Mario Molina

MIT / University of California, San Diego

Mario José Molina was a Mexican-American chemist at MIT and UCSD who, together with F. Sherwood Rowland and Paul Crutzen, received the 1995 Nobel Prize in Chemistry for their work on atmospheric chemistry, particularly concerning the formation and decomposition of ozone. In a landmark 1974 paper with Rowland, Molina predicted that chlorofluorocarbons (CFCs) — the propellants and refrigerants widely used at the time — would diffuse into the stratosphere, where ultraviolet radiation would release chlorine atoms that catalytically destroy ozone. This ozone depletion would increase UV-B radiation reaching Earth's surface, posing severe risks to human health and ecosystems. Molina's prediction, subsequently confirmed by measurements of the Antarctic ozone hole in the 1980s, prompted the Montreal Protocol in 1987 — one of the most successful international environmental agreements ever negotiated. Molina later contributed to our understanding of polar stratospheric cloud chemistry and aerosol climate forcing. He passed away in 2020.