Scientists who work in the Alaskan Arctic have discovered that local shrubs are growing larger and spreading across previously bare areas of the tundra. Researchers looked through aerial photos taken 50 years ago and compared them with new photos and found that shrub growth in some of the areas has increased as much as 15 percent.
?The Alaskan Arctic for three decades has gotten considerably warmer and experimental and model studies have shown that there should be more shrubs,? says Matthew Sturm, a U.S. Army geophysicist working in Alaska. ?We come along and find these photos, and that?s exactly what we?re seeing.?
?It certainly opens the door for more work to support the theory that temperature is rising,? says Jeff Hicke of the University of Colorado. He recently conducted a separate study of tundra vegetation using satellite imagery.
According to Sturm, ?When you increase the shrub cover you trap more snow, which keeps the soil warmer. We?re not sure how the trend will go.? However, another study suggests that the additional shrub growth will remove more carbon dioxide from the atmosphere, slowing down future global warming.
A firsthand account of Arctic warming comes from Boerge Ousland, a Norwegian explorer who has just skied over the top of the world. As he crossed the Arctic, he said he saw evidence that hints strongly at the effects of climate change.
?The ice toward the North Pole seems to be much thinner than normal and this made it much more broken so that the conditions were much more difficult than they had been in 1994,? he said, referring to an earlier expedition to the same area.
?I think personally that things are happening with [global] warming?that the ice is getting thinner and there is less ice,? says Ousland.
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