in the state have increased by 5 degrees in the summer and 10 degrees in the winter over the past 30 years. said Gunter Weller, director of the Center for Global Change and Arctic System Research at the University of Alaska in Fairbanks.
Moreover, the Arctic ice field has shrunk by 40 percent to 50 percent over the last few decades and lost 10 percent of its thickness, studies show.
"These are pretty large signals, and they've had an effect on the entire physical environment," Weller said.
"The only question is, is it man-made? Is it the greenhouse effect? Or is it natural variability? I think the consensus in the scientific community almost certainly is that it is both," Weller said. "Certainly, we can't ignore factors like solar variability. But there is no question, I think, in anybody's mind left that there's an anthropogenic effect due to the greenhouse effect. How much is it? Is it 50 percent? More? We don't know, but it's significant."