The world’s permafrost holds vast stores of carbon. What happens when it thaws?

The remote Arctic tundra may seem like the last place on Earth human pollution should be causing a problem — yet it’s filled with mercury contamination.

The most recent study noted that Arctic thaw is occurring one to two weeks earlier than the first study, and the North Slope growing season is lengthening by 15 to 21 days. At the same time, however, caribou are maintaining the same reproductive timeline.