"I can not, and I will not, cut my conscience to fit this year's fashions," remarked the American playwright Lillian Hellman many years ago. Most meteorologists aspire towards a similar stability of outlook, but public interest in their work is often dictated by the latest scare. Different facets of meteorology wax and wane in their current popularity.
Back in the 1950s, for example, analysis of the atmosphere for radioactivity was all in vogue as the Great Powers flexed their nuclear muscles. Then as agreement emerged that the testing of nuclear weapons should be banned, interest in such matters significantly declined - until an unfortunate incident at Chernobyl during the 1980s. Likewise, the energy crises of the 1970s gave great impetus to research into solar radiation, but interest waned again with the falling price of oil.
Nowadays, of course, the emphasis is on climate change and related matters concerning the environment.
The ozone layer was very much an issue in the early 1970s. On that occasion, the worry was caused, not by the CFCs that trouble us today, and which no one then had ever heard of, but by the arrival of SSTs, supersonic transport in the form of Concorde and the Russian Tupolev.
Aircraft engines emit oxides of nitrogen, and if these reach the ozone layer they act as a catalyst to facilitate the chemical destruction of ozone. Most subsonic aircraft operate well below the ozone layer, and the processes of the atmosphere are such that there is little upward transport of these pollutants to levels where they can act destructively in this way.
But SSTs are high flyers. They operate 17 km or more above the ground, just on the fringes of the ozone layer, and there was a very reasonable fear that great numbers of such aircraft would cause a serious depletion of the ozone.
At that time 500 such aircraft were planned for construction in the United States; scientists calculated that all these SSTs would cause a 16 per cent reduction in stratospheric ozone in the northern hemisphere, and a corresponding increase of some 6 per cent in the ultra-violet radiation penetrating to the surface of the Earth.
But the concern turned out to be ephemeral. Firstly, plans for the US fleet were abandoned, so a major part of the problem was removed; and secondly, more research and a better understanding of the stratosphere led scientists to believe the depletion would be less drastic than at first believed. As a result, everyone forgot about the ozone for a while - until an unexpected "hole", discovered over Antarctica in the 1980s, caused the UV panic to begin anew.