James Hansen

James E. Hansen (born 1941) is an American climatologist best known for his research on Earth’s climate and for bringing scientific findings on global warming to public attention. He served as director of NASA’s Goddard Institute for Space Studies (GISS) in New York City from 1981 to 2013. Hansen’s work includes early climate modeling studies and analyses of temperature trends that helped clarify the role of greenhouse gases in recent warming. In 1988 he testified before the U.S. Senate, stating that human-caused global warming had begun, a moment widely seen as pivotal in climate communication. He later continued research and advocacy after leaving NASA.