COMFORT will close knowledge gaps for key ocean tipping elements within the Earth system under anthropogenic physical and chemical climate forcing through a coherent interdisciplinary research approach, and aims to provide added value to decision and policy makers in terms of science-based safe marine operating spaces, refined climate mitigation targets, and feasible long-term mitigation pathways. It focuses on the triple threat of (1) warming, (2) deoxygenation, and (3) ocean acidification, and how to optimally deal with this threat.