Negotiations on a new international climate pact are underway in Germany this week, but the United States’ top climate envoy is headed in the opposite direction with a planned trip this weekend to China. Special Envoy for Climate Change Todd Stern on Wednesday said he hopes the world’s two biggest polluters can reach consensus on a path forward.

Stern said he does not expect a formal agreement to emerge from the talks, but he said during a presentation at the Center for American Progress that the United States is seeking a bilateral agreement with the Chinese this year in order to set the stage for a global deal at the U.N.-sponsored climate talks this December in Copenhagen.

“No deal will be possible if we don’t find a way forward with China,” said Stern.

China and other developing nations have argued that they should be exempt from binding emissions targets for at least a decade after the world’s rich nations commit to cuts, an idea that Stern rebuffed.

“Developed countries who do agree to take strong action won’t long accept a world in which economic competitors are allowed to free-ride with respect to CO2 emissions,” he said.

He noted that, even if every other nation in the world besides China reduced emissions 80 percent between now and 2050, China’s emissions alone would drive carbon dioxide concentrations up to 540 parts per million.

While he called the assertion that is often heard in Washington that China refuses to take action “inaccurate and unfair,” Stern was clear that China “will need to do more than it is already doing if we are going to confront climate change.”

Stern will travel to Beijing on Saturday, accompanied by David Sandalow, assistant secretary of energy for policy and international affairs, and John Holdren, head of the White House Office of Science and Technology Policy. They will be joined by officials from the Environmental Protection Agency and the Department of Treasury, according to Stern.

He said he believes the two countries could come to some agreement on things like building efficiency goals, electric vehicle deployment, and the development of carbon capture and sequestration technology for coal-fired power plants, which could help move both nations forward in the international negotiations process.

Stern stressed that developing countries like China should be willing to take steps that show quantifiable action on climate under the international treaty that will succeed Kyoto.

“China and other developing countries do not need to take the same actions that developed countries are taking, but they do need to take significant national actions that they commit to, internationally, that they quantify, and that are sufficient enough to be consistent with the lessons of science.”

The specific commitments, he said, should come from the developing countries themselves, and might include things like reducing energy intensity, increasing the use of renewables, or sectoral emission reduction targets. Each country should be able to decide what is politically and economically feasible for them, he said, with the requirement being that their goals yield quantifiable results. “You can’t just cut just cut a political deal for the sake of cutting a deal,” said Stern, “but you also have to be mindful of art of possible.”

‘Let’s get this damn thing started’

While Stern had tough words for China and other developing nations, he offered high praise for the climate and energy bill set to go to a vote before the U.S. House of Representatives this summer, even as some in the environmental community are concerned that it does not give the U.S. very good bargaining material going into the international negotiations.

China’s leaders have indicated that they think developed nations should reduce their emissions 40 percent below 1995 levels by 2020. The Waxman-Markey bill only seeks a 2020 target of 4 percent below 1990 levels.

Other developing countries argue that developed nations should aim for 25 to 40 percent cuts by 2020, compared with 1990 levels. This would meet the criteria that the Intergovernmental Panel on Climate Change has said is needed to keep warming at less than two degrees Celcius over pre-industrial times. Among developed nations, the European Union has set the highest target thus far, at 20 percent below 1990 levels by 2020, and has said it would be willing to go as high as 30 percent if other major economies consent.

Asked at Wednesday’s forum about the gap between China’s expectation and what rich countries are likely to agree to do, Stern dismissed a 40 percent goal as “not real.” He also downplayed the gap between the targets in the Waxman-Markey bill and what the European Union has put forward as “small differences.”

He said the House bill “is enormously ambitious” and brings together “science and pragmatism,” and praised it for setting concrete emissions reductions goals. “There is not just an aspirational goal out there for 2050, there is an actual policy, a cap that ratchets down year by year,” said Stern. “Let’s get this damn thing started,” he said.

“The much larger piece of the equation,” he said, “is what the major developing economies are going to do.”

Stern said the monetary and technological support that the United States can lend to developing nations will play an important role in international talks over the next months, but he rebuffed another suggestion from Chinese leaders that the U.S. should devote between 0.5 and 1 percent of GDP to international adaptation and technology assistance. “They’re not serious,” he said.

But in order to get some sort of bilateral deal in the next months, U.S. needs to “meet China halfway” and develop a “genuine collaborative partnership on climate change,” he said.

“If the two Goliaths on the world stage can join hands and meet each other at the highest levels to form a long-term climate and energy partnership, it will truly change the world,” said Stern.