绿色高铁:高铁开通的减排效应及作用机制

Green High-speed Railway: Emission Reduction Effect and Mechanism of High-speed Railway

作为现代化的绿色交通运输方式,高铁对于我国生态环境改善具有重要的促进作用。本文基于我国城市面板数据,运用双重差分模型、中介效应模型等方法,实证分析了高铁开通的减排效应及其作用机制和空间异质性特征。研究发现,高铁开通能够有效抑制城市污染物排放量,包括城市二氧化硫排放量和废水排放量,并且基于多种方式进行的稳健性检验均证实了这一结论。分位数回归结果表明,随着城市污染程度的提升,高铁开通的减排效应也呈现出先增强、后减弱的"U"型动态变化特征。此外,高铁开通能够有效促进城市科技创新,尤其是绿色技术创新,进而抑制二氧化硫排放量。但需要指出的是,高铁开通虽然能够促进发明专利申请量的提升,但难以由此进一步有效抑制城市废水排放量,而仅能够通过促进城市绿色技术创新,进而抑制城市废水排放量;控制了绿色技术创新的中介效应后,高铁开通抑制城市废水排放量的直接效应并不显著。

As a modern green transportation mode,high-speed rail plays an important role in promoting the improvement of ecological environment in China.Based on China’s urban panel data,this paper uses the methods of double difference model and intermediary effect model to empirically analyze the emission reduction effect,mechanism and spatial heterogeneity characteristics of high-speed rail opening.It is found that the opening of high-speed rail can effectively inhibit the urban pollutant emissions,including the urban sulfur dioxide emissions and wastewater emissions,and the robustness test based on various ways confirms this conclusion.The quantile regression results show that with the improvement of urban pollution,the emission reduction effect of high-speed railway also shows the"U-shaped"dynamic change characteristics of first strengthening and then weakening.In addition,the opening of high-speed rail can effectively promote urban science and technology innovation,especially green technology innovation,and then suppress sulfur dioxide emissions.However,it should be pointed out that although the opening of high-speed rail can promote the application of invention patents,it is difficult to further effectively inhibit the discharge of urban wastewater,but only through promoting the innovation of urban green technology,and then inhibit the discharge of urban wastewater.After controlling the intermediary effect of green technology innovation,the direct effect of high-speed rail on the inhibition of urban wastewater discharge is not significant.This paper affirms the important role of highspeed rail in the development of green economy in China,opens the black box of the mechanism of"Green high-speed rail",which is of great theoretical significance for enriching and improving high-speed rail economics and green development theory.