Visit msnbc.com for breaking news, world news, and news about the economy December 30 (MSNBC) – Jim Maceda travels to Siberia to interview Sergei Zimov, who has published a series of scientific papers exposing the importance of permafrost and high-latitude carbon dioxide and methane emissions in the global carbon cycle. Zimov initiated the Pleistocene Park project in 1988 in Northeast Siberia near the Northeast Science Station in Cherskii, Republic of Sakha, Russia. Pleistocene Park seeks to test the hypotheses that large herbivores maintained the Pleistocene tundra steppe and that overhunting by humans caused both the animals and Pleistocene ecosystem to vanish. As Siberian permafrost melts, methane seeps out