Climate Change Feedback

I've posted before about the dangers of melting permafrost.  As the Arctic climate warms, permafrost melts and releases carbon dioxide into the atmosphere further warming the atmosphere.  It's called a negative feedback cycle.

There is now another feedback route adding to it accelerating the negative feedback even more.   

Even as climate change shrinks some populations of arctic animals like polar bears and caribou, beavers may be taking advantage of warming temperatures to expand their range. But as the beavers head north, their very presence may worsen the effects of climate change.

Take the dams they build on rivers and streams to slow the flow of water and create the pools in which they construct their dens. In other habitats, where the dams help filter pollutants from water and mitigate the effects of droughts and floods, they are generally seen as a net benefit. But in the tundra, the vast treeless region in the Far North, beaver behavior creates new water channels that can thaw the permanently frozen ground, or permafrost.

“When you start flooding areas with permafrost you immediately trigger permafrost degradation,” said Ken Tape, an assistant professor at the University of Alaska in Fairbanks who has researched the beavers. “You start thawing the frozen ground that’s holding the soil together, and that water and soil and other things are washed away.”

What remains is a pitted landscape, with boggy depressions, that directs warmer water onto the permafrost, leading to further thawing. As permafrost thaws it releases carbon dioxide and methane, which in turn contributes to global warming and helps increase the speed that the Arctic, which is already warming faster than the rest of the planet, defrosts. Worldwide, permafrost is estimated to contain twice as much carbon as is currently in the atmosphere.

The melting arctic ice and the actions of beaver are just two of the feedback mechanisms making climate change much worse than just what we are doing by pouring carbon dioxide into the atmosphere, just two.  There may be many more.  Our situation isn't just getting worse, it's getting worse faster.