Facing Destruction by Refrigeration

February 09, 1992|By DOUGLAS BIRCH | DOUGLAS BIRCH,Douglas Birch covers science for The Baltimore Sun.

While the threat of nuclear annihilation seems to be fading, we find ourselves menaced by a far humbler technology: some of our cherished consumer appliances.

When NASA scientists said last week they discovered record levels of ozone-destroying chemicals over the Arctic, we didn't need any Strategic Defense Initiative to spot the weapons of mass destruction.

There they are, many of them: 160 million home refrigerators, 130 million air conditioned autos and 80,000 office buildings with chillers that keep us crisp in the blistering summer heat.

Millions of other long-discarded and forgotten aerosol cans, appliances and other items are also to blame.

All these products use or used a family of gases called chlorofluorocarbons, or CFCs, which eventually leak from their containers and migrate into the upper atmosphere.

There, through a complex chain of chemical reactions, they form reactive chlorine that destroys ozone -- a molecule of three oxygen atoms that keeps most of the sun's damaging ultraviolet light from reaching our planet's surface.

In the 1970s, concern about the global ozone layer led to $H restrictions on the use of CFCs. Then, the discovery of a seasonal hole in the ozone over Antarctica in the early 1980s led to a worldwide ban on their manufacture by the year 2000.

But it wasn't until this year that scientists began focusing on the effects of ozone destruction in the populous, industrialized Northern Hemisphere -- where most of the CFCs are produced and used.

A group of NASA scientists, who launched their study of the arctic atmosphere last fall, grimly told reporters last week they had found the highest levels ever recorded of reactive chlorine over the Arctic.

They warned it was "increasingly likely" those chemicals will chew a huge hole in the ozone layer above the North Pole, exposing the Northern Hemisphere to high levels of damaging ultraviolet light.

"None of the news is good," said James G. Anderson of Harvard University.

The announcement prodded the Bush administration to say it will support accelerating the worldwide CFC ban, implementing it in 1996 or 1997.

But CFCs are stubbornly long-lived. Even after the ban, the chemicals' ozone-damaging breakdown products -- including chlorine monoxide and bromine monoxide -- are expected to remain in the atmosphere at destructive levels until the middle of the next century.

Erosion of the ozone layer will be a quiet catastrophe, more likely to show up in tables of numbers published by the World Health Organization than on the 11 o'clock news.

Pedestrians will not be burned to cinders as they stroll down the street. Ambulances wouldn't speed stricken sunbathers to emergency rooms.

Instead, over the next decade or so, people who work or play outside might notice they tan more quickly and burn more easily.

Gradually, more people are expected to get cataracts and skin cancers. Infectious diseases may spread more quickly, crops might wither and plant and animal species might disappear at a faster rate.

How many people would get sick? How many would die?

A U.N. study, released in November, said the world will see 300,000 more skin cancer cases, a 26 percent increase, by the turn of the century and 1.6 million more cataract cases.

Melanoma, a deadly form of skin cancer, was expected to claim an extra 3,000 deaths a year worldwide by 2000.

But Stephen Seidel, deputy director of the Global Change Division of the Environmental Protection Agency, said there will be more illnesses than the U.N. predicted if Arctic ozone destruction is as massive as NASA fears it could be.

How much worse could it get? "Until we see what depletion has occurred, it's really impossible to say," he said.

Should we get nervous?

Should Marylanders wear suntan lotion and hats, spend more summer weekends indoors and avoid long days on the beach at Ocean City?

Well, maybe.

So far, ozone destruction hasn't had much of an impact at this latitude, said John E. Frederick, a professor of atmospheric sciences at the University of Chicago.

For Marylanders, the increase in ultraviolet radiation over the past ten years is the equivalent of having stayed in the sun an extra three minutes each hour.

Dr. Jose Rodriquez, a scientist with Atmospheric and Environmental Research Inc. in Cambridge, Mass., said a day sunbathing on a Caribbean island today would be much riskier, in terms of ultraviolet radiation poisoning, than a day living in the northern United States -- even with a significantly thinner ozone layer.

Even a significant thinning of ozone might be blunted over most of the United States by several factors. One is pollution. Smog, it turns out, helps screen out ultraviolet light.

Dr. Frederick also said that Arctic ozone holes are most likely to occur toward the end of February or beginning of March -- a time when few people spend a lot of time outdoors.

While the center of the hole will remain over the pole, he noted, any portion that drifts south over more populated regions is likely to pass quickly overhead.

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