A legally-binding international treaty may not be the best way to tackle climate change.
Leading economist Lord Nicholas Stern said that a commitment to sustainable development was more important than a binding deal that “lacked credibility”.
He was speaking in Lima, Peru, where negotiators from 194 countries are heading into a second week of UN talks.
They hope to agree a text that would form the basis of new global compact, to be signed in Paris next year.
Many developing countries support a legally binding deal that would be structured in a similar way to the Kyoto Protocol, signed back in 1997.
One key element of that agreement was that countries faced sanctions if they failed in their commitments to cut carbon.
According to Lord Stern, a deal in Paris would work better if it steered away from this format.
“Some may fear that commitments that are not internationally legally-binding may lack credibility,” he said.
“That, in my view, is a serious mistake. The sanctions available under the Kyoto Protocol, for example, were notionally legally-binding but were simply not credible and failed to guarantee domestic implementation of commitments.”
In Lima, negotiators are trying to hammer out the format that mitigation efforts should take. By the end of March next year countries have to declare their hands, but they have yet to formalize what will be included in these commitments and what will not.
Lord Stern believes that grounding the process in the laws and promises that countries undertake by themselves is a better model for a deal than a top-down process like Kyoto.
“It will be enforceable and deliverable through the arrangements and laws in the countries themselves.
“That way you will get stronger ambition as countries won’t be tempted to be hesitant about some type of international sanction.”
While the European Union has stated that it is committed to legally binding mitigation targets, other countries have sought different formats.
According to US special envoy on climate change, Todd Stern, the US is unhappy with the prospect of a legally binding deal, knowing that getting it ratified in the Senate would be an uphill battle.
“Proposals that would involve, in effect, a kind of designated burden-sharing on how reductions should be split up among countries of the world has extremely little chance of political viability,” he said, speaking to reporters last month.