Scientist whose work led to phase out of CFCs dies
Joe Farman, a geophysicist with the British Antarctic Survey and one of the discoverers of the hole in the ozone layer over Antarctica in the early 1980s, died last month on 11 May. Their results reporting a ‘thinning’ of the ozone layer, which protects the Earth from biologically harmful ultra-violet light, by nearly 50% were published on 16 May 1985 and attributed to the release into the atmosphere of the widely used (including air conditioning,refrigeration and thermal insulation) category of chemicals known as CFCs. Such was international concern that the Montreal Protocol to phase out their use was signed by 24 countries just over two years later in September 1987.
CFC refrigerants widely used at the time included R11, R12 and R13. The Montreal Protocol also covered R22, an HCFC with an ozone-depletion potential 5% that of CFCs. It is the chlorine content of CFCs and HCFCs that is destructive of ozone The final phase out of R22, which has much less chlorine, in the EU, is the end of 2014. A vital step was explaining how small amounts of CFCs could destroy large amounts of ozone.
It was the Montreal Protocol that led to the development of the HFC refrigerants (no chlorine) in common use today for air conditioning — such as R134a, R407C and R410A — and interest in HFs as refrigerants.
The discovery of the hole in the ozone layer prompted years of controversy, with many politicians and industrial companies extremely sceptical of the suggestion that the release of CFCs all over the world could have such an effect on a small part of the Earth’s atmosphere.
The measurements by Joe Farman and his colleagues were not corroborated by any other measurements. A NASA satellite was taking measurements but produced data faster than it could be analysed. As a result, high and low measurements of ozone concentration were disregarded.
The chemical reactions that were predicted to destroy ozone were confirmed by a research plane in 1985. NASA reviewed its records and confirmed what Joe Farman and his team had found.
The Montreal Protocol is proving successful in helping the ozone layer repair itself, and the gaps in the atmosphere should close by 2080 at the current rate of progress.
