An article by Geoffrey Supran and Naomi Oreskes just published in Environmental Research Letters concludes that "ExxonMobil contributed to advancing climate science -- by way of its scientists' academic publications -- but promoted doubt about it in advertorials. Given this discrepancy, we conclude that ExxonMobil misled the public."
This is not a new accusation, though the paper by Supran and Oreskes goes into extensive detail in examining what the company's scientists had concluded and what it had claimed in numerous communications with the public. Two years ago, Inside Climate News published an article by Neela Banerjee, Lisa Song, and David Hasemyer pointing out that according to a senior Exxon scientist named James F Black, in 1977 he had given a presentation in Exxon headquarters telling executives that there was general scientific agreement that CO2 from fossil fuels was leading to potentially serious global warming.
In 1982 Exxon distributed to executives a package of documents (which you can read here) that among other things explained that while there was at the time some remaining uncertainty, the scientific consensus was that human-caused global warming would likely raise global temperatures by about 1.3 to 3.1 degrees Celsius before the end of the 21st century, but that the warming would not be uniform across the Earth, with the polar regions warming by as much as 10 degrees Celsius (18 degrees Fahrenheit). Without a major reduction is fossil fuel use there was a possibility of irreversible "potentially catastrophic events."
While the cover letter indicated the documents were not to be distributed outside Exxon, it also said that the information could be "used as a basis for discussing the issue with outsiders as may be appropriate." In practice, however, a lot of Exxon's advertising and public relations going forward minimized the problem, and by the 1990s Exxon was striving to block government efforts to limit carbon emissions and to create the impression that the science was uncertain and there was no urgent need to act.
Here's a short, three-minute piece from the PBS series Frontline summarizing Exxon's efforts to understand and then conceal information about global warming:
See also the related article titled "Investigation Finds Exxon Ignored Its Own Early Climate Change Warnings" at this link.