Washington Post: As the frozen Arctic soil known as "permafrost" thaws, it could release large amounts of carbon in the form of both carbon dioxide and methane to the atmosphere. And this new source of greenhouse gas emissions could be large enough that it could substantially undermine attempts to cut down on emissions from fossil fuels. Now, an overview of what we know about the permafrost carbon problem has just come out in Nature, written by a group of 17 experts on the matter. In other words, this...