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Cities in the United States had taken oil companies to court, arguing that they should pay for climate-related problems caused by the burning of fossil fuels.

P. A. Lawrence, LLC/Alamy Stock Photo

In a San Francisco courtroom, climate science gets its day on the docket

U.S. District Court Judge William Alsup strode into his San Francisco, California, courtroom Wednesday morning wearing a necktie chosen for the occasion. It was his “science tie,” he told the packed chamber: blue decorated with an image of a solar system.

Alsup’s sartorial statement was an idiosyncratic footnote to an unusual day in the annals of climate change policy. In an unprecedented move in a federal lawsuit, Alsup presided over a crash course in climate science with a single student: himself.

For 5 hours, opposing sides in a closely watched climate change lawsuit pitting the cities of San Francisco and Oakland against some of the world’s biggest oil companies offered Alsup their accounts of the history and current state of climate science. The cities allege that, for decades, the companies sold fossil fuels they knew were contributing to climate change, while engaging in a multimillion-dollar campaign to sow doubt about global warming. And they want the companies to pay for measures such as sea walls to cope with rising sea levels they blame on carbon emissions from burning fossil fuels. 

The lessons broke no new scientific ground. But the day gave a preview of how science will fit into the two sides’ legal strategies, and a taste of the judge’s wide-ranging scientific curiosity. The day was also punctuated with its share of memorable moments. A leading British scientist did a “chicken dance” to show how carbon dioxide traps heat. At one point, a shrill alarm sounded as a scientist spoke about the threats of sea level rise. “Coastal flood alert,” Alsup deadpanned.

Spectators hoping for a showdown between climate science champions and people denying humans are causing global warming were disappointed. Alsup started the session by warning that it would not be a version of the Scopes trial, the famous 1925 case that pitted evolutionary science against creationism. “This will not be withering cross-examinations and so forth. This will be numbers and diagrams, and if you get bored you can just leave,” he told the audience. Many had waited hours for a seat in the high-ceilinged room. None left.

The lead attorney for oil giant Chevron, meanwhile, quickly declared the company is convinced humans are playing a major role in climate change—a split from some fossil fuel advocates, including top officials in President Donald Trump’s administration. “From Chevron’s perspective there’s no debate about climate science,” said attorney Theodore Boutrous Jr.

But the two sides weren’t in accord on everything.

Speaking for the cities, Myles Allen, a physicist and climate scientist at the University of Oxford in the United Kingdom told Alsup the science was clear enough more than 3 decades ago to realize global warming would be caused by greenhouse gas pollution, even if measurements hadn’t definitively picked it up. “It wasn’t necessary for scientists in the late 1970s to detect the warming in order for them to predict what was likely to happen next as a result,” he said.

Gary Griggs, a geologist at the University of California, Santa Cruz, who led an expert panel examining sea level rise threats in California, told Alsup that research suggests the coastal flooding that now happens in San Francisco once every 10 years is expected to happen once every 3 days by the end of the century, even if greenhouse gas pollution slows.

While the city relied on a trio of prominent scientists to deliver lectures to Alsup, Boutrous was the lone speaker on the oil industry side. He leaned heavily on the Intergovernmental Panel on Climate Change’s (IPCC’s) fifth climate science assessment report, issued in 2014. He emphasized passages about scientific uncertainty, including discussion of the challenges associated with predicting how much sea levels will rise in specific parts of the globe, as well as modeling how Antarctic ice is responding to rising temperatures. The fossil fuel industry has a history of arguing that climate science is fraught with uncertainties.

Boutrous also highlighted IPCC’s emphasis on the roles population growth and economic development—rather than the actions of any one industry—play in rising greenhouse gas levels. The IPCC report “doesn’t say that it’s the production and extraction [of fossil fuels] that’s driving the increase. It’s the way people are living their lives,” Boutrous said.

A bevy of questions

Throughout the morning, Alsup—an appointee of former President Bill Clinton who is now in his 70s—showed an appetite for probing the minutia of climate science, and for heading down other scientific side roads. He is known for mastering the technical details of complex cases. He learned the Java programming language while overseeing a dispute between computer companies Google and Oracle. In a recently settled case between Uber and Google’s Waymo over self-driving car technology, Alsup in 2017 ordered a similar tutorial on the science in that field.

Among his questions to the witnesses:

  • Q: Could heat from power plants add much to the planet overall?
    A: No, it’s dwarfed by the energy trapped by greenhouse gases.
  • Q: Was the relationship between rising temperatures and rising greenhouse gases logarithmic or linear?
    A: Logarithmic.
  • Q: How high would sea levels get if all the ice in Greenland, Antarctica, and other continents melted?
    A: More than 60 meters.
  • Q: During the last ice age, could people have walked across land in what is now the Bering Strait?
    A: Yes.

At one point, Alsup asked Griggs whether the country should have turned more toward nuclear energy decades ago. “We might get some radiation if we drive by, but we don’t get any [carbon dioxide],” the judge said. “Maybe in retrospect we should have taken a harder look at nuclear.”

Chevron was the only defendant to participate in the tutorial. The other companies—including Exxon, BP, ConocoPhillips, and Royal Dutch Shell—stayed away because they are challenging Alsup’s jurisdiction to even hear the case. But the judge on Wednesday put the missing companies on the spot. Speaking to their attorneys in the audience, he gave them 2 weeks to submit paperwork, noting any disagreements with the Chevron attorney’s presentation. Otherwise, he said, he’ll assume they agree. Said Alsup: “You can’t get away with sitting there in silence and then later saying, ‘Oh, he wasn’t speaking for us.’”

Legal implications

The eventual outcome of this case could have major implications, with billions of dollars at stake. It’s one of a small, but growing number of lawsuits by cities alleging oil companies broke state or federal laws by creating a public nuisance. Several other California cities and counties have a similar case before another federal judge. New York City filed one in January.

The fortunes of these cases have varied. Oakland and San Francisco originally filed suit in state court, considered a friendlier venue for their complaints. Alsup ruled the case belonged in federal court.

Meanwhile, U.S. District Court Judge Vince Chhabria last week issued a conflicting ruling: Cases before him involving Marin and San Mateo counties and the city of Imperial Beach belonged in state court, he said.

The oil companies on Tuesday filed motions to have the Alsup cases thrown out altogether. They have filed similar motions in the New York City suit.

Because Wednesday’s session was so unorthodox, it’s not clear how it will fit into the legal case, says Michael Burger, executive director of the Sabin Center for Climate Change Law at Columbia Law School. “Does any of this count as evidence? Or does it count as an admission or denial of facts that are pled in the complaint? I don’t think anybody really knows,” he says. “Maybe the judge knows.”

Given the legal wrangling ahead, Burger says, he’s sure of one thing: “A trial is a long ways off in any calculation.”