According to a group of US economists, China's carbon dioxide (CO2) production is higher than previously thought, which will hinder global efforts to stabilize atmospheric greenhouse gases. China is the second-largest CO2 emitter in the world, with some studies suggesting it may have surpassed the United States in emissions last year. The report may lead to increased pressure for China to commit to binding emission reductions, a step it has so far resisted. Researchers from the University of California, Berkeley, and UC San Diego, writing in the May edition of the Journal of Environmental Economics and Management, predict that China's CO2 emissions will increase by at least 11 percent annually from 2004 to 2010. This is significantly higher than previous estimates, such as those used by the UN's Intergovernmental Panel on Climate Change, which projected a 2.5 to 5 percent annual increase in CO2 emissions for the region that includes China during the same period. The article's release coincides with a meeting of energy and environment ministers from the world's top 20 greenhouse gas emitting nations in Japan. These nations, including the United States and China, are responsible for about 80 percent of global greenhouse gas emissions. There is increasing pressure on these countries to come to an agreement to reduce CO2 emissions, the main culprit of global warming. According to a report in a journal, U.S. researchers predict a significant increase in China's CO2 emissions by 2010, which would outweigh the carbon emissions reductions promised by developed countries under the Kyoto Protocol. China is not required to reduce greenhouse gas emissions from 2008 to 2012 according to the Kyoto Protocol, but it did participate in talks in Bali with almost 190 other countries to begin creating a new global agreement to fight emissions starting in 2013. Researchers used pollution data from 30 provinces in China and official waste gas emissions data to study CO2 emissions up to 2004. Maximillian Auffhammer, an assistant professor at UC Berkeley, noted that while it was expected that China's power generation efficiency would improve with increasing income, the rate of CO2 emissions growth has actually been higher than anticipated, making the goal of stabilizing atmospheric CO2 much more challenging. According to the report, one of the issues was a change in policy post-2000 that allowed provinces more control over constructing power plants. Richard Carson, an economics professor at UC San Diego, noted that while wealthier coastal provinces built modern, efficient power plants, poorer interior provinces opted for outdated Soviet technology. Carson pointed out that these decisions have long-term consequences as power plants are built to last for several decades. As a result, China is now facing higher emissions due to the prevalence of old and inefficient power plants.