The Impact Of Urban Polycentricity On Carbon Emissions

With the advancement of urbanization in China,the contradiction between urban development and carbon emissions has become increasingly prominent.The expansion of urban scale and the increase of construction land have increased the consumption of cement and steel.At the same time,it will encroach on a large number of green space and forest areas,reduce the city ’s carbon emission reduction and carbon capture capacity,resulting in a large increase in urban emissions.Polycentric city-single center is a description of a kind of dimension of urban spatial structure.At present,cities at home and abroad have implemented polycentric strategy in order to make the city grow organized and healthy,and solve the problems existing in the city,such as traffic congestion and heat island effect.However,in reality,the implementation of polycentric strategy is not satisfactory.In this context,scholars need to conduct more in-depth research on urban spatial structure from the perspective of polycentricity,and further test its spatial organization can play a corresponding performance in transportation,environment,society and economy.Therefore,from the perspective of urban emission reduction,clarifying the relationship between urban multi-centralization and carbon emissions,and exploring the ideas and countermeasures of urban emission reduction are one of the keys to achieving future carbon peaks and carbon neutrality.Taking the Yangtze River Delta region as an example,based on the long-term population distribution data of Lascan,this thesis identifies the urban centers of each city through the nonparametric method,constructs the urban polycentric index,and further improves the perspective and thinking of the measurement and evaluation of urban polycentricity.On this basis,this thesis analyzes the spatial and temporal changes of urban multi-centralization and carbon emission level in the Yangtze River Delta region from the long-term urban scale,and then empirically tests the impact of urban multi-centralization on carbon emissions in the Yangtze River Delta region,so as to provide scientific reference for China to build low-carbon cities,achieve 2030 carbon peak and 2060 carbon neutral target.The results show that :(1)On the whole,the spatial structure of cities in the Yangtze River Delta region shows a trend of multi-center,and the average value of urban multi-center index changes little from 2006 to 2017.The average urban carbon emissions increased from about 76 t in 2006 to about 123 t in 2017,an increase of about 1.6 times.(3)The increase in the degree of urban polycentricity in the Yangtze River Delta region will increase the carbon emissions of the city and reduce the average carbon emissions of other cities in the region.Specifically,an increase of 1 % in the degree of urban polycentricity will lead to an increase of 3.034 % in the total carbon emissions of the city and an average reduction of 2.856 % in the total carbon emissions of other surrounding cities.By replacing the data source of the explained variable and eliminating some samples,this conclusion is also drawn by two robustness tests,which verifies the possibility that urban multi-centralization will increase the carbon emissions of the city and reduce the carbon emissions of surrounding cities to some extent.In the subsequent heterogeneity test,it is verified that the inhibition and promotion effect of urban polycentricity on carbon emissions will not change with the size of the city and the region,but the impact size shows the heterogeneity of the region and the city size.