| In the course of steady growth of population in China, rural population experienced the transition from a positive decelerating growth to a negative one, while urban population keeps exploding and nowadays played the leading role in the current show of national population growth. Urban population gradually trended to concentrate in top large scale cities. Cities with population of over a million increased in number, and experienced the increase in population scale as well as the percentage over the total population of the whole country. Large cities, especially giant ones, become the significant growth pole of urban population. Both cities and rural areas had the household energy consumption rebounded strongly in the last decade. Although there was a decrease trend in scissor difference of household energy consumption per capital between urban and rural China, the ratio of urban household energy consumption per capital to rural one was always bigger than 1. Therefore, cities would be the key areas for controlling household energy consumption and carbon emission when accelerating the urbanization in China.This study estimated the carbon emission of direct household energy consumption among 261 cities at prefecture level and above (including municipalities) in time series from 2000 to 2010, by introducing regional grid emission factor into different energy products for 2000-2010. Household energy consumption in urban families highly relied on electricity, and thus electricity power significantly dominated the factors of carbon emission. Therefore, it works effectively for urban energy conservation and emission reduction that decrease the carbon density of electric power by improving technology and structure of power supply.Each deviated apparently from equilibrium state of the three maps of spatial distribution of population, economy and household energy consumption carbon emission. The spatial distribution of population was relatively in uniform, and then the economic one was the most centralized, and the carbon emission distribution placed in between. Relatively concentrated was carbon emission, which meant that household energy consumption carbon emission was mainly concentrated into a few cities. Then this study investigated the amount and structure of carbon emission and their interacted relationships with population and economy respectively in three major regions (the east, central and west) and cities of different population scales. Both urban population and carbon emission presented in the national map gradually in decreasing order from east to west, which exhibited a strong correlation to the economic gradient along three major, the east, central, and west, regions. Firstly, from the population point of view, both in mega and giant cities increased annually the population amount and its percentage of total national urban populations. Meanwhile, the contribution share to carbon emission decreases corresponding to the dwindling order of population size among the cities. Secondly, from the angle of structure of energy supplies, the more population cities had, electric power dominated much more in. The efficiency of urban carbon emission indicated by carbon emission per capital and the one per unit of GDP differed in changing tendencies caused by that urban population, economy and carbon emission distributed in non-uniform space and had different growth rates significantly among the cities. From 2000 to 2010, carbon emission per capita increased while carbon emission per unit of GDP decreased. And in the national distribution map of carbon emission per capital, eastern cities were higher than the central, the west and the nation average level, and the central cities were also higher than the west. However, household energy consumptions per unit of GDP in these three regions were just in the opposite sequence, which exhibited that the west had the biggest one, then following the central and the east. Generally, cities with more population showed higher carbon emission per capita but small and medium cities were at always relatively higher, in term of carbon emissions per unit of GDP, than that in the giant, mega and large cities.This paper studied the variation of carbon emission in countries of G7 plus 5, and also compared it among them, against the background of worldwide escalading trend of total carbon emission and emission per capital. Advanced countries were implementing carbon emission reduction, but emerging developing countries like China tended to accelerate to produce more carbon emission. China currently had the highest total carbon emission in the world, and the emission per capital was slightly over the world’s average level, falling far behind the developed countries, especially the United States. The total amount of China urban household carbon emissions displayed a decelerating growth during 2000-2010, and the growth of carbon emission was much more unbalanced distributing in space than the carbon emission itself. Only a short list of cities, like Beijing, Shanghai, Guangzhou, apparently showed the feature of high level and high growth rate of carbon emission. The cities with that feature, from the point of regional distribution, were mainly located in the east coast, while in the central and west regions of China, had that feature only the provincial capital cities, most of which were keeping a slowing down growth yet.By using logarithmic mean divisia index (LMDI), on the basis of Kaya identity, the driving force of carbon emissions growth could be decomposed into carbon density effect, energy intensity effect, wealth effect and population effect, and is calculated for each effect on carbon emissions growth. The national and regional scale study in different cities are found, the energy structure carbon density affects carbon emissions in the alternative law of positive and negative effects; reducing energy consumption per unit of GDP is a key factor in stabilizing carbon emissions growth inhibition showing a significant negative effect, in the United States and China, in particular. The decrease of the energy intensity has impact on the carbon emissions of cities in eastern China significantly, and the wealth effect is an important driving force to promote the increase of carbon emissions; the changes in population size contribute to the carbon emissions growth positively. The results shows that the total urban life carbon emissions is mainly due to the energy density, and in 2007, mainly to the decrease of the carbon density in eastern cites of China. In 2009, the contribution of the carbon density in western cities to the decrease of emissions is significantly improved, with the same effect on the role of carbon density in the eastern cities in China, which not only curbs carbon emissions growth rate effectively, but also achieves to reduce the absolute amount of carbon emissions.Wealth effects and population effects as both are play roles in promoting the positive effects on the growth of carbon emissions in the national and city levels. From the perspective of relative contributions, the yearly growing emissions of China, the United States and major developed countries are mainly affected by the impact of economic development, while population growth is in a relatively small effect. Mexico, South Africa, and Brazil are affected mainly by population effect. Chinese relative contribution rate of population effect is declining year by year. The study of comparing the relative contribution of population effect and the wealth effect by the urban scale shows, the increased per capita GDP has more significant impact than urban population growth on carbon emission, and rapid economic growth is the primary driving force, in particular for the ’high-level, high-growth’ cities.The increase of population explains the growth of energy demand as well as associated carbon emissions, and also shows stable positive effects on carbon emissions growth. Since the reform and opening up policy, the urban population growth is mainly dependent on the migration growth. From the point of view of energy saving, the migration of population migration behavior from both itself and its natural growth promotes urban population growth, while on the other hand, in the transition from ’peasant’ to ’resident’ process, lifestyle changes and life quality improving lead to the increase of energy demand. Changes in energy consumption and shift from emigration to immigration area, accompanied with population migration, pose serious new challenges to total carbon emissions control.The strength of regions differs significantly when attracting the local population to move into, the three major economic regions in the relatively developed eastern coastal areas (the Bohai Economic Rim, the Yangtze River Delta, Pearl River Delta), especially the Yangtze River Delta and the capital area showed a gradual " the pole of attracting migration "features, and the intensity regional distribution of the choice to move out is relatively disperse. By migration patterns, rural-urban migration is always the migrate mainstream, other than the town-urban migration flows. Among them, the southeast economic zones and coastal cities are main migrants gathering places. Eastern developed cities and the city of regional center in the western (the capital city in a province as the representative) always maintained a very strong ability to attract non-native population. From the perspective of urban population scale, the proportion of immigration population in giant cities over 4 million is relatively higher than other cities in the rest levels.This exploratory essay estimates transferred emissions per capita caused by migration from the level of carbon emissions in the resettlement areas. Regional differences in per capita carbon emission levels and net immigration uneven spatial distribution of population effects are superimposed, to further increase the level of transferred emissions caused by migration in the amount of total emissions from the city scale. From the perspective of total control, the migration growth is an important factor to increase the city’s carbon emissions. Immigration moving to the eastern cities and giant cities with more than 400 million populations further promotes the growth of carbon emissions. On the other hand, concentrated migration leads to human capital overflow and technology diffusion and creates the necessary conditions for reducing carbon emissions per unit of GDP. Carbon emissions efficiency is relatively the highest in the eastern cities (the same minimum carbon emissions with total GDP target in the eastern cities), followed by the central city, and the western cities have the lowest carbon emission efficiency. Giant cities with more than 4 million populations have technical efficiency advantages. The results of the carbon emissions transferred growth driving force decomposition of the major capital cities in provinces proved population migration concentration drives economic agglomeration, promote a significant increase in per capita GDP as well as a decrease in per unit of GDP, and effects of technology play important roles when offsetting the demographic effect and wealth effect on the emissions growth of Beijing, Shanghai and Guangzhou.Conducting assessments of per capita emissions, not only reflects the thinking of total control, but more directly reflects the overall comprehensive energy under the premise of people’s living standards and the guarantee of economic development. Regression model confirms that the carbon emissions per unit of GDP and per capita income levels promote carbon emissions significantly. Meanwhile, the higher the coldest January average temperature, the lower the heating energy demand, the lower the per capita carbon emissions. Urban central heating in densely populated areas can play an important role to enhance energy efficiency. Urban are major areas undertaking population to move into. Among them, the working age population is the main army, and to meet liquidity needs, the trend of household size to be smaller will increase levels of per capita carbon emissions.Based on the full consideration of socio-economic factors and natural environmental conditions, actively developing green power, advocating low-carbon consumption to promote high-carbon lifestyle changes, fully considering the city agglomeration effect to lower the amount of carbon emissions, adjusting measures to local conditions to build low-carbon city would achieve a beautiful Chinese dream in the future. |
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