Administrative divisions of China By its political level, when a "city" is referred to, it can be a: By its actual area and population, it can be: When used in the statistical data, the word "city" may have three different meanings: It is important to specify the definition of "city" when referring to statistical data of Chinese cities, otherwise, confusion may arise. For example, Shanghai is the largest city in China by population in the urban area but is smaller than Chongqing by the population within the administration area. Before the establishment of the Qin Dynasty, China was ruled by a network of kings,
Climate change in the United States produced 6,930 mt (15.7% of the world's total). In the cumulative emissions between 1850 and 2007, the U.S. was at the top in terms of all world nations, involved with 28.8% of the world's total. China's emissions have outpaced the U.S. in CO2 from 2006 onward. The U.S. produced 5.8 billion metric tons of CO2 in 2006, compared to the 6.23 billion coming from China. Per capita emission figures of China are about one quarter of those of the U.S. population. The single largest source of greenhouse gas emissions in the U.S. is power generation. For example, data from 2012