Six big European oil and gas firms called on June 1st for a globally co-ordinated price on carbon-dioxide emissions, to restrain the impact on the climate of burning fossil fuels. It was a bombshell, in its way. Five years ago no one would have expected the move: as producers of much of the world’s dirty fuels, their industry was disinclined to join forces and advocate accelerating the switch to cleaner ones. “It is a sort of revolution,” says Patrick Pouyanné, the boss of one of the six, Total. And it is not just the energy firms. As world leaders prepare to meet in Paris in December to produce an agreement on reducing greenhouse-gas emissions, attitudes towards climate change have altered profoundly among businesses of all kinds.