In 1996, scientists from ExxonMobil wrote in a peer-reviewed publication by Cambridge University Press that, “the body of statistical evidence… now points towards a discernible human influence on global climate.”

The next year, in a advertorial in The New York Times, which reached millions more people, the corporation had a different take: “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 wrote. “Scientists cannot predict with certainty if temperatures will increase, by how much and where changes will occur.”

The divide between the science going on at the oil and gas giant – and their public presentation of the science available – is the subject of a new investigation by two Harvard academics in the journal Environmental Research Letters.

Geoffrey Supran and Naomi Oreskes conclude: ExxonMobil did not “suppress” the science over the course of almost 40 years. Instead, the corporation “misled” the public through a deliberate public-relations campaign independent of the inquiries underway in their labs – which found anthropogenic climate change to be a real and growing danger to the globe.

“We conclude that ExxonMobil contributed to advancing climate science – by way of its scientists’ academic publications – but promoted doubt about it in advertorials,” they write, in the study.

Spanning the years 1977 to 2014, the pair looked at four kinds of corporate communications: internal documents, peer-reviewed papers, non-peer-reviewed publications, and advertorials they ran in the pages of The New York Times.

The 187 documents they collected were scored and coded for their core message. The stances included whether anthropogenic climate change was real and human caused; whether it was a serious global problem; and whether it was potentially solvable.

The findings showed a flurry of internal documents that acknowledged the climate change phenomenon in the 1970s and early 1980s, and showed a “mixed internal dialogue” within the corporation as to whether it was really happening. But there was a sharp divide starting in the mid-1990s when published research in peer-reviewed and non-peer-reviewed studies by the company’s scientists started to acknowledge man-driven climate changes on the globe. At the same time, advertorials in the Times began to appear at an accelerating pace.

Hence, the divide in the 1996 scientific findings in a small academic publication – and the public doubt in the newsprint pages.

“Around this time, ExxonMobil set up two parallel initiatives: climate science research, and a complimentary public relations campaign,” the Harvard academics write. “According to a 1978 ‘Request for a credible scientific team,’ these initiatives targeted four audiences: the scientific community, government, Exxon management, and the general public and policymakers.”

Upon the online publication of the latest paper, ExxonMobil attacked the two authors as “activists” with ulterior motives.

“The study was paid for, written and published by activists leading a five-year campaign against the company. It is inaccurate and preposterous,” the corporation wrote. “Rather than pursuing solutions to address the risk of climate change, these activists, along with trial lawyers, have acknowledged a goal of extracting money from our shareholders and attacking the company’s reputation.”

The corporation, they added, “acknowledges the risk of climate change is real and warrants action.”

More than a dozen state attorneys general have announced they are pursuing investigations of ExxonMobil and other fossil-fuel corporations, as to whether they concealed climate-change data and information from their shareholders and the public. The latest Harvard study, however, specified that they could take no stance on the question of legal culpability.