Losing Our Ozone Shield

November 08, 1991

The discovery of the "ozone hole" over Antarctica aroused worldwide concern when it was announced. The first definitive evidence of deterioration in the upper atmosphere's protective layer, it led to the Montreal Protocol mandating phaseouts of ozone-depleting CFCs used in refrigerants and the manufacture of plastic foams, and halons used in fire extinguishers. The U.S. and other industrialized countries have until 2000 to comply; developing nations must do so by 2010.

But the Montreal Protocol provides too little, agreed upon too late. New findings show the ozone shield thinning out and not recovering during summer months as once believed. This thinning allows heavier than normal doses of ultraviolet radiation to pass through the atmosphere and reach the ground. That heightens the risk of skin cancer for people who vacation or engage in extensive outdoor activity. It also threatens damage to agricultural crops and disruption of marine feeding patterns.

The situation is deteriorating. In April, the Environmental Protection Agency said that during the last decade, the size of upper-air ozone diminished by 4.5 percent over the U.S. The EPA said this meant 12 million Americans would develop skin cancer. More than 200,000 could die in the next half-century.

A 80-member U.N. team used new ground instruments and satellites to find that during the 1980s the Northern Hemisphere ozone layer shrank by 3 percent in the months of May through August, triple the rate for the 1970s; the Southern Hemisphere's ozone layer decreased by 5 percent from December to March -- its summertime.

This data persuaded Germany to accelerate its phaseout timetable. Instead of 2000, Germany plans to end CFC use in 1995. Europe generally had been ahead of the United States on the phaseout, due to Bush administration recalcitrance. Now, with new evidence that atmospheric deterioration is accelerating, every country will need to reassess its stance -- without delay.

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