Independent, 7 December 2000:
Your report “CFC ban ‘should close up hole in ozone layer’” (4 December) is over-optimistic. The problem lies in the relationship between ozone depletion and global warming. Profound ozone losses are seen over Antarctica because of chemical reactions involving chlorine monoxide that take place on the surface of ice crystals within the polar stratosphere. Global warming aggravates this situation because greenhouse gases trap heat in the lower part of the atmosphere, thus cooling the stratosphere and accelerating ozone depletion.
Stratospheric levels of chlorine monoxide are similar at every latitude. It is the stratospheric temperature that determines the rate of ozone loss, so global warming has the potential to . produce profound ozone depletion over highly populated areas and thus increase the rate of malignant melanoma and other skin cancers induced by ultraviolet light.
The recent failure of the climate change negotiations in The Hague and the rising level of greenhouse gases in the atmosphere mean that the ozone layer faces an unstable and unpredictable future.
Dr Robin Russell-Jones
Skin Tumour Unit
St Thomas’ Hospital