This startling discovery in 1985 alerted scientists and the world at large to a major environmental threat, as it was found that he accumulation of chlorofluorocarbons (CFCs) used in refrigeration and air conditioning systems, and industrial solvents deplete the protective layer of ozone that surrounds the Earth.

It led to significant global government action and the 1987 Montreal Protocol which has now been signed by all members of the United Nations. An agreement was made to phase out the production and consumption of ozone-depleting substances, and as part of his work in the Atmospheric Chemistry Research Group (ACRG), Professor Rigby helps to monitor how well countries are sticking to their promises on protecting the ozone layer.

Professor Rigby appeared on the show alongside Emeritus Professor Jonathan Shanklin of the British Antarctic Survey, who was one of the three scientists to first report the discovery of the hole in the journal Nature, and Alice Bell, head of climate and health policy at the Wellcome Trust.

The programme is available on BBC Sounds​.