Hansen, James (1941-)

DIRECTOR OF THE National Aeronautics and Space Administration (NASA) Goddard Institute for Space Studies in New York and adjunct professor in the Department of Earth and Environmental Studies at Columbia University, James Hansen has come to the public attention in contemporary debates about global warming for his harsh critique of the environmental policies pursued by the George W. Bush Administration. He has also unequivocally stated that, because of such criticism, it is increasingly difficult for him to speak freely about the emission of greenhouse gases and global warming. In 2005 and 2006, Hansen claimed, in several interviews with the Washington Post and the New York Times, that officials at NASA headquarters were ordering the public affairs staff to review his coming lectures, papers, postings on his mailing lists and website, and requested interviews from journalists. This was due to his critical statements made during a lecture at the American Geophysical Union in San Francisco in December 2005. In Al Gores Academy Award-winning documentary, An Inconvenient Truth (2006), Hansen has repeated the charge of having been manipulated. Since the late 1980s, Hansen has been issuing public statements about the long-term threats deriving from heat-trapping emissions, dominated by carbon dioxide. To Hansen, these are an unavoidable byproduct of burning coal, oil and other fossil fuels.

Born on March 29, 1941, in Denison, Iowa, Han-sen was educated at the University of Iowa where he obtained a B.A. in Physics and Mathematics with highest distinction in 1963, an M.S. in Astronomy, in 1965, and a Ph.D. in Physics, in 1967. He took part in the NASA graduate traineeship program from 1962 to 1966 and, at the same time, between 1965 and 1966, he was a visiting student at the Institute of Astrophysics at the University of Kyoto and in the Department of Astronomy at the University of Tokyo. After serving as a Postdoctoral Fellow at the Leiden Observatory in the Netherlands, in 1969, and as a Research Associate at Columbia University, from 1969 to 1972, Hansen joined the Goddard Institute for Space Studies. He has directed the Institute since 1981, and has worked as an adjunct professor at Columbia since 1985. As a college student, Hansen was first attracted to the James Van Allen Space Science Program, but later focused on planetary research dealing with climate change on Earth resulting from anthropogenic changes of the atmospheric composition.

One of Hansens main research interests is radiative transfer in planetary atmospheres, especially interpreting remote sounding of the Earth's atmosphere and surface from satellites. Analyses of such data could constitute one of the most effective ways to monitor and study global change on the Earth. Han-sen is also interested in the development and application of global numerical models for the purpose of understanding current climate trends and assessing potential human impacts on climate.

In the 1980s, Hansen was one of the first scientists to point out that the process of global warming was already taking place and that its effects would be visible beginning in the 1990s, not 2020, as most of his [Page 491]colleagues argued at the time. He suggested in his paper, “Global Warming in the Twenty-First Century” (2000), an “alternative scenario” for global warming and its possible solution. In it, Hansen claims that we should focus on non-CO2 gases and black carbon in the short run, giving more time to make reductions in fossil fuel emissions. According to his alternative scenario, the current warming up of temperatures is largely due to non-CO2 gases. Hansen stresses the role of climate-cooling aerosols emitted with fossil fuel burning in offsetting CO2 warming and he points out that non-CO2 gases, taken together, are responsible for roughly 50 percent of greenhouse gas warming. In “Defusing the Global Warming Time Bomb” (2003), Hansen has further developed his ideas on climate change, reaching the conclusion that human actions now far surpass the impact of natural elements in changing the climate. He has pleaded for an urgent and unprecedented international cooperation to control climate change. Hansen has predicted that 2016 will be the global tipping point (also known as the runaway effect) for global warming, if the human population is unable to reduce greenhouse gases.

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