THE HOLE IN THE SKY

The destruction of ozone by chemical pollution threatens our planet,

writes Myles Harris FOR many years now scientists in the Antarctic have been paying particular attention to the density of the ozone layer, a condensation of gas in the upper atmos- phere that protects us from the harmful effects of sunlight. Fears had been express- ed that it might be the first of the atmos- pheric gases to crumble under the strain of pollution. Ozone is known to be particular- ly vulnerable to the constituents of aerosol sprays, refrigeration fluids, fire exting- uisher propellants, industrial solvents and the gases used to expand polystyrene in such products as egg boxes and fast-food cartons.

Substances known as CFCs used in the manufacture of these products contain chlorine in a harmless form. They are very light and when released into the air float up into the ozone layer. There, under the action of sunlight, the chlorine is released. One part of raw chlorine will destroy 100,000 parts of ozone.

Losing the ozone layer, ecologists say, would expose the surface of the planet to a considerable rise in the amount of ultra- violet light coming from the sun. Not only would this produce an increase in skin cancers and cataracts in humans but also a partial destruction of the world's vegetable and aquatic life. While there is some debate as to how serious the latter effects might be, what is in no doubt is the effect of such gases on the world's temperature. As well as the destructive effect of chlor- ine, CFCs possess 100,000 times the insulating properties of the normal consti- tuents of air, and should they reach the upper atmosphere in appreciable amounts they would, in effect, wrap an extra blank- et around the earth.

In 1975 the Americans, reacting to the mention of their biggest tribal bogey, cancer, banned the most obvious source of these poisons, aerosols. But they did no- thing about a whole range of other pro- ducts. The average air-conditioned car, for instance, spills two pounds of chlorine into the upper atmosphere each year, while the crushing of a hamburger carton releases millions of tiny balloons of toxic waste into the air.

The other major producer, the British, probably scandalised by the thought of air-conditioned cars, formed a Stratospher- ic Research Advisory Committee.

As it turned out, American fears were unfounded. Between 1957 and 1979 the density of the ozone layer remained, within minor limits, so constant that interest was largely lost. After a few years the Strato- spheric Committee was allowed to die in one of the upper rooms of the Department of the Environment and the Americans, thinking they had better things to do with their 20-million-dollar Nimbus satellite, reset its chemical nose to measure more exciting things than low concentrations of ozone.

But, down on the southern ice cap, scientists of the British Antarctic Survey saw no reason to change their time- honoured routines. In meteorology you need patience. With instruments invented in 1931 they went on taking measurements over the pole. Even the name of the instrument they used, the Dobson spec- trophotometer, relegated the whole busi- ness to a world of Ovaltine, wireless and Winnie the Pooh. This was British science at its best — underfunded, socially divided and rather working class. The more these chaps are starved of money, you could almost hear the Sir Humphreys of the The EEC must have gone into family planning.' Treasury saying over their sherry, the harder they'll try.

They were right. In 1985 the ancient spectrphotometers, brushing aside the radio signals of the American weather satellite, announced one of the major scientific discoveries of the century.

A giant hole, swirling about in the cold Antarctic air currents like water going down a plug hole, had appeared in the sky over the Antarctic cap. Reaching from 30,000 feet to 150,000 feet it covered an area roughly the size of the United States. Through the camera eyes of the hastily reset American Nimbus satellite the hole appeared as a mass of conflicting colours — purples, blacks, yellows and reds. A bruise on the earth's surface. What exactly it meant for our future nobody knew. It appeared in early September, reached its maximum size in mid November and by early December was gone. It was to come back earlier and earlier. . . .

Last week, at the British Antarctic Survey headquarters just outside Cam- bridge, I met the man who discovered it. Described by a colleague as 'one of the last of the gentleman scientists', Joe Farman is a rather sparrow-like man with bright blue eyes and a highly diverting, if apparently random, flow of ideas. A physicist, he started life making abstruse calculations on missile flight paths for De Havilland but, tired of engineers who never listened to scientific predictions, and a keen moun- taineer with an interest in seismology, he joined an expedition to the Antarctic in 1956. I asked him what the Antarctic was like. 'Beautiful and dreadful,' he said.

Lighting a pipe that smelled like old blankets, he spoke about 1985. 'It was beyond all belief. One day we woke up to the discovery that the ozone over the Antarctic was falling away from us.' He reached down behind his desk and held up three telephone-directory-sized books, a Nasa compendium of everything known about ozone. 'All these', he said with a grin, 'had to be rewritten.'

I asked him about later reactions to his discovery. While their figures were never disputed the theory of how the hole was caused came under attack. Many scientists said it could be a natural phenomenon unique to the Antarctic, an idea that, not unexpectedly, found considerable support among industrial producers. But the con- sensus now is that chlorine pollution is the cause.

He did not think it was safe to wait for further proof. If we did the results might be catastrophic. What we are seeing over the pole we might well see elsewhere very soon, suddenly and without warning. He showed me the latest readings from the Antarctic. A thin, pencilled line staggered across the page. This year the hole is much bigger.

Last week in Montreal negotiations be- gan between 40 countries to try to reach international agreement on limiting the use of CFCs, a million tons of which leak into the stratosphere each year. The Americans want an 85 per cent cut, Britain and the rest of Europe 20 per cent. If you allow for the difficulties of policing such a treaty, the latter probably represents a small increase, something that Britain's Department of the Environment may have been after all along. Certainly, Fiona McConnell of the DoE was, when I spoke to her, sceptical of the American position, describing it as having 'an element of hype'. It is however unlikely that the DoE will be disappointed. Third World countries, including Brazil and Argentina, are negotiating an increase in production. At the time of writing, reports from Montreal speak of 'the forg- ing of a historic treaty to ban CFC produc- tion'. Details of the agreement, arrived at in secret against a background of third world objections, represent, it is said, a compromise between the American posi- tion and that of the EEC. The treaty is yet to be voted upon by the conference in plenary session. More importantly it has to pass the difficult hurdle of individual rati- fication by member states, many of whom, especially in the third world, feel their commercial interests are being damaged. But even if they all agree, any cut less than the 85 per cent asked for by the United States in the first place will be woefully inadequate.

This is a pity, because in Europe and North America CFC manufacturers will go along with any legislation, however strin- gent, that is imposed on them — if it is effective. Self limitation and 'codes of practice' in an industry that turns over 30 billion dollars a year are out. Competition is too fierce. Governments must make the law, not companies. In the third world it is anybody's guess.

What could happen? Nobody now doubts the warming effects over the next 50 years. The most frightening possibility is that something will happen suddenly. Many scientists, although reluctant to admit it, even to themselves, believe that the world's atmosphere is poised on a knife edge. Just as the hole in the sky appeared without warning so a large volcanic erup- tion, a surface nuclear explosion or perhaps some external event such as a solar flare might start a chain of events which will rapidly dim the lights of civilisation. As the earth heats rapidly violent atmospheric disturbances could come, while within a year we could look on fields that had withered under a sun which had the power to blind and destroy. For many more countries, even in Europe, famine would no longer be something watched on televi- sion.

Before I left Cambridge I asked Joe Farman if he felt frightened about the future. He was not, he said, doing much singing and dancing about it. 'Nature', he added, 'has not yet found the instruction manual on how to deal with this, but when she does, watch out.'