Impact of very short-lived halogens on stratospheric ozone abundance and UV radiation in a geo-engineered atmosphere
The impact of very short-lived (VSL) halogenated source species on the ozone layer and surface erythemal ultraviolet radiation (UV ERY) is investigated in the context of geo-engineering of climate by stratospheric sulfur injection. For a projected 2040 model atmosphere, consideration of VSL halogens at their upper limit results in lower ozone columns and higher UV ERY due to geo-engineering for nearly all seasons and latitudes, with UV ERY rising by 12% and 6% in southern and northern high latitudes, respectively. When VSL halogen sources are neglected, future UV ERY increases due to declines in ozone column are nearly balanced by reductions of UV ERY due to scattering by the higher stratospheric aerosol burden in mid-latitudes. Consideration of VSL sources at their upper limit tips the balance, resulting in annual average increases in UV ERY of up to 5% in mid and high latitudes. Therefore, VSL halogens should be considered in models that assess the impact of stratospheric sulfur injections on the ozone layer.