Stratospheric ozone depletion by chlorofluorocarbons

PHYS 223

F. Sherwood Rowland, rowland@uci.edu, Department of Chemistry, University of California, 571 Rowland Hall, Irvine, CA 92697
The abstract of the first paper by M. J. Molina and F. S. Rowland read: (Nature, June 28, 1974, pages 810-812) “Chlorofluorocarbons are being added to the environment in steadily increasing amounts. These compounds are chemically inert and may remain in the atmosphere for 40-150 years, and concentrations can be expected to reach 10 to 30 times present levels. Photodissociation of the chlorofluoromethanes in the stratosphere produces significant amounts of chlorine atoms, and leads to the destruction of atmospheric ozone.”

Extensive experimental study by very many scientists has established that ozone depletion has occurred, especially in the springtime Antarctic stratosphere. The further manufacture and release of chlorofluorocarbon molecules into the atmosphere has been banned under the 1987 Montreal Protocol of the United Nations and its subsequent modifications. The atmospheric burden of CFCs is now slowly decreasing, well short of the expected concentrations had they not been banned.