Frustrated at past failures, climate negotiators began a critical two-week conference Monday with a call from Mexico's president to think beyond their nations' borders and consider all humanity as they bargain over an agreement to fight global warming.
"The atmosphere is indifferent to the sovereignty of states," President Felipe Calderon said in the keynote speech opening the conference in this well-guarded coastal resort.
"It would be a tragedy if our inability to see beyond our personal interests, our group or national interests makes us fail," Calderon said in a speech to 15,000 delegates, business leaders, activists and journalists.
Three years of talks have been stymied by a sometimes acrimonious divide among industrial and developing countries about their responsibilities in fighting climate change and accepting legal limits on how much they can continue to pollute.
The Cancun conference is the first full U.N. meeting since the letdown last December of the Copenhagen summit, which brought 120 world leaders to the Danish capital in an abortive attempt to adopt an overarching accord governing emissions of made-made greenhouse gases blamed for global warming.
Instead, that summit ended with a three-page political statement, including an intention to raise $100 billion annually to help poor countries fight the effects of climate change and move toward green development that does not rely on fossil fuels.
Adoption of the Copenhagen Accord was blocked by a half dozen countries, raising questions about whether the U.N. negotiations were capable of reaching any decisions by the rules of consensus requiring at least tacit agreement from every country.
The U.N. process "is growing increasingly irrelevant," Papua New Guinea delegate Kevin Conrad told the conference Monday, suggesting a rule change allowing for a vote on crucial issues as a last resort if a consensus proves out of reach. The proposal met swift objections and was referred to closed-door consultations.
The conference aimed to conclude an agreement on how to raise and distribute the funding agreed in Copenhagen, including $30 billion "fast-track funds" over three years up to 2012 to help poor countries prepare for climate change. It also hoped for an agreement on saving tropical forests and transferring green technologies to developing nations.
Christiana Figueres, the top U.N. climate official, said the conference also should clarify the future of the Kyoto Protocol, the 1997 accord that required industrialized countries to reduce carbon emissions by a total 5 percent by 2012. No arrangements have been made for what happens when Kyoto's terms expire.
She said delegations should formalize commitments they submitted after Copenhagen to reduce emissions or constrain their growth. Those commitments, which fall far short of reductions scientists say are necessary, have no legal standing.
"Cancun will not solve everything," Figueres told reporters. But "the outcome needs to be pragmatic."
The talks end next week with three days of meetings among government ministers. About 25 heads of government or state also will attend, but neither President Barack Obama nor Chinese Premier Hu Jintao, two key players, will be among them.
Jonathan Pershing, the U.S. deputy special envoy for climate change, said Energy Secretary Steven Chu and Agriculture Secretary Tom Vilsak will join the conference next week.
Pershing said some of the differences between the U.S. and China appear headed toward a resolution.
"My sense is we have made progress. It remains to be seen how this meeting turns out," he told reporters.
He acknowledged that Cancun can produced a balanced set of agreements only if the U.S. and China are in accord.
A plague of natural disasters this year added urgency to the talks. Floods in Pakistan, a Russian heat wave that choked Moscow in smoke from forest fires, and global temperatures at least matching the highest ever recorded provided a grim background.
"Climate change is beginning to make us pay for the fatal errors we as humanity have committed against the environment," Calderon said. Mexico this year suffered the worst drought in six decades followed by intense rain and hurricanes that killed 60 people and displaced thousands, he said.
Continued emissions of carbon and other gases that trap heat in the atmosphere increases the risk of reaching "tipping points" that could bring dramatic changes, like the drying up of the Amazon rain forest or the disruption of India's vital monsoon rains, said Mario Molina, the Mexican scientist who won the 1995 Nobel Prize in chemistry for his studies of the ozone layer.
"Such catastrophes will have devastating effects" for perhaps billions of people, he warned.
The tools are at hand to limit the planet's warming at little cost, he said, but it could mean "astronomical costs for future generations" if nothing is done.