Pleistocene Park is an experiment that reintroduced mega fauna in a region of Siberia in 1996. It is expected that the animals will destroy the mosses and forests that have taken over in the last twenty thousand years and return it to grassland. And so they have. That change in turn should sequester carbon, preserve the permafrost and prevent methane from being released from subsurface soil. In other words, reduce greenhouse gases.
—David Foss