Joe Farman died in Cambridge on 11 May 2013. His name is unknown to most people. He was a British physicist who along with fellow researchers, Brian Gardiner and Jon Shanklin, caused a sensation when they published their findings in Nature in May 1985 revealing that the levels of ozone above the Antarctic had fallen by about 40% between 1975 and 1984. This had caused a very large hole (more correctly a reduction in the concentration of ozone) to appear in the ozone layer, a thin layer in the earth’s stratosphere which absorbs virtually all the ultraviolet rays from the sun which are harmful to life.
The hypothesis of ozone depletion had been put forward in the 1970s but had been dismissed by NASA scientists after satellites failed to substantiate the loss. Since 1957, Farman and his colleagues had been looking at atmospheric data collected by the British Antarctic Survey station at Halley Bay, Antarctica, using old-fashioned devices like weather balloons and a Dobson meter, a rudimentary ozone measuring machine that had to be wrapped in a duvet to work properly. At first the figures were questioned, even by the team. Perhaps the discrepancy was just above Halley Bay? Measurements were taken 1,000 miles further north, but these showed the same result? Why had NASA’s satellites not picked up the anomaly. Much later and to NASA’s embarrassment, the data had been collected by the satellites but had been overlooked.
The British team also demonstrated that the ozone depletion was not a natural occurrence but the result of reactions triggered by man-made chlorofluorocarbons (CFCs) in the stratosphere. This led to the 1989 Montreal Protocol, the international agreement to control and phase out global production of CFCs and other ozone-damaging chemicals which had been used in refrigerators, spray cans, and solvents.The ozone layer is slowly repairing itself but it will not return to its early 1980s state until 2070 due to the long life of CFCs. After the discovery, Farman became an energetic advocate for environmental concerns, criticising governments for their naive approach to scientific research. His final research trip to Antarctica was in 1990, shortly before he retired. Thereafter he cycled daily to work in Cambridge University’s Department of Chemistry, and latterly was a consultant to the European Ozone Research Unit. The discovery of the hole is widely accepted as one of the biggest environmental discoveries of the 20th century.