Study On The Impact Of Urban Agglomeration Expansion On Carbon Emission

The work report of 19th National Congress of the Communist Party of China clearly issued the regional coordinated development strategy,stressed the critical status of urban agglomeration in building a coordinated development of different kind of cities and towns.On November 5,2018,at the first China International Import Expo,President Xi Jinping announced to support the development of the Yangtze River Delta regional integration and elevate it to a national strategy in his keynote speech.In August 2020,President Xi Jinping proposed that the Yangtze River Delta region should pay close attention to "Integration" and "High quality" at the Yangtze River Delta Integrated Development Forum.Carbon emission reduction is an important embodiment of high-quality development.It is clearly state in China’s 14th Five-Year Plan and the Outline of Long-term Goals for 2035 that carbon emissions will stabilize and decline after peaking in 2035.Shanghai proposed that the total carbon emissions reach a peak in 2025,and Jiangsu,Zhejiang,Anhui and other provinces have made strategic arrangements to achieve carbon peaks.Therefore,it is highly essential to study the impact of coordinated regional development of the Yangtze River Delta on carbon abatement,and testifies the impact of urban agglomeration expansion on carbon emissions.This paper focuses on the Yangtze River Delta integration policy and explores the environmental impact of urban agglomeration expansion using the two-phase expansion policy of the Yangtze River Delta Urban Economic Coordination Committee.Firstly,this paper defines urban agglomeration expansion,overviews the existing research on the measurement and factors of carbon emissions,policy effects of urban agglomeration expansion,the relationship between urban agglomeration expansion and carbon emissions,and put forward the paths of urban agglomeration expansion affecting carbon emissions.Then,using 285 city-level data in China from 2006 to 2017,this paper constructs quasi-natural experiments on capacity expansion in the Yangtze River Delta in 2010 and 2013,with the expansion incorporated into the classic STRIP AT model.Using the staggered DID model,this paper examines and compares the common trend and regional difference of carbon emission reduction effect of expansion of Yangtze River Delta in whole cities,situ cities and new cities,considering both total carbon emission and carbon emission efficiency.Further,this paper comprehensively carrys out the robustness test by applying DID method,PSM-DID method,placebo test method,and tackling other carbon abadement policies through time,which examined the validity of baseline.Furthermore,this paper accounts for the underlying mechanism of urban expansion on the carbon amount and carbon efficiency,discusses the expansion degree of regional integration through ascension,promote industrial restructuring and upgrading and affect the mechanism of carbon emissions and efficiency,and shone a light on the expansion of carbon reduction synergies.Key findings in this paper concluded:first,the twice expansion of Yangtze River Delta agglomeration significantly reduces the total carbon content and carbon efficiency of the whole cities and the new cities,but shows no obvious effect on the situ cities.And carbon reduction effect is stronger in new cities than in the whole cities.In the third year after expansion,the carbon reduction effect of expansion is particularly significant.Second,in terms of provincial heterogeneity,among the three provinces and one city,Zhejiang Province enjoys the largest proportion carbon emission reduction effect with the twice expansion.Thirdly,the expansion of the Yangtze River Delta urban agglomeration produces carbon emission reduction effects by enhancing economic connection between the neighboring cities,breaking down regional trade barriers set by local government,and enhancing intergovernmental environmental collaborative governance.Meanwhile,it is a great help of the expansion of the Yangtze River Delta to achieve carbon reduuction by propeling forward regional industrial transformation and upgrading;the market integration mechanism of expansion only has a significant carbon reduction effect on in situ cities,and the industrial upgrading mechanism has a significant carbon reduction effect on both in-situ cities and new cities;while achieving carbon reduction,expansion fails to achieve synergy with pollution reduction,which inhibits the environmental positive externalities of expansion.In addition to carbon reduction,expansion fails to coordinate with pollution reduction,which inhibits the positive environmental externalities of expansion.Not only the development phase and advanced level of various cities within the urban agglomeration should be taken into account,but coordination and cooperation between governments needs to be strengthened to create a good environment for green development and strive for carbon reduction in development.Also,reasonable industrial policies are required to be formulated to encourage technological innovation to improve energy efficiency per unit of carbon,and promote regional low-carbon energy transformation and industrial low-carbon development.