In 2015, New York attorney general Eric Schneiderman launched an investigation into what exactly ExxonMobil knew about climate change decades earlier and whether it covered up its findings. The following year, Virgin Islands attorney general Claude Walker issued a subpoena to Exxon as part of an investigation into whether the company had violated racketeering laws by misrepresenting its knowledge of climate science. Massachusetts attorney general Maura Healey launched her own probe into the company’s dealings shortly after. The investigations paved the way for a flood of lawsuits from cities, states, and other entities and groups against many of the world’s largest oil companies.

These legal actions have made a range of specific allegations, from consumer fraud to civil conspiracy, but the fundamental claim underpinning all of them is that Big Oil knew about the dangers posed by climate change and lied about them in order to keep digging up, refining, and selling its product.

ExxonMobil, Chevron, BP, Shell, ConocoPhillips, and other major oil companies have put up a fierce, and largely successful, fight in court over to avoid getting pinned for their role in the climate crisis. As oil companies racked up win after win for in 2018 and 2019, it seemed like the climate lawsuit was doomed. Most recently, a judge ruled in favor of Exxon in the New York case, which alleged investor fraud, in December.

But two new lawsuits from Minnesota and Washington, D.C., hint that climate lawsuits against Big Oil might be mounting a comeback.

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The new lawsuits mirror Massachusetts’ ongoing lawsuit against Exxon, which alleges that the oil giant violated the state’s consumer and investor protection law. In Minnesota on Wednesday, state attorney general Keith Ellison announced a lawsuit against ExxonMobil, Koch Industries, and the American Petroleum Institute, a trade association, that alleges that these entities have deceived consumers about the negative impacts of fossil fuel consumption and climate change. At the press conference announcing the suit, Ellison held up an internal ExxonMobil engineering document from 1979 that acknowledged that the company knew that climate change was caused by fossil fuel combustion. “They knew CO2 was going to go up because of burning fossil fuels, they knew it would cause climate change, and they knew that there would be negative catastrophic effects to the world and to Minnesota,” Ellison said.

The case bears similarity to a past case brought by Minnesota against tobacco companies: In 1998, Minnesota settled a lawsuit against the tobacco industry under similar allegations of consumer fraud, resulting in the creation of a $6.5 billion fund that has been used for public health programs and anti-smoking campaigns. Doug Blanke, director of the Public Health Law Center at Mitchell Hamline School of Law, oversaw the consumer protection division of the Minnesota attorney general’s office at the time of the ‘98 suit. “The lies of the tobacco industry … echo through every page of today’s lawsuit, because the alleged actions of these defendants are ripped straight from the playbook of the tobacco industry,” Blanke said at the press conference announcing the lawsuit.

The press conference announcing the Minnesota lawsuit emphasized the disproportionate effects of climate change on Black and Indigenous communities. Winona LaDuke, an Anishinaabekwe activist and the director of the Native environmental nonprofit Honor the Earth, emphasized the impacts of climate change on Indigenous communities. “This last year was a very hard year on a lot of our rice all across the north country,” LaDuke said. “They’re expecting a 25 percent increase in these heavy rain events over the next years. That’s going to be disastrous to our rice. Our rice is who we are, that’s who we are as people.”

The D.C. lawsuit, which was announced by D.C. Attorney General Karl Racine on Thursday, alleges that BP, Chevron, ExxonMobil, and Shell knowingly misled District consumers about the role their products play in exacerbating climate change for the past five decades. “Defendants continue to mislead D.C. consumers to this day,” says the complaint, which was filed in D.C. Superior Court. Racine brought the suit against four of the world’s largest oil companies under the District’s Consumer Protection Procedures Act, a statute that bans businesses from engaging in deceptive trade practices and misleading consumers. “These companies were not simply irresponsible in their reckless pursuit of profit,” Racine said on a press call on Thursday. “Their deceptive advertisement and misleading claims violate the D.C. consumer protection law.”

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Deputy attorney general Kathleen Konopka said Racine’s office wasn’t aware of the Minnesota lawsuit until it was filed on Wednesday. But she noted that D.C.’s lawsuit echoes some of the environmental injustice claims brought by the Minnesota suit. “There are indications that certain vulnerable populations will be more susceptible to rising temperatures and climate change,” she said on the call, “particularly in low-income communities and particularly our seniors.”

If successful, the D.C. lawsuit would prohibit the four oil companies from engaging in what Racine’s office considers deceptive advertising campaigns. The companies would also have to pay civil penalties and provide financial relief to consumers in D.C.

William Boyd, a law professor at the University of California, Los Angeles, says the two new lawsuits might get more traction than past attempts. “These are broad consumer protection statutes, and the facts that are alleged in the complaints are pretty damning for the big oil companies in the sense that they show a systematic effort to suppress and divert climate science and to mislead the public about the impacts of climate change,” said Boyd. Oil companies did “essentially what the tobacco companies did in funding and supporting a whole campaign through a whole network of organizations to essentially mislead the public,” Boyd said.

In statements to the Washington Post and Reuters, an ExxonMobil spokesperson dismissed both the Minnesota and the D.C. lawsuit, saying that the suits are part of a “coordinated, politically motivated campaign against energy companies.”

Boyd thinks more lawsuits could be in store for Big Oil. “I suspect many other states could be or are already thinking about similar actions,” Boyd said. “I think the overarching litigation strategy here is to find a legal theory that gets traction, and then others can jump on board.”

If the attorneys general succeed, the cost for the oil companies could be high. Ellison said that the settlement could be in the range of the state’s 1998 $6.5 billion settlement with the tobacco industry. “If you put it all together you’re looking at claims that could move into the many billions of dollars fairly quickly,” said Boyd. It’s unclear whether these lawsuits will actually achieve their intended goal. But one thing is obvious: cities and states aren’t giving up pinning the blame for climate fallout on major oil companies just yet.