On the stratospheric ozone layer More than 90% of refrigeration equipment relies on vapour compression using refrigerants and this figure will not change in the near future: other technologies do not generally have enough efficiency. Chlorinated refrigerants (chlorofluorocarbons – CFCs, and to a lesser extent, hydrochlorofluorocarbons – HCFCs) contribute to the depletion of stratospheric ozone if released into the atmosphere due to equipment leaks or if refrigerants are not properly recovered when disposal of the equipment takes place. CFCs and HCFCs are gradually being phased out thanks to the Montreal Protocol. Current measurements of the ozone layer show overall stability and probable recovery to the previous level around 2060. They are often replaced by hydrofluorocarbons (HFCs) which do not deplete the ozone layer but are potent greenhouse gases, as are HCFCs, when released into the atmosphere. CFCs were also greenhouse gases and their global warming potential was much higher. The impact of the Montreal Protocol is thus also positive regarding global warming. However, it is not enough.