Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: WEDNESDAY, April 10, 1991 TAG: 9104100417
SECTION: EDITORIAL PAGE: A-6 EDITION: METRO
SOURCE:
DATELINE: LENGTH: Medium
This means, according to the Environmental Protection Agency, that during the next 50 years, about 12 million Americans will get skin cancer, and more than 200,000 will die from it. But, hey, 50 years is a long way off, and who knows anyway what range of risks life will pose after we're gone?
The long lead times are part of the problem; they ought to be part of the solution. Ozone depletion is a reversible process, but change can take many years - reducing any sense of urgency.
Ozone is a form of oxygen that contributes to air pollution at Earth level if combined with certain emissions. Far up in the atmosphere, though, it helps screen out the sun's ultraviolet rays.
Chlorofluorocarbons, or CFCs, are chemicals that have long been used in aerosol sprays and refrigerants. Down here they're inert and harmless. However, when they ascend to the atmosphere - which takes about seven years - the chlorine in them reacts with the air to destroy ozone. This effect first was noted in the mid-1970s, and the scientific evidence was so strong that the federal government banned use of CFCs in non-essential spray propellants.
But these cheap and handy chemicals kept spreading. Worldwide use of CFCs in 1988 totaled 2.5 billion pounds. Having limited some use, the U.S. government settled back for a decade and did nothing.
The ozone-depletion theory jumped off the graphs and into the real world in 1985, when British scientists discovered that every year for the past decade, ozone levels in the Antarctic had plunged when the summer sun returned. Concern about these discoveries brought about an international conference and a treaty, in effect since January 1989, calling for CFC production to be halved by the year 2000.
Meantime, the reports get worse. A re-evaluation of measurements worldwide showed in 1988 that ozone was dropping everywhere, not just over the South Pole. Now come data indicating the depletion rate over America is twice as bad as had been thought. Efforts are afoot to strengthen the 1989 treaty.
Chemical giants such as Du Pont are gearing up to produce a replacement, hydrochlorofluorocarbons, or HCFCs. These can destroy ozone too, but at only about a tenth the rate of CFCs. Environmentalists would also like to put a cap - say, the year 2010 - on how long HCFCs could be used. Given the pay-back interval industry needs for such investments, that may not be enough time to get full-scale production of HCFCs and develop still another alternative.
Refrigeration is not just a luxury. Cooling food, drugs, certain chemicals and other products is essential to a healthy life for millions of people.
But neither is ozone depletion just a curiosity. If more ultraviolet rays reach the Earth, not only would skin cancers increase; the light also can destroy proteins and DNA, the stuff of heredity. It can kill tiny organisms on which ocean life feeds, disrupting aquatic food chains.
We have advance warning. Precious time was frittered away between the mid-1970s and mid-1980s. That shouldn't be allowed to happen again.
by CNB