"The science is very clear -- it's loud, articulate and incontrovertible. On this basis I think it's time the world moved on," Pachauri told Reuters a day before he and climate activist Al Gore receive the 2007 Nobel Peace Prize in Oslo.

The IPCC has said action to curb greenhouse emissions are needed to avert irreversible changes in climate that would threaten those living in low-lying areas that could be engulfed by rising seas, endanger food and energy security and stoke more severe and less predictable weather the world over.

"You will never get a more robust set of conclusions and findings than what we have provided. If this doesn't move the world to action, then I don't know what will," Pachauri said.

"The time for contemplation and vacillation is over. Let's move on, and that's the decision we hope to get in Bali," Pachauri said, referring to talks in Indonesia on setting a timeframe for a new global deal on limiting emissions to replace the Kyoto Protocol which runs out in 2012.

Pachauri said if the world did not put in place a system to curb total emissions from 2015 a window of opportunity would close and leave the earth with dire consequences.

Pachauri said industrialised nations, the world's biggest polluters per capita, could not expect poorer countries to put aside their own aspirations for a better life.

"Developing countries need to be given time and space to develop. Even the poorest slum in any city of the developing world has a television set that shows life as it exists in the developed world, and that fuels aspirations and desires," he told a news conference with Gore.

"As long as you have this major divide you are not going to be able to influence people in developing countries to move away from what they have seen as the good life."

Both the western world and developing states must find their own sustainable paths of development, Pachauri said.

"I have no doubt that if the developed countries took the lead, you would get a measured and very clear response on the part of the developing countries as well," he said.