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BBC News Online: Sci/Tech

Friday, 25 February, 2000, 02:46 GMT

Ozone layer 'thinning over Europe'

There is fresh evidence that the ozone layer is thinning over the UK and northern Europe.

Scientists are alarmed by the depletion, which was previously thought to be a problem mostly confined to the Southern Hemisphere.

Ozone protects the Earth from the Sun's ultraviolet radiation, and doctors are concerned that if it is eroded more people will suffer from skin cancer.

Meteorological readings taken in the stratosphere over the Arctic show that in six of the past 10 winters, ozone has thinned to half its normal concentration.

Gradual warming

It seems that the same gases responsible for the "greenhouse effect" - claimed by many scientists to be gradually warming the Earth - are simultaneously making the stratosphere cooler.

The main greenhouse culprit is carbon dioxide, largely created by the burning of fossil fuels.

While in the lower atmosphere, it is quick to absorb heat which it reflects back towards the planet.

However, once in the stratosphere, above about 12 km, the greenhouse gases cool quicker than ordinary air and ice crystals form in the lower temperatures.

That is bad news for the ozone layer because the ice clouds give ozone-depleting chemicals - particularly chlorine - somewhere to come together and react.

Cancer warning

The ozone layer normally absorbs a certain amount of the Sun's ultra-violet radiation but where it is depleted more of the radiation passes through to the Earth. Dr Hanson

Scientists are so worried about the evidence of thinning ozone they have gathered in Kiruna, Sweden, to undertake the biggest investigation yet into how the gas is being destroyed.

They are concerned not only about low ozone levels over the Arctic but about further data which shows a thinning over a large part of northern Europe, including the UK.

Doctors warn that if the ozone layer is depleted, people will be at greater risk from skin cancers such as melanoma, which has increased four-fold in Sweden since the 1960s.

Stockholm hospital doctor Johan Hanson says there is a direct link between UV radiation and skin cancer.

"If there is an increase in the levels of UV radiation through the depletion of ozone, that will also increase the numbers of skin tumours and melanomas and also the numbers of people who will die from this disease," he said.

An ozone hole opens over Antarctica in the southern spring.

Related to this story:
Scientists join forces to study Arctic ozone (19 Nov 99 | Sci/Tech)
Climate change warning (18 Nov 99 | Sci/Tech)
Ozone hole opens again (22 Sep 99 | Sci/Tech)
Severe Arctic ozone hole predicted (30 Apr 99 | Sci/Tech)

Internet Links: UN Ozone secretariat Ozone Tour
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