Joe Farman

Joe Farman, who has died aged 82, was one of the scientists responsible for the biggest environmental discovery of the 20th century: the fact there was a hole in the ozone layer over Antarctica. Mr Farman and his colleagues made the discovery while working at the Halley research station on the Brunt Ice Shelf and their paper in Nature reporting the findings led directly to the Montreal Protocol which controls ozone damaging chlorofluorcarbons.

At the time of the discovery in the mid-1980s, he was working for the British Antarctic Survey after serving as scientific officer of its predecessor, the Falkland Islands Dependency Survey; he was also head of the survey's Physics Unit at the University of Edinburgh in the 1960s and 1970s.

He joined the Survey in the 1950s, training at the Met Office station in Lerwick, but by the 1980s the work carried out by Mr Farman and his colleagues was under-valued and under threat. They were close to being shut down when, with a fraction of the equipment and funding available to American scientists working in the same field, he made the world-changing discovery with Brian Gardiner and Jon Shanklin.

He had always wanted to work in the Antarctic. As a boy, his heroes were Scott and Shackleton. Born in Norwich, he won a scholarship to read natural sciences at Cambridge and for a time worked for the de Havilland Aircraft Company. In 1956 he saw an advert for a position in Antarctica working with the Falkland Islands Dependency Survey and got the job. He was sent to the Met Office in Lerwick for six months to become familiar with the sort of instruments he would be using.

He then sailed for the Falkland Islands, which in those days took four weeks. It took a further week to reach the base on Antarctica. The clothes and facilities were basic compared to modern standards, but he took to the difficult but exciting life straight away. Initially based on the Argentine Islands base, now called Faraday, he was part of an 11-strong team measuring radiation and ozone and, on that first trip, spent 27 months there.

By 1983 he was running two stations for the British Antarctic Survey with Mr Gardiner and Mr Shanklin. Working with a machine called a Dobson spectrophotometer, the three men were shocked to discover what appeared to be catastrophic depletion of ozone and at first Mr Farman wasn't sure what to do. "I was very worried about what our findings meant," he said, "but I didn't know what to do about it. Does one go and knock on the Prime Minister's door? But once the press got hold of it, I didn't have to worry about banging on anybody's door."

The men revealed what they had discovered in the scientific journal Nature in 1985, confirming theoretical worries that chlorofluorcarbons, or CFCs, could damage the ozone. The report showed levels of ozone in the Antarctic had fallen by 40% between 1975 and 1984 and the drop was the result of changes in the atmosphere caused by CFCs. At the time, CFCs were used in everyday items such as fridges and spray-on deodorants, but in the wake of the report, Prime Minister Margaret Thatcher ordered that funding for the British Antarctic Survey be protected and the international community began to discuss what should be done. Two years later, 24 countries signed the Montreal Protocol that phased out CFCs. Kofi Annan, the former UN Secretary General, has said the protocol may be the most successful international agreement ever signed.

Mr Farman was always cautious about claiming the protocol was a success and right up until his death was warning about the threat to the planet from global warming. "Computer models say the ozone will not return to its 1950 state until 2080," he said. "Even that assumes nothing else upsets the temperature structure of the atmosphere. Given that we can't forecast what global warming means, I'm afraid I don't believe them."

He received great acclaim for his discovery during his lifetime, particularly as his work had been done on a relative shoestring compared to the facilities available to American scientists working in the same area. He continued to work with British Antarctic Survey until his retirement in 1990 and was made a CBE in 2000. He also carried out research as a consultant to the European Ozone Research Coordinating Unit.

He is survived by his wife Paula.