Unfrozen ground: Earth’s permafrost is thawing

It may not be as dramatic as cracking, melting glaciers, but it could be more dangerous – Earth’s permafrost is thawing out. Permafrost is sub-surface ground that has been frozen for at least two years. In the Arctic and Antarctic, most permafrost has been frozen for thousands of years, and it can be hundreds or even thousands of feet thick. And if it is thawing out, that can mean bad news, because Earth’s permafrost is not just made up of frozen soil. It also holds the remains …