Exxon knew of climate change in 1981, email says – but it funded deniers for 27 more years

A newly unearthed missive from Lenny Bernstein, a climate expert with the oil firm for 30 years, shows concerns over high presence of carbon dioxide in enormous gas field in south-east Asia factored into decision not to tap it

ExxonMobil, the world's biggest oil company, knew as early as 1981 of climate change - seven years before it became a public issue, according to a newly discovered email from one of the firm's own scientists. Despite this the firm spent millions over the next 27 years to promote climate denial.

The email from Exxon's in-house climate expert provides evidence the company was aware of the connection between fossil fuels and climate change, and the potential for carbon-cutting regulations that could hurt its bottom line, over a generation ago - factoring that knowledge into its decision about an enormous gas field in south-east Asia. The field, off the coast of Indonesia, would have been the single largest source of global warming pollution at the time.