NEW DELHI/LONDON (Reuters) – China and other big developing nations rejected core targets for a climate deal such as halving world greenhouse gas emissions by 2050 just five days before talks start in Copenhagen, diplomats said on Wednesday. China, the world's top emitter, together with India, Brazil and South Africa demand that richer nations do more and 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...