Explainer: hydrofluorocarbons saved the ozone layer, so why are we banning them?

On October 28, Australia ratified the Kigali Amendment to the Montreal Protocol. Australia is the tenth country to ratify, joining others as diverse as Mali, Norway and Rwanda in a global commitment to dramatically reduce hydrofluorocarbons (HFCs) in the atmosphere. Once 20 countries have ratified the amendment, it will become binding. HFCs were designed specifically to replace ozone-destroying compounds previously used in air conditioners and refrigerants. Unfortunately, we now know that HFCs are massively potent greenhouse gases - thousands of times more powerful than carbon dioxide (albeit released in far smaller quantities).