Actions that reduce or eliminate HFC-134a emissions can make an important contribution toward lowering the overall climate impact of the global auto fleet. In the early 1990s, the automotive industry replaced CFC-12 refrigerant in air conditioning systems with HFC-134a to eliminate impacts on stratospheric ozone. This move also produced reductions in greenhouse gases, generating between 10 and 13 Gt CO2-eq fewer emissions per year. Despite this success, HFC-134a remains among the most potent greenhouse gases emitted by motor vehicles.
Over a 100-year period, one kilogram of HFC-134a will cause warming 1400 times greater than an equivalent amount of carbon dioxide. Over a 20-year period, the impact can be nearly 4000 times greater. Emissions of the refrigerant are a consequence of poor servicing of the air conditioning system, improper disposal, and leakage from valves and hoses. Improvements in the design and durability of system components can reduce this leakage, along with better training of vehicle technicians and management of vehicle disposal. But perhaps the single most effective approach is to replace HFC-134a with commercially available alternatives that have a climate impact as much as 99 percent lower.
The European Union now requires auto makers to supply new model vehicles with refrigerants whose global warming potential (on a 100-year basis) is no greater than 150. In addition, automakers in the United States beginning with MY 2012 will soon be eligible for credits toward meeting tailpipe GHG standards when refrigerant replacement or other control measures are undertaken. These measures focusing on refrigerant emissions and their climate impacts could make substantial gains toward lowering the overall climate impact of the transportation sector.