UNITED NATIONS (Reuters) -- China and the United States, the world's top greenhouse gas emitters, will try to ignite efforts to secure a UN global warming pact as worries grow of a "dangerously close" deadlock in talks.
U.S. President Barack Obama and Chinese President Hu Jintao address a special UN summit just 2 1/2 months before representatives from 190 nations gather in Copenhagen to negotiate a deal to combat climate change.
Talks leading to the December meeting have not gone well.
Developed and developing countries are at odds over how to distribute emissions curbs while poorer nations press richer ones to contribute huge sums of money to help them cope with rising temperatures.
Obama and Hu, who are scheduled to meet one-on-one after the summit, could help break the climate impasse.
The Chinese leader, whose country is the world's biggest emitter of carbon dioxide and other climate-warming gases, is expected to lay out new proposals that may include a "carbon intensity" target -- a pledge to cut the amount of greenhouse gasses produced for each dollar of national income.
"This suite of policies will take China to be the world leader on addressing climate change," said Yvo de Boer, the UN climate chief, on September 21, anticipating the announcement.
An aggressive move by China to tackle its emissions -- even if short of an absolute cap -- could blunt criticism by leaders in Washington, many of whom are reluctant to commit to U.S. emission cuts without evidence that Beijing is doing the same.
Obama, whose legislative initiatives to reduce U.S. emissions have been overshadowed by his push for health-care reform, will try to fulfill his promise of showing leadership toward getting a global deal, even as chances that the U.S. Senate will pass a climate bill by December dim.
Martin Kaiser, climate policy director for environmental group Greenpeace International, said the president had allowed "vested interests" to undermine his promises so far.