President Barack Obama told a special U.N. summit on climate change the United States understands the gravity of the problem and is determined to act. The U.N. meeting, which brought together about 100 world leaders, is aimed at advancing lagging negotiations in advance of a critical conference on global warming at year's end in Copenhagen.
The summit speech was the U.S. president's first address to the world body and he used the message to reassure delegates that the United States, which shunned the 1997 Kyoto climate pact, is determined to make the successor Copenhagen process a success.
Mr. Obama provided no new proposals. But he said the United States and other developed economies, which caused much of the damage to the world climate over the last century, have a responsibility to lead.
He said the fast-growing developing nations, which will produce almost all the growth in global carbon emissions in the decades ahead, must do their part as well.
With the world economy mired in recession, Mr. Obama said there should be no illusion that producing the sweeping changes needed for success at Copenhagen will be easy.
"But I am here today to say that difficulty is no excuse for complacency," the president said. "Unease is no excuse for inaction. And we must not allow the perfect to become the enemy of progress. Each of is must do what we can to grow our economies without endangering our planet, and we must do it together. We must seize the opportunity to make Copenhagen a significant step forward in the global fight against climate change."
U.N. Secretary-General Ban Ki-moon opened the meeting with an appeal to accelerate the lagging pace of pre-Copenhagen negotiations. He said that failure to reach broad agreement in the Danish capital in December would be morally inexcusable, economically-short sighted and politically unwise.
But perhaps the most forceful appeal for action came from President Mohamed Nasheed, of the Indian Ocean's Maldives islands, large parts of which are little more than a meter above sea level and which stand to be swamped by rising waters if global warming is not checked.
Mr. Nasheed said he and his countrymen are frustrated over international gatherings that feature verbal pledges for climate change action, but afterwards the delegates drift away, empathy for the plight of the Maldives fades, and there is return to business-as-usual.
"If things go business-as-usual, we will not live, we will die," he said. "Our country will not exist. We cannot come out from Copenhagen as failures. We cannot make Copenhagen a pact for suicide. We have to succeed and we have to make a deal in Copenhagen."
Negotiators hope the Copenhagen meeting will produce specific limits for overall emissions by developed countries, and specific goals for cuts in the rate of growth of carbon output by the developing nations.
Chinese President Hu Jintao, whose country, like the United States accounts for one-fifth of all world greenhouse gas pollution, announced a set of specific emissions curbs.
"We will endeavor to cut carbon dioxide emissions per unit of GDP by a notable margin by 2020 from the 2005 level," he said. "Second, we will vigorously develop renewable energy and nuclear energy. We will endeavor to increase the share of non-fossil fuels in primary energy consumption to around 15 percent by 2020."
New Japanese Prime Minister Yukio Hatoyama reaffirmed his campaign pledge for Japan to reduce its greenhouse gas emissions 25 percent from 1990 levels by 2020.
Environmental activists hope momentum from Tuesday's one-day climate summit will spur climate treaty negotiators who convene again next week in Bangkok.