At the height of the Cold War in the 1950s, the Greenland ice sheet hosted a number of clandestine U.S. Army bases whose job it was to get an estimated 600 medium-range ballistic missiles with nuclear warheads ready for deployment. The largest of these sites was Camp Century, which had the public facade of a science station.

The Army never finished what it started at Camp Century. It abandoned the base in 1967, scrapping Project Iceworm, as its secret mission was called. But the Army left behind a nasty legacy buried under all that ice and snow?—?tons of toxic waste that military officials assumed would stay frozen forever.

Guess they didn't count on climate change.

Fifty years ago, the Army probably didn't know about climate change. But now, thanks to global warming, the ice has begun to melt, leaking chemicals the Army thought would stay frozen in perpetuity. This poses a danger to the marine ecosystem, not to mention the potential diplomatic nightmare that could result between the United States and the host country.