Warning that the climate change was posing "existential" threat to several small countries, they said a global solution "is central to the survival of peoples, the promotion of development and facilitation of a global transition to a low emission development path."

Noting that the grouping represents one-third of the world's population, a declaration issued at the end of the two-day Commonwealth Heads of Government (CHOGM), attended by Prime Minister Manmohan Singh among others, said that "internationally legally binding agreement is essential" and its voice has to be heard at Copenhagen.

The agreement at the December 7-18 Copenhagen summit "must address the urgent needs of developing countries by providing financing, support for adaptation, technology transfer, capacity building, approaches and incentives for reducing emissions from deforestation and forest degradation, and for afforestation and sustainable management of forests," it said.

"We need an ambitious mitigation outcome at Copenhagen to reduce the risks of dangerous climate change without compromising the legitimate development aspirations of developing countries. We stress our common conviction that urgent and substantial action to reduce global emissions is needed...," the declaration said.

Prime Minister Singh had yesterday told the delegates to the Commonwealth summit that India is willing to sign on to an ambitious global target for emission reduction or limiting temperature increase if it is accompanied by an equitable burden-sharing paradigm.

Pushing for a legally binding substantive outcome at Copenhagen, Singh denounced attempts by some developed nations to junk the Kyoto Protocol on greenhouse gas emissions and said climate change "is becoming the pretext for pursuing protectionist policies under a green label" which would be rejected by India and other developing nations.

Voicing concern over the "undisputed threat" posed by the climate change to the security, prosperity, economic and social development of people, the Commonwealth said "we pledge our continued support to the leaders-driven process ... to deliver a comprehensive, substantial and operationally binding agreement in Copenhagen leading towards a full legally binding outcome no later than 2010."

In addition, the Commonwealth backed a multi-billion-dollar initiative to help developing countries deal with the climate change. The fund, proposed by the UK and France would start next year and build to a level of USD 10 billion annually by 2012.

"We welcomed the initiative to establish, as part of a comprehensive agreement, a Copenhagen Launch Fund starting in 2010 and building to a level of resources of $10 billion annually by 2012. Fast start funding for adaptation should be focussed on the most vulnerable countries.

"We also recognise the need for further, specified and comparable funding streams, to assist the poorest and most vulnerable countries, to cope with, and adapt to the adverse impacts of climate change. We recognise that funding will be scaled up beyond 2012," the declaration said.

The Commonwealth asked the developed nations to continue to lead on cutting their emissions and emphasised that the developing countries, in line with their national circumstances, should also take action to achieve a substantial deviation from "business-as-usual emissions".

"Science, and our own experience, tells us that we only have a few short years to address this threat. The average global temperature has risen because of the increase in carbon and other greenhouse gas emissions.

"The latest scientific evidence indicates that in order to avoid dangerous climate change that is likely to have catastrophic impacts we must find solutions using all available avenues. We must act now," the Port of Spain Climate Change Consensus stated.