An analysis of nearly 200 climate change documents spanning almost 40 years of ExxonMobil communications has found that the company consistently and systematically misled the public on climate change. The peer-reviewed study conducted by science historians Geoffrey Supran and Naomi Oreskes, discovered huge discrepancies between public statements made by the oil and gas giant denying and casting doubt over climate change and internal communications that acknowledge a changing climate. A series of media reports in 2015 claimed that the company has engaged in decades of climate denial, even when its own researchers were working to confirm the science. Supran and Oreskes sifted through 187 climate change communications released by the company between 1977 and 2014, confirming that, as the communications became more publicly accessible, the tone on climate change — whether it was real, human-caused, and a serious issue — underwent a serious shift. They found that around 80 percent of internal documents acknowledged that climate change is real and human-caused, while 81 percent of the company's advertorials expressed doubt. The researchers are not suggesting that ExxonMobil suppressed, withheld, or hid climate change from the public, but that they consistently misled the public about climate change and its causes, and did so for decades. To find out more check out Assessing ExxonMobil's climate change communications (1977–2014).