Material and carbon implications of future mobility infrastructure expansion around the world

Global mobility infrastructure is expected to expand significantly, especially in the Global South, potentially requiring a substantial share of the remaining carbon budget. However, the resource use and carbon emissions associated with the anticipated expansion of roads, railways, and other mobility infrastructure, as well as the potential of mitigation measures, have so far not been explored systematically. Using high-resolution infrastructure and mobility data, we assess seven demand- and four supply-side circular economy and decarbonization measures aiming to mitigate resource use and associated embodied CO₂ emissions. We find that without demand reduction, infrastructure stocks could double or triple by 2060, with cumulative emissions reaching 10 to 20 GtCO₂. We find that a global shift to rail would increase embodied emissions to 37 GtCO₂ due to carbon-intensive materials. Combining mobility reduction with enhanced recycling and industrial decarbonization can cut emissions by 63% while providing adequate global infrastructure. This would help to offset increases in emissions from public transport infrastructure expansion required to reduce operational emissions.