One scientist's hobby: recreating the ice age - BusinessWeek

Wild horses have returned to northern Siberia. So have musk oxen, hairy beasts that once shared this icy land with woolly mammoths and saber-toothed cats. Moose and reindeer are here, and may one day be joined by Canadian bison and deer.

Later, the predators will come -- Siberian tigers, wolves and maybe leopards.

Russian scientist Sergey Zimov is reintroducing these animals to the land where they once roamed in millions to demonstrate his theory that filling the vast emptiness of Siberia with grass-eating animals can slow global warming.
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Today he has 70 animals in the park. He wants thousands to restock Siberia. To bring 1,000 bison from North America would cost $1 million, Zimov says, a small price to pay.

"If permafrost melts, 100 gigatons of carbon will be released this century," he said. "What's $1 million? One regular grant."