Air conditioners in passenger cars, vans, buses and freight trucks – collectively known as mobile air conditioning – consume large amounts of energy. The fuel they use and their leaks of refrigerant are also responsible for a significant amount of greenhouse gas emissions. This report explores the current global energy consumption from mobile air conditioning systems, along with the resulting greenhouse gas emissions from the energy consumption and the leaking refrigerants. With no further policy action, energy use from mobile air conditioning may almost triple to over 5.7 million barrels of oil equivalent per day by 2050. At the same time, annual combined emissions from energy consumption and refrigerant leakage could more than triple to 1 300 million tons of CO2 equivalent.