Why I Must Speak Out About Climate Change

by James Hansen

This presentation in the TED series took place on February 29, 2012.  

Dr. James Hansen heads the NASA Goddard Institute for Space Studies in New York City and is Adjunct Professor of Earth and Environmental Sciences at Columbia University’s Earth Institute.  He was trained in physics and astronomy in the space science program of Dr. James Van Allen at the University of Iowa. His early research on the clouds of Venus helped identify their composition as sulfuric acid. Since the late 1970s, he has focused his research on Earth's climate, especially human-made climate change.  Link.