The Newest Threat to a Warming Alaskan Arctic: Beavers

Alaskan beavers are carving out a growing web of channels, dams and ponds in the frozen Arctic tundra of northwestern Alaska, helping to turn it into a soggy sponge that intensifies global warming, a new study warns. The number of new beaver dams and lakes continues to grow exponentially in the region, researchers say, destabilizing permafrost and triggering a cascade of effects.