How do high-speed rails influence city carbon emissions?

Identifying the factors that contribute to carbon reduction is important for achieving carbon neutrality. Despite scholars investigating the environmental effects of HSR, the relationship between High-speed railways (HSR) and carbon emissions is not well understood. In this study, carbon emission data for 285 prefecture-level cities in China from 2000 to 2017 and the time-varying difference-in-difference (DID) method was used to investigate whether the opening of a high-speed rail will affect regional carbon emissions. The results showed that the opening of a high-speed rail may reduce regional carbon emissions, particularly when the city's economic development model relies on outside investors and secondary industries. A series of examinations, such as parallel trend, endogeneity, and placebo tests, were conducted to ascertain that our results are robust. It should be noted that our study highlights the environmental effects of HSR from both direct and indirect perspectives. •HSR operation bring in social pressure for city to reduce its carbon emissions.•Using a series of robustness checks to empirically provide strong evidence.•Comparing the HSR carbon emission reduction effect under different contexts.