About the Report
The Montreal Protocol has been an effective instrument for protecting the Earth’s stratospheric ozone layer by providing an international framework for phasing out ozone depleting substances (ODSs), including chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). The phase-out of ODSs, however requires either substitute chemicals or other approaches, and hydrofluorocarbons (HFCs) have become one of the major replacements in many ODS applications. HFCs, which have no known natural sources, are used because they do not deplete the stratospheric ozone layer and can be used with relative technical ease to replace CFCs and HCFCs.
HFCs do not deplete the ozone layer but they contribute to global warming due to their potent greenhouse properties. Although, their current contribution to climate forcing is less than 1% of all other greenhouse gases combined, HFCs have the potential to substantially influence climate in the future. This UNEP report shows that the adoption of HFCs as ozone friendly alternatives is resulting in their rapid increase in the atmosphere. Emissions of HFCs are growing at a rate of 8% per year and by 2050, without action, they could rise so high that they almost cancel the tremendous climate benefits won earlier by the phase-out of CFCs and other ozone depleting substances.
The good news outlined in this report, is that alternatives exist that can assist in bringing down the projected growth in HFCs, if immediate action is taken. The available options ranges from designing buildings that avoid the need for air conditioning to the use of alternative substances such as hydrocarbons and ammonia, and the use of HFCs with less global warming potential and shorter lifetimes than those of current concern.