This Report published by the German Environment Agency critically assess the global mitigation potential of Nature-based Solutions (NbS) as provided in existing literature to derive recommendations for international climate policy. Firstly, it compares and evaluates different understanding of NbS to highlight key characteristics of NbS and propose a working definition to inform the scope of the study. Then, the study provides a critical assessment of global mitigation potentials of NbS in forests, croplands, grasslands, terrestrial and coastal wetlands, and settlements to get a sound understanding of a plausible contribution of NbS towards long-term climate targets. It concludes that the NbS potentials reported in the scientific literature probably overestimate the realistic potential of NbS for climate change mitigation. Nevertheless, the uncertainties associated with quantifying the mitigation effects of NbS should not be used as an argument against their implementation. In addition to their mitigation effect, NbS deliver a range of benefits for people and the environment and should be promoted actively.