Tiny Tuvalu drove a wedge in the bloc of developing nations at UN climate talks on Wednesday by calling on China, India and other emerging giants to take on legally binding commitments to slash CO2 pollution.

Through an arcane diplomatic manoeuvre, the Pacific archipelago cracked a diplomatic axiom that has prevailed since the UN climate convention came into being in 1992: rich countries caused global warming, and it was their responsibility to fix it.

On the third day of the December 7-18 negotiations, Tuvalu proposed opening discussions on a "legally binding amendment" to the Kyoto Protocol that would set targets for the reductions of greenhouse gas emissions for major emerging economies starting in 2013.

But the move was blocked by China, India, Saudi Arabia and other large developing countries.

"The constraints would mostly remain on developed countries but also, partly, on big developing economies as well," Taukiei Kitara, head of Tuvalu's delegation, told AFP.

Kitara acknowledged that the proposal constituted the first serious breach in the up-to-now united front of the "G-77 plus China," a bloc of 130 developing nations.

"We know the implementation of the Kyoto Protocol is not complete and we want to create an impulse for a stronger commitment," Kitara said, referring to the landmark treaty that imposes emissions cuts on rich nations up to 2012.

Today more than half of global carbon pollution comes from developing countries, led by emerging giants China, India and Brazil, and the proportion is set to rise as their high-population economies grow.

The 42-member Alliance of Small Island States (AOSIS), including Tuvalu, and the bloc of mainly African Least Developed Countries, have rejected the widely held goal of keeping global temperatures from rising more than 2.0 degrees Celsius as inadequate.

Only a cap of 1.5 C compared to pre-industrial times would give these nations a chance of fighting off rising seas or crippling drought, they say.

ARCHBISHOP Desmond Tutu and former Irish President Mary Robinson have lead a candlelight vigil at the Copenhagen climate conference.
Their actions came after a mass demonstration marred by some violent incidents marked the half way point in the rocky negotiations to reach a global climate deal.

“We want to remind you that they marched in Berlin and the wall fell. They marched in Cape Town and apartheid fell. They marched in Copenhagen and we are going to get a real deal,” Archbishop Tutu told the gathering.

Organisers claimed 100,000 participated in the largely peaceful protest, but Danish police estimated the numbers at closer to 30,000. The protest was the centre-piece of a global day of action, which began with rallies in Australia.

But anti-capitalist protesters have also flocked to the Danish capital alongside the environmental activists and several hundred black-clad demonstrators were arrested during violent incidents in the streets of the capital.

“We can't change the science, we have to change the politics _ and if we can't change the politics, we have to change the politicians,” Kumi Naidoo, the new head of Greenpeace International, told the main Copenhagen rally.

With the negotiations still grid locked and progress in the first week very slow, the leaders of the negotiations were painfully aware of the bitter disappointment and political consequences if the talks failed, after expectations had been raised so high around the world.

Asked whether the disappointment in civil society played on negotiators' minds, Danish environment minister and conference chair Connie Hedegaard said: “I am absolutely sure that leaders consider that very much, and personally I think it has taken years to build up the pressure we have seen around the worldand I believe that has contributed to making the political price for not delivering in Copenhagen very high.”

The executive secretary of the United Nations convention on climate change, Mr Yvo de Boer, who met demonstrators outside the conference centre to receive climate messages from the sails of ships that yesterday entered Copenhagen Harbour, said that outside the conference the people of the world were “making their voices heard".