Current mitigation finance flows are inadequate and unfair Despite overwhelming evidence that the world needs to make rapid and substantial investments in climate mitigation in this decade to meet the ambitious goals of the Paris Agreement (1–3), political and financial barriers continue to hinder mitigation efforts (2). Global mitigation investment pathways modeled in the sixth assessment report (AR6) of the Intergovernmental Panel on Climate Change (IPCC) reach global climate goals in a cost-effective manner. These are agnostic about who should finance these and how to fairly allocate costs and benefits of mitigation efforts. We apply equity considerations to global cost-effective mitigation investment needs and derive “fair-share” regional contributions, which describe the direction and magnitude of interregional financial flows that align with each consideration. We find that flows from North America and Europe to other regions would have to increase substantially relative to present levels to meet the Paris Agreement goals under most equity considerations.