Scientists report ancient roots and bones locked in long-frozen soil in Siberia are starting to thaw. This vast carbon reservoir contains about 75 times more carbon than the amount released into the atmosphere each year by burning fossil fuels.
Siberia isn't the only place on Earth with massive lodes of permafrost -- parts of Alaska, Canada and northern Europe have them too. The Siberian area is possibly the world's largest, covering nearly 400,000 square miles, with an average depth of 82 feet, and probably holds about 500 billion metric tons of carbon.
By any measure, this is a lot, and it is in fact twice what scientists previously believed was there, ecologist Ted Schuur of the University of Florida said in a telephone interview.
"There's a huge pool of carbon, even more than people thought before, perhaps double the amount of carbon that we thought," said Schuur, one of the article's co-authors. "If you have twice as much carbon there, essentially in the future twice as much could be released into the atmosphere."