The Chinese urban metabolisms based on the emergy theory

By using emergy indices of urban metabolisms,this paper analyzed 31 Chinese urban metabolisms' systematic structures and characteristics in 2000 and 2010.The results showed that Chinese urban metabolisms were characterized as resource consumption and coastal external dependency.Non-renewable resource emergy accounted for a higher proportion of the total emergy in the inland cities' urban metabolisms.The emergy of imports and exports accounted for the vast majority of urban metabolic systems in metropolises and coastal cities such as Beijing and Shanghai,showing a significant externally-oriented metabolic characteristic.Based on that,the related policies were put forward:to develop the renewable resource and energy industry;to improve the non-renewable resource and energy utilization efficiencies;to optimize the import and export structure of services,cargo and fuel;and to establish the flexible management mechanism of urban metabolisms.