Comment by callmemclovin

That's true, old school refrigerants like R-12 are awful. The downside of modern replacement refrigerants are high operating pressure (>100 bar for R-744/CO2) or high flammability for natural refrigerants like R-290 (Propane) and R-600a (Isobutane). But these are solely engineering problems, and I'm happy to know that my R-290 heat pumps at home (Panasonic L & Wolf FHS) and A/C (Midea Xtreme Save Blue) aren't awful to the environment, once they reach EOL.