In 1987, countries around the world agreed upon the Montreal Protocol, a treaty to eliminate chemicals which deplete the ozone layer. Frank Rowland and Mario Molino deserve the credit for this, for they showed exactly how CFCs destroy ozone.
Frank Sherwood Rowland was born in Ohio, USA in 1927. He obtained his BA from Ohio Wesleyan University in 1948. He went on to do his M.S. and then Ph.D. at the University of Chicago. In 1964, he became Professor of Chemistry at the University of California, Irvine, where he still works.
José Mario Molina-Pasquel Henríquez (pictured) was born in Mexico City in 1943. He studied chemical engineering at the National Autonomous University of Mexico in 1965, and then did his postgraduation from the Albert Ludwigs University of Freiburg, West Germany in 1967. He got a PhD in Chemistry from University of California, Berkeley in 1972. He now works at the University of California, San Diego.
Molina worked as a post-doctoral scholar in Rowland’s laboratory in 1974. They together heard a lecture, in which James Lovelock’s data on CFCs in the atmosphere was presented. Intrigued, they started further investigations. They discovered that CFCs decompose in sunlight, to release chlorine atoms. Chlorine atoms convert ozone to oxygen, and can then attack other ozone molecules. A single atom can destroy millions of ozone molecules before it is neutralized.
Cl + O3 -> ClO + O2
ClO + O3 -> Cl + 2O2
Molina and Rowland’s findings were published in 1974 and shocked the entire world. Their findings were later confirmed by scientists around the world, especially the British Antarctic Survey in 1986. This led to the Montreal Protocol of 1987 that banned CFCs around the world. They received the Nobel Prize for Chemistry in 1995.
Rowland and Molina showed how a single chlorine atom can destroy millions of ozone molecules.