Nobel Prize winner who revealed threat to the ozone
Mario Molina exposed the damaging effect of CFCs on the atmosphere and was a prominent voice in climate debates
Mario Molina shared a Nobel Prize in Chemistry for demonstrating the threat to the ozone layer posed by CFCs, chemical compounds often found in refrigerants and hair sprays and whose use was later curtailed by a landmark international accord.
He died on 7 October at his home in Mexico City. He was 77. The cause was a heart attack, says Lorena Gonzalez, a spokesperson at the Centro Mario Molina, a nonprofit environmental organisation Dr Molina
founded in Mexico City.
CFCs were widely used in air conditioner and refrigerator coolants, spray paint, deodorant sprays and other aerosol products. Working with Rowland, Molina discovered that, far from having no significant effect on the environment, CFCs presented a grave risk to the ozone layer, a thin segment of the atmosphere that absorbs the ultraviolet rays of the sun. Unfiltered, those rays can cause skin cancer and other health problems in humans and damage the natural environment on Earth.
According to research by the two scientists, CFCs released into the atmosphere floated to ever-higher altitudes, where they broke down and released chlorine atoms – even one of which could destroy 100,000 ozone molecules. “We were alarmed at the possibility that the continued release of CFCs into the atmosphere would cause a significant depletion of the Earth’s stratospheric ozone layer,” Molina wrote.
In 1974, he and Rowland published their findings in the journal Nature. They met fierce resistance from industry leaders whose lucrative businesses relied on CFCs. In 1977, according to the Los Angeles Times, the chief of one aerosol manufacturer alleged that their theory was “orchestrated by the Ministry of Disinformation of the KGB”.
But in 1985, British researchers tracking ozone readings in the Antarctic announced the discovery of a significant thinning – a hole, as it became known – in the ozone layer above the South Pole.
Those findings spurred international action to curb the use of CFCs. Adopted in 1987, the Montreal Protocol regulating man-made ozone-depleting chemicals is today the only treaty ratified by all members of the United Nations. In an obituary for Molina, Science magazine described the accord as “the most successful international effort to fight climate change and environmental degradation”.
In 1995, the Nobel Prize in chemistry was awarded to Molina, Rowland and Paul Crutzen, a Dutch-born scientist then associated with the Max Planck Institute for Chemistry in Mainz, Germany.
The three researchers have contributed to our salvation from a global environmental problem that could have catastrophic consequences
“The thin ozone layer has proved to be an Achilles’ heel that may be seriously injured by apparently moderate changes in the composition of the atmosphere,” the Royal Swedish Academy of Sciences said in announcing the Nobel.
“By explaining the chemical mechanisms that affect the thickness of the ozone layer, the three researchers have contributed to our salvation from a global environmental problem that could have catastrophic consequences.”
Jose Mario Molina-Pasquel y Henríquez was born in Mexico City on 19 March 1943. His father was a lawyer and later a Mexican ambassador to several countries. Molina was drawn to science even as a child and