Montreal Protocol

Early History of the Ozone Layer Issue

Stratospheric ozone layer concentrations are rather small, making up only 8–10 parts per million of air at around 15–35 kilometers in altitude. A healthy ozone layer would average only 3 millimeters in thickness if compressed and measured at the Earth's surface. In the atmosphere, it is much less concentrated. However, this small concentration of ozone buffers ultraviolet radiation and aids in the regulation of the Earth's temperature and air circulation. In short, without the ozone layer, life on Earth could not exist. In 1974, chemists F. Sherwood Rowland and Mario Molina published an article predicting that chlorofluorocarbons (CFCs) would deplete the ozone layer. Molina and Rowland discovered that CFCs would persist long enough in the atmosphere to reach the stratosphere, where they could then be broken down by ultraviolet radiation that would release chlorine from the CFC molecule. These chlorine atoms could then potentially break down large quantities of ozone. Molina and Rowland would be awarded the Nobel Prize in Chemistry for their groundbreaking work on the ozone layer issue. However, early scientific research on the effect of CFCs on the ozone layer was hotly contested by the chemical industry. Yet, after Molina and Rowland testified before the U.S. House of Representatives in 1974, considerable funding was provided to tackle the problem. In 1976, the U.S. National Academy of Sciences confirmed the link between CFCs and ozone layer loss, leading to a flood of research on modeling the exact effect of CFCs on the ozone layer.

[Page 280]Based on this and other scientific evidence, in 1985—the same year that the first ozone hole was discovered in Antarctica—the Vienna Convention for the Protection of the Ozone Layer was established to initiate international cooperation in research on the potential of ozone layer loss resulting from human activity. Although not a legally binding agreement, the Vienna Convention set the stage for creating a framework for an international response to ozone layer protection. As late as 1987, the chemical industry still denied the validity of the scientific findings on CFCs, evidenced by the Alliance for Responsible CFC Policy's testimony before the U.S. Congress. Nevertheless, in 1987, the Montreal Protocol was ratified by 29 countries and the European Community, representing 83 percent of world CFC consumption.

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