Assessment for Decision-Makers – Scientific Assessment of Ozone Depletion: 2014

This analytical report reveals that, as a result of the implementation of the Montreal Protocol on Substances that Deplete the Ozone Layer, the ozone layer is expected to recover to 1980 benchmark levels. However, the Assessment finds that climate benefits of the Protocol could potentially be offset by hydrofluorocarbons (HFCs) emissions, used to replace ozone depleting substances (ODS). The report notes that HFC emissions are growing at 7% a year and, left unabated, will significantly contribute to climate change over the coming decades. It suggests that replacing HFCs with low global warming potential alternatives would limit this problem. The report also concludes that concentrations of carbon dioxide (CO2), methane and nitrous oxide will influence the state of the ozone layer in second half of this century. Specifically, the report predicts that nitrous oxide, which is both a powerful greenhouse gas (GHG) and an ozone depleting gas, will become more important in future ozone depletion.