Pleistocene Park

In Siberia, scientist Sergey Zimov is attempting something radical — recreating the grassland ecosystem of the Ice Age. He has introduced bison, horses, musk oxen, and yaks to trample and graze the land back to its ancient state. The hypothesis is that restoring grasslands will reflect more sunlight than dark forest, slowing permafrost thaw.

The logic is counterintuitive but solid. Arctic permafrost holds twice the carbon of the entire atmosphere. Grasslands reflect more sunlight and stay colder than dark forests. Large grazers compact snow in winter, letting cold air freeze the ground deeper.