BBC Science Focus
Beavers are contributing to permafrost decline
Alaskan beavers are contributing to the decline of the Arctic permafrost at an ‘exponential’ rate, a study carried out by researchers at the University of Alaska, Fairbanks has found. Permafrost is a layer of soil, rocks and ice that has remained frozen for at least two years. Permafrost locks up greenhouse gases, so if it degrades, methane and carbon can leach into the atmosphere. In the northern hemisphere, almost a quarter of land has permafrost underneath. Over the last few decades, researchers have noticed beaver populations spreading to previously uninhabited regions of Alaska, creating dams and new lakes. As these bodies of water are warmer than the surrounding soil, it can cause the permafrost underneath them to thaw.