This study examines the role of nature-based solutions (NbS) for global climate protection and in international climate policy. It provides a critical assessment of global mitigation potentials of NbS in forests, croplands, grasslands, terrestrial and coastal wetlands, and settlements and provides recommendations for international climate policy such as under UNFCCC. The results show that the potential of NbS to mitigate emissions is probably overestimated in the scientific literature due to various factors. Nevertheless, NbS can bring multiple benefits for people and the environment and should be promoted actively.