Big Oil now says that climate change is real, but it’s not their fault.

Yes, after nearly thirty years of denying that “global warming” was happening; then admitting it’s happening but denying that it’ll be that bad; then admitting it’ll be bad but denying human beings have anything to do with it, the oil companies have again changed their tune. Now, they say, it is happening, it is bad, it is human beings’ fault… but don’t blame us.

What caused this change of heart? A lawsuit.

San Francisco, Oakland, four other California cities, and several counties have sued half a dozen oil companies for damages they are suffering, and will suffer more in the future, from rising sea levels. Sea level rise is caused by the melting of polar ice caps and the expansion of water when it is warmed, both triggered by global warming.

The cities say that the oil companies have known about the risks of anthropogenic climate change, but that rather than disclose what they know, the companies engaged in a decades-long campaign to deceive the public that the science is uncertain.

“These companies knew their products were causing sea-level rise, and they deceived people about it,” San Francisco City Attorney Dennis Herrera said in a statement. “Now, that bill has come due.”

In a highly unusual move, Judge William Alsup of the Northern District of California invited the parties to present a “tutorial” on climate change, answering eight idiosyncratic questions regarding climate science. That took place Wednesday.

Chevron, which took the lead in the tutorial, surprisingly chose to “anchor its presentation” on the 2014 report UN Intergovernmental Panel on Climate Change (IPCC). For years, industry-sponsored puppets have decried the IPCC as unreliable, uncertain, or, if you prefer, a giant global conspiracy meant to destroy American capitalism.

Now, however, the IPCC is right: Human-caused climate change is real, and dangerous. Someone tell President Trump!

But there’s a footnote.

According to Chevron, there are so many contributors to climate change that “anyone in the world could be brought in in the case, including the plaintiffs themselves.” Sure, fossil fuel companies do their part, but so do a lot of other people. So, they say, you can’t pin this on us.

Chevron’s about-face is part of the fossil fuel industry’s recent strategy to co-opt, rather than deny, the reality of climate change. That strategy is part triangulation, part greenwashing.

For example, an ExxonMobil webpage entitled “Our position on climate change” states that “the risk of climate change is clear and the risk warrants action. Increasing carbon emissions in the atmosphere are having a warming effect. There is a broad scientific and policy consensus that action must be taken to further quantify and assess the risks.”

That sounds pretty progressive, and is certainly greener than the position of EPA Administrator Scott Pruitt, who has explicitly denied the “broad scientific and policy consensus” on climate change.

Only, the devil’s in the details.

First, Exxon and Mobil were the leading funders of climate denial for over 30 years. Internally, it has known about the causes and effects of climate change since the 1970s. Externally, it has not only denied the truth but created multiple initiatives to lie to the public.

In 1989, Exxon co-founded the Global Climate Coalition, whose mission was to claim that climate science was uncertain, even as its own internal memos warned that it “cannot be denied.” In 1998, it joined the American Petroleum Institute’s plan to challenge climate science by creating new “experts” to counter the scientific consensus. And it funded puppet “think tanks” such as the Heartland Institute, George C. Marshall Institute, the Competitive Enterprise Institute, Center for Strategic and International Studies, and Annapolis Center for Science-Based Public Policy.

All of these publish bogus disputes of climate science, written by people on the fossil fuel industry payroll. People like Willie Soon, who hid the fact that ExxonMobil was funding him, lied about his credentials, called his scientific papers “deliverables” to Exxon, and is still at it, weighing into the case over which Judge Alsup is presiding. To his credit, Judge Alsup required all scientists filing their opinions to reveal who’s paying them.

Finally, ExxonMobil’s green-sounding statements turn brown when exposed to sunlight. When it comes to specific climate “actions,” the company continues to oppose hard emissions reduction targets, investments in alternative energy, and the “clean power plan” that Trump’s EPA has now shelved.

And in the California lawsuit particularly, ExxonMobil has taken an extremely aggressive response: the company has counter-claimed, arguing that the California cities are restricting its “First Amendment right to participate in the national dialogue about climate change” and are failing to warn their own municipal bond investors of the risks of climate change. The fact that the cities don’t include those risks in their bond offerings, Exxon says, proves that they don’t really believe them.

Instead, Exxon has said in court pleadings that the whole lawsuit is a “conspiracy” hatched at a June, 2012, meeting of climate activists in La Jolla, California (“the La Jolla Playbook”). It is filing its own suit in Texas “to investigate potential claims of abuse of process, civil conspiracy, and constitutional violations” and is seeking to depose a number of environmental activists who took part in that meeting.

Of course, the sheer cost of doing so is enormous for the activists, trivial for ExxonMobil, whose annual revenue was $237 billion last year.

In some ways, it’s encouraging that oil companies now admit what their own scientists have known for several decades. But really, it’s just a change in tactics. They’ve denied the inevitable for decades, and now, under oath and under the cloud of climate reality, they’ve switched to denying responsibility.

That strategy makes sense in the context of a court case, which Big Oil will probably win. But as a political strategy, it is perhaps a preview of more evasions to come.