The Committee to Nuke Elysium

Zimov is trying to recreate an ecosystem that disappeared 10,000 years ago with the end of the ice age, which closed the 1.8 million-year Pleistocene era and ushered in the global climate roughly as we know it.

He believes herds of grazers will turn the tundra, which today supports only spindly larch trees and shrubs, into luxurious grasslands. Tall grasses with complex root systems will stabilize the frozen soil, which is now thawing at an ever-increasing rate, he says.

Herbivores keep wild grass short and healthy, sending up fresh shoots through the summer and autumn. Their manure gives crucial nourishment. In winter, the animals trample and flatten the snow that otherwise would insulate the ground from the cold air. That helps prevent the frozen ground, or permafrost, from thawing and releasing powerful greenhouse gases. Grass also reflects more sunlight than forests, a further damper to global warming.

It would take millions of animals to change the landscape of Siberia and effectively seal the permafrost. But left alone, Zimov argues, the likes of caribou, buffalo and musk oxen multiply quickly. Wherever they graze “new pastures will appear … beautiful grassland.”