Arctic’s Newest Climate Feedback: The Beaver Effect

Climatologists frequently talk about “positive feedback” effects – where one first order effect of planetary warming “feeds back” or enhances another knock-on effect, which makes the first one worse, which feeds back again, etc.
Prime example is, warming Arctic ocean water means melting sea ice, which replaces highly reflective white ice with dark ocean water, absorbing more solar radiation, creating more warming.

There are a number of others.

Now we have a furry, fuzzy, busy, new one.

Business Insider:

Beavers are taking over the Alaskan tundra, completely transforming its waterways, and accelerating climate change in the Arctic.

The changes are so sudden and drastic that they’re clearly visible from space.

As the Arctic tundra warms, woody plants are growing along its rivers and streams, creating perfect habitats for beavers.

As the furry rodents move into these waterways, they make themselves at home by doing what they do best: chewing and carrying wood to build dams, and clogging rapid rivers and streams to make lush ponds.

What was once a thin line of water cutting across the tundra has become a train of bulbous beaver ponds:

“There’s not even a lot of other animals that leave a footprint you can see from space,” Ken Tape, an ecologist at the University of Alaska Fairbanks, told Insider. “There is one, and they’re called humans. The funny thing is that humans could not get a permit to do what beavers are now doing in this state.”

This swimming, furry rodent’s invasion of the North American tundra is a mixed bag. The beaver ponds create lush oases that could increase biodiversity, but they also play a role in accelerating the climate crisis.

Tape and his colleagues assessed aerial photos from the early 1950s and found no signs of beaver presence in Alaska’s Arctic tundra. The first signs of beavers appeared in 1980 imagery. In satellite imagery from the 2000s and 2010s, the beaver ponds doubled.

All in all, satellites reveal more than 11,000 beaver ponds have appeared across the tundra.

“All of western Alaska is now really densely populated with beaver ponds,” Tape said.

That’s consistent with what Indigenous people in the area have observed. It’s especially obvious on the ground in towns like Kotzebue, where there were no beavers 20 years ago, and now they’re everywhere, Tape said.

UPDATE:

I found this conversation with Katey Walter Anthony – expert on Arctic Lakes, on the general topics of lakes in the arctic.
More research needed.