Environmentalists rejoice: ExxonMobil is on your side. Well, sort of. In his characteristically plain-speaking way, Rex Tillerson, Exxon’s chief executive, last week set out a view of climate change that could not have been more clear: the planet is warming because of carbon dioxide emissions from burning fossil fuels.

Before they get too excited about the repentant sinner, though, environmentalists should follow the rest of his argument. Mr Tillerson sees climate change as a “manageable” problem, best addressed not by trying to stop it but by adapting to it: re-engineering our societies and economies so that they are able to withstand a warmer world.

He makes some valid points, in particular about the drawbacks of many renewable energy technologies and the difficulties in finding substitutes for fossil fuels. Yet his answer is incomplete.