Today, humans are rapidly changing the world's climate-but some anthropologists think climate may have once changed us. In this podcast, Rick Potts, director of the Human Origins Program at the Smithsonian Museum of Natural History, explains why a rapidly shifting environment could have shaped early human behavior. Podcast produced by David Levin. Original interview by Graham Townsley. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by ExxonMobil, David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and public television viewers. To learn more, go to pbs.org/nova/becominghuman