Satellite images taken over decades show two seemingly contradictory events that indicate global warming is affecting Alaska.
Thousands of satellite images show Alaskan tundra becoming greener, while also indicating that forests stretching from Alaska's interior into northeast Canada are becoming less green, the Anchorage (Alaska) Daily News reported Thursday.
"Everyone (assumed) these forests were (also) going to continue to green, and it turns out that there may be other factors that are causing unexpected results," Scott Goetz, a senior scientist at Woods Hole Research Center in Massachusetts and one of four scientists analyzing the satellite data told the newspaper.
Alaskan snow researcher Matthew Sturm said some scientists theorize tundra bushes that grow above the snow make the surface darker, accelerating heating by up to 70 percent and, therefore, increasing tundra greening,
Fairbanks ecologist Glenn Juday said the forests are becoming less green because the trees are rapidly drying in the increasing warmth.
The study appears online in the Proceedings of the National Academy of Sciences.
Copyright 2005 by United Press International
Explore further: Climate change has doubled western US forest fires