Exxon's In-House Climate Models From 1977 Onward Predicted Global Warming More Accurately Than NASA's Did. The Company Spent the Next Three Decades Paying Other People to Say the Models Were Wrong.

In July 1977, an Exxon scientist named James Black stood before the company's Management Committee and told them there was "general scientific agreement" that burning fossil fuels was warming the planet. The following year he put a number on it in a memo to a vice president: doubling atmospheric CO2 would raise global average temperatures 1 to 3°C, with the poles warming as much as 10°C. Exxon did not shelve this as a hypothetical. Between 1979 and 1982 it ran its own climate research program, instrumenting the supertanker Esso Atlantic to measure how much CO2 the oceans were absorbing.

A 2023 study in Science — the first systematic check of any oil company's internal climate math against what actually happened — found that Exxon's models from 1977 to 2003 scored an average "skill rating" of 72%, peaking at 99%, against reality. Independent academic and government models from the same era averaged 69%. NASA scientist James Hansen's own famous 1988 congressional warming projections scored 38 to 66%. Exxon's in-house scientists, in other words, had already out-predicted the space agency. The company then spent the next three decades funding people to say none of this could be known.

The forecast nobody was supposed to see

The numbers didn't stay filed away for posterity. They sat in internal memos while the company's public posture moved in the opposite direction, a gap that only became visible to the public decades later.

• 1977–1978: Black's briefings and memo establish the CO2-warming link internally, with a stated 5-to-10-year window to gather more data before the science would be settled beyond dispute.
• 1979–1982: Exxon's tanker-based ocean CO2 measurements run as a bona fide research program, not a PR exercise.
• 2015: An eight-month Inside Climate News investigation, paired with a Los Angeles Times/Columbia Journalism School project, publishes "Exxon: The Road Not Taken," built from the company's own internal documents, and launches the #ExxonKnew campaign.
• 2023: The Science study confirms, with statistics rather than leaked memos, that Exxon's models were not just aware of the problem — they were accurate about it, projecting roughly 0.20°C of fossil-fuel-driven warming per decade, a figure that held up.

Thirty years of paid second opinions

Having correctly calculated the problem, Exxon spent the next three decades bankrolling the argument that the problem was uncertain. The uncertainty was the product being purchased.

• 1989–2002: Exxon co-founds and funds the Global Climate Coalition, an industry group that spends tens of millions of dollars lobbying against binding emissions cuts ahead of the 1997 Kyoto Protocol before dissolving in 2002.
• 1998: The American Petroleum Institute, drafting with Exxon, Chevron, Southern Co. and allied think tanks, writes a communications plan whose stated victory condition is that "average citizens 'understand' (recognize) uncertainties in climate science" — not that uncertainties be resolved, that they be recognized.
• 1998: Exxon wires $50,000 to the Atlas Network to seed climate-denial-oriented think tanks in developing countries.
• By the mid-2000s, Exxon's documented cumulative funding of groups working to undermine climate science reaches roughly $23 million, peaking above $3.5 million in 2005 alone. Even after a 2008 pledge to stop funding some of these groups, $1.3 million still goes out in 2009 to more than two dozen organizations.

The scientist on the payroll

The funding wasn't just institutional — it reached individual researchers whose credentials could be cited independently of any oil-company letterhead.

• Willie Soon, based at the Harvard-Smithsonian Center for Astrophysics, received more than $1.25 million over roughly fourteen years from ExxonMobil, the American Petroleum Institute, and Koch-run foundations. Nearly all of his climate research during that period was industry-funded.
• Exxon dropped him in 2010 — not a renunciation of the underlying strategy, just a change of vendor.

What the executives said out loud

The internal memos were private. The public statements were not, and they ran in the opposite direction from what the company's own scientists had written down years earlier.

• 1996: CEO Lee Raymond calls the link between fossil fuels and climate change "the unproven theory."
• October 13, 1997, addressing the World Petroleum Congress in Beijing: "the case for so-called global warming is far from air tight... there's a lot we really don't know about how climate will change."

By 1997, Exxon's own models were two decades into consistently getting this right.

The courts weigh in

Litigation has tested the disclosures, not the underlying science, and the distinction has mattered to the outcomes so far.

• December 2019: In People (New York) v. Exxon Mobil Corp, a $1.6 billion securities-fraud case over investor disclosures, Justice Barry Ostrager rules for Exxon on the narrow claims tested — but adds: "Nothing in this opinion is intended to absolve ExxonMobil from responsibility for contributing to climate change through the emission of greenhouse gases."
• Massachusetts's separate consumer-protection case, alleging deception rather than securities fraud, remains in active pre-trial discovery as of 2026. Exxon is countersuing the state over access to public records.

Exxon's scientists calculated, in 1977, that doubling atmospheric CO2 would raise global temperatures 1 to 3°C. Independent researchers now measure the company's full modeling record at 72% average predictive skill, ahead of the 69% average for outside academic and government models of the era, and ahead of the 38-to-66% range NASA's own James Hansen posted in his celebrated 1988 testimony. Exxon spent an amount in the tens of millions of dollars over the following decades funding the position that these numbers could not be trusted, distributed to a coalition, a communications plan, a think-tank seeding grant, and a Harvard-Smithsonian researcher, arriving at a courtroom in 2019 where a judge cleared the company on disclosure and, unprompted, declined to clear it on the climate.

Filed from public reporting:

• Inside Climate News — "Exxon's Own Research Confirmed Fossil Fuels' Role in Global Warming Decades Ago"
• Inside Climate News — "Exxon Accurately Predicted Global Warming, Years Before Casting Doubt on Climate Science"
• Science — Supran, Rahmstorf, Oreskes, "Assessing ExxonMobil's global warming projections"
• Harvard Gazette — "Harvard-led analysis finds ExxonMobil internal research accurately predicted climate change"
• Climate Files — 1978 Exxon Memo on Greenhouse Effect
• Climate Files — 1998 API "Global Climate Science Communications Team Action Plan"
• Climate Files — 1997 Exxon Lee Raymond Speech at World Petroleum Congress
• DeSmog — "ExxonMobil's Funding of Climate Science Denial"
• Wikipedia — People v. Exxon Mobil
• CNBC — "Exxon Found Not Guilty in New York Climate-Change Securities Fraud Trial"
• Bloomberg Law — "Exxon Must Face Massachusetts Suit Claiming Climate Deception"