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Exxon scientists accurately predicted the pace and scale of climate change more than 40 years ago, according to a study that its authors say adds weight to claims the oil firm knew about and sought to downplay the risks posed by continued fossil fuel use.

Ů��С��Ƶs working for Exxon between 1977 and 2003 accurately forecasted the rate at which global average temperatures would rise as a result of carbon emissions, correctly predicted that human-caused global warming would first be detectable by around 2000 and reasonably estimated how much carbon dioxide would lead to dangerous warming, according to the study.

suggest Exxon, which became ExxonMobil in 1999, was aware of climate change in the 1970s and knew the threat could cause “dramatic environmental effects before the year 2050”.

But this is the first time Exxon’s quantitative climate projections have been assessed. , then at Harvard University, and his colleagues analysed all publicly available internal documents and research publications disclosed by the company between 1977 and 2014 to assess the accuracy of Exxon’s scientific predictions against both contemporary models and subsequent real-world changes in temperature.

The results were in line with scientific thinking at the time of writing, the team found. Meanwhile, 63 to 83 per cent of the projections were accurate in predicting subsequent rates of global warming.

“Most of Exxon’s projections accurately forecast warming, consistent with subsequent observations, but also, at least as skillfully as those of independent models,” says Supran. “Excellent scientists modelled and predicted global warming with shocking skill and accuracy, only for the company to spend the next couple of decades denying that very climate science.”

ExxonMobil is one of a number of oil companies in the US accusing them of seeking to conceal the true impact of fossil fuel use from the public.

For decades, Exxon executives argued in public that the science of climate change was still uncertain, with former CEO Lee Raymond warning in 2000 that research wasn’t robust enough to “justify drastic measures” to cut emissions. The firm has also been criticsed for .

Supran says Exxon took a “two-handed” approach to the issue of climate change. “In private and academic circles, they contributed quietly to climate science,” he says. “But at the very same time, and then thereafter, they contributed loudly to promoting doubts about that very science.”

In response to the findings, an ExxonMobil spokesperson denied accusations it had sought to cover up the science of climate change and said the firm is “committed to being part of the solution to climate change and the risks it poses”.

“Those who suggest ‘we knew’ are wrong,” he said in a statement. “Some have sought to misrepresent facts and ExxonMobil’s position on climate science, and its support for effective policy solutions, by recasting well intended, internal policy debates as an attempted company disinformation campaign.”

The spokesperson added: “ExxonMobil is actively engaged in efforts to reduce emissions while providing affordable energy to the communities that need it.”

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