Compact 15-minute cities exhibit lower carbon intensity in urban transport

arXiv:2409.01817v3 Announce Type: replace Abstract: The 15-minute city concept, which advocates cities where essential services are accessible within a 15-minute walk or bike ride, has gained significant attention in recent years. However, despite being celebrated for promoting sustainability, large-scale empirical evaluations of the effectiveness of the 15-minute concept in reducing emissions remain limited. To address this gap, we investigate whether cities with better walking accessibility to services, such as 15-minute cities, are associated with lower transportation emissions. Analysing 662 cities worldwide, we find that cities with better walking accessibility to services emit less CO2 per capita for transport. An increase of 10 percentage points in the share of residents living in 15-minute accessible areas is associated with an approximate 5% reduction in transport-related CO2 emissions per capita. Moreover, among cities with similar levels of accessibility, those covering larger areas and exhibiting lower population densities tend to emit more. Our findings highlight the effectiveness of decentralised urban planning, especially the proximity-based 15-minute city, in promoting sustainable mobility. At the same time, our results also emphasise the need to integrate local accessibility with urban compactness - both in terms of population density and of urbanised area - to support sustainable mobility.