Research On The Impact And Path Of Economic Agglomeration On Carbon Emission Intensity

The rise of urban agglomeration in China has led to economic agglomeration.Negative externality of agglomeration induces energy consumption so that carbon emission becomes severe.It is crucial to probe into the influence and the transmission path of economic agglomeration on carbon emission intensity.Based on the panel data of 61 cities in Beijing-Tianjin-Hebei,the Yangtze River Delta,Guangdong-Hong KongMacao Greater Bay Area and Chengdu-Chongqing urban agglomeration from 2004-2016,we use STIRPAT model and threshold effect model to analyze the impact of economic agglomeration on carbon intensity and explore its influencing mechanism.The airport construction situation of each city in 2003 is innovatively applied as an instrumental variable to solve the endogeneity problem.A mediation effect model is built to test the transmission mechanism of economic agglomeration on carbon emission intensity through environmental regulation and urbanization.Besides,we investigate diverse influence paths of economic agglomeration on carbon emission intensity under economic density heterogeneity.The results show that:(1)The overall carbon emission intensity shows a rising and fluctuating trend.The carbon emission intensity of cities with high economic density is lower than that of cities with low economic density.(2)61 cities,cities with high economic density and cities with low economic density all have the characteristics of ? convergence.It also shows the absolute ? convergence and conditional ? convergence.There is a catch-up effect between low-carbon emission intensity cities and high-carbon emission intensity cities.(3)There is a significant u-shaped relationship between economic agglomeration and carbon emission intensity.The improvement of economic agglomeration is beneficial to reduce carbon emission intensity in most cities.(4)Economic agglomeration not only has a direct impact on carbon emission intensity but also has an indirect effect on it through environmental regulation and urbanization.The intermediary effect is obvious.(5)There is an inverted U relationship between economic agglomeration and carbon emission intensity in cities with low economic density,while economic agglomeration has a significant U effect on carbon emission intensity in cities with high economic density.(6)In cities with low-economic density,the economic agglomeration indirectly influences carbon emission intensity through urbanization.In cities with high-economic density,the economic agglomeration indirectly influences carbon emission intensity through environmental regulation.(7)Under the test of an intermediary threshold effect,it can be found that with the gradual improvement of technology level,the effect of economic agglomeration on reducing carbon emission intensity gradually weakens.Moreover,when the ratio of the tertiary industry reaches a certain threshold,a further increase of the ratio may enlarge energy consumption,weakening the carbon reduction effect of economic agglomeration.This paper suggests that the government should promote the urban agglomeration economy to boost regional integration development and realize the cooperation between enterprises to enhance economic agglomeration.Governance tools should be targeted for different cities.High-economic density cities should regard environmental regulation as the main means of reducing carbon emission,while low-economic density cities should focus on urban construction and improve economic agglomeration.