1. Big oil suits progressed but faced challenges
In recent years, 70-plus US states, cities, and other subnational governments have sued big oil for alleged climate deception. This year, courts repeatedly rejected fossil fuel interests’ attempts to thwart those cases. The supreme court denied a plea to kill a Honolulu lawsuit, and turned down an unusual bid by red states to block the cases. Throughout the year, state courts also shot down attempts to dismiss cases or remand them to federal courts which are seen as more favorable to oil interests.
But challenges against big oil also encountered stumbling blocks. In May, Puerto Rico voluntarily dismissed its 2024 lawsuit under pressure. Charleston, South Carolina also declined to appeal its case after it was dismissed.
In the coming weeks, the supreme court is expected to decide if it will review a climate lawsuit filed by Boulder, Colorado, against two major oil companies. Their decision could embolden or hinder climate accountability litigation.
“So far, the oil companies have had a losing record trying to get these cases thrown out,” said Richard Wiles, president of the Center for Climate Integrity, which backs the litigation against the industry. “The question is, does Boulder change that?”
After Colorado’s supreme court refused to dismiss the lawsuit, the energy companies filed a petition with the supreme court asking them to kill the case on the grounds that it is pre-empted by federal laws. If the high court declines to weigh in on the petition – or takes it up and rules in favor of the plaintiffs – that could be boon for climate accountability cases. But if the justices agrees with the oil companies, it could void the Boulder case – and more than a dozen others which make similar claims.
That would be a “major challenge”, said Wiles, “but it wouldn’t be game over for the wave of litigation”.
“It would not mean the end of big oil being held accountable in the court,” he said.
The American Petroleum Institute, the nation’s largest oil lobby group, did not respond to a request to comment.
2. New and novel litigation
Climate accountability litigation broke new ground in 2025, with Americans taking up novel legal strategies to sue big oil. In May, a Washington woman brought the first-ever wrongful-death lawsuit against big oil alleging the industry’s climate negligence contributed to her mother’s death during a deadly heat wave. And in November, Washington residents brought a class action lawsuit claiming fossil fuel sector deception drove a climate-fueled spike in homeowners’ insurance costs.
“These novel cases reflect the lived realities of climate harm and push the legal system to grapple with the full scope of responsibility,” said Merner.
Hawaii this year also became the 10th state to sue big oil over alleged climate deception, filing its case just hours after the Department of Justice took the unusual step of suing Hawaii and Michigan over their plans to file litigation. It was a “clear-eyed and powerful pushback” to Trump’s intimidation, Merner said.
3. Accountability shield
Big oil ramped up its efforts to evade accountability for its past actions this year, said Wiles. They were aided by allies like Trump, who in April signed an executive order instructing the Justice Department to halt climate accountability litigation and similar policies.
In July, members of Congress also tried to cut off Washington DC’s access to funding to enforce its consumer protection laws “against oil and gas companies for environmental claims” by inserting language into a proposed House appropriations bill. A committee passed that version of the text, but the full House never voted on it.
2025 also brought mounting evidence that big oil is pushing for a federal liability shield, which could resemble a 2005 law that has largely insulated the firearms industry from lawsuits. In June, 16 Republican state attorneys general asked the Justice Department to help create a “liability shield” for fossil fuel companies against climate lawsuits, the New York Times reported. Lobbying disclosures further show the nation’s largest oil trade group, as well as energy giant ConocoPhillips, lobbying Congress about draft legislation on the topic, according to Inside Climate News.
Such a waiver could potentially exempt the industry from virtually all climate litigation. The battle is expected to heat up next year.
“We expect they could sneak language to grant them immunity, into some must-pass bill,” said Wiles. “That’s how we think they’ll play it, so we’ve been talking to every person on the Democratic side so that they keep a lookout for this language.”
4. What to watch in 2026: plastics and extreme weather cases
Despite the challenges ahead, 2026 will almost definitely bring more climate accountability lawsuits against not only big oil but also other kinds of emitting companies. This year, New York’s attorney general notched a major win by securing a $1.1m settlement from the world’s biggest meat company, JBS, over alleged greenwashing. The victory could inspire more cases, said Merner, who noted that many such lawsuits have been filed abroad.
Wiles expects more cases to accuse oil companies of deception about plastic pollution, like the one California filed last year. He also expects more lawsuits which focus on harms caused by specific extreme weather events, made possible by advances in attribution science – which links particular disasters to global warming. Researchers and law firms are also developing new theories to target the industry, with groundbreaking cases likely to be filed in 2026.
“Companies have engaged in decades of awful behavior that creates liability on so many fronts,” he said. “We haven’t even really scratched the surface of the numerous ways they could be held legally accountable for their behavior.”
