A new study by Harvard researchers has found that decades of scientific research by ExxonMobil contradicted a public messaging campaign by the fossil fuel giant that raised doubts about climate change and its hazards.

The study, to be published Wednesday in the journal Environmental Research Letters, validated investigations in 2015 by the Los Angeles Times and the nonprofit agency InsideClimate News.

That reporting concluded that top executives at ExxonMobil were warned by their own scientists about the dangers of greenhouse gases, including potential threats to the company’s operations. At the same time, the oil corporation invested millions in advertising campaigns that would call into question whether climate change was a threat to humans.

ExxonMobil called the media coverage misleading, and created a website featuring an archive of its peer-reviewed research and internal communications.


“Reading the documents shows that these allegations are based on deliberately cherry-picked statements attributed to various ExxonMobil employees to wrongly suggest definitive conclusions were reached decades ago by company researchers,” the website reads.

Harvard historian of science Naomi Oreskes — who was explicitly named by ExxonMobil on its website as a purveyor of such misinformation — decided to take up the challenge.

“I know what it’s like to have your work taken out of context,” she said. “That’s a fair complaint, if it’s true. We think that our study shows that it’s not true.”

ExxonMobil — which declined to comment for this story — has routinely denied that it suppressed its climate science.


“(O)ur scientists and researchers were among the first to grapple with the fact there might be a connection between the carbon dioxide emissions from humanity’s use of fossil fuels and climate fluctuations,” the company’s website reads. “It should surprise no one that we have remained committed to pursuing climate change research since that initial discovery.”

Oreskes and a post-doctoral researcher at Harvard, Geoffrey Supran, reviewed 187 documents dating back to 1977, including peer-reviewed scientific papers, internal documents, company pamphlets, conference materials and books.

The researchers compared those with dozens of paid advertisements published in The New York Times between 1989 and 2004.

The report analyzed these materials based on a number of criteria, including positions on whether humans have caused climate change and if warming posses a serious threat.


Using a content-analysis methodology, Oreskes and Supran found that 83 percent of ExxonMobil’s peer-reviewed scientific papers that expressed a position on the topic acknowledged that climate change was caused by humans.

Conversely, the study found that of the relevant advertising, 81 percent raised doubts about whether humans were causing global warming. That messaging campaign starts largely around 1996, a year after the International Panel on Climate Change first concluded that climate change was most likely driven by greenhouse-gas emissions linked to human activities.

Only 10 out of 72 peer-reviewed publications addressed the potential for adverse impacts from climate change, of which six acknowledged serious risks, according to the report.

Meanwhile, the report found that ExxonMobil’s internal documents broadly acknowledged the idea of human caused warming and routinely addressed the question of impacts.


Of such documents with a position, nearly half expressed doubt but also recognized the potential risks associated with climate change. Another 35 percent of the materials focused more on the likelihood of serious fallout from a warming planet, such as from melting ice sheets and sea-level rise.

Of the advertising that dealt with the impacts of climate change, about 62 percent expressed doubt and 24 percent offered mixed messages, according to the report.

One such ad from ExxonMobil detailed in the report read: “Just as changeable as your local weather forecast, views on the climate change debate range from seeing the issue as serious or trivial, and from seeing the possible future impacts as harmful or beneficial.”

The research comes as the Securities and Exchange Commission, as well as the attorneys general of New York and Massachusetts, continue an investigation into whether ExxonMobil violated shareholder trust by concealing the potential impacts of climate change on the company’s bottom line.


Publicly traded companies must disclose to shareholders financial risks, such as from possible government regulations to curb greenhouse gases. The company could face significant financial liability if it’s found to have concealed documents outlining the potential for financial losses.


Twitter: @jemersmith

Phone: (619) 293-2234

Email: joshua.smith@sduniontribune.com