PARIS, Nov. 17, 2009 (AFP) — With less than three weeks left before the UN climate showdown in Copenhagen, hopes are pinned on the United States, which is keeping everyone guessing on when — or if — it will declare its hand.

A US-China summit and ministerial-level talks among 44 countries placed the spotlight Tuesday on prospects for a US offer able to end the deadlock threatening the December 7-18 talks.

For the past two years, the road towards a post-2012 climate pact has been stymied to a large degree by the US position – firstly under George W. Bush, an unenthusiastic participant in the process, and secondly under Barack Obama, cautiously steering a climate bill through Congress.

The big question is whether the United States can put forward detailed proposals, with percentages, for curbing its massive carbon output, the second highest in the world.

In Beijing, President Obama and Chinese counterpart Hu Jintao, whose country is the planet's biggest carbon emitter, jointly declared any Copenhagen accord should "include emission reduction targets of developed countries."

Emmanuel Guerin, a climate analyst at France's Institute for Sustainable Development and International Relations (IDDRI), said the message, while vague, carried a positive tone.

Through it, Obama implicitly acknowledged "Copenhagen is not just about building a framework of rules, it's the place for announcing hard numbers," he said.

In a separate statement, Obama said the common Sino-US aim "is not a... political declaration, but rather an accord that covers all of the issues in the negotiations, and one that has immediate operational effect."

Obama's statements suggest a refreshed, if still verbal, ambition, said Alden Myer of the Washington-based Union of Concerned Scientists, attending the ministerial-level talks in Copenhagen among 44 countries.
"The president acknowledged the need to bring some kind of concrete proposals to Copenhagen both on emissions reduction and finance," he told AFP by phone.

Even so, any numbers the US brings to Copenhagen are likely to be tied to climate legislation wending its way through Congress, he stressed.

In the run up to Copenhagen, developing countries demanded that rich nations as a bloc commit to a 40 percent cut in carbon pollution by 2020 compared to a 1990 benchmark, and an 80 percent cut by 2050.

Europe has promised to unilaterally slash its CO2 output by 20 percent by 2020, and go to 30 percent if other industrialized nations follow suit. Japan has made a conditional offer of a 25 percent cut.

UN scientists say rich nations must cut emissions by 25-40 percent over the next decade to keep global average temperatures from surpassing pre-industrial levels by more than two degrees Celsius (3.6 degrees Fahrenheit), a widely-held threshold for dangerous warming.

By comparison, the most ambitious bill, in the Senate, would commit the US to about a 20 percent drop in CO2 pollution by 2020 compared to 2005 levels, equivalent to a fall of roughly four percent over 1990.

The latest US declarations are "reassuring" and a "positive sign," said Paul Watkinson, France's top climate negotiator.

"But they are not enough. The pressure has to be kept up because what is on the table [from the US] is too weak compared to what is needed," he said.