November 12, 1982 Exxon’s M.B. Glaser, manager of the Environmental Affairs Program, sends a memo to Exxon management on the CO2 greenhouse effect intended for the management staff to familiarize themselves with the subject. Glaser includes the April 1, 1982 “CO2 Greenhouse Effect: Technical Review” report. In Glaser’s summary to management, he writes that the carbon dioxide concentration in the atmosphere now stands at 340 ppm and that fossil fuel combustion along with clearing of virgin forests are the contributions to the trend. Glaser writes, “our best estimate is that doubling of the current concentration could increase average global temperature by about 1.3 degrees celsius to 3.1 degrees celsius.” Glaser acknowledges that there is “considerable uncertainty” about the impact this warming will have on society and that there is “currently no unambiguous scientific evidence that the earth is warming.” Glaser writes that greenhouse effect could be detected by 1995 or 2020 if the climate models are exaggerating.
Glaser writes that mitigation of the greenhouse effect will require reductions in fossil fuel combustion, and that the warming might not be reversible.