Alaska’s beavers have expanded into many tundra regions, building more and more dams and creating numerous new water bodies. Because the water they contain is somewhat warmer than the surrounding soil, these lakes and ponds can further accelerate permafrost thawing and intensify climate change. In one small area from just two dams in 2002, the number rose to 98 by 2019, a 5,000-percent increase, with more than 5 new dams being constructed per year. The growth in Canada might be even more extreme.
www.sciencedaily.com/releases/2020/06/200629202009.htm