Stratospheric ozone depletion at northern mid latitudes in the 21st century:: The importance of future concentrations of greenhouse gases nitrous oxide and methane -: art. no. 1051

[1] There is evidence that the halogen loading of the atmosphere has peaked and stratospheric ozone levels are expected to recover to pre-1980 levels this century. However, N2O concentrations in the atmosphere are increasing, resulting in increasing levels of NOx in the stratosphere. In addition, the growth rate in the atmospheric methane burden has declined in recent years, leading to the suggestion that methane emissions have stabilized. A 2-D chemical transport model is used to calculate stratospheric ozone from 2000 to 2100 for a range of IPCC scenarios. The model predicts that mid-latitude stratospheric ozone will recover only partially towards pre-1980 levels over the next 50 years, but will then decline, largely due to increases in stratospheric NOx. If greenhouse gas mitigation strategies result in lower future methane levels, mid-latitude stratospheric ozone levels in 2100 are predicted to be lower than current values, particularly in late summer and autumn.