High-speed railway ripples on the greenness: Insight from urban green vegetation cover

Less attention has been paid to the potential ecological pressures brought about by high-speed rail (HSR) while promoting urban prosperity. Based on Normalized Difference Vegetation Index and multiple socio-economic and ecological data, this study examines the local effect and spatial spillover effect of HSR operation on green vegetation coverage (GVC) in Chinese cities from 2003 to 2014, using a difference-in-differences design and spatial econometrics. Main findings are: 1) HSR operation has reduced GVC of local cities by about 6.0%. Because HSR-triggered economic agglomeration has intensified the land development and increased the pollution emissions (represented by SO2 and dust), leading to the degradation of local green vegetation. 2) The local effects of HSR on urban GVC are heterogeneous. HSR operation seriously cuts down the GVC for development-saturated cities, slightly undercuts the GVC for cities with conventional railways, but positively boosts the GVC for ecotourism cities. 3) HSR operation increases the GVC of adjacent cities (cities contiguous to HSR-located cities) by about 3.8%. Because the economic siphoning effect of HSR on adjacent cities reduces their land needs and pollution emissions, thus providing conditions for the vegetation expansion. Note that the HSR's impact on adjacent cities' GVC is influenced by the economic disparity between HSR cities and their neighbors. This study re-identifies the role of the transportation infrastructure in reshaping ecological patterns, providing insights into regional sustainable development.