Nature’s Answer to Terraforming
(Published in The EarthSphere Blog; Cover image: Flatland Pond (by WM House & CF Lovelace; ArcheanArt)
We don’t have to read science fiction novels to find stories about terraforming planets. We just need to read the news about our own Arctic. Beavers, nature’s master landscapers, are hard at work changing the Arctic tundra. While this story is not directly about climate change wrought by human hands, it is part of the Anthropocene climate change saga we are all experiencing. The Arctic beavers are following their instincts and, in the process, accelerating the rate of Arctic permafrost melt and carbon release.
Beavers build dams. They don’t work from blueprints or engineering analysis, and there is no conscious, long-range plan. They build because their genetic code demands it. All successful species develop survival strategies where the premise is simple; eat but don’t be eaten. Beavers are much like medieval feudal lords protecting themselves with moats surrounding their castles. The moats keep out the riffraff and more sinister characters.
A beaver dam creates a lake, and in the middle of the lake lies their castle of twigs and sticks, the “beaver lodge.” The lodge has an underwater entrance, and the surrounding lake protects this large rodent and its family from predators.
There were no beavers in most northern Arctic tundra environments fifty years ago. Today they are becoming endemic thanks to global warming. Beavers aren’t worrying about climate change, but they are proactively adapting to it.
Water and Warming
The Arctic is warming twice as fast as the global average and dramatically affecting the rest of the planet. The key to understanding why the Arctic has an oversized effect on climate change lies in its permafrost cover. Permafrost contains large quantities of frozen organic remains from plants and animals. Normal bacterial decay is interrupted in the Arctic because of prevailing low temperatures, leaving massive amounts of “undigested” organic carbon.
But when permafrost melts, bacteria swing into action and eat the unfrozen organic remains, releasing methane and carbon dioxide into the atmosphere. There is almost twice as much carbon frozen in the Arctic as existing atmospheric carbon. Put simply; the Arctic contains a huge supply of greenhouse gases, which it releases into the atmosphere as its permafrost melts. Global warming and even more rapid Arctic warming ensure increasing permafrost melt in the future.
Beavers are unwittingly accelerating the rate of permafrost melt by building more dams. Each dam creates a new pond. NOAA research in a region of western Alaska documented more than 12,000 ponds in an area where there were none in 1955. The number of ponds has doubled over the past two decades.
The connection between permafrost melt and dams comes from the ability of open water to readily absorb heat from the sun. Shallow ponds are warmer than the surrounding permafrost, accelerating the melting process. More ponds equate to more permafrost melt.
Geography and Genetics
The Arctic tundra is particularly susceptible to beaver terraforming due to its geographical profile. Tundra ecosystems are defined as barren, treeless terrains found in the Arctic, Antarctica, and in high mountainous areas. But vast Arctic tundra regions are low and flat with subtle changes in topographic relief and lots of water drainage. Due to the low topographic relief, water moves slowly and easily backs up into shallow ponds, providing a bit of paradise for beavers.
These crafty rodents create large, shallow ponds using relatively small dams. Essentially, they get more bang for their efforts because low dams flood large areas with wide, shallow ponds. This combination of Arctic geography and the beaver’s genetic predisposition is a great match for the beaver but not so good for climate change mitigation.
These ponds are more effective at capturing solar heat than the grasslands they displaced. So, the beavers are inadvertently hastening permafrost melt and accelerating the rate at which Arctic greenhouse gases enter the atmosphere. The vast stores of organic carbon in the Arctic raise an unsettling proposition where Arctic carbon release from natural processes like beaver terraforming is enough to sustain our global warming trend even as humanity tries to reduce fossil fuel emissions — the Arctic tipping point scenario.
Beavers didn’t initiate climate change and global warming, but they are certainly adapting to a warmer planet, and in the process, accelerating the warming. Let’s hope human climate adaptation moves us into the future without exacerbating the underlying causes of our current climate dilemma.
ArcheanArt
Sources:
Beavers Are Reshaping the Arctic Tundra. Here’s Why Scientists Are Concerned (Rasha Aridi; Smithsonian Magazine)
Beaver Engineering: Tracking a New Disturbance in the Arctic (by K. D. Tape, J. A. Clark, B. M. Jones, H. C. Wheeler, P. Marsh, and F. Rosell; NOAA Arctic Program)
Beaver (Source: Smithsonian’s National Zoo & Conservation Biology Institute)
