Denis Meyer/Hans Lucas
Headlines this week proclaimed the worst-case scenarios for climate change were “debunked” and “not credible”. As you might expect, things aren’t that simple.
The stories were sparked by a study by Peter Cox at the University of Exeter, UK, and his colleagues, who attempted to work out how much warming will result from a given increase in carbon dioxide levels. Specifically, if we doubled CO2 levels in the atmosphere and waited for the temperature to stabilise, how much would the world warm?
This is known as the equilibrium climate sensitivity, and climate scientists have been trying to work it out for decades. Hundreds of studies have produced a wide range of results, which means there is a lot of uncertainty, but the consensus says 1.5 to 4.5°C is most likely.
Cox’s study narrows this to between 2.2 and