Five years ago, on October 16, 2016, the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer agreed to the Kigali Amendment. The Kigali Amendment will phase down ozone-safe hydrofluorocarbon (HFC) greenhouse gases (GHGs). These GHGs were once necessary to rapidly protect stratospheric ozone against tipping points but are no longer necessary because environmentally superior technology is available or soon to be available.