Trying to Fix Holes in the Sky

OF all the scientific meetings held in the United States, the annual meeting of the American Association for the Advancement of Science is one of the oldest and certainly is the most diverse. Therein lies its broad appeal.

This year's gathering of the 146-year-old AAAS drew some 5,000 scientists, administrators, policymakers, teachers, students, and just plain interested folks. They came to join in a variety of discussions seasoned with concern for the common welfare and enlivened by a desire to ``do something'' about such challenges as destruction of the ozone layer and general environmental decay.

With such an eclectic assembly and such ``hot button'' topics, you couldn't be sure what would come up when some 700 speakers addressed more than 125 concurrent sessions and 30 press conferences. So even a reporter who has covered the AAAS for 43 years was caught off guard when a distinguished scientist leaned across the speakers' table and apologized to the reporter for what he was about to say.

The topic was the danger of looking for a quick technological fix for environmental damage. The venue was a press conference on ``Engineering the Earth's Climate.'' Stanford University environmental scientist Stephen Schneider explained that the reporter would have heard it all before because they had discussed it 25 years ago. However, he added that, far from being ``old hat,'' the caveat should be reemphasized today. He warned that yearning for a technological fix can lead politicians and the public to misinterpret what scientists say on the subject and induce a false sense of security.

That may explain why an editor later asked the reporter about healing the Antarctic ozone hole by spraying propane into the air. What atmospheric chemist Ralph Cicerone of the University of California at Irvine actually told the press was that his group had studied that possibility and found it wouldn't work. Apparently, the idea is so appealing that a radio news report of Dr. Cicerone's comments conveyed the opposite message.

That's the way it is at AAAS meetings. Scientists try to promote better understanding of public issues. Sometimes their caveats and reservations are misunderstood or twisted by advocates of a ``cause.'' But as many of them repeatedly explain, they feel both a professional and a moral obligation to contribute what they can to the debates.

Actually there is some good news about the ozone layer to report from this AAAS meeting. The Montreal Protocol is beginning to bite. That's the international agreement to phase out release of ozone-destroying chloroflurocarbons (CFCs) by 1996. University of California, Irvine, chemist F. Sherwood Rowland says the rate of increase in atmospheric CFC concentrations has been cut in half - dropping from a four percent annual increase in the 1980s to two percent. His group routinely samples CFC concentrations from Alaska to New Zealand.

Dr. Rowland said we can look forward to an end of CFC buildup by the end of the decade. But these compounds have such a long lifetime in the stratosphere that it will take a century to be rid of them.

Meanwhile, Cicerone said he will continue to study possible ways of repairing ozone damage. But it is a far-out prospect. He hopes his listeners will remember that when he reports progress at future AAAS meetings.

He further explained that the real purpose of his work is not so much to find ecological fixes for environmental problems right now as it is to lay the groundwork for thinking about such things. He said that it was a very complex subject with many ramifications. But humanity should be prepared to do whatever it could several decades from now if serious trouble is encountered.