Mario Molina was a postdoctoral fellow at the University of California in 1974 when he published a paper in the journal Nature, outlining the threat to the environment posed by chemicals used in everyday spray cans, refrigerators and air conditioners. Chlorofluorocarbons -- CFCs -- were destroying the Earth's ozone layer, the atmospheric shield that protects living organisms from the ultraviolet radiation of the sun. Without the ozone layer, animals and plants could not exist on land, and the balance of oceanic life would be destroyed.
For years, Molina's ideas were dismissed and ridiculed by the chemical industry, but in 1985, a huge hole in the Earth's ozone layer was discovered above Antarctica, and Molina's hypothesis was vindicated. Today, the nations of the Earth have collectively abandoned the use of CFCs, and a global environmental catastrophe has been averted.
Mario Molina was awarded the Nobel Prize in Chemistry for his discovery. He is the first Mexican-born scientist to receive the chemistry prize. Today, he continues his work in the United States and Mexico, to prevent and repair human-made damage to the Earth's atmosphere.