A Toxic Time Bomb Is Ticking in the Arctic

Once the ground is no longer frozen enough to form a barrier, those contaminants will seep into rivers and ponds, corrupting highly sensitive ecosystems. “This, we think, could also be a dangerous situation for people living up in the high north,” says Langer, as the contaminants mix with drinking water.

That water will eventually empty into the ocean and ride elsewhere on currents. Toxicants can also get airborne: Indeed, the Arctic is already dusted with lead from burning leaded gasoline. Mercury, too, could escape mining operations by taking to water and air. “Mercury that came from the burning of coal and fossil fuels from a century or two centuries ago is still cycling through our biosphere,” says Kevin Schaefer, a climate scientist at the University of Colorado, Boulder, who studies permafrost contaminants but wasn’t involved in the new paper.

Human activity in the Arctic only exacerbates the thaw. Dark-colored roads absorb the sun’s energy, heating the soil. Digging up dirt and tossing it on top of snow darkens the whiteness that would normally bounce light off…