China and other big developing nations have rejected core targets for a climate deal such as halving world greenhouse gas emissions by 2050 just days before talks start in Copenhagen, it has been revealed.

The world’s top emitter China, together with India, Brazil and South Africa demand that richer nations do more. They have drawn ‘red lines’ limiting what they themselves would accept, the diplomats told Reuters.

The four rejected key targets proposed by the Danish climate talks hosts in a draft text – halving global greenhouse gases by 2050, setting a 2020 deadline for a peak in world emissions, and limiting global warming to a maximum 2°C above pre-industrial times, European diplomats said.

“We cannot agree to the 50/50 (halving emissions by 2050) because it implies that the remaining [cuts] must be done by developing countries,” South Africa’s chief climate negotiator Alf Wills said, reports Reuters.

The dispute underscored a rich-poor rift, which has haunted the two-year talks to agree a new global climate deal to succeed the Kyoto Protocol in 2013 and dampens hopes of rescuing the December 7-18 Copenhagen summit, writes Reuters.