The science on global warming is now incontrovertible: the climate is changing, man is helping to make that happen, and the damage could be irreversible. But the contest over the economics of what to do about this is open, or at least was until the UK government published its big study chaired by Sir Nicholas Stern. This report rebuts any fatalistic notion that the world would do better to spend its economic resources just adapting to inevitable climate change, a counsel of despair. Instead, the Stern review suggests that the economic benefits of early action to curb greenhouse gases would far outweigh the costs – by eventually as much as $2.5 trillion a year.

So for the first time we have, spelt out in copious detail over some 600 pages, an economic rationale for action on climate change. It bills itself somewhat optimistically as “a pro-growth strategy”, when in fact it is more a strategy to protect growth from the catastrophic fall it could eventually suffer from higher temperatures around the world. But the report will serve a valuable purpose if it can convince the US, China and India – the three big economies that lie outside the Kyoto protocol on climate change – that growth is compatible with international action to cut carbon emissions. It is by its effect on these three countries particularly that the Stern review must finally be judged.