“We must restore order to nature. Then it will take care of the climate.”
Sergei A. Zimov
Sergei Afanasyevich Zimov (born 1955) is a Russian geophysicist specializing in Arctic and subarctic ecology. He graduated from the Far Eastern State Technical University in Vladivostok, is the director of the North-Eastern Scientific Station, which he founded in 1977 near the town of Chersky in Yakutsk, and is a senior scientist at the Pacific Geographical Institute and founder of the Pleistocene Park project.
Sergei Zimov is best known for his work in advancing the theory that overhunting of large herbivores by humans during the Pleistocene caused the extinction of the Siberian grass steppe ecosystem; and for drawing attention to the important role played by permafrost and thermokarst lakes in the global carbon cycle. In 1991, he was awarded the Wolf Vishnyak Prize at the Tenth International Symposium on Environmental Biogeochemistry (ISEB). It is reported that Sergei Zimov is today the most cited Russian scientist in Earth research in the West.
Zimov's Northeast Scientific Station – a research institute of the Russian Academy of Sciences and one of the three largest Arctic stations in the world – is located at the mouth of the Kolyma River (150 kilometers south of the Arctic Ocean) and serves as a year-round base for international Arctic research, focusing on carbon cycles, methane flows, paleoclimate and ecosystem changes. Sergei Zimov, who is called the “permafrost oracle”, was one of the first to draw attention to the potentially serious and incalculable impacts of permafrost melting due to global warming: the release of huge methane reserves from the so-called thermokarst lakes associated with this melting, which would result in further intensification of global climate change and subsequently further progressive permafrost melting and greater emissions of methane and carbon dioxide. Permafrost contains more than twice the amount of carbon currently in the planet’s atmosphere. Scientific papers published by Zimov in collaboration with prominent American ecologist Terry Chapin and Alaskan aquatic ecologist and biochemist Katey Walter-Anthony in the journal Nature, have become fundamental texts for determining the impact of permafrost melting on climate change.
Project Pleistocene Park (see https://pleistocenepark.ru/) Zimov started in 1988 and located it near the North-Eastern Scientific Station. The aim of this project is to test the hypothesis that large herbivores (mammoths, woolly rhinoceroses, bison, horses, musk oxen, elk, saigas and yaks) maintained the Pleistocene tundra steppes and that their excessive hunting by humans (due to improving technologies) caused their extermination and extinction ten thousand years ago, leading to the disappearance of the original Pleistocene grassland ecosystem and its replacement by mossy and forest tundra. According to Zimov, the reintroduction of large herbivores in Siberia would initiate a positive feedback loop supporting the restoration of grassland ecosystems: "Animals disturb the mosses with their hooves and let grass grow in their place. The soil dries out, the animals deposit their manure, thanks to which more grass grows and other animals can graze". Zimov demonstrated that after mosses were anthropogenically removed, grasses would dominate the landscape within one to two years.
He believes that during the Pleistocene, the grassy steppe in the Arctic acted as a buffer against permafrost, against its thawing, and he wants to recreate the grassy steppe for this purpose. His theory is based on the warming effect of snow: a reduction in the snow cover during the winter would allow more cold air to reach the permafrost. This can be done mechanically or with the help of horses, musk oxen, bison, sheep and reindeer. These animals break up bushes and disturb the soil, which allows the re-emergence of grassy areas. In summer, thanks to the albedo effect – light areas reflect heat, dark areas absorb it – the light grass would remain cooler than the brown bushes that cover the tundra today and absorb heat. Current scientific research by Sergei Zimov and his son Nikita has shown that animals introduced to the Pleistocene Park have reduced snow density by half and the average permafrost temperature by almost two degrees Celsius. Scientists estimate that the widespread introduction of large herbivores could save thirty-seven percent of Arctic permafrost from thawing.
Zimov's concept of the Pleistocene Park and the reintroduction of the Mammoth Steppes was included in the Drawdown Project's "100 Most Essential Solutions to Global Warming". Currently, the Pleistocene Park covers an area of 160 km2 and is home to over 150 large mammals representing six major herbivore species (horses, elk, reindeer, musk oxen, reindeer and bison). Sergei and Nikita Zimov's goal is to increase the number of large herbivores in the park to twenty per square kilometer and then reintroduce predators, including wolves, bears and Siberian tigers. Based on an international co-production (France, Belgium, Russia), a documentary film about Sergei Zimov's work was made in 2021 Zimov's hypothesis (script and direction by Denis Sneguirev).
George Zemanek
