Cities and urban areas are central to global decarbonization pathways

Cities and subnational governments are increasingly adopting mitigation targets and plans toward net-zero goals, yet the global pathways used to assess decarbonization remain too spatially coarse to directly evaluate their contribution. Here, we develop a policy-compatible framework that links Current Policies (Medium) and below-2 °C (Low) pathways from the IMAGE integrated assessment model (IAM) to dynamically changing urban administrative units through a Kaya-based downscaling approach. We find that urban administrative areas account for most modeled emissions and mitigation under both scenarios, with their share remaining high across regions despite substantial and heterogeneous spatial restructuring over time. Integrating pledges from 1363 subnational entities across 48 countries, we estimate that by 2050 these commitments could deliver additional mitigation beyond those already accounted for under national policies, equivalent to 14.6–15.9% of the global urban Medium pathway and 17.5–18.4% across the G20. If fully implemented, these commitments would bring participating jurisdictions collectively close to the Low pathway, but would remain insufficient on their own to shift the overall global emissions trajectory onto a pathway likely to keep warming below 2 °C. Our findings demonstrate the potential significance of subnational action while highlighting the need for coordinated mitigation across multiple levels of government.