China, the world's largest emitter of greenhouse gases, has lauded the outcome of a historic UN climate conference that ended with a nonbinding agreement that urges major polluters to make deeper emissions cuts - but does not require it.
Foreign Minister Yang Jiechi said the international climate talks that brought more than 110 leaders together in Copenhagen produced "significant and positive" results.
The Obama administration on Sunday also defended the agreement as a "great step forward" - despite widespread disappointment among environmentalists that the pact does not include mandatory targets that would draw sanctions.
"Nobody says that this is the end of the road. The end of the road would have been the complete collapse of those talks. This is a great step forward," White House adviser David Axelrod told CNN's State of the Union show.
Disputes between rich and poor countries and between the world's biggest carbon polluters - China and the United States - dominated the two-week conference.
Tens of thousands of protesters took to the streets to demand action to cool an overheating planet. The meeting ended Saturday after a 31-hour negotiating marathon, with delegates accepting a US-brokered compromise.
The so-called Copenhagen Accord calls for reducing emissions to keep temperatures from rising more than 2degC above preindustrial levels.
It gives billions of dollars in climate aid to poor nations but does not require the world's major polluters to make deeper cuts in their greenhouse gas emissions.
UN Secretary-General Ban Ki-moon said he would work with member states to convert the commitments into a global, legally binding treaty as soon as possible in 2010.
But the international response was not all rosy.
Former Cuban president Fidel Castro said the agreement was "undemocratic" and called President Barack Obama's address to the conference "misleading."
In one of his regular essays, Castro wrote that only industrialised nations could speak at the summit, while emerging and poor nations only had the right to listen.
Bolivian President Evo Morales urged the world to mobilise against the failure of the Copenhagen summit and said that he would organize an alternate climate conference.
German Chancellor Angela Merkel, however, defended the outcome as a first step toward "a new world climate order."
The Bild am Sonntag newspaper quoted her as saying that "anyone who just badmouths Copenhagen now is engaging in the business of those who are applying the brakes rather than moving forward."
China's Yang said the outcome upheld the principle of "common but differentiated responsibilities" recognized by the Kyoto Protocol, and made a step forward in promoting binding emissions cuts for developed countries and voluntary mitigating actions by developing countries.
Under the 1997 Kyoto Protocol - that was rejected by the US - 37 industrial nations were already modestly cutting back on their emissions of greenhouse gases.
Under the new, nonbinding agreement, those richer nations, including the US, are to list their individual emissions targets, and developing countries must list what actions they will take to reduce the growth in their global warming pollution by specific amounts.
"Developing and developed countries are very different in their historical emissions responsibilities and current emissions levels, and in their basic national characteristics and development stages," Yang said in a statement. "Therefore, they should shoulder different responsibilities and obligations in fighting climate change.
"The Copenhagen conference is not a destination but a new beginning," Yang said.
China has said it will rein in its greenhouse gas output, pledging to reduce its carbon intensity - its use of fossil fuels per unit of economic output - by 40 to 45 percent.
The European Union has committed to cutting emissions by 20 percent by 2020, compared with 1990 levels; Japan to 25 percent, if others take similar steps, and the US provisionally to a weak 3 to 4 percent.
The Copenhagen Accord emerged principally from Obama's meeting with Chinese Premier Wen Jiabao and the leaders of India, Brazil and South Africa. But the agreement was protested by several nations that demanded deeper emissions cuts by the industrialised world.
Its key elements, with no legal obligation, were that richer nations will finance a $US10 ($NZ13.79) billion-a-year, three-year program to fund poorer nations' projects to deal with drought and other impacts of climate change, and to develop clean energy.
A goal was also set to mobilize $100 billion a year by 2020 for the same adaptation and mitigation purposes.
In a US concession to China and other developing nations, text was dropped from the declaration that would have set a goal of reducing global emissions by 50 percent by 2050.
Developing nations thought that would hamper efforts to raise their people from poverty.
Despite the lack of mandatory targets, Axelrod defended the agreement and credited Obama's leadership for winning the cooperation of other major economies.
"Now, China, India have set goals. We're going to be able to review what they're doing. We're going to be able to challenge them if they don't meet those goals. We're going to pursue this anyway, because the president understands that our future lies with a clean energy economy," he said.
