中国城市网络地位对碳排放效率的影响

Examining the impacts of network position on urban carbon emissions efficiency in China

提升城市碳排放效率是中国实现“双碳”目标和经济社会可持续发展的关键。在流动空间环境下,城市碳排放效率不再仅仅取决于集聚经济,而是越来越多地受到网络经济的影响。本文利用中国制造业500强企业投资联系数据构建城市网络,研究了2005—2020年城市网络地位对全要素碳排放效率的影响机理及特征。研究发现:(1)网络地位对城市碳排放效率具有显著正向影响,结论经过稳健性和内生性检验后依然成立。(2)网络地位不仅通过价值链重组效应、中间产品多样化效应和网络竞争效应正向影响着城市的碳排放效率,还通过促进绿色技术创新、科技企业孵化和风险资本投资的中介机制改善了城市碳排放效率。(3)网络地位对城市碳排放效率的影响呈现多维异质性特征,东部城市、非资源型城市、人口规模较大城市和行政等级较高城市的碳排放效率更多从网络地位的增强中获益。未来中国政府应将碳达峰碳中和目标与城市网络建设结合起来,充分发挥城市网络对碳排放效率提升的推动作用,同时高度关注网络环境下不同类型城市碳排放效率的协调发展。

Improving the urban carbon emissions efficiency(UCEE)is the key for China to achieving carbon peaking and carbon neutrality goals and enhancing sustainable development capabilities.In recent years,increased attention has been given to the role of city network economies in promoting factor productivity and economic growth.However,it is still unknown whether network position of cities translates into a higher level of UCEE.This paper sets out to explore the impact of network position on UCEE through the lens of investment networks of China's top 500 manufacturing enterprises.To this end,the Window model and super-efficient SBM model in data envelopment analysis(DEA)are combined to measure the total factor carbon emissions efficiency of cities.In addition,a set of panel Tobit models are employed to assess the positive influence,transmission channels and multidimensional heterogeneity of cities'network position.The analysis finds that:(1)Network position has a significant positive impact on UCEE.The conclusion is still valid considering the replacement of carbon emissions efficiency measurement methods,spatial autocorrelation effects,and endogeneity issues.This result confirms that network linkages provide a basis for cities to balance economic growth and carbon emissions reduction on a larger spatial scale.(2)Two types of effects through which network position enhances UCEE are identified.On the one hand,network position exerts a direct effect through value chain reorganization,intermediate product diversification and network competition.On the other hand,green knowledge innovation,technology-based enterprise incubation and venture capital investment play mediation roles between network position and UCEE.(3)The influence of network position on UCEE is heterogeneous.The carbon emissions efficiency of eastern cities,non-resource-based cities,cities with larger population size and cities with higher administrative rank benefit more from the enhancement of network position.This indicates that network linkages have increased the inter-city gaps of carbon emissions efficiency in China on different dimensions over the past 20 years.The paper provides important implications for policymakers.In the future,the Chinese government should combine the"dual carbon"goal with the construction of city networks,and give full play to the role of network economies in promoting UCEE.Besides,great efforts should also be made to narrow the multidimensional UCEE gaps to achieve a balanced low-carbon society.