The shift to R1234yf is under way. The new chemical, HFO-1234yf, has a GWP of only 4, versus over 1,400 for the current refrigerant (R-134a).
More than 10M cars are already using it worldwide. Based on European regulations, from 1 January 2017, all new passenger cars are required to use a low-GWP refrigerant.
Moreover, it is a near drop-in replacement for R-134a, thus, the most practical choice. Packaging is 4.5 kg per cylinder.