Several years ago, all the major European oil and gas "majors" (Shell, BP, Total) were publicly advocating for a globally consistent "carbon tax".
But Exxon and Chevron, the two largest U.S. based oil companies, declined to join the group, saying they wanted to retain individual control of their "messages" on these issues.
So now, as we enter 2017 and Exxon's former CEO is nominated for Secretary of State, what is Exxon's position? The company supports a carbon tax. You can read it in the NY Times, December 30, 2016 opinion page (below). And this has been their position for awhile, and for good reason.
As for Chevron, they support ... well, lots of nice vague words on their website policy page about the need for global solutions to complex problems. It looks like a bunch of baloney to me that refuses to face up to a life and death issue. And they are selling their Asia geothermal operations which are the bulk of their global geothermal assets. I guess they need the cash to complete major natural gas investments, so no place for renewables when the projects being sold represent the bulk of their portfolio?