[UPDATE, 2:46 p.m. Copenhagen time: Even as I type, word is racing around that Wen and Obama have "made progress" in a "constructive" face-to-face meeting. And that other world leaders are still going at it over a text that at least half of them can live with.] 

The UN climate conference has near-breathlessly anticipated today's appearances by Chinese Premier Wen Jiabao and U.S. President Barack Obama.

When their wait ended late this morning, the plenary of about 119 world leaders was treated to two heavy loads of diplomatic boilerplate.

But the speeches did offer clues that one major disagreement between the two leaders is still being debated: How nations should be held accountable for their promised reductions in greenhouse gas emissions.

In the early hours prior to the speeches, according to Andrew Revkin of The New York Times, both Obama and the European Union had been outraged when Wen snubbed a closed-door meeting with around 18 other heads of state to hammer something tangible out of the two-week negotiations. (The premier sent vice minister He Yafei in his place.)

When he took the stage, President Obama reiterated the dangers of global warming, the successes of the U.S. thus far, and the nation's intentions to cut its greenhouse gas pollution. He called for mandatory monitoring and reporting of carbon cuts as part of any climate agreement -- all ongoing U.S. positions.

Then leaving his prepared text behind, Obama vented some frustration with China, stating testily that "I don't know how you have an international agreement where we all are not sharing information and assuring that we are meeting our commitments. That doesn't make sense. It would be a hollow victory."

"We are ready to get this done today," Obama said with some heat, still off-piste from the written speech. "But there has to be movement on all sides to recognize that it is better for us to act than to talk."

Premier Wen, speaking before President Obama, seemed to leave little room for negotiation, underlining that although China is an economic powerhouse, it still has millions living in pre-industrial levels of poverty as well. Wen insisted that China would not accept the mandatory emissions cuts and progress reporting required of industrial nations.

But Tan Copsey of ChinaDialogue detected some signs that suggest that China and the U.S. may be largely coming to terms on these questions of "transparency":

Chinese Premier Wen Jiabao talked about making China's actions 'transparent' a sentiment echoed by United States President Barack Obama ...
 ...This confirms what a number of people close to the US and Chinese delegations have told chinadialogue. Specifically that they were expecting a compromise between the United States and China on making Chinese actions 'Measurable, reportable and verifiable' (MRV).
Both speeches were otherwise rudimentary and predictable.

Many life-or-death issues have been raised by nations large and small over the past two weeks. From island nation Tuvalu's stand for stronger and faster cuts in carbon emissions, to the African Group raging over paltry aid offers for climate adaptation, the lives, health, and prosperity of millions of the world's poorest people hang on their resolution. 

But it still seems to be coming down to whether the world's two greatest carbon polluters can come to terms.

Image: "President Barack Obama meets with Chinese Premier Wen Jiabao during a bilateral at the United Nations Climate Change Conference in Copenhagen, Denmark, Dec. 18, 2009." (Official White House photo by Pete Souza)

See more of Emily's reports from Copenhagen as part of OnEarth's ongoing coverage.