Here, to support the path towards net-zero urban emissions, we review the existing literature on urban-scale carbon dioxide removal (CDR), seeking to quantify the potential negative contribution of cities to emissions globally. Urban CDR options considered here include carbon sequestration in urban vegetation, soil and buildings, and CO capture ₂ from the indoor environment through decentralized direct air capture. Our estimates of carbon storage and sequestration potential suggest that the deployment of urban-scale CDR options could make a significant contribution to global climate change mitigation, along with supporting the scale-up of climate action from local to regional and national levels. (Quirina Rodriguez Mendez, Sabine Fuss, more at nature.com)