Exxon research scientists warned about the effects of fossil fuels as early as 1977.
Exxon has known about climate change for almost 40 years, despite its efforts to continue to promote fossil fuels and deny its existence throughout the 1990s as a leader of the Global Climate Coalition, according to an internal investigation by InsideClimate News.
The reporters reviewed internal records from Exxon XOM and found that the company long knew about the harmful effects of fossil fuels on the environment. Exxon researchers even said in a 1978 internal memo that a doubling of carbon dioxide levels would increase average global temperatures by as much as 2 to 3 degrees Celsius.
Read more and watch a Frontline special on the issue at PBS.org.