In the Aug. 12 Washington Post a statement taht depletion of ozone and chlorofluorcarbons in the atmosphere could cause profound changes in the climate and agriculture was attributed to Herbert L. Wiser, an Environmental Protection Agency science adviser. Wiser was referring to climate changes because of alterations in the amount of carbon dioxide in the atmosphere.
Government scientists have found the first evidence from the field that chlorofluorocarbons -- once used as propellants in aerosol sprays and still widespread in American industry -- may be eating away at the ozone layer that protects Earth from dangerous ultraviolet radiation.
If enough ozone is destroyed, more radiation could reach Earth and cause climate changes, crop damage and many more cases of skin cancer.
Since 1974, scientists have theorized that chlorofluorocarbons -- CFCs for short-- damage the ozone. But this is the first evidence of actual depletion in the ozone layer.
These heretofore-unpublished scientific findings are preliminary, and researchers are quick to caution that the depletion is slight. However, the findings appear to contradict assertions of the chemical industry, echoed by congressmen, that ozone depletion from chlorofluorocarbons is just a theory that never has been supported by actual study of the ozone layer itself.
CFCs were banned from most aerosol sprays in 1978 because of concerns for the ozone. However, more than 800 million pounds of CFCs continue to be produced in the United States each year and used in foam products, refrigerators, air conditioners and solvents.
New data from satellites show that some depletion apparently has occured in recent years in the area of the ozone layer most vulnerable to CFCs -- about 30 miles above the ground, according to three scientists with the National Aeronautics and Space Administration.
"This is the first real indication we've had that there is any stratospheric depletion," said Shelby G. Tilford, chief of atmospheric processes at NASA. The other two are Robert T. Watson, a program scientist, and Lawrence R. Greenwood, director of environmental observations.
They cannot establish a cause-effect relationship between CFCs and the depletion, but say that nothing else seems a likely culprit. They also stressed that overall ozone -- including ozone near ground level-- actually may have increased in the last decade. But they said that because ozone in the upper levels is most sensitive, any depletion there may be an omen of larger reductions to come.
To further study the cause-effect relationship of CFCs on ozone, a Harvard University scientist will launch a giant helium balloon, 100 times as large as the Goodyear blimp, that will act as a giant yo-yo in the stratosphere. There the balloon will gather data on chemical reactions and help establish the causes of ozone depletion.
James G. Anderson, a Harvard professor of chemistry, said the balloon will ascend 28 miles above Earth, and then in an hour's time will lower an instrument packet on a line down 12 miles and reel it back up. Anderson said he would launch the balloon, which is paid for by a $150,000 grant from NASA, from New Mexico within nine months.
CFCs, often known by their DuPont trademark, Freon, are inert, very stable, non-toxic and non-flammable. These virtues also are a vice, for their hardiness means that they do not break down at ground level but survive until they float up to the ozone level. There, about six to 30 miles above Earth's surface, the CFCs are thought to react with the ozone and destroy it.
Measurements taken from balloons show steady increases in the number of CFCs in the stratosphere, said William D. Kleis, a program development scientist at the National Oceanic and Atmospheric Administration in Boulder, Colo. Ground stations also show steady increases in CFCs at ground level, even in isolated places in Alaska and Hawaii, Kleis said.
The Environmental Protection Agency published a notice in the Federal Register last October that it might set limits on the production of CFCs, but EPA seems to have backpedaled since then. New EPA Administrator Anne M. Gorsuch indicated in a letter to a Senate committee she would be suspicious of new regulation of CFCs.
While research for alternatives is continuing, largely by industry, there now is no cheap, safe and effective substitute for CFCs for most uses. However one variety, known as CFC-22, contains hydrogen and is much less damaging to ozone. While CFC-22 is not as cheap as other types, it perhaps could be used in their place for many applications, said Paul W. Halter, environmental manager of the Freon Products Division of E. I. duPont de Nemours & Co.
Bolstered by an extremely well-organized lobby of CFC producers and users, Sen. Lloyd M. Bentsen (D-Tex.) and Rep. Thomas A. Luken (D-Ohio) have introduced bills that would impede the EPA from placing new limits on CFCs. Luken's bill has 64 cosponsors; Bentsen's has 17.
The crux of the issue is how much ozone the CFCs will destroy. The earliest figures were that if production remained steady, CFCs would deplete the ozone by about 7 percent. A National Academy of Sciences report raised that to 16.5 percent, but now most scientists place the figure back in the range of 5 to 10 percent.
These are figures in the long term, up to 100 years away, and one problem that has made actual detection of ozone depletion difficult is that CFCs can take decades to rise to the stratosphere and disintegrate.
Increased ultraviolet radiation resulting from ozone depletion apparently can damage crops, kill fish, and cause skin cancer, said Herbert L. Wiser, an EPA science adviser who awards $1 million in grants each year for further research in the effects of such radiation.
The degree to which fish or crops could be damaged is not known, Wiser said, but each percentage point drop in ozone levels is thought to cause a 4 percent increase in non-fatal skin cancer. Thus an 8 percent depletion in ozone could increase this form of skin cancer by 32 percent. Ultraviolet radiation also contributes to fatal skin cancer, but the relationship is less certain, he said.
CFCs and ozone depletion also could change the climate, potentially creating havoc in agriculture and changing Earth's geography, Wiser said, although he stressed that this is speculative.