The prospect of a global deal to combat climate change has been receding for two years. The latest round of talks in Durban has so far done little to reverse this. Barely a year before the main provisions of the Kyoto protocol are due to expire, delegates are deadlocked on the issue that has bedevilled climate talks for a decade: should the international community agree on legally binding carbon emissions targets, or will voluntary pledges by individual states suffice?

Legal commitments are clearly preferable. They make it more likely that countries will actually follow through on their promises. And by providing a degree of predictability in policy, they make it easier for businesses to decide to invest in green technologies.

Persuading nearly 200 countries to agree such a deal would be a challenge in good times. With the world economy in poor shape, it is all but impossible. Leadership is conspicuously absent. The US is doing its best to escape binding commitments. Despite its mushrooming economic clout, China, the world’s largest carbon emitter, insists that it should be regarded as a developing country, and thus exempt from binding targets.