In late February Peter Coates, Glencore’s non-executive director, appeared at an event in Sydney to make a rare intervention from a mining leader — a full-throated defence of the coal industry, whose very existence is under threat because of its role in global warming.

“Our industry has allowed itself to be cast as the villain too often,” said Mr Coates, a veteran coal executive, at the mining industry event. “We have allowed the vacuum, about what we do and how we do it, to be filled by celebrity scientists and radical activists whose purpose is not to seek solutions but to divide and destroy.”

Six months later, the industry decided to take action to improve the image of the dirty fuel. Coal21, an industry body in Australia that is backed by 26 mining groups including BHP, Anglo American and Glencore, launched a new $4m advertising drive. It issued a tender for a campaign on Australian TV, social media, radio and print advertising, according to a document seen by the FT.