Reducing black carbon emissions will help in avoiding climate tipping points, building resilience and delivering clean air. This policy brief outlines the latest science on black carbon, examples of cost effective solutions, and recommendations for policymakers, funders and governments. This briefing by Clean Air Fund, the Center for Study of Science, Technology and Policy (CSTEP), Berkeley Air Monitoring Group and Orbis Air highlights the importance of reducing black carbon emissions, alongside deep decarbonisation. The Case for Action on Black Carbon points to the gap between the growing evidence on black carbon’s regional climate impacts and its absence from global climate strategies.