Assessing the CO2 reduction target gap and sustainability for bridges in China by 2040

In China, rapid and continuing infrastructure growth will significantly affect the feasibility of achieving CO2 emission reduction targets. It is uncertain whether the current infrastructure designs are consistent with the national emission targets of China, consequently posing a threat to the national commitment to reaching carbon neutrality. To illustrate the gap in achieving the emission targets with respect to bridges, we present carbon intensity reduction targets relevant to bridges by 2040. By exploring three policy–economic scenarios that combine with CO2 emission reduction policy scenarios of the International Energy Agency and shared socioeconomic pathways, we assess the adaptability of the bridge designs to short-, medium- and long-term carbon intensity targets. We propose a new sustainability design approach based on a bridge big data set that integrates reliability, environmental impacts, and cost. We show that, under the current policy–economic scenario, more than 50% of code-based bridges would meet the five-year CO2 emission target, whereas only one in ten thousand could meet the ten-year target under the new policy–economic scenario. Under the sustainable development policy–economic scenario, none of the bridge designs would meet the carbon reduction targets over the next 20 years. Our findings highlight that the bridges in China need to be duly considered in setting CO2 reduction targets, and in the national move toward zero carbon, careful consideration should be given to implementing our proposed bridge sustainability design.