Global warming time bomb trapped in Arctic soil: study
Previous estimates of the Arctic carbon pool relied heavily on a relative handful of measurements conducted outside of the Arctic, and only to a depth of 40 centimetres (15.5 inches).
The study, published in the British journal Nature Geoscience, found that the stock of organic carbon "is considerably higher than previously thought" -- 60 percent more than the previously estimated.
This is roughly equivalent of one sixth of the entire carbon content in the atmosphere.
And that is just for North America.