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Farman, Joseph C

ozone layer depletion cfcs

(1930– ) British atmospheric scientist: found the Antarctic ozone hole.

After graduating from the University of Cambridge in mathematics and natural sciences, Farman worked briefly in the aerospace industry before embarking on a career with the British Antarctic Survey in 1956.

In 1984 Farman and his colleagues discovered an ‘ozone hole’ in the stratosphere above the Antarctic. This finding, made using ground-based instruments, was confirmed by American satellite observations and a review of past satellite data revealed that winter ozone levels had been declining for the past 10 years and by the mid-80s were down to about 50% of the 1957 level. This had not been noticed earlier because the computers that processed the satellite measurements had been programmed to ignore such low values as ‘impossible’, although ozone loss was foreseen by P Crutzen, M Molina and S Rowland in the 1970s, who won a Nobel Prize for this in 1995.

The stratospheric ozone layer plays a vital role in protecting the Earth’s life from the more harmful effects of the Sun’s ultraviolet rays. Increased levels of UV light have been shown to cause skin cancers and eye cataracts, to kill phytoplankton and therefore disrupt the marine food chain, and to decrease crop yields. Long-term depletion of the ozone layer could have very serious effects for life on Earth.

For the first few years after Farman’s discovery it was hoped that the depletion of the ozone layer, which undergoes natural seasonal variations, was a natural and transient phenomenon. However, the depletion has both continued and increased in severity, and has also been observed in the ozone layer of the more heavily populated northern hemisphere, which is losing its ozone at a rate of about 5% per decade.

It is now widely accepted that the depletion is due to the effects of man-made chemicals, notably chlorofluorocarbons (CFCs), released into the atmosphere over the past 20–30 years. CFCs have been widely used in refrigeration and insulation materials, but also have the unforeseen property of catalysing the breakdown of ozone (O3 ). Although governments are now taking measures to reduce the release of CFCs into the atmosphere, it is estimated that even if CFC production were completely halted immediately, it would take another 70 years before this had a significant effect on restoring the ozone layer.

Farman’s discovery has been of the utmost importance in highlighting the fact that man’s polluting activities are now of such a scale as to jeopardize the whole future of life on Earth. Within 3 years of his discovery the Montreal Protocol took the first steps to limit worldwide CFC production. Farman has remained extremely active in lobbying governments and other bodies on the consequences of ozone depletion and in campaigning for increased restrictions on the manufacture of CFCs.

[back] Farley, James Conway(1854–1910) - Photographer, Finds His Niche, Chronology

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