Possible ozone reductions and UV changes at the Earth's surface

Abstract

During recent years there have been suggestions^1– that man's activities might reduce the thickness of the atmospheric ozone layer. Reductions in ozone could then give rise to an increase in potentially harmful solar UV radiation at the Earth's surface. Concern has been expressed particularly about the possibility of subsequent increases in skin cancer. Most calculations of ozone reduction have employed one-dimensional (height-only) models and few have calculated the solar radiation reaching the ground. Rather, it has been assumed that, for example, a 1 % depletion in ozone is equivalent to a 2 % increase in UV–B (the biologically important radiation in the wavelength range 280–320 nm) (refs 4, 5). However, studies using two-dimensional models^6,7 indicate that any change in ozone will not be uniform, but will show significant variations with latitude and season. We show here first, that the commonly accepted idea that a depletion of ozone of a particular figure is equivalent to an UV increase of twice that figure does not hold generally; second, we point out the importance of seasonal and-latitudinal variations in ozone changes on the UV radiation reaching the Earth's surface.