Development patterns, material metabolism, and life-cycle greenhouse gas emissions of high-speed railway in China

Abstract

China built the longest high-speed rail (HSR) network by consuming massive construction materials. However, the characterization of HSR material metabolism and associated emissions at national level remains less explored. Here, we revealed the material metabolism and life-cycle GHG emissions from 2008 to 2035 in China’s HSR network. We show that material stocks temporally amount from 0.6 gigatons in 2010 to 3.7 gigatons in 2020, dominated by aggregate and cement rather than steel. Spatially, material distributions across provinces are becoming balanced. Growing HSR speed increased the construction material demands and flows, but technological advances significantly offset these increasing consumptions, especially for developing bridge-girder spans and ballasted tracks. Our results demonstrate the life cycle emissions of HSR, with 1,008 megatons of carbon replacement value and annually 31 megatons of operational GHG emissions in 2020, and highlight the environmental benefits of HSR to inform green transportation transitions.