The UN’s annual climate conference began in the steamy South African city of Durban on Monday amid signs of deep discord over how countries should curb their carbon emissions.

The gathering comes 12 months before the expiry of the main provisions of the 1997 Kyoto protocol, the world’s only comprehensive treaty that legally obliges countries to cut emissions.

Developing countries, exempt from the pact, insist the wealthy countries that signed up for the first phase of Kyoto must make fresh pledges to cut emissions at the conference, which runs until December 9.

But only the European Union and a small group of other industrialised countries have said they were willing to consider a second phase of Kyoto. Even they say they would not do so unless all countries agreed to consider some form of legally binding reductions at some point, including China, which overtook the US to become the world’s biggest emitter in 2007.

“The world economy of 2011 is simply not like it was in 1997 when the Kyoto protocol was done,” said Connie Hedegaard, EU climate commissioner.

EU countries accounted for just 11 per cent of global emissions, she said, while China contributed 24 per cent and had higher emissions per head than some European nations.

But at Durban’s sprawling convention centre there was little evidence of a shift within the two countries whose differences have long dogged the negotiations – China, and the US, which signed but never ratified the Kyoto pact. “I’m not sure that the issue of legal form will be resolved here, or needs to be resolved here,” said the US deputy envoy for climate change, Jonathan Pershing.

He pointed to the last UN summit in Cancún, Mexico, where countries accounting for some 80 per cent of global emissions formally agreed to make voluntary pledges to curb their carbon pollution up to 2020, without a legally binding treaty.

“To my way of thinking, that’s an enormous way forward in solving the problem,” he said. However, Su Wei, Chinese negotiator, told state radio that while the EU had put forward a proposal to extend Kyoto, “the prospects are not very optimistic” at Durban.

The possibility of the summit collapsing into acrimonious disagreement is weighing on its South African hosts. “With sound leadership, nothing is impossible here in Durban,” said Jacob Zuma, president.