LOS ANGELES — Big Oil lost a pair of court battles Tuesday that could lead to trials in lawsuits by California cities and counties seeking damages for the impact of climate change.

The 9th U.S. Circuit Court of Appeals rejected arguments by energy companies and ruled state courts are the proper forum for lawsuits alleging producers promoted petroleum as environmentally responsible when they knew it was contributing to drought, wildfires, and sea level rise associated with global warming.

The lawsuits claim Chevron, Exxon Mobil, ConocoPhillips, BP, Royal Dutch Shell and other companies created a public nuisance and should pay for damage from climate change and help build sea walls and other infrastructure to protect against future impact — construction that could cost tens of billions of dollars.

The ruling overturned a decision by one federal judge, who had tossed out lawsuits brought by the cities of San Francisco and Oakland.

“It is time for these companies to pay their fair share,” San Francisco City Attorney Dennis Herrera said in a statement applauding the ruling. “They should not be able to stick taxpayers with the bill for the damage they knew they were causing. We will continue to hold these companies accountable for their decades-long campaign of public deception about climate change and its consequences.”

While the rulings were victories for the coastal counties and cities — all in the San Francisco Bay Area except for the tiny city of Imperial Beach in San Diego County — and cheered by environmental groups, it could take years before they ever get to a jury, if they make it that far.

The 3-0 rulings are expected to meet continued challenges that could include a review by a larger 9th Circuit panel and, eventually, review by the U.S. Supreme Court.

An appeals court in Virginia ruled that a similar case brought by Baltimore belonged in Maryland courts and lower federal courts in other cities have issued similar decisions.

A group that is a project of the National Association of Manufacturers issued a statement saying climate liability lawsuits should be resolved by the Supreme Court to prevent years of court proceedings.

Chevron did not say how it would proceed but said the cases involve issues of national law and policy and do not belong in state courts.

The Companies Had Argued That Federal Law Controls Fossil Fuel Production

“In whichever forum the cases are ultimately determined, these factually and legally unsupported claims do nothing to sensibly address the significant national economic, legal and policy issues presented by climate change,” said Sean Comey, a Chevron spokesman.

Ann Carlson, an environmental law professor at the University of California, Los Angeles, said the rulings move the cases closer to the discovery process and requesting potentially damaging documents.

“This means they can depose top executives about what they knew and when they knew it and what oil companies did to fund a campaign to dissuade the American public that climate change was happening,” said Carlson, who has provided free counsel to cities in the cases. “The oil companies’ strategy is to keep the light from shining on their own behavior. This gets closer to allowing plaintiffs to shine that light.”

The ruling written by Judge Sandra Ikuta, picked for the court by President George W. Bush, move the cases back to state courts, where they were initially filed. The other judges on the panel were nominated by Presidents Barack Obama and Donald Trump.

Oil companies got the cases transferred to San Francisco federal court, where two judges reached different conclusions.

After holding a unique five-hour “tutorial” by top researchers on the science of climate change, U.S. District Judge William Alsup in 2018 threw out the Oakland and San Francisco litigation. He ruled Congress and the president — not the courts —- were best suited to address the contribution of fossil fuels to global warming.

“The problem deserves a solution on a more vast scale than can be supplied by a district judge or jury in a public nuisance case,” Alsup wrote.

In cases brought by the the counties of San Mateo, Marin and Santa Cruz, and the cities of Richmond and Imperial Beach, Judge Vincent Chhabria ruled the cases belonged in state court, but he allowed the oil companies to appeal.

The companies had argued that federal law controls fossil fuel production, and Congress has encouraged oil and gas development. They said the harm claimed was “speculative” and part of a complex chain of events that includes billions of oil and gas users and “environmental phenomena occurring worldwide over many decades.”