Rewilding Arctic Tundra Might Prevent Runaway Climate Change

Bison (and horses) in the Arctic could save the world, and these ones look just determined enough to do it. David Osborn/Shutterstock.com

The key to preserving Arctic ecosystems, slowing the thawing of permafrost, and preventing the release of vast quantities of greenhouse gasses could be the reintroduction of large herbivores. Despite the hopes of a few dreamers, it is too late to bring back the mammoths that shaped the region during the ice age, but a new proposal claims surviving animals could do the trick.

Perhaps the most concerning aspect of global warming is the possibility that above a certain temperature, the environment may start to release stored carbon, leading to continued hotter conditions even if we stop human emissions. Among the top three candidates for such a vicious spiral is the Arctic tundra, where enormous amounts of methane are trapped just below the surface, leading to a slow release in some locations and something much more sudden in others.

Although we think of forests as carbon stores, Dr Marc Macias-Fauria of Oxford University argues that in the Arctic, trees have the opposite effect. Being much darker than snow, they absorb sunlight and cause local warming and melting snow. Meanwhile, grasslands trap carbon in the soil much better than the currently dominant moss and induce a winter freeze so deep it survives the summer warmth.

Macias-Fauria claims in the Philosophic Transactions of the Royal Society what we need then is “eco-system engineers” to do the job mammoths once did of keeping woody plants down, encouraging grass growth with their dung, and trampling the snow, freezing the ground below. Bison appear to start the process well, and horses maintain it. The authors used the fossil record to calculate how many large animals roamed the tundra during the Pleistocene era per square kilometer and propose restoring this, mammoths aside.

“The Arctic is already changing, and fast. Taking a ‘do nothing’ approach now is a decision to allow rapid, irreversible changes to occur,” Macias-Fauria said in a statement. “Although the science of Arctic eco-engineering is largely untested, it has the potential to make a big difference and action in this region should be given serious consideration.”

The process of reintroducing key species to an environment in the hope they will return it closer to its natural state is known as re-wilding, made famous by the great success in Yellowstone Park. To see whether the idea is viable, Macias-Fauria looked at an existing experiment run by one of the co-authors in Yakutia, Russia, since 1996, known as Pleistocene Park. The paper models the costs of scaling the park up. Although it acknowledges the difficulties involved – breeding enormous herds would be a challenge, even if mortality is minimized – it suggests it may be commercially viable if the price of carbon credits rises or supplementary income sources are found.
 

Failure to act could be devastating. The authors estimate that without action, annual emissions from melting permafrost will be almost half those of fossil fuels today. Even if we switched entirely to clean energy, we might be doomed to a vastly hotter world, unless something like the proposal outlines can be implemented.

B) Aerial view of Pleistocene. The black line is the park's fence. (c) Yakutian horses in the park; (d) European bison browsing, one of the ways herbivores transform the environment; (e) herd of yaks grazing on a drained lake, which represent some of the easiest environments to turn into grasslands

 

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