The climate-change organization that shared the 2007 Nobel Peace Prize with Al Gore hopes its latest report, released Saturday, will influence governments around the world to curb greenhouse-gas emissions.

Timing is key, as world leaders prepare for a conference in Bali next month to begin updating the 1997 Kyoto Protocol. The report from the Intergovernmental Panel on Climate Change is the fourth in a series, and the culmination of four years of research. The report's summary condenses 2,500 pages of previous publications into a policy-focused 23 pages.

"With this final report, the scientists have done their job and explained that global warming is happening and we need to do something about it," said Eben Burnham-Snyder, spokesman for the House Select Committee on Energy Independence and Global Warming. "We have to stop hiding behind China, and China has to stop hiding behind us."

But there's no guarantee the hiding by the world's two worst environmental offenders will in fact stop.

The IPCC is credited with mainstreaming the idea that climate change is a direct result of human activity – specifically by burning fossil fuels which release greenhouse gases like carbon dioxide into the atmosphere. The international panel wants world governments to initiate a process under the UN Framework Convention on Climate Change that results in hard caps for emissions.

The IPCC hopes the report will frame the Bali meeting. A new international climate-change deal must be settled in time to ensure that action continues after 2012, when the current phase of the Kyoto Protocol ends. But China and the United States are unlikely to agree to a negotiating process with that goal.

"I have no reason to suspect that the Bush administration will support a real negotiating process in Bali," said Elliot Diringer, director of international strategies at the Pew Center on Climate Change. "And as long as the U.S. takes that position, there is no reason for China or other developing countries to support emissions caps."

While many policy experts doubt that a deal with teeth will emerge from Bali, they remain optimistic about the long-term future of capping greenhouse-gas emissions. The influence of renewable energy businesses in the United States will reach around the world, said Christopher Flavin, president of Worldwatch Institute, a sustainability think tank.

"Climate change is changing the business sector, and that will soon change the political sector," said Flavin. "Over time these new energy industries will start to become politically influential in China, like they have in Silicon Valley."

Critics say the Kyoto Protocol is largely symbolic, because it has not slowed global greenhouse-gas emissions. The newest climate data available, published earlier this year in the Proceedings of the National Academy of Sciences, suggests that greenhouse-gas emissions accelerated through the early part of the decade.

"No region is decarbonizing its energy supply. The growth rate in emissions is strongest in rapidly developing economies, particularly China," the study's authors wrote.

But Flavin noted that the news out of China isn't all bad. Worldwatch released a report last week projecting that China would become the world's leader in renewable energy within the next three years. While China has balked at international agreements, Flavin said, the government was moving to address climate change domestically.

China's president, Hu Jintao, outlined his country's plan at September's Asia-Pacific Economic Cooperation forum. Energy efficiency and investment in renewable energy sources are key to his plan. Hu wants to reduce energy use per unit of GDP by 20 percent by 2010. Worldwatch's analysts project that China will invest $10 billion in renewable energy capacity in 2007.

"You could make a case that China has gone further than the U.S. has in embracing the kinds of national goals that are part of the commitment to reducing carbon dioxide," Flavin said.

Kent Hughes, consulting director of the Woodrow Wilson Center's Global Energy Initiative, believes an international agreement will eventually be hammered out that addresses greenhouse-gas emissions.

"Longer-term, I'm a bit more optimistic, because there has been a shift in public thinking about climate change," he said. "But I think we'll be at this for the rest of the century."