There’s an excellent post about this, well worth the read, at Climate Progress
Leonard S. Bernstein was Exxon’s “in-house climate expert” during much of his 30 years of working for the oil industry (including both Exxon and Mobil). In 2014 he sent an email to to the director of the Institute for Applied and Professional Ethics at Ohio University, revealing that the oil giant was aware of the climate impact of CO2 emissions way back in the early 1980s.
According to Bernstein’s email, “Corporations are interested in environmental impacts only to the extent that they affect profits, either current or future. They may take what appears to be altruistic positions to improve their public image, but the assumption underlying those actions is that they will increase future profits. ExxonMobil is an interesting case in point.”