What Exxon's Own Scientists Projected About Warming in the 1970s and 1980s

In July 1977, a senior scientist named James Black stood before Exxon's management committee, the small group of executives who ran what was then the largest oil company in the world, and talked about carbon dioxide. According to documents later made public by journalists, Black told the executives that there was general scientific agreement that burning fossil fuels was most likely affecting the climate through the release of carbon dioxide. A year later, in a written summary, he warned that the company might have a window of only five to ten years before hard decisions about energy strategy would be needed. Exxon did not ignore him. It did something more interesting. It funded serious research of its own, hired capable scientists, equipped a supertanker to measure carbon dioxide in the air and ocean, and built climate models. Those scientists produced projections of how much the planet would warm as carbon dioxide rose. Forty years later, a team of researchers checked those projections against what actually happened. They were, for the most part, right.

In short: In the late 1970s and early 1980s, Exxon ran a serious climate research program whose scientists projected warming that closely matches what has since occurred, according to a 2023 study in the journal Science. In the following decades, the company and industry groups it funded emphasized uncertainty and opposed binding climate policy. Exxon disputes the charge that it misled the public, and courts are still sorting out what, if anything, the company owes.

A research program with real scientists

Exxon's research in the late 1970s was not a token effort. The company outfitted one of its oil tankers, the Esso Atlantic, with instruments to sample carbon dioxide in the air and the surface ocean on its voyages, a project meant to understand how much of the gas the oceans would absorb. Company scientists worked with academic researchers, including scientists at Columbia University's Lamont-Doherty Geological Observatory. They published some of their work in peer-reviewed journals, a point Exxon emphasizes today.

In-house climate modeling followed. By the early 1980s, company scientists were estimating how much the planet would warm as carbon dioxide doubled from its pre-industrial level, and when that doubling might occur. A 1982 internal document circulated to Exxon managers summarized the science, describing the likely warming and potentially serious consequences, including effects on agriculture and rising seas. The company's own experts were treating the basic physics as settled and the open questions as matters of how fast and how much.

It is worth being fair to the scientists themselves. Nothing in the public record suggests that the researchers who sailed with the tanker or built the models did shoddy work or hid what they found from their managers. By the account of the documents, they did what good scientists do: they measured carefully, compared notes with university colleagues and reported their best estimates, uncertainties included, up the chain. Their projections are the reason the 2023 study had anything to check. The question this story raises is not about them. It is about what an institution does with knowledge that its own experts hand it, when that knowledge is bad news for the product it sells.

The research program was scaled back in the mid-1980s, during a period when oil prices fell sharply and the company cut spending across the board. Exxon has said this was a business decision, not a scientific one.

The 2023 check on the projections

In January 2023, three researchers, Geoffrey Supran, Stefan Rahmstorf and Naomi Oreskes, published a paper in Science that did something nobody had done systematically before. They collected the global warming projections that Exxon and ExxonMobil scientists had produced in internal documents and published papers between 1977 and 2003, and they compared them with the temperatures the world actually recorded.

Their conclusion: most of the projections accurately predicted the warming that followed, and they were about as skillful as the projections of independent academic and government scientists of the same era. The study estimated that the company's projections, on average, implied warming of about 0.2 degrees Celsius per decade, close to what has been observed. The authors also found that the company's scientists correctly rejected the idea, popular in some circles at the time, that the world was heading toward an ice age, and reasonably estimated when human-caused warming would first be detectable.

The study's most pointed finding was not about any single model. It was about the contrast between what the company's scientists projected and what the company's leaders said publicly in the years that followed.

What the company said in public

From the late 1980s on, as climate change became a political issue after the 1988 congressional hearings, the oil industry organized. Exxon was a leading member of the Global Climate Coalition, an industry group formed in 1989 that opposed binding emission limits and emphasized scientific uncertainty. The company's executives publicly questioned whether warming was happening, whether humans were causing it and whether models could be trusted. In a 1997 speech in Beijing, shortly before the Kyoto climate negotiations, Exxon's chief executive, Lee Raymond, argued that the world was not warming as predicted and that the case for drastic cuts was weak. Exxon and ExxonMobil, the company formed after the 1999 merger with Mobil, also ran opinion-page advertisements in major newspapers for years questioning the science, and the company funded think tanks that challenged climate policy.

Researchers who studied those advertisements and the company's internal documents argued in a 2017 paper that its public messaging emphasized doubt in a way its internal research did not. In the mid-2000s, ExxonMobil said it had stopped funding some of the groups that disputed climate science, and in later years it acknowledged that climate change is real and that human activity contributes to it, and it supported a carbon tax in principle.

Exxon's side of the story

A fair account has to give the company's defense its full weight. ExxonMobil's position is that its scientists published their research openly, so there was no secret to hide; that the climate science of the 1980s was genuinely uncertain on important questions; that the company's public statements reflected reasonable skepticism about policy, not denial of science; and that the campaign summed up in the hashtag ExxonKnew is a coordinated political effort by activists and plaintiffs' lawyers. The company also argues that climate change is a global problem caused by billions of people using energy, and that singling out one producer, or using state courts to set energy policy, is unfair and unworkable.

There is something in the last point. Every driver, every power plant and every factory has burned the fuel Exxon sold, and climate policy has to change how everyone uses energy, not just punish the companies that produced it.

Here is our answer. The question is not whether ExxonMobil caused climate change by itself. It is whether a company that understood the risk unusually well, because its own scientists had told it, used its wealth and influence to slow the public's response. The record of the company's public campaign suggests it did. That delay mattered: the decades between the late 1980s and the 2020s were the years when a gradual transition would have been cheapest.

Into the courts

The revelations, first reported in 2015 by the news outlet InsideClimate News and by reporters working with the Columbia Journalism School and the Los Angeles Times, led to investigations and lawsuits. New York's attorney general sued ExxonMobil, accusing it of misleading investors about how it accounted for the cost of climate regulation. In December 2019, a New York judge ruled for the company, finding the state had not proved its fraud claims. Massachusetts brought a consumer and investor protection case that has continued in its state courts.

Dozens of cities, counties and states have filed lawsuits against major oil companies, including ExxonMobil, seeking money for climate damage and claiming that the companies deceived the public. The companies have fought them on many fronts, arguing that federal law, not state law, governs pollution that crosses borders. In January 2025, the Supreme Court declined to hear the oil companies' attempt to stop Honolulu's case, allowing it to go forward in Hawaii's courts. In 2025, the Trump administration's Justice Department sued several states, including Hawaii and Michigan, to block their climate suits and climate superfund laws. How these cases end is still being decided, and for the latest, our court watch page tracks the Supreme Court's opinions and orders.

Making polluters pay: the superfund idea

The newest front in the fight borrows from an old law. In 1980, after the toxic waste disaster at Love Canal in Niagara Falls, New York, Congress created the federal Superfund program, which makes companies responsible for cleaning up hazardous waste sites they created, even long after the fact. The principle is simple: whoever made the mess pays for the cleanup, rather than taxpayers.

In 2024, Vermont became the first state to apply that idea to climate change. Its law directs the state to estimate the cost of climate damage within its borders and to assess the largest fossil fuel producers for a share of it, based on their past emissions. New York passed a similar law at the end of 2024. Other states have considered their own versions. The money would pay for things like stronger culverts and roads, flood protection and cooling centers, the unglamorous work of adapting to a climate that is already changing.

The industry and its allies argue that these laws punish companies retroactively for selling a legal product that the whole economy depended on, that states cannot regulate global emissions, and that the costs will simply be passed on to consumers. Those are serious legal questions, and courts will decide them. The case for the laws is that the people of Vermont, who did not choose the decades of delay, are paying for flood damage now, and that the companies that profited most from the delay are in the best position to share the cost. Either way, the fight over who pays is no longer hypothetical, and both the industry and the federal government have sued to stop the laws.

The tobacco parallel, carefully drawn

People who follow the Exxon story often compare it to tobacco, and the comparison is useful as long as it is drawn carefully. In 1999, the federal government sued the major cigarette makers under the racketeering law, arguing that they had conspired for decades to deceive the public about the dangers of smoking. In 2006, a federal judge in Washington, Gladys Kessler, ruled that the companies had violated the law, and she later ordered them to publish corrective statements about their products.

The parallel is in the pattern: an industry that understood a risk from its own research and emphasized doubt in public. The differences are also real. Cigarettes harm the person who uses them; fossil fuels power hospitals, farms and homes, and the world cannot stop using them overnight. Climate damage comes from the combined emissions of everyone, over more than a century. That is why the remedy for climate change cannot be just a court judgment. It has to be a transition, and the companies that knew the most have a responsibility to help pay for it and not to obstruct it.

What this tells us about corporate power

The Exxon story is not unique. Researchers have documented similar patterns at other fossil fuel companies. What makes the Exxon case distinctive is the quality of its internal science, and the 2023 study's finding that the company's own projections hold up.

The broader lesson concerns what happens when knowledge and power sit in the same hands and the incentives point the wrong way. A company whose business depends on selling fossil fuels faced a choice between telling the public what its scientists projected and protecting its core product. Expecting any company to choose against its own bottom line is naive. That is why public institutions, independent science, a free press and laws that require honest disclosure exist. When any of those are weakened, private interests fill the gap.

The people who pay most for delay are rarely the people who chose it. They are farmers watching a drought, families on the Gulf Coast rebuilding after another storm, workers in the heat, and children who will live most of their lives in a warmer world. They deserve a full account of what was known and when, and they deserve a policy that finally matches the projections Exxon's own scientists got right.

What you can do

• See who is polluting near you. The polluter lookup by ZIP code lists EPA-regulated facilities, their violations and their penalties, a small piece of corporate accountability you can check yourself.
• Support disclosure rules. When agencies propose rules on climate risk disclosure or emissions reporting, the public can comment. Look for open dockets on the comment page and write about why honest disclosure matters to you as an investor, a customer or a neighbor.
• Follow the cases and the industry. Our page on big oil and fossil fuels collects reporting on the lawsuits, and the page on corporate power follows the wider fight over accountability.
• Ask your state officials where they stand. Attorneys general and legislatures decide whether to bring or defend climate cases and superfund laws. Ask candidates directly at forums and town halls.