The results suggest that, when it comes to the climate, both the doom-mongers and optimists are wrong. On the other hand, they have prompted a heated debate over how certain you can be about uncertainty.

‘People are quite rightly looking at what we’ve done, because we’re claiming quite a big reduction in uncertainty, based on a pretty simple analysis,’ said lead author Professor Peter Cox of the University of Exeter in the UK.

The climate is a complex beast. To make predictions about how much temperatures will rise in the future, scientists employ hugely detailed computer simulations, which rely on swathes of experimental data as input.

But there is a big unknown in these simulations: how much warming do you get for a certain amount of CO2? This simple parameter is known as the climate’s sensitivity, and it dominates our uncertainty about future global warming.

Normally, climate sensitivity is estimated…