( bing rather than reflecting incoming so...)Lands surface change on Alaska tundra creating longer, warmer summers in Arctic

"The vegetation change is pretty dramatic," Epstein said. "The tundra is getting greener, and there is a noticeable increase in shrubs. This is observable from satellite data and by observations on the ground. Native American people in the region and nearby areas also have noted the changes in weather and vegetation."

Because there is a shorter period of snow on the ground, solar radiation is absorbed by the land surface more readily and contributes to heating, thus accelerating the melting of snow and allowing for more plant growth. Over time, as the permafrost begins to melt, ancient organic matter that has been frozen for thousands of years is exposed, potentially adding more carbon dioxide to the atmosphere.

The result is a positive feedback loop that could continue to raise temperatures in the region and further lengthen the snow-free period each year.

Since the early 1960s, scientists have identified "hotspots" of slowly increasing average summer temperatures in the Arctic, from 0.15 degrees Celsius to about 2 degrees Celsius for an average increase of 1.2 degrees Celsius in the summertime.

"We know that certain parts of the Arctic are warming pretty substantially and more so than in other regions around the globe," Epstein said. "This is significant because conditions in the Arctic affect global atmosphere conditions. The Arctic is dominated by snow and ice, and if this condition were to change, even subtly, there is potential for further change to the global climate."