Exxon predicted global warming in 1970s despite publicly dismissing climate change, research finds

Scientists working at oil giant Exxon Mobil in the 1970s predicted global warming with "astonishing" accuracy while the company publicly contradicted the research, a study has found.

The study found that Exxon's research, which dated from 1977, used around a dozen sophisticated computer models that correctly forecasted the globe would warm by around 0.2 degrees Celsius every decade.

Exxon's scientists predicted the climate crisis with precision equal to or better than government and academic research at the time.

But the oil company publicly cast doubt on suggestions that climate change was real and dismissed the accuracy of studies that modelled future global warming.

The new study, published in the journal Science, found that between 63% and 83% of Exxon's historic research fitted strict academic standards of accuracy.

Read more: Climate change: What progress has been made

The study's co-author, Harvard science history professor Naomi Oreskes, said Exxon's research was "actually astonishing" as she referred to the company's "hypocrisy because so much of the Exxon Mobil disinformation for so many years…was the claim that climate models weren't reliable".

A collection of internal documents made public by a former Exxon employee in 2015 showed the company knew of climate change years before it became a public issue.

But the new study uncovers the accuracy and extent of Exxon's internal research.

Todd Spitler, a spokesman for Exxon, said the company's understanding of climate science developed along with the broader scientific community, and its four decades of research in climate science resulted in more than 150 papers, including 50 peer-reviewed publications.

"This issue has come up several times in recent years and, in each case, our answer is the same: those who talk about how 'Exxon Knew' are wrong in their conclusions," he said.

"In 2019, Judge Barry Ostrager of the NY State Supreme Court listened to all the facts in a related case before him and wrote: 'What the evidence at trial revealed is that ExxonMobil executives and employees were uniformly committed to rigorously discharging their duties in the most comprehensive and meticulous manner possible….The testimony of these witnesses demonstrated that ExxonMobil has a culture of disciplined analysis, planning, accounting, and reporting'."

But the study's lead author, Geoffrey Supran, from the University of Miami, said: "Our analysis really seals the deal on 'Exxon knew'.

"[It] gives us airtight evidence that Exxon Mobil accurately predicted global warming years before, then turned around and attacked the science underlying it."

The study quoted former Exxon CEO Lee Raymond saying in 1999 that future climate "projections are based on completely unproven climate models, or more often, sheer speculation".

Exxon, one of the world's largest oil and gas companies, has faced several lawsuits that allege the company knew how damaging fossil fuels were to the environment.

Alongside other oil companies, Exxon was also accused in US congressional hearings in 2021 of spreading misinformation about climate. Company executives denied the accusations.