Obama: 'Meaningful breakthrough' on climate change

The official spoke on condition of anonymity in order to be able to talk about the sensitive diplomatic events of the day.

Late in the evening, Obama and Secretary of State Hillary Rodham Clinton held talks with European leaders, including British Prime Minister Gordon Brown, French President Nicolas Sarkozy and German Chancellor Angela Merkel. Asked how negotiations were going as he entered the meeting, Obama replied: "Always hopeful."

The direct talks between Obama and Wen underscored efforts to resolve differences that represent one of the major roadblocks in reaching a global climate deal. The U.S. has been insisting that China, the only nation that emits more heat-trapping gasses than the U.S., make its emissions-reduction pledges subject to international review.

Hours before his announcement of the limited agreement, without mentioning China specifically, Obama said, "I don't know how you have an international agreement where we all are not sharing information and making sure we are meeting our commitments. That doesn't make sense. It would be a hollow victory."

Obama indirectly acknowledged that some nations feel the United States is doing too little to reduce greenhouse gas emissions, and he urged leaders to accept a less-than-perfect pact. Meanwhile, he offered no new U.S. concessions.

"No country will get everything that it wants," Obama said.

It's possible that Obama's biggest success here will have nothing to do with the climate. He met with the Russian president and said afterward that the United States and Russia are "quite close" to a new nuclear arms control agreement to replace an expired Cold War-era arms control treaty.

The U.S. commitment to reduce greenhouse gasses mirrors legislation before Congress. It calls for 17 percent reduction in such pollution from 2005 levels by 2020 — the equivalent of 3 percent to 4 percent from the more commonly used baseline of 1990 levels. That is far less than the offers from the European Union, Japan and Russia.

Even that target was hard-won in a skittish Congress, and Obama has decided he can't go further without potentially souring final passage of the bill, approved in the House but not yet considered in the Senate. He also could imperil eventual Senate ratification of any global treaty that emerges next year.