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Antarctica : The Hole Below Zero

August 31, 1986|Michael Parfit

SANTA BARBARA — Sometime in the next two months, word will come from 13 scientists in Antarctica about the condition of this planet's torn sky. Human beings everywhere will--or should--listen with attention. The voices that come floating up from the bottom of the Earth will be using words like ozone and chlorofluorocarbons and stratosphere, but they will be talking about human survival.

If this were fiction, the 13 would be astronomers tracking the collision course of a comet. But this is real life, as always more subtle than adventure novelists might prefer. The 13 are chemists and physicists and they went to Antarctica late this month to study a part of the atmosphere called the ozone layer. The occasion is stirring enough and this is a pilgrimage. There is symmetry and solemnity to this dramatic National Ozone Expedition, already known as NOZE at the National Science Foundation. The men and women who flew south on an extraordinary flight to the United States base at McMurdo Sound went to the continent that has become the world's first global community, in search of clues to what may be humankind's first true global disaster.

Some of the clues have already been identified; they lent urgency to this emergency expedition. In the 1970s scientists suggested that chlorofluorocarbons, more simply known as CFCs, were starting to eat away the ozone layer in the stratosphere. CFCs have been used, among other things, to blast aerosol spray out of the can. Ozone, which is three linked atoms of oxygen (regular oxygen is two), screens out much of the sun's ultraviolet radiation; if it is depleted, life on earth could be broadly damaged. Skin cancer would proliferate, crop yields could diminish, the ocean's food chains could suffer and climatic change might spread drought or floods across the globe. So the '70s CFC debate was one of the big environmental issues of the decade. Later, however, a well-publicized ban on CFC use in aerosol cans (they are still used in many other applications, like insulating foam and refrigeration), plus some ambiguous scientific reports, gave the impression that the problem was solved.

But down in Antarctica, on a remote British station at Halley Bay, the message from the sky was different. The lonely men based there trained their instruments on the dark and windy skies of Antarctica's bitter spring, and, from 1975 to 1985, saw the ozone layer coming apart. By last year, the spring-season ozone was about 50% thinner than what had been recorded before 1973. After they published their account for Nature magazine in 1985, a number of other groups that had also been looking upward went back to their computer printouts. They discovered that they had been recording the same thing; but, like a fisherman staring into water for trout who fails to notice the reflection of a bear on the bank, they hadn't taken alarm. Once the scientists took new notice, they found that data from NASA satellites and balloons sent aloft from other antarctic stations told the same story. The winds of summer always replenished the ozone over Antarctica, but each spring the thin spot--the hole, the rent in the protective fabric--returned. And it was getting bigger.

The early concern of the '70s was based on predictions of a decline of between 7% and 13% in the ozone layer. Now, suddenly, was an area of ozone about the size of the United States that was far thinner than anything previously expected. It was as if, in that science-fiction novel, the obscure astronomer charting his distant new comet had suddenly noticed the converging paths of Earth and star.

The discovery obviously raises questions. Is the bear on the bank a grizzly or just an odd-shaped tree stump? Is it likely to attack? So far, answers are vague. Antarctica is a special place on the globe, where almost everything is unique--life, weather, sky. This seasonal hole in the ozone may be caused by several factors, not all of them dangerous. It may be a natural pattern of weather, a cycle scientists haven't been able to chart because of its slow rhythm.

Susan Solomon of the National Oceanic and Atmospheric Administration, leader of the expedition, told a Colorado press conference before she left that the damage could be related to the special coldness of Antarctica. The stratosphere is so cold there that clouds form higher than anywhere else on earth. If the ozone is affected by chemical action within those particular clouds, that process might not hurt the rest of the planet at all. However, if this thinning is caused by CFCs in reactions that can gnaw at the sky anywhere, life on Earth is in trouble.

So, with these questions hanging, the expedition was put together in haste. It is supported by the National Science Foundation, NASA, NOAA and the Chemical Manufacturers Assn., which clearly has a stake. But blame, if there is to be any, must be shared among those who use the CFC stuff as well as those who manufacture it.

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