James E. Hansen

James E. Hansen, lead climate scientist and director, NASA Goddard Institute for Space Studies (GISS), New York, and adjunct professor, earth and environmental sciences, Columbia University

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James Hansen is perhaps best known for his testimony regarding the human impact on climate change given to congressional committees in the 1980s that helped raise broad awareness of the global warming issue, testimony that government officials initially sought to discredit but which has now been largely accepted. Hansen has warned that a global “tipping point” will be reached in the near future if levels of greenhouse gases like methane and CO2 are not reduced. Human-made forces, especially greenhouse gases, soot, and other small particles, now exceed natural forces, and the world has begun to warm at a rate predicted by climate models.

Hansen was educated at the University of Iowa, where he earned a B.A. in physics and mathematics (1963), an M.S. in astronomy (1965), and a Ph.D. in physics (1967). He joined the Goddard Institute for Space Studies as a resident research associate in 1967, researching radiative transfer in planetary atmospheres and the development of global climate models. He became a space scientist at GISS in 1972 and later was given responsibility for GISS Planetary and Climate Programs. In 1981 he was named director of the institute.

Hansen has received numerous awards from NASA and conservation groups for his achievements and service as well as for some of his many research publications and professional papers, including the Roger Revelle Award from the American Geophysical Union, the National Wildlife Federation Conservation Achievement Award, two NASA Presidential Rank Awards and an Exceptional Service Medal, and GISS Best Scientific Publication peer awards for papers including “Global warming in the 21st century: an alternative scenario” (2000) and “Earth’s energy imbalance: confirmation and implications” (2005).