The COP15 climate talks famously failed to reach such a result but, said Lord Stern, it is imperative that an explicit political deal is thrashed out at the next UN climate conference, to be held at the Mexican resort.

“World leaders should achieve a strong political agreement that builds on the Copenhagen Accord, which has become a platform for going forward,” he said.

“More than 100 countries have now associated themselves with the Accord, and countries that are together responsible for more than 80 per cent of global annual emissions of greenhouse gases have made pledges.

“The agreement must recognise the size of the reductions in global annual emissions that are required over the coming decades to provide a reasonable chance of avoiding a warming of more than 2˚C above pre-industrial levels, which was the overall target set in the Accord.

“Global emissions must peak within the next decade and fall to 10% lower than today by 2020. Emissions should be more than 60 per cent lower than now in 2050, and rich countries must cut emissions much more strongly than this.

“In addition, the agreement should set out how US$30bn will be provided to developing countries over the next three years to assist them with making the transition to low-carbon economic development and growth, and to adapt to those impacts of climate change that cannot now be avoided.

“It should also indicate how this initial support will be increased to a level of US$100 billion per year by 2020, in particular by introducing new and innovative sources of funding.

“With explicit political agreement in Cancún on these crucial issues and key details, we should have the basis for an international treaty which could be signed at the United Nations climate change conference in South Africa at the end of 2011.

“Whilst progress is being made on finance and forestry, it is urgent to move quickly as well on technology development and sharing, and on the monitoring of emissions reductions.”

Sam Bond

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