Saying the health of the planet is at stake, UN Secretary-General Ban Ki-moon urged 190 nations meeting in Mexico on Tuesday to agree to steps to fight climate change that fall short of a perfect deal.
"We cannot let the perfect be the enemy of the good," Ban told a first session of environment ministers at the 29 November to 10 December talks in the Caribbean resort of Cancun, where rich and poor nations are divided over cutting greenhouse gas emissions.
After US President Barack Obama and other leaders failed to work out a UN climate treaty at a 2009 summit in Copenhagen, Ban repeatedly stressed lower ambitions for the Cancun talks despite calls by some nations for radical action.
Ban told the ministers: "The stability of the global economy, the well-being of your citizens, the health of our planet, all this and more depend on you."
The Cancun talks are seeking a package deal to set up a fund to oversee climate aid, ways to slow deforestation, steps to help poor countries adapt to climate change and a mechanism to share clean technologies such as wind and solar power.
Some developing nations, with Bolivia the most outspoken, have said that far more radical action by the rich is needed now to cut greenhouse gas emissions and deadly floods, droughts, desertification and rising sea levels.
Speaking on behalf of Africa, Ethiopian Prime Minister Meles Zenawi said he was "deeply dismayed" by the loss of momentum since Copenhagen. "Every day of delay is being paid for by the lives of countless numbers of Africans," he said.
About 1500 people marched in Cancun in protest the low ambitions of the talks and dumped buckets of animal excrement in the street. Overnight, some protesters threw eggs at riot police and defaced a fast-food restaurant.
Developed and developing countries are most split about the future of the UN's 1997 Kyoto Protocol, which obliges almost 40 rich nations to cut emissions by an average of 5.2 percent below 1990 levels in the five-year period 2008-12.
"The Kyoto Protocol issue continues to be very tough. It's not clear whether it's resolvable," US climate envoy Todd Stern told a news conference. He said that the Kyoto dispute was distracting time from other parts of the negotiations.
The United States is the only rich nation outside of the Kyoto Protocol after arguing that the treaty wrongly omitted targets for 2012 for developing nations and would cause US jobs losses. The US absence is a core part of the problem in designing a new deal.
Japan, Russia and Canada have been adamant that they will not approve an extension to Kyoto when the first period runs out in 2012. They want a new, broader treaty that will also bind the United States and emerging powers like China and India to act.
Asked if Japan might ever agree to extend Kyoto, Akira Yamada of Japan's foreign ministry told Reuters: "Yes. If US, China and other major emitters become Annex One countries." Annex One lists rich nations bound by Kyoto.
Many rich countries, suffering weak growth and budget cuts, want emerging economies led by fast-growing China and India to do far more to reflect their growing power, including greater oversight of their curbs on greenhouse gas emissions.
Developing states say rich nations have emitted most greenhouse gases since the Industrial Revolution and must extend Kyoto before poor countries sign up for action. Kyoto underpins carbon markets guiding a shift away from fossil fuels.
Christiana Figueres, head of the UN Climate Change Secretariat, said positions were "diametrically opposed" and the future of Kyoto was not due to be decided in Cancun.
"Germans have a wonderful word 'yein' which means both 'yes' and 'no' and I think that's the kind of attitude countries are now engaged in," she said.
A UN report showed that residents of the Himalayas and other mountain areas face a tough and unpredictable future as global warming melts glaciers and threatens worse floods.
