Court filings by the Massachusetts attorney general’s office include previously undisclosed documents, revealing new details about internal deliberations at the oil giant.
By Nicholas Kusnetz
October 7, 2026
If there was a year the world began waking up to climate change, it might have been 1988. That June, the NASA climatologist James Hansen testified to Congress that the climate was warming and would continue to do so as long as humans pumped fossil fuel pollution into the atmosphere. Months later, the United Nations established the Intergovernmental Panel on Climate Change.
And, just weeks before the U.N. vote, Frank Sprow of Exxon’s corporate research department warned his colleagues in an internal memo, “If a worldwide consensus emerges that action is needed to mitigate against Greenhouse gas effects, substantial negative impacts on Exxon could occur.”
Sprow’s memo is part of a batch of previously undisclosed documents released earlier this year without fanfare as part of an ongoing lawsuit Massachusetts filed against ExxonMobil in 2019. While the memo was quoted in a 2023 article by The Wall Street Journal, it has not been published in full. Several other documents included in the filings are being reported on here for the first time, including more recent statements from Exxon scientists challenging the company’s climate-solution claims about its work on biofuels and carbon capture and storage.
While the documents align with hundreds of confidential files that have previously come to light through reporting by Inside Climate News and other news organizations, as well as lawsuits and other sources, experts say they provide new details on internal deliberations at Exxon from the 1980s to the 2010s.
The release of the documents comes at a pivotal time for the oil industry and for efforts to hold it accountable for its role fueling climate change. This week, the U.S. Supreme Court heard arguments from Exxon and oil producer Suncor Energy that a lawsuit filed by the city and county of Boulder, Colorado, should be halted. The outcome of that decision could decide whether more than two dozen other claims against oil companies proceed.
Aaron Regunberg, director of climate accountability at the advocacy group Public Citizen, said the documents from the Massachusetts case underscore why Exxon and other companies are fighting to block the lawsuits from even proceeding to the discovery phase.
“They are really scared of the public finding out about this reality,” Regunberg said of oil companies. The Massachusetts filings, he said, suggest “that we have seen just a sliver of the evidence that they actually have that they’ve spent decades knowingly deceiving the public about this crisis. How many more reports are they sitting on?”
Most of the lawsuits assert that oil companies should help pay the escalating costs being imposed on the public by climate-fueled extreme weather because they knew the risks their products posed but worked to publicly question climate science and stymie efforts to curb emissions. Those costs have surged, topping $100 billion in the U.S. in four of the last five years. Exxon, meanwhile, reported nearly $19 billion in earnings over the first six months of this year alone.
Exxon did not respond to requests for comment, but it has denied misleading the public or investors about climate change. In its annual securities filing, the company said of the lawsuits, “We believe the legal and factual theories set forth in these proceedings are meritless and represent an inappropriate attempt to use the court system to usurp the proper role of policymakers in addressing the societal challenges of climate change.”
The case brought by the Massachusetts attorney general’s office in state court is slightly different from others, arguing that the company deceived the state’s consumers and investors into thinking it was taking action to limit warming when those efforts were more about public relations than real action. The state is seeking fines and an injunction blocking Exxon’s allegedly deceptive practices.
The new documents, filed as part of a dispute over whether Exxon should be forced to hand over more files and testimony, help lay out the state’s case.
Take biofuels. For years, Exxon ran a sustained public relations campaign touting its research into using algae to make fuel, which it said could be a sustainable alternative to petroleum.
In March, The Wall Street Journal reported on internal documents that showed Exxon’s scientists told executives the company’s targets were not feasible. The new disclosures in the Massachusetts case add to the evidence with excerpts from a deposition by an Exxon scientist who worked on the program.
Asked whether a 2018 press release, which said Exxon anticipated “10,000 barrels of algae biofuel per day could be produced by 2025,” was misleading, the scientist said “yes,” adding, “All the clauses in there are patently false.”
The scientist testified that the 10,000-barrel-per-day target was “completely impossible to achieve,” and that he told this to others at the company before the press release was issued.
In another instance, the scientist said a research development on algae that Exxon publicly claimed as a breakthrough was, in fact, “a dead end.”
Exxon later dropped its research into algae biofuels but has continued to promote carbon capture and storage as a climate solution. The documents include some statements which, according to the attorney general’s office, show Exxon knew that technology was also unlikely to present a scalable solution to cutting emissions.
A 2014 presentation on Exxon’s carbon capture portfolio included a slide listing challenges to reaching commercial scale. It noted widespread deployment would require a “massive investment” and an eventual storage rate “comparable to current oil and gas production.” It said costs were high and there were no market-based incentives.
Three years later, a different Exxon scientist was asked by a colleague to record an advertisement for the technology. He noted that the company was calling itself a leader in carbon capture but said he was “not a big fan” of the claim. At the time, Exxon’s carbon capture operations were largely restricted to gas processing plants that stripped the climate pollutant out of methane and injected it into oil or gas fields. That technology, he said, “has nothing to do” with the type of carbon capture that Exxon and others were promoting for power plants and industrial facilities.
That scientist later appeared in an ad promoting research he was conducting on carbon capture without any claim that Exxon was a leader in the technology.
Another presentation from 2017 appears to show the advertisements for algae and carbon capture were among the company’s highest performing, calling them “All-Around Winners.”
In 2021, Exxon was still promoting its work in carbon capture. An internal presentation about an advertising campaign targeting political and financial leaders said its objective was to get people to “believe ExxonMobil is committed to helping solve climate change” and to proving the company and carbon capture and storage “play an indispensable role in facilitating the transition to a lower carbon energy system.”
Under a header of “what we’re doing,” the presentation listed a proposed hub for carbon capture in Houston that Exxon no longer promotes.
While the Massachusetts case focuses on these more recent campaigns, the filings include earlier records that serve as concise roadmaps for what would become Exxon’s climate strategy in the following decades, said Geoffrey Supran, an associate professor of environmental science and policy at the University of Miami. He has published studies comparing Exxon’s public statements with its internal documents and is a consulting expert on some climate-related legal actions.
It was November 1988, five months after Hansen’s congressional testimony, when Sprow filed his draft memo.
With the threat of climate action looming, he wrote, the company’s research and development on “Greenhouse” should have two primary goals: “Protect the value of our resources (oil, gas, coal),” and “Preserve Exxon’s business options.”
Sprow then laid out an agenda for how to achieve those ends.
With modeling critical to climate science, he wrote, “it could be considered important to be at the forefront of this modeling effort.” Sprow proposed “supporting a person on staff at one of the leading modeling centers (e.g. Princeton) or by sending one of our people to work in such a center.”
Sprow also recommended monitoring alternative energy technologies, including nuclear, solar and biofuels, to understand their viability as alternatives to fossil fuels or, eventually, for possible business development. Finally, he added, Exxon could look for “a research breakthrough” in one of these areas that would align with the company’s business.
Sprow did not respond to requests for comment from Inside Climate News, but he told The Wall Street Journal that his memo was adopted as corporate policy.
“This is the playbook all in one place.”
— Geoffrey Supran, University of Miami associate professor
By the late 1990s, Exxon and other oil companies were working assertively to convince the public and government officials that enacting policies to limit climate pollution would impose grave costs on society.
One newly published Exxon memo summarizing a 1997 meeting of a climate steering group at the American Petroleum Institute, a trade group, outlines many key elements of the strategy.
With governments poised to negotiate an international climate agreement in Kyoto, the steering group would recommend that API “continue to question the scientific basis and cite the high economic cost” of policies to address climate change and “avoid pressures to negotiate a compromise.”
The memo cited polling about which arguments would “resonate with the public.”
It also said Exxon was planning to fund a climate change project by Jonathan Adler of the free-market oriented Competitive Enterprise Institute, who had come to the meeting seeking support. Exxon asked Adler to “focus their project more narrowly” on the impacts of climate policy proposals on individuals and trade competitiveness. The memo outlined a grassroots campaign and efforts with labor unions, and said API continued to work with the American Enterprise Institute, another conservative think tank, to arrange a seminar about a letter written by economists. The goal was to “prevent its misuse by advocates or near-term action.”
“These are sophisticated strategies to use and we-ponize experts in order to perpetuate their denial,” said Supran, who co-authored an amicus brief supporting Boulder in the case against Exxon and Suncor. “This is the playbook all in one place.”
In an interview, Adler rejected the argument that he was promoting climate denial. “I can’t speak to what API or Exxon’s motivations were,” said Adler, now a professor at William & Mary Law School. “What I can say is the work we did at CEI at the time was very much focused on what was accurate and correct and consistent with the principles the organization was founded on.”
He said it was natural for his organization to seek funding from companies and entities that also supported limited government regulation.
This year, Adler wrote a brief supporting Boulder in the case before the Supreme Court, arguing that its claims were not preempted by federal law and should be allowed to proceed in state court. He did not take a position on the merits of Boulder’s claims.
By 2005, when Exxon was facing public criticism for its support for groups that questioned climate science, a company spokesperson told Mother Jones magazine that Exxon believed “the scientific evidence on greenhouse gas emissions remains inconclusive and that studies must continue.” She also said Exxon had devoted large sums to university research programs, including a planned $100 million to Stanford University’s Global Climate and Energy Project.
The following year, documents from the Massachusetts case now show, a colleague arranged a meeting for the spokesperson with two self-identified global warming skeptics.
By the 2010s, Exxon’s public position on climate change had evolved. It was no longer questioning science, a position that became harder to maintain as scientists’ conclusions grew stronger and the United States joined the Paris Agreement in 2015. In fact, following Sprow’s advice, the company had one of its research scientists contributing to the Intergovernmental Panel on Climate Change.
Exxon was fending off concerns from shareholders that it was failing to prepare its business for the risks posed by climate change, so it began work on a “climate risk matrix,” the documents show. In 2016, the Exxon scientist who contributed to the U.N. climate panel warned colleagues of the risk of climate tipping points, the probability of which were “poorly understood but probability is expected to rise with temperature change.” He noted that failure to limit emissions would have a growing influence on temperatures beyond 2040 and cited concerns that the impacts of hitting tipping points “would be significantly larger” than the direct effects of heat.
And yet, the Massachusetts case shows, Exxon continued to promote solutions that its own scientists said were unlikely to reach commercial scale. The vast majority of its money instead went to oil and gas, the production of which Exxon plans to expand more than 15 percent by 2030.
This story was updated Oct. 7, 2026, to clarify that Jonathan Adler is now a professor at William & Mary Law School.
https://insideclimatenews.org/news/07102026/exxonmobil-climate-deception-new-evidence/