Upstream climate impacts of R-134a and R-1234yf

All common refrigerants used in air conditioning and refrigeration systems in vehicles today are potent greenhouse gases (one kilogram of the common refrigerant R-134a is equivalent to 1430 kg of CO₂), and governments are actively seeking a transition to alternatives.

Upstream climate impacts may be substantial for refrigerants that undergo energy-intensive and complex production processes, require high-GWP inputs, or produce high-GWP waste products that are not disposed of properly. Each of these aspects will likely reduce the climate benefit of the alternatives under consideration.

This study assesses the upstream climate impacts of the two refrigerants used in passenger vehicles today, R-134a and R-1234yf. For every kilogram of R-1234yf that could replace R-134a, it estimates a net reduction in CO₂-equivalent emissions of 98.7% on a life-cycle basis. In comparison, European and U.S. regulations assume a 99.7% reduction based on existing GWP values, without inclusion of the life-cycle impacts analyzed here. This analysis suggests that if GWP values were to take upstream emissions into account, R-1234yf would have an equivalent GWP of 15, whereas under existing regulations R-1234yf has a GWP value of 4. If a 20-year time horizon GWP were applied, the climate impact relative to CO₂ would be doubled.

Although upstream emissions of refrigerant production are substantial, R-1234yf is expected to generate nearly the same magnitude of climate benefit when upstream impacts are included because its GWP is substantially lower. Nonetheless, this research points out that future analysis of the life-cycle emissions of new refrigerants, new materials, and manufacturing processes may be warranted to ensure that full climate impacts beyond the vehicle tailpipe are known.