Developing countries, including China and India, are unwilling to sign up to a new global climate change pact to replace the Kyoto protocol in 2012 because the rich world has failed to set a clear example on cutting carbon emissions, according to the United Nation's top climate official.

Rajendra Pachauri, head of the Intergovernmental Panel on Climate Change (IPCC), said too many rich countries, including the US, had failed to take the action needed to convince the developing nations to sign up to a deal in Copenhagen next year that could help to stabilize global emissions.

"You may not be able to get an agreement in one shot, let's say by Copenhagen, that sets you on the path of stabilization in keeping with some kind of long-term target," Pachauri told the Guardian. "Looking at the politics of the situation, I doubt whether any of the developing countries will make any commitments before they have seen the developed countries take a specific stand."