Copenhagen, Dec 14 : Grassroots action, especially by the youth, will have to solve the climate change problem as the "nation state does not seem capable" of doing it, Rajendra Pachauri said here Monday, as the Dec 7-18 climate summit got bogged down in yet another round of bickering between governments.

The head of the Intergovernmental Panel on Climate Change (IPCC) told youth NGO groups: "Politicians can only be aroused by each one of you. Spread knowledge about the science of climate change".

On a day when a treaty to tackle climate change looked further than ever, Pachauri urged the youth: "You may lose a great deal but don't lose hope". In reply to a question from a despondent activist, he said: "Not having a legally binding agreement is positive. Copenhagen cannot and should not be the end of the world."

But he did regret that negotiations towards a possible treaty between the 192 governments gathered here were "becoming solely political, and there's no discussion on the science. I hope some negotiators at least have taken positions based on IPCC findings."

The benchmark 2007 report of the IPCC brought global attention to the threats of climate change - lowered farm output, more frequent and more severe droughts, floods and storms and a rise in sea level.

Pachauri said: "The impacts of climate change are becoming progressively more serious and in several parts of the world can possibly pose a threat to peace and stability. On the other hand, the cost of taking action are very low and there are huge co-benefits." (IANS)