Dr. James Hansen, director of the NASA Goddard Institute for Space Studies in New York, sounded the alarm about global warming in testimony before a Senate subcommittee exactly 20 years ago.
He returned to the topic Monday with a speech at the National Press Club in Washington, D.C., given to the Worldwatch Institute.
"Special interests have blocked the transition to our renewable energy future," Hansen writes in an opinion piece posted on the institute's Web site. "Instead of moving heavily into renewable energies, fossil fuel companies choose to spread doubt about global warming, just as tobacco companies discredited the link between smoking and cancer. Methods are sophisticated, including funding to help shape school textbook discussions of global warming."