Restore the Climate by bringing back Mammoths?

When I first heard the proposition, I snorted. Bringing mammoths back from extinction could help slow climate change? It seemed like technological rationalization gone wild. Like trying to justify an extra bottle of wine because it is good for you. If you are going to revive a species, I can imagine many good reasons — you hardly need to rationalize it with a solution to global warming.

I recently spoke to Nikita Zimov, the scientist behind Pleistocene Park, an effort to restore an ecosystem that disappeared with the end of the last ice age. Now I am not so jaded. It still sounds crazy when I say it out loud but it deserves a serious hearing.

What changed my mind is listening to Nikita’s rationale and approach. He is not focused on mammoths, actually, despite featuring them prominently in his logo. When you listen carefully to his strategy, having mammoths might be important, but his real goal is restoring an ecosystem that existed before humans showed up. In practice that means getting to a density of large mammals — including bison, elk, moose, musk ox, yak, wolves, and tigers — that don’t exist anywhere else other than the African savana. If a woolly mammoth is in the mix, so much the better. They already have a large number and variety of animals in their Pleistocene Park in Siberia.

Nikita’s logic is that the tundra is under threat due to global warming and capable of sequestering more carbon dioxide. The key is is restoring the ecosystem from 20,0000 years ago. The key difference between now and then is not climate in his analysis, but a lot of large mammals. His hypothesis is that they were the key in an ecosystem that had more grassland, less moss, less shrubs and less trees. If he is successful and can scale the solution, it would have three positive impacts on climate.

Grasslands reflect more energy into space year around. This is especially important when there is snow on the ground, which is most of the year in Siberia. Notably, when Siberian forests burn down, the albedo effect increases, resulting in a cooling effect (of course the released carbon dioxide increases warming).

Second, large mammals trample down the depth of snow, reducing its insulation effect, making the underlying land slightly colder by around 2 degrees (C). That could be important as temperatures rise in the Arctic regions, potentially thawing permafrost and resulting in much more greenhouse gas emissions.

Finally, by growing more biomass, a return to this ancient ecosystem would sequester carbon into the soils at a rate higher than the currently. In addition, Nikita claims a grassland would suck up more water from the land, reducing standing water. That could be a way to reduce another potent greenhouse gas source — methane emissions from the bogs, ponds, and lakes of the area.

Of course, most this is Nikita’s hypothesis, for which he and his team are measuring results, and publishing papers. What distinguishes his effort is his willingness to take on his hypothesis with a massive, large scale test and the determination to keep at it for decades. It reminds me of the Marin Carbon Project, a more recent effort to modify agricultural techniques to sequester carbon in California and other range lands. They too found that adding a high density of large mammals (cows in their case), combined with other techniques like composting, increased the carbon in soils.

Are woolly mammoths required? Nikita thinks they might do a more effective job at tearing down the forest than north american prairie bison, which they hope to introduce soon. Of course, it depends on progress with creating a cold-weather elephant. Cloning an actual mammoth is taking longer than expected. Frank Church is taking a different approach, using CRISPR to modify the genome of an asian elephant to have better blood supply, hair, and thicker fat. Those efforts are epic milestones in science and humanity and I hope they succeed. But they are worthy regardless of their impact on the climate. I promise not to snort with laughter next time I hear the idea.