Tyler Volk presents his new book, CO2 Rising: The World's Greatest Environmental Challenge, and answers questions. Booksigning to follow. Volk is the director of the environmental studies program and an associate professor of biology at New York University. For more than 20 years his research has focused on the global carbon cycle and the dynamics of the biosphere. He is a systems thinker, authoring Metapatterns: Across Space, Time, and Mind, and Gaia’s Body: Toward a Physiology of Earth.