In total, we analyzed 187 documents generated between 1977 and 2014. We coded each document to characterize its positions on climate change as real, human-caused, serious and solvable. (Research has shown that these four factors are key predictors of public support for climate policies. Not coincidentally, they also underpin most narratives of climate skepticism and denial.) We found that, from as early as the 1970s, Exxon Mobil (and its predecessors Exxon and Mobil) not only knew about emerging climate science, but also contributed research to it. Scientific reports and articles written or cowritten by Exxon Mobil employees acknowledged that global warming was a real and serious threat. They also noted it could be addressed by reducing fossil fuel use, meaning that fossil fuel reserves might one day become stranded assets.

For the most part their research was highly technical, hidden behind the walls of Exxon Mobil offices, or reported in academic publications with access only through a paywall.

In contrast, the company’s advertorials in The New York Times discussing climate change were designed to reach and influence the public, and the potential readership was in the millions. Each advertorial cost roughly $31,000. They overwhelmingly emphasized scientific uncertainties about climate change and promoted a narrative that was largely inconsistent with the views of most climate scientists, including Exxon Mobil’s own. [The Times’s policy on accepting such advertising can be found here.]

In 1997, for instance, in an ad titled “Reset the Alarm,” the company argued: “Let’s face it: The science of climate change is too uncertain to mandate a plan of action that could plunge economies into turmoil.” The company added, “We still don’t know what role man-made greenhouse gases might play in warming the planet.”

Some advertorials conflicted with Exxon Mobil research published the very same year.

In some cases, they included explicit factual misrepresentation, for instance, directly contradicting the Intergovernmental Panel on Climate Change and presenting data in a “very misleading” way, according to the independent researcher who produced that data, Lloyd Keigwin, a senior scientist in geology and geophysics at the Woods Hole Oceanographic Institution.

In short, Exxon Mobil contributed quietly to climate science and loudly to raising doubts about it. We found that, accounting for reasonable doubt given the state of the science at the time of each document, roughly 80 percent of the company’s academic and internal papers acknowledged that climate change is real and human-caused. But 81 percent of their climate change advertorials in one way or another expressed doubt.