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ExxonMobil’s climate predictions from the late 1970s were eerily accurate, study finds

Exxon's climate models were as accurate or more accurate than those of the leading climate scientists of their day.

(CN) — ExxonMobil's climate projections, made by in-house scientists between 1977 and 2003, were startlingly accurate — as prescient or even more prescient than those made by other leading climate scientists of the day — according to a new study published Thursday in Science.

"Our analysis here seals the deal and cements our understanding of what Exxon knew, when," said the paper's lead author, Harvard University Research Associate Geoffrey Supran. "They didn’t just vaguely know something about global warming decades ago, they knew as much as anyone else, as much as independent scientists of the day. And arguably, they knew all they needed to know."

The research draws on documents first unearthed in 2015 by Inside Climate News, detailing Exxon's long history of internal research showing that the burning of fossil fuels by humans was warming the planet. Those revelations led to protests, under the banner of "ExxonKnew," as well as lawsuits filed against the publicly traded corporation, which has long denied any wrongdoing.

In 2017, Supran, along with another researcher, Naomi Oresekes, combed through the nearly 200 documents to show how often Exxon, in internal communications, acknowledged that climate change was real and caused by humans, despite public statements to the contrary.

This new paper is based on those same documents, but takes a more quantitative approach.

Summary of all global warming projections reported by ExxonMobil scientists in internal documents and peer-reviewed publications between 1977 and 2003 (gray lines), superimposed on historically observed temperature change (red). (Courtesy of Geoffrey Supran)

“We find that most of their projections accurately forecast warming consistent with subsequent observations,” the report concludes. “Their projections were also consistent with, and at least as skillful as, those of independent academic and government models.”

Exxon correctly predicted that fossil fuel burning would lead to roughly .2 degrees Celsius of global warming per decade. According to Supran's analysis, Exxon's exact projections had an "average skill score" of 72%.

"For comparison, NASA scientist James Hansen’s global warming predictions presented to the U.S. Congress in 1988 had skill scores ranging from 38% to 66%," the paper reads.

At the same time Exxon was making these internal projections, it was funding research to sow doubt about climate science, and placing advertisements in newspapers convince the public that the science was far from settled.

Todd Spitler, a spokesman for ExxonMobil, said in an email: "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." In another email, he added: "ExxonMobil’s understanding of climate science has developed along with that of the broader scientific community."

Since the revelations of 2015, Exxon has been sued by numerous states and local governments for allegedly deceiving the public. New York state's lawsuit against ExxonMobil for securities fraud made it all the way to trial in 2019, but ended in the judge clearing Exxon of the two remaining charges.

“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," wrote New York Supreme Court Justice Barry Ostrager in his ruling, which found that the prosecutors had "failed to prove, by a preponderance of the evidence, that ExxonMobil made any material misstatements or omissions about its practices and procedures that misled any reasonable investor."

A similar suit brought by the state of Massachusetts is pending; the judge in that case denied Exxon's motion to dismiss, a ruling that was upheld by the state Supreme Court in May.

"The allegation is that the public, or the policy makers, have been misled," said Supran. "Establishing what they knew through our research may help inform those cases."

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