In the mid-1980s, scientists uncovered a troubling phenomenon: The ozone layer, which protects all living things on Earth from the Sun’s ultraviolet radiation, was rapidly thinning over Antarctica. The discovery set off a race by scientists to figure out what was causing the ozone hole, and eventually the realization that chlorofluorocarbons used in refrigerators, air conditioners and aerosol cans were reacting in the stratosphere and producing chlorine-containing compounds that were depleting the ozone layer. This work led to the signing of the Montreal Protocol and several key amendments, which banned most ozone-depleting substances and is considered one of the greatest environmental achievements of the 20th century.

In this second episode of Third Pod from the Sun’s Centennial Series, hear from two NASA scientists who started their careers just as the ozone hole was discovered, and who have continued working on and monitoring the issue for decades.