UNITED NATIONS -- Secretary-General Ban Ki-moon opened the UN's climate-change summit with an appeal to the international community to act quickly on a draft proposal so a treaty might be signed at the UN climate conference in Copenhagen in December.
Ban asserted that "now is the moment to act in common cause."
"History may not offer us a better chance," he continued. "Distinguished leaders of the world, excellencies, ladies and gentlemen, I urge you to seal a deal in Copenhagen in December this year -- an equitable, scientifically robust deal that strengthens sustainable development and powers green growth for every country."
China was quick to respond. President Hu Jintao promised to slow the growth of his country's greenhouse gas emissions in the next decade, to generate 15 percent of its energy from renewable sources, and to plant enough trees to cover more than 300,000 square kilometers.
Hu acknowledged that "the common interests of the entire world" are at stake, and was met with agreement on this issue by U.S. President Barack Obama.
Obama also urged quick action on a global treaty and said his 9-month old administration has already taken action at home.
"It is true that for too many years mankind has been slow to respond or even recognize the magnitude of the climate threat," Obama said. "It is true of my own country as well. We recognize that. But this is a new day; it is a new era. And I'm proud to say the United States has done more to promote clean energy and reduce carbon pollution in the last eight months than at any other time in our history."
Pressure has been building for wealthier states -- attending both the UN summit and the G-20 economic summit in Pittsburgh on September 24 -- to make commitments to lowering greenhouse-gas emissions in 2013 and to give poorer nations the aid they need to avoid burning coal or cutting down forests for firewood.
"A deal must make available the full range of public and private resources so developing countries can pursue low emissions growth as well as adapt," Ban told participants.
Rajendra Pachauri, chairman of the UN Intergovernmental Panel on Climate Change, which shared the 2007 Nobel Peace Prize with former U.S. Vice President Al Gore, told the summit that if poorer nations don't receive help from their wealthier neighbors, at least a dozen of them would become "failed states."
Other poor countries, Pachauri said, would face the possibility of internal conflict because of soil degradation and a lack of food and clean water.
This summer, the EU committed to spending $15 billion annually for the next decade to help developing nations cope with the challenges of climate change and adapt their economies to be less polluting.
Pachauri said the international community faces a critical choice: Either take decisive action to confront climate change and enjoy tangible improvements in the world economy, or face the prospect that all humankind will live in a different kind of "failed state."
"Avoiding the impacts of climate change through mitigation of emissions would provide incalculable benefits including economic expansion and employment," Pachauri said. "If those in this august gathering do not act on time, all of us would become leaders and citizens of failed states, because we would be failing in our sacred duty to protect this planet."
The meetings in Copenhagen will last from December 7 to December 18, and wealthy and poor countries are still arguing about the levels of financial aid that will be needed.
Ban said it would be "morally inexcusable, economically short-sighted, and politically unwise" not to reach a comprehensive agreement in Copenhagen.
French President Nicolas Sarkozy proposed a preliminary meeting a month before the Copenhagen talks to make sure that a meaningful treaty can be reached.
Otherwise, Sarkozy said, the effort is bound to end in failure.