Urban Size, Structure And Carbon Emissions

Urbans burn from the agglomeration of population and industries which is pushed by urbanization. The speed of China’s urbanization since the reform and opening-up policy is attractive to all of the world, during which the urban size and spatial structure suffered large change. The sprawl and evolution of China’s cities due to government’s intervening, market’s distribution, influence of industrial agglomeration and improvement of labor force. The spatial structure are also influenced by the traffic system and industrial structure. Under the urbanization rule found by Northam, China’s urbanization will speed up in the following ten years and city space will expand at a fast rate. Carbon emission during the urbanization is attracting more and more researchers’ attention. The research on optimal low-carbon city size and spatial structure will be helpful to China’s low-carbon urbanization.Based on the theory and conclusion of new economic geography and endogenous growth, this paper studies the effects of city size expansion and spatial evolution on carbon emission using China’s city statistic data and analyses the effect of local government. We focuses on the mechnism of urban sprawl and spatial restructuring and studies government and market influence on caibon emission. After the review of relevent papers(chapter2), we analyses the government function on poplation migration and spatial expansion(chapter3). We studies the mechnism between city size and carbon emission(chapter4). In chapter5, we analyses the effect of traffic system and industry structure change on urban spatial structure and carbon emission. In last chapter, we draw a conclusion:1. the urbanization during which the factors are distorted and population migration are controled by the government is both inefficient and unsustainable. City’s population rising-up, economic growth and spatial sprawl will increase energy use and carbon emission. When population agglomeration in cities, the land finance transform too much farm land into construction land and hukou system limits the population migration, which decreases the space efficiency. The low-efficiency space structure wastes energy and increases carbon emission.2. the cities with0.5-10million population can be more low-carbon than the other scale population in China. We find that the large(1-10million population)and middle(0.5-1million population) size cities are more energy-efficient than small(with less than0.5million population) and super large(with over10million population) cities. China should develop more large and middle size cities.3. the industry agglomeration can improve energy efficiency and reduce greenhouse gas emission. The rise of agglomeration degree can makes the cities more specialized, which can improve the productivity. This will increase energy efficiency of urban economic system. The sporting industy propotion rise up by1%, the caibon emission will decrease by8.33%-10.57%. the energy efficiency rises up by1%, the carbon emission will decrease by1.23%-1.42%.4. the effect of techology improvement on carbon emission lasts long and retardant. The technology improvements happening in this term will affect the carbon emission of the following terms. Due to the learning by doing effect and spillover effect, technology improvement will sprawed between the industries and areas. The10%decrease of carbon density happened in last term can reduce carbon density of this term by7%.5.the traffic system has important effect on the spatial struture and carbon emission. Optimalization of traffic system can make urban space structure more reasonable and low-carbon. The development of traffic system has two kinds of effects on energy use. On one hand, the optimalization of public transport can promote economic growth and drive up energy use. On the other hand, optimalization of public transport can rise energy efficiency and save energy.6. industry structure has dicisive role on energy efficiency, the spatial structure and industry structure can influence industry carbon emission. The industry structure has long-term and robust effect on carbon emission. The second industry proportion rises up by1%and industry carbon emission increases1.7%-3%.