Research On The Impact Of Infrastructure Construction On The Urban Green And Smart Development Level

At present,China’s urbanization process has not yet been separated from the extensive development model at the expense of the environment.In 2020,cities carrying 63.9% of the country’s population,while generated more than 70% carbon emissions of the nation,which indicated that cities were the "main battlefield" for China to achieve low-carbon economic transformation and sustainable development of economy and society.With the implementation of national strategies such as green development and "double-carbon" goals,the construction of green and smart cities has been carried out in various prefecture-level cities.As the leading capital and hardware support for the sustainable development of society,the construction of crucial infrastructure such as energy,transportation and communication is vital condition for cities to seize the development opportunities of green and smart transformation.As a consequence,cities in China have actively deployed pivotal infrastructure constructions,which intend to provide support for low carbon emissions,transportation structure adjustment,comprehensive transportation network efficiency,logistics cost reduction,and resources sharing,which are conducive to the development of green and smart cities.However,redundant infrastructure construction will also cause high energy consumption and low efficiency.What’s more,the new sewage sources would occur when using infrastructure for commodity trade and productive activities,which might become a bottleneck that restricting urban green-smart development.Based on the green total factor productivity measurement framework,the urban green-smart development level(GSDL)of 221 cities was estimated considering the smart input-outputs with the SBM model and GML index from 2005 to 2019.Then this paper discussed the dynamic influence and spatial differences of energy,transportation,communication infrastructure construction on urban GSDL,clarified the threshold characteristics of urban scale.The spillover effects on the urban GSDL considering geographical factors of infrastructure construction were explored.Accordingly,policy implementations were put forward to promote the green and smart development of cities.And the crucial study findings are as follows:(1)From 2005 to 2019,urban GSDL in China showed a "U" fluctuation trend,and there were significant differences among regions.Urban GSDL in east China was almost always at an advanced level.After 2013,urban GSDL in the southwest and central China improved significantly,and the urban GSDL in the northeast and northwest China was always backward.(2)From the perspective of the overall benchmark regression results,the construction of energy,transportation and communication infrastructure played a significant role in promoting urban GSDL in China,but the effects were different at different subs.Energy and transportation infrastructure construction tended to inhibit urban GSDL at low level,while promoted it with the increase of subs.By contrast,the communication infrastructure construction only inhibited urban GSDL when Q=0.9,and promoted urban GSDL with the increase of subs.(3)Regional and period heterogeneity results showed that the direct impacts of infrastructure construction on urban GSDL were characterized by spatial and temporal heterogeneity.Among them,the results of regional heterogeneity indicated that energy infrastructure construction had no significant impacts on urban GSDL in North China,northeast China,and northwest China,but showed transparent promotion effect on other regions.Furthermore,the construction of transportation infrastructure improved the urban GSDL in eastern China and northwest China,respectively,while the construction of communication infrastructure only promoted the urban GSDL in eastern China.The heterogeneity results of the period showed that the negative impact of energy infrastructure construction on urban GSDL changed from negative to positive after the year 2013,while the promoting effect of transportation and communication infrastructure construction on urban GSDL was further strengthened from the year 2013 to 2019.(4)From the perspective of the role of control variables,the impacts of economic development level,industrial structure,and government size showed significant regional heterogeneity on the urban GSDL.While the positive effect of human capital level on urban GSDL was not consistent with expectation.(5)From the perspective of the threshold effects of urban scale,there was a single threshold effect for infrastructure construction in east China,northeast China,and northwest China,but not significant in other regions.Overall,the impacts of these three infrastructure constructions on urban GSDL were heterogeneous with the development of urban scale.(6)From the perspective of intermediary effect results,the level of domestic trade and opening-up level played partial intermediary role in the process of energy infrastructure construction affecting urban GSDL.Furthermore,domestic trade level could mediate the impact of transportation infrastructure construction on the urban GSDL,while other intermediary effects were not robust or significant.(7)From the perspective of spillover effects,the spillover effects of energy,transportation,and communication infrastructure construction on urban GSDL were significantly positive,and the economic development level,government scale also showed promoting spillover effects on the urban GSDL.Nevertheless,industrial structure and the human capital level did not realize the expected spillover effects.