N-War ‘threat to ozone layer

Press, 6 May 1983, Page 7

N-War ‘threat to ozone layer

Half the ozone layer in the world’s atmosphere could be destroyed if there was a full-scale nuclear war, Professor Hans Panofsky told a meeting of the Christchurch branch of the Royal Society .

The amount of damage to the ozone layer would depend on the types of weapons and where they were used, but the damage would make it “a very hard world to live in, even in New Zealand,” he said.

The ozone layer would eventually be replaced, but it would take a very long time.

Professor Panofsky, an Erskine visiting fellow in the department of mechanical engineering at the University of Canterbury, was speaking to the society about threats to the ozone layer.

He has been in New Zealand for four months and will leve in a week. He is the Evan Pugh research professor of atmospheric sciences at Pennsylvania State University. For more than six years he has been a member of the United States committee which studied the ozone problem and which recommended the banning of fluorocarbon propellants in the United States.

Professor Panofsky said that there was little ozone in the stratosphere. There was only one ozone molecule for every 100,000 molecules. If all the ozone was brought down to Earth’s surface it would measure only 4mm deep. But this small amount of

ozone had big effects It cut out the range of ultra-violet light which caused both the mild form of skin cancer caused by a lot of ejposure to sunlight and the more deadly melanoma. It was estimated that if the ozone layer was reduced 10 per cent there wodd be a 20 per cent increase in the amount of ultra-violet light, which would lead to an increase in skin cancer. A cut in ozone codd also lead to a potentially ierious change to the vorld’s weather, although it was not clear whether the dimate would cool down or warm

up. Professor Panofsky said that small amounts ol trace gases could destroy the ozone. Such gases wets generated by supersonic transport, fluorocarbons if propellants, air condiioning and refrigeration unit, and by certain types of fertiliser.

Experts in the fidd no longer felt that contols on the use of fluorocarbons were urgently needid, he said.

When the United States set up the commitee to investigate the ozone problem in 1976, it was. bought that fluorocarbons coild reduce the ozone layei 7 per cent, which would leid to a 20 per cent increase in skin cancer. Fluorocarbore were seen as a danger lecause they produced chokride in the stratosphere. Thi chloride broke down ozode..

After further investigations, the prevailing opinion now was that fluorocarbons were not such a bjd problem.

“It may lead to a de-

crease in the ozone layer of something in the order of 5 per cent, which is not very serious.”

However, the whole question was complicated and it could change again. Climatic changes were another complicating factor. The amount of carbon dioxide in the atmosphere was increasing. It trapped heat radiation near the ground, which led to warmer temperatures on the ground and cooler temperatures in the stratosphere. By the middle of next century temperatures were expected to be an average of 2deg. warmer near the ground. Although many people might like that thought, it could become a serious problem if the polar ice caps melted and raised the ocean level.