This report is the background document providing the basis for the Cooling Emissions and Policy Synthesis Report by the United Nations Environment Programme (UNEP) and the International Energy Agency (IEA) that is being published simultaneously. The planet has already warmed 1.0°C or more since pre-industrial times, and at the current pace will add 50% more warming to surpass 1.5°C as early as 2030, reaching levels outside human experience and making it more difficult for human and natural systems to adapt. As temperatures continue to increase, heat waves will become more frequent and intense, and societies will necessarily adapt by using more air conditioning and refrigeration to reduce heat-related illness and death, ensure continuing productivity, and minimise food loss. This implies a potentially very large additional demand for electricity with additional carbon emissions. Fast policy action can keep the growing demand for cooling from using up a significant amount of the remaining carbon budget for limiting warming to 1.5°C. The initial schedule of the Kigali Amendment to the Montreal Protocol will avoid up to 0.4°C or more of warming by the end of the century from a phasedown of HFCs. Robust policies to promote best technologies currently available for efficient and climate-friendly cooling have the potential to reduce climate emissions from the stationary air conditioning and refrigeration sectors by 210–460 GtCO2e by 2060. A quarter of this mitigation is from phasing down HFC, and three-quarters from improving energy efficiency of cooling equipment and reducing electricity demand, which helps achieve a more rapid transition to carbon free electricity worldwide.