A bold plan to slow the melt of Arctic permafrost could help reverse global warming

Yakutian horses

Yakutian horses are a semi-wild breed that have an extra-long, thick coat suited for Siberia’s frigid winter temperatures. When they and other grazing animals trample down the insulating snow, the freezing Siberian air reaches more deeply into the ground’s permafrost. Credit: Pleistocene Park

Siberia’s melting permafrost has enormous implications for the Earth’s climate.

In some areas of Siberia, permafrost extends 5,000 feet below the surface. It contains vast amounts of carbon dioxide and methane. The top 3 feet alone is estimated to contain twice as much carbon as what’s already in the Earth’s atmosphere. As the carbon and methane are released over the coming decades, scientists say it could spell climate disaster.

Nikita Zimov believes he knows how to thwart that. “There is only one theoretical chance to prevent that from happening. We must restore the Ice Age ecosystem,” he says.

Pleistocene Park lies in a remote and desolate corner of Siberia a couple of hundred miles north of the Arctic Circle. Wintertime temperatures average around 17 degrees below zero. During the Ice Age, millions of animals roamed this territory. Back then, the Zimovs say, herds of bison, musk ox, reindeer, moose and woolly mammoths compacted the snow in the wintertime, which lowered the permafrost temperature.

Today, in the wintertime, the ground is covered by a meter-thick layer of fluffy snow, which acts much like a down comforter that insulates the ground from the cold air. So the Zimovs have begun the process of restoration by bringing in climate-adapted species, like stocky Yakutian horses, musk ox, wisent and European bison.

“When animals trample down the snow, they actually thin that layer of snow, making it dense, and this allows much deeper freezing during winter,” he explains.

Although the Zimovs’ research is still ongoing, early comparisons of soil temperatures below the compacted snow and ungrazed terrain indicate that trampling does cool the ground. Other research supports the basic idea.

Some scientists, such as Ted Schuur, a permafrost expert at Northern Arizona University, worry that putting grazing animals back on the landscape might have unanticipated effects, however.

“Animals would also be there in the summertime, and another possible effect of increasing your animals is that they might disturb the moss and soil organic layer that exists on top of the active layer,” Schuur says. “In the summertime, that has sort of the opposite effect: If you disturb the surface layer, it actually exposes the permafrost to warm summer temperatures.”

The Zimovs have an answer for this: The summer is three months long and the winter is nine months long, and the winter is colder than the summer is warm. So, the effect of removing winter snow is greater than the effect of removing summer insulation, which will keep the temperature of permafrost lower and more stable.


Source/More: Public Radio International

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