Editor's note: Exactly 20 years ago, on June 23, 1988, James Hansen of the NASA Goddard Institute for Space Studies testified before a Senate committee that he could state with "99 percent confidence" that a recent, persistent rise in global temperature was occurring, and had long been expected. That landmark statement, and the dawn of the global warming discussion, was covered by Andy Revkin, then a DISCOVER senior editor and now an environmental reporter for
The New York Times.
Here we republish Revkin's groundbreaking 1988 article that helped begin to raise awareness of the issue. DISCOVER's science and politics blog, Reality Base, also has an interview with Revkin about what's happened with regard to global warming over the past 20 years.
On June 23 the United States sizzled as thermometers topped 100 degrees in 45 cities from coast to coast: 102 in Sacramento; 103 in Lincoln, Nebraska; 101 in Richmond, ...