When green transportation backfires: High-speed rail's impact on transport-sector carbon emissions from 315 Chinese cities

Abstract

High-speed rail is often viewed as a green transportation mode, substituting for carbon-intensive vehicular and aviation trips. However, its potential to induce additional travel demand and transport-sector carbon emissions has been largely overlooked. Here, we empirically examine the impacts of high-speed rail accessibility, the ease with which one city can reach other cities via the high-speed rail network, on transport-sector carbon emissions across 315 Chinese cities between 2010 and 2020, using a two-stage least squares model. Contrary to the anticipated emission-reduction effect, our analysis suggests a net positive impact of high-speed rail on transport-sector carbon emissions. Specifically, a 1% increase in high-speed rail accessibility leads to a 0.18% increase in transport-sector carbon emissions in the long run, as carbon emissions generated from induced travel demand have outweighed the carbon savings from substitution for carbon-intensive inter-city trips. This high-speed rail-induced increase in carbon emissions is observed in the road transport subsector, while the aviation subsector exhibits a compensatory reduction. Moreover, we find that integrating the high-speed rail network into local subway systems can curb the emission-intensifying effect, highlighting the importance of joint public transit planning. This study reveals an unexpected environmental impact of high-speed rail, conveying valuable insights into transport-sector decarbonization.