A group of US economists have stated that China is producing more carbon dioxide (CO2) than previously believed, which will hinder global efforts to stabilize atmospheric greenhouse gases. China is the second-largest emitter of CO2 in the world, and some studies suggest it may have surpassed the United States in emissions last year. This report may increase pressure on China to agree to mandatory emissions reductions, a step it has so far resisted. Researchers from the University of California, Berkeley, and UC San Diego wrote in the May issue of the Journal of Environmental Economics and Management that China's CO2 emissions are projected to increase by at least 11 percent annually from 2004 to 2010. Earlier estimates, including those used by the UN's Intergovernmental Panel on Climate Change, predicted a 2.5 to 5 percent annual rise in CO2 emissions for the region that includes China during the same period. The article was released in anticipation of a meeting among energy and environment ministers from the top 20 greenhouse gas emitting nations, who will be discussing climate change, clean energy, and sustainable development in Japan. These nations, including the United States, China, Indonesia, Brazil, and South Africa, are responsible for about 80 percent of the world's greenhouse gas emissions. There is increasing pressure for these countries to come to an agreement to stop and reverse the growing emissions of CO2, which is the main gas contributing to global warming. According to U.S. researchers, China is projected to see a 600 million metric ton increase in CO2 emissions by 2010 compared to 2000 levels, surpassing the 116 million metric ton reduction in carbon emissions pledged by developed countries under the Kyoto Protocol from 2008-2012. China is not required to reduce greenhouse gas emissions during 2008-12 as per the Kyoto agreement. However, they participated in talks in Bali to create a new global emissions-fighting pact starting in 2013. Researchers used pollution data from 30 provinces and China's official waste gas emissions data to analyze CO2 emissions up to 2004. According to Maximillian Auffhammer, UC Berkeley assistant professor of agricultural and resource economics, it was expected that China's CO2 emissions growth rate would slow down as income increased, but it has actually exceeded expectations, making it much more challenging to stabilize atmospheric CO2 levels. The report indicated that a contributing factor to the problem was a shift towards granting provinces more control over the construction of power plants after 2000. According to Richard Carson, an economics professor at UC San Diego, wealthier coastal provinces invested in clean-burning power plants with advanced technology, while poorer interior provinces opted for outdated Soviet technology from the 1950s. Carson emphasized that power plants are typically built to last for several decades, meaning that these choices have locked provinces into high emissions levels for the long term. Consequently, China now faces the challenge of dealing with power plants that are both dirty and inefficient.