I Was an Exxon-Funded Climate Scientist | Peak Oil News and Message Boards (2017) - Exxon's strategists had known for a long time that fossil-fuel CO2 accumulation and global warming are real, even as the company officially denied the reality of them. Exxon more recently merged with Mobil to make ExxonMobil.
This came up recently:
'So they knew': Ocasio-Cortez questions Exxon scientist on climate crisis denial – video | Business | The Guardian
The graph in it is taken from this document: 1982 Exxon Primer on CO2 Greenhouse Effect.pdf
Exxon sowed doubt about climate crisis, House Democrats hear in testimony | Business | The Guardian - has some transcripts.
“What they did was wrong. They spread doubt about the dangers of climate change,” testified Martin Hoffert, who was a scientist consultant for Exxon Research and Engineering in the 1980s. “The effect of this disinformation was to delay action internally and externally … As a result, in my opinion, homes and livelihoods will likely be destroyed and lives lost.”
AOC called Exxon's scientists' predictions "startlingly accurate".
“In 1982, seven years before I was even born, Exxon accurately predicted that by this year, 2019, the Earth would hit a carbon dioxide concentration of 415 parts per million and a temperature increase of 1C. Dr Hoffert, is that correct?”
“We were excellent scientists,” Hoffert said to laughter from the audience.
“Yes you were, yes you were,” Ocasio-Cortez responded. “So they knew.”