The final collapse of the Doha Round of world trade talks, after seven years of immense effort, may cost the global economy only one tenth of 1 per cent, estimates suggest. But that is still valuable growth forgone. Even greater was the deal’s value as a bulwark against protectionism – and as a model for formidable climate change talks ahead.

There is, rightly, a huge sense of loss among those involved after Tuesday’s announcement that agreement was impossible. The overeloquent blog by Peter Mandelson, the European Union Trade Commissioner (which ends with his exhausted team walking by Lake Geneva just before midnight, enjoying “the quiet and the cool presence of the water”), captures the surge of hope and then the shattering deflation. It would be wrong now to accept either of the comforts on offer: the argument that small, bilateral deals will compensate (unlikely); or that poor farmers would have suffered from Doha (some would, but more should have been helped).

But the lament, while justified, does not get you far. One lesson may be that farming is so politically charged that it will make giant pacts impossible until those profound societal shifts have happened. Less contentious deals (such as trade in environmental products, and giving poor countries exemption from some duties and quotas) may still be salvaged from the wreckage. That is worth doing.

The trade talks that began in Doha, Qatar, in 2001, covering 153 countries and most of the kinds of goods traded in the world, were always difficult. They marked the coming of age of the giants of the developing world: India, China and Brazil. The talks, with the explicit aim of helping the development of poorer countries, tried to break out of the old model where the most powerful economies set the terms.

In tone they succeeded, with the new giants asserting themselves as equals. What was missing was agreement – although on the most important points, by the end, that was there. Last week raised hopes of a successful climax, and then the talks crashed on one dispute between three countries. India and China felt they were not able to protect small farmers under the terms of opening markets to the US. America refused to give the assurances they demanded, on the principle that it would give up farm subsidies only in return for access.

That narrow issue is worth almost nothing to the world economy, compared with the talks overall. EU and World Trade Organisation estimates reckon that a Doha deal could have saved consumers and firms more than $100 billion in taxes; economists put the benefit at perhaps 0.1 per cent of the world’s gross product. That sounds like small beer, but at a time of faltering growth it is a real loss.

It would be wrong to demonise India and China. They had a point about their vulnerability, although it may prove shortsighted as their societies shift more to manufacture and services. But in a competition for stubbornness, the US wins on points. Its unyielding defence of its own farmers (Congress has just approved more subsidies) was an insurmountable hurdle.

The best that can be done now is to salvage some “side deals” within Doha; to try to preserve the spirit of free trade against protectionism; and for the US and EU to use high food prices to cut farm subsidies. And not to assume that the failure of these talks, huge in scope and endlessly shifting in details, implies failure for talks on climate change.

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