Scientists give chilling reminder of ozone fears

The ozone hole, which opens up each spring above heavily populated areas of northern Europe, including Ireland and Britain, may be causing colder weather which in turn helps to destroy ozone even faster. The last three winters were the coldest on record in the upper atmosphere where damage to the earth's protective ozone occurs, according to a British scientist, Dr John Pyle. There are now fears that the lost ozone might have some part to play in the colder temperatures.

Dr Pyle, of the University of Cambridge and chairman of an international group studying ozone loss, was speaking at the annual festival of the British Association for the Advancement of Science in Leeds. Ozone helps to reduce the amount of ultraviolet radiation reaching the earth and any reduction means more rays can get through. Higher cancer incidence, cataracts and potential damage to plant life are linked to excessive ultraviolet exposure. The chemistry involved in ozone depletion is well understood, Dr Pyle said, with chlorine and bromine-based chemicals able to destroy ozone during the Arctic and Antarctic springs when temperatures 10 to 30 km above the earth are at their coldest within the "polar vortex".

The Arctic has been losing about 0.8 per cent of total ozone each year throughout the 1980s and 1990s, he said. The damage is less if the temperatures do not fall low enough but there has been a gradual trend towards colder air above the Arctic during the spring, with the last three years giving record low temperatures. "The important question we are still looking at is why the last three winters had record lows," he said. There are concerns that the ozone loss might have a role, creating a feedback which could serve to accelerate the loss. New studies show that ozone loss is unexpectedly accelerating beyond the edges of the polar vortex, well down into the middle latitudes over Ireland, Britain, Scandinavia and northern Germany.

More than 20 per cent of ozone above the middle latitudes was lost last spring and almost 25 per cent the year before, he said. This loss provides a new focus for research, with naturally occurring sulphur compounds thought likely to interact with the man-made chemicals in an unexpected reaction. The chief executive of Britain's Natural Environment Research Council, Prof John Krebs, warned that human health and environmental health could not be separated.

Science, he said, was helping to "disentangle the complicated web" of the earth's environmental systems, but it was a difficult task. Efforts were not made easier by "short-termism" in research funding and planning.

The director of the International Geosphere and Biosphere programme, Prof Chris Rapley, said that sustained development could not occur without the involvement of scientific research.