Policy Documents

James Hansen Increasingly Insensitive

World Climate Report –
April 28, 2005

It seems that the longer NASA scientist Jim Hansen studies the climate, the more insensitive he, or should we say, his interpretation of the climate, becomes.

Climate “sensitivity” is the change in surface temperature expected for each additional Watt of energy that is re-radiated onto the earth’s surface and lower atmosphere by slight changes in the greenhouse effect. The main cause of these changes in the greenhouse effect, of course, is the increasing levels of atmospheric carbon dioxide caused by the combustion of fossil fuels.

You would think that it would be big news when Hansen—the guy who started all this mess with his incendiary 1988 congressional testimony—lowers his estimate for the sensitivity to two-thirds of the value he used back then.