China became the world's largest energy consumer in 2009, surpassing the United States, which held the title for more than 100 years, according to the International Energy Agency (IEA).[a] The recession took a toll on U.S. industrial output, adding to a decline in total energy consumption that was almost 5 percent below 2008 levels.[ii] The United States leads the world in oil consumption, consuming more than twice China's level, but China leads the world in coal consumption and hydroelectric capacity, using more than twice the U.S. level of coal and having more than twice the U.S. hydroelectric capacity. Because coal emits twice the level of carbon dioxide as natural gas and because of China's extensive coal use, it surpassed the United States in carbon dioxide emissions in 2007 and continues to hold that lead.
