By Brandi Buchman, Courthouse News Service

(CN) – Fossil-fuel giant Exxon Mobil has knowingly misled the public for nearly 40 years about the dangers of climate change, according to a new study (pdf) analyzing company communications.

Harvard researchers Geoffrey Supran and Naomi Oreskes published their peer-reviewed study on Exxon Mobil’s climate-change communications in the journal Environmental Research Letters on Wednesday.

Supran and Oreskes reviewed roughly 200 documents of Exxon-based research on climate change as well as a litany of public statements the energy giant has issued on the effects of greenhouse-gas emissions.

From 1977 to 2014, the researchers found that Exxon acted in accord with scientific thinking of the time: nearly 80 percent of their internal research acknowledged that climate change is real and man-made.

But in public editorial-style advertisements, or “advertorials,” Exxon expressed considerable doubt on the matter in roughly 80 percent of its released statements.

“We stress that the question is not whether Exxon Mobil ‘suppressed climate change research,’ but rather how they communicated about it,” the study found. “Exxon Mobil contributed quietly to the science and loudly to raising doubts about it.”

ExxonMobil spokesman Scott Silvestri told the New York Times on Wednesday that the findings are “inaccurate and preposterous.” He contends the research is just another attempt by environmentalists to “extract money from our shareholders” and attack the company’s reputation.

Supran and Oreskes’s study primarily relied on textual content analysis to reach their conclusion. The authors admitted that particular process is “inherently subjective.”

But their findings were reaffirmed by a clear trend of skepticism and denialism they found spread out over dozens of documents. Skeptics of the study will have more than 100 pages of supplemental research by Supran and Oreskes to audit.

The report could be tapped as a resource for state and federal attorneys and the Securities Exchange Commission, who are investigating whether Exxon obfuscated information on climate science to company investors.

Exxon has suggested that high costs of low-carbon technologies made renewable energy investment deeply prohibitive. The company suggested that limiting global warming caps would raise carbon costs to $2,000 per ton by 2100, eventually pushing gas costs in the U.S. to $20 per gallon.

Silvestri said Exxon’s statements over the years have been “consistent with our understanding of climate science.”

He criticized the recent findings as “cherry picked.”

In response, Supran told Agence France-Presse, “We looked at the whole cherry tree.”

Supran said he and Oreskes found “gaping, systematic discrepancy” between what Exxon said about climate change in private and in academic circles and what it said to the public.

“We conclude that ExxonMobil contributed to advancing climate science—by way of its scientists’ academic publications—but promoted doubt about it in advertorials,” according to the study. “Given this discrepancy, we conclude that ExxonMobil misled the public.”

To Learn More:

Judge Orders ExxonMobil to Release Financial Records in Climate-Change Fraud Investigation (by Adam Klasfeld, Courthouse News Service)

State Regulators Accuse U.S. Lawmaker of “Unprecedented” Meddling into ExxonMobil Fraud Investigations (by Adam Klasfeld, Courthouse News Service)

Investigations Grow into Alleged Exxon Mobil Climate-Change Deception (by Jake Pearson, Associated Press)

ExxonMobil May Only Be First of Oil Giants to Be Investigated for Obscuring Climate Science (by Steve Straehley, AllGov)

ExxonMobil Accused of Deceiving Public on Climate Change Risks to Protect Profits (by Steve Straehley, AllGov)