Environment: High-speed rail networks help reduce China’s carbon emissions

Expansion of the high-speed rail network in China between 2008 and 2016 led to a significant reduction in carbon emissions from its transport sector, according to a paper published in Nature Climate Change. The study suggests that this reduction comes mainly as a result of the transportation of goods shifting from highways to conventional rail because high-speed networks free up capacity on conventional railways.

High-speed rail (HSR) is an important form of long-distance public transport that is well-established across East Asia and Europe. Although HSR is believed to be more energy-efficient and environmentally-friendly than road and conventional rail, it is unclear to what extent new rail routes could reduce carbon emissions from the transport sector.

Using national traffic-monitoring data and statistical approaches, Yu Qin and colleagues provide evidence that the expansion of the Chinese HSR network between 2008 and 2016 has led to a reduction in annual greenhouse gas emissions equivalent to 14.76 million tons of carbon dioxide through reductions in both highway passenger and freight traffic in response to HSR. This substitution effect is the major contributor to the overall reduction of greenhouse gas emissions by HSR. This figure corresponds to 1.75% of the total greenhouse gas emissions in China’s transport sector. The authors suggest that this mitigation mainly comes from freight transport switching from road to conventional railways, which are indirectly freed up by passengers using HSR. The authors also project that greener electricity conditions could further increase the climate benefits of HSR.

In an associated News & Views, Armin Schmutzler notes the ‘very useful insights’ this paper presents in what ‘appears to be the first contribution identifying greenhouse-gas reduction effects of high-speed rail systems’.