Chevron would like you to know that it believes in climate change. It also believes people cause it by burning carbon-based fuel—the kind Chevron extracts from the ground, refines, and sells. In fact, Chevron believes all this so hard that today its lawyer said so, in a federal court in San Francisco. Intergovernmental Panel on Climate Change? Yup. They’re right.

That’s not as up-is-down as it might sound; Chevron representatives have said as much before. The follow-up questions, though, will be the tricky part. Because what was at stake in that courtroom was not whether the effects of climate change—sea level rise, ocean acidification, weather extremes, wildfires, disease outbreaks—are people’s fault. It was whether a lawsuit could show that specific effects (floods) are specific people’s fault. Specifically, the people at Chevron.

...and BP and ExxonMobil, because San Francisco and Oakland are suing those companies for money to build seawalls and other protective infrastructure. The idea isn’t just that petrochemical transnationals extract, produce, and sell the fuel that puts carbon into the atmosphere. It’s that they knew that was bad, kept doing it anyway, and cut ads and marketing that tried to convince people it wasn’t a problem.

But before they could really dig into that, the judge in the case, William Alsup, asked for what he termed a “tutorial.” On March 6, he sent the lawyers on both sides a list of nine questions digging into the basic history and science of climate change (Number two: What is the molecular difference by which CO 2 absorbs infrared radiation but oxygen and nitrogen do not?), with a special eye on sea level rise. Which is as odd as it sounds.

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Outside the usual procedural kabuki of the courtroom, the truth is no one really knew what to expect from this court-ordered “tutorial.” For a culture based in large measure on precedent, putting counsel and experts in a room to hash out climate change for a trial—putting everyone on the record, in federal court, on what is and is not true about climate science—was literally unprecedented.

What Alsup got might not have been a full on PowerPoint-powered preview of the trial. But it did reveal a lot about the styles and conflicts inherent in the people who produce the carbon and the people who study it.

The other petrochemists put forth Theodore Boutrous, an AC-130 gunship of a lawyer who among other things got the US Supreme Court to overturn the California law against same-sex marriage. Here, retained specifically by Chevron, Boutrous argued what seemed to be climate change’s chapter-and-verse. He extolled the virtues of the several IPCC reports, 2013 most recently, and quoted them liberally. Boutrous talked about how the reports’ conclusions have gotten more and more surefooted about “anthropogenic” causes of climate change—it’s people!—and outcomes like sea level rise. “From Chevron’s perspective, there’s no debate about climate science,” Boutrous said. “Chevron accepts what this scientific body—scientists and others—what the IPCC has reached consensus on.”

Still, over the course of the morning, Boutrous nevertheless tried to neg the IPCC in two specific ways. One was a classic: He challenged the models that climate scientists use to attempt to predict the future. These computer models, Boutrous said, are “increasingly complex. That can make the modeling more powerful.” But with great power comes great potential wrongness. “Because it’s an attempt to represent things in the real world, the complexity can bring more risk.” He assured the court that Chevron agreed with the IPCC approach—posting up a slide pulled from an IPCC report that showed the multicolored paths of literally hundreds of models, using different emissions scenarios and essentially describing the best case and worst case (and a bunch of in-between cases). It looked like a blast of fireworks emerging from observed average temperature, headed chaotically up and to the right.