The Harvard study could add to the controversy and legal scrutiny surrounding Exxon's (XOM) handling of climate change.
Exxon dismissed the Harvard study as "inaccurate and preposterous," saying in a statement that the research was "paid for, written and published by activists.".
The study found that the more public-facing the Exxon communication, the more doubt it expressed about climate change.
The Harvard study found that Exxon did not "suppress" climate science as some have alleged.
Exxon rejected the findings, noting that in 2000, it published two op-eds that said climate change may pose a "legitimate long-term risk.".
"Our statements have been consistent with our understanding of climate science," Exxon said, adding that the "risk of climate change is clear and warrants action.".
Exxon is being investigated by New York Attorney General Eric Schneiderman over allegations it concealed the risk of climate change. »