In which year did James Hanse deliver his Congressional testimony on climate change?
James Edward Hansen (born 29 March 1941) is an American adjunct professor directing the Program on Climate Science, Awareness and Solutions of the Earth Institute at Columbia University. He is best known for his research in climatology, his 1988 Congressional testimony on climate change that helped raise broad awareness of global warming, and his advocacy of action to avoid dangerous climate change.
The first Goddard Institute for Space Studies (GISS) global temperature analysis was published in 1981. Hansen analyzed the surface air temperature at meteorological stations focusing on the years from 1880 to 1985. Temperatures for stations closer together than 1000 kilometers were shown to be highly correlated providing a way to combine the station data to provide accurate long-term variations. They concluded that global mean temperatures can be determined even though meteorological stations are typically in the Northern hemisphere and confined to continental regions. Warming in the past century was found to be 0.5-0.7 °C, with warming similar in both hemispheres.
When the analysis was updated in 1988, the four warmest years on record were all in the 1980s. The two warmest years were 1981 and 1987. During a senate meeting on June 23, 1988, Hansen reported that he was ninety-nine percent certain the earth was warmer then than it had ever been measured to be, there was a clear cause and effect relationship with the greenhouse effect and lastly that due to global warming.