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Credit: Dean Conger

Coming Attractions

Repopulating the Mammoth Steppe

Migratory woodland reindeer being driven by an Evenks herder through a valley in the Oymyakon region of the Sahka Republic in the Indigirka River Basin, Russia. The Evenks are famed reindeer riders and pastoralists. Their unique saddles are situated on the reindeer’s shoulder and employ no stirrups; their balance is guided by a long stick that you see in the photograph.

To keep the planet cool, you want grasses in subpolar regions, not trees, and you get grasses when you reintroduce herbivores. That is the driving logic for Sergey and Nikita Zimov, Russian father-and-son scientists working to protect the world’s permafrost.

Permafrost is a thick layer of perennially frozen, carbon-rich soil that covers 24 percent of the Northern Hemisphere. Perma indicates permanence, except it is thawing as the world warms, releasing greenhouse gases from defrosted ground. A vast grassland ecosystem called the mammoth steppe once spanned the regions where permafrost is found. Today, herbivores no longer roam and steppe has been replaced by taiga forest and mossy tundra.

The Zimovs created the Pleistocene Park in Siberia to demonstrate that by restoring grazers and grasslands, permafrost melting can be prevented. How so? When horses, reindeer, musk oxen, and other denizens of the frozen north push away snow and expose the turf underneath, the soil is no longer insulated and is 3 to 4 degrees Fahrenheit colder—perhaps just cold enough.

1.4 trillion tons of carbon are buried in permafrost—two times more than what is held in all the forests worldwide. Restoring the mammoth steppe might create the margin of safety needed to keep that carbon where it is.


Yakutian horses: Librado, Pablo, Clio Der Sarkissian, Luca Ermini, Mikkel Schubert, Hákon Jónsson, Anders Albrechtsen, Matteo Fumagalli et al. “Tracking the Origins of Yakutian Horses and the Genetic Basis for their Fast Adaptation to Subarctic Environments.” Proceedings of the National Academy of Sciences 112, no. 50 (2015): E6889-E6897.

1.4 trillion tons of carbon [buried in the Arctic]: Tarnocai, Charles, J. G. Canadell, E. A. G. Schuur, Peter Kuhry, G. Mazhitova, and S. Zimov. “Soil Organic Carbon Pools in the Northern Circumpolar Permafrost Region.” Global Biogeochemical Cycles 23, no. 2 (2009).

Permafrost…is thawing; emissions: Harvey, Fiona. “1.5C Rise in Temperature Enough to Start Permafrost Melt, Scientists Warn.” The Guardian. February 21, 2013; Wolf, Adam. “The Big Thaw.” Stanford. September/October 2008.

soil…3 to 4 degrees Fahrenheit colder: Zimov, Sergey A. Wild Field Manifesto.

von Humboldt’s description of climate change: Wulf, Andrea. The Invention of Nature: Alexander von Humboldt's New World. New York: Knopf, 2015.

[value of] frozen mammoth steppe: Wolf, Adam. “The Big Thaw.” Stanford Magazine. September-October 2008.


Additional Background Sources

Guthrie, R. Dale. Frozen Fauna of the Mammoth Steppe: The Story of Blue Babe. University of Chicago Press, 2013.

Kintisch, Eli. “Born to Rewild.” Science 350, no. 6265 (2015): 1148-1151.

Lewis, Martin W. “Pleistocene Park: The Regeneration of the Mammoth Steppe?” GeoCurrents. April 12, 2012.

Zimov, Sergey A. “Pleistocene Park: Return of the Mammoth’s Ecosystem.” Science 308, no. 5723 (2005): 796-798.

Zimov, Sergey A., N. S. Zimov, and F. S. Chapin III. “The Past and Future of the Mammoth Steppe Ecosystem.” In Paleontology in Ecology and Conservation, 193-225. Springer Berlin Heidelberg, 2012.

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