During the summer of 2007, lightning strikes sparked five tundra fires on Alaska’s North Slope. Two of the fires — rare events north of the Arctic Circle — began in neighboring drainages, only a couple of days apart. That, in itself, might have gained the attention of tundra researchers. But the 2007 fire season would ultimately burn a record swath across the North Slope, while reshaping the way scientists think about the Arctic’s response to global warming.
Researchers have known for years that the Arctic landscape is being transformed by rising temperatures. Now, scientists are amassing growing evidence that major events precipitated by warming — such as fires and the collapse of slopes caused by melting permafrost — are leading to the loss of tundra in the Arctic. The cold, dry, and treeless ecosystem — characterized by an extremely short growing season; underlying layers of frozen soil, or permafrost; and grasses, sedges, mosses, lichens, and berry plants — will eventually be replaced by shrub lands and even boreal forest, scientists forecast.
http://www.e360.yale.edu/content/feature.msp?id=2229