AFP: Emerging economies must turn climate talk into action: EU

"The negotiating text is more than 250 pages long, has little structure and is peppered by (unagreed) elements in parentheses," one source said.

"There is no doubt that total agreement (in Copenhagen) will be impossible," he added.

What will be important is the number of points outstanding, the will to sort them out and the time it takes to do so, he underlined, as the Kyoto deal will last until 2013.

On Friday, Zhang Guobao, the head of China's National Energy Administration, said China will continue to rely on heavily polluting coal for most of its energy needs "for a long time."