On June 24, 1988 – after sabotaging the air conditioning, James Hansen told Congress:
Global Warming Has Begun, Expert Tells Senate
New York Times Published: June 24, 1988
Dr. James E. Hansen of the National Aeronautics and Space Administration told a Congressional committee that it was 99 percent certain that the warming trend was not a natural variation but was caused by a buildup of carbon dioxide and other artificial gases in the atmosphere.
June 24, 1988 was a hot day in DC during the hottest summer of the past 30 years in the US. But something strange was going on with the weather. Temperatures just a few miles away were quite cool. Beltsville, MD was 95 degrees that day, but Laurel (a short bike ride away) was only 82 degrees. And the following day, Beltsville was only 79 degrees.