EUROPEAN scientists are forecasting that the density of the ozone layer over Europe is threatening to fall to dangerous levels in coming weeks, and produce a hole in the gaseous shield that protects the earth from excessive solar radiation.
Researchers from the 17-nation European Arctic Stratospheric Ozone Experiment (EASOE) based in Kiruna, northern Sweden, say the falling ozone levels were triggered by last June's eruption of the Mt. Pinatubo volcano in the Philippines.
Dust and ash from the eruption are combining with pollutants from industrial activity on earth to form chlorine compounds that eat into the ozone layer.
In a telephone interview with the Monitor from Kiruna, John Pyle of Cambridge University, head of the EASOE team of 250 scientists, says the atmosphere above Europe is "plainly highly perturbed," with "a lot of potent ozone-destroying gases in the lower stratosphere."
He added that so far there was not an actual hole above the Northern Hemisphere such as the one already detected above the Antarctic, but the trend revealed by his team's research is "very, very worrying."
EASOE began its research last November and will complete the current phase in March. Last week's findings, Dr. Pyle says, were issued as an interim report. More details of the research will be released later in the year.
"The findings so far make it plain that governments should take much more urgent steps ... to safeguard the ozone layer," Pyle says. "Most of the chlorine in the lower stratosphere is in a form capable of attacking ozone. When sunlight levels rise in the weeks up to the spring, we can expect ozone loss."
Pyle dissented however from suggestions that people in Northern Europe should wear sunglasses and use suncreams this February and March to guard against the effects of excessive ultraviolet rays from sunshine.
Greenpeace and other environmental groups, however, are advising people to be prepared to take such special precautions, in case the ozone hole appears.
Pyle and his associates are seeking to advance scientific understanding of the complex chemical reactions caused by the emission of chlorofluorocarbons (CFCs) into the atmosphere by industrial activity on earth, mainly from aerosol sprays, coolants, and industrial cleaners. National Aeronautics and Space Administration (NASA) scientists are doing similar work in the United States.
The ozone layer envelops the earth at altitudes between 10 and 15 miles. In healthy condition it absorbs a high proportion of the sun's ultraviolet rays, but without this filtering process the earth could be subjected to levels of radiation lethal to plants and likely to endanger human health.
Pyle says the Mount Pinatubo eruption has worsened an already troubling situation. "When we came up to the Arctic we had the theory that clouds forming in the lower stratosphere could convert less active forms of chlorine into the more active ozone-eating forms," Pyle said. "We have now discovered that material from the Pinatubo eruption is doing this at a high rate. In effect, we are seeing an interaction between a natural event - the eruption; and a most unnatural event - the continuing emission of CFC s by European industrial nations."
EASOE researchers have been releasing high-flying balloons to take samples. Additional evidence became available Jan. 20 when a NASA U-2 plane detected the highest levels of ozone-destroying chemicals in the upper atmosphere ever recorded. The plane took its samples above New England and Canada.
The EASOE and NASA findings have prompted Greenpeace and other protest groups in Britain to demand urgent action by governments to order an immediate ban on the production and use of CFCs.
Environmentalists attending a seminar at Prime Minister John Major's 10 Downing Street home called on Mr. Major to raise the question of the northern ozone hole when he attends the Earth Summit in Rio de Janiero in June.
Ann Taylor, British opposition Labour Party environmental protection spokesperson, says an emergency meeting should be called of the signatories of the Montreal Protocol, the international treaty under which countries have undertaken to reduce the use of CFCs.
Under the protocol, most developed countries plan to ban CFC pollutants by the year 2000, with other countries stopping their use by 2010.
Tracy Heslop, Greenpeace's ozone expert in London, says that when members of her organization gave Major details of the EASOE research it appeared to take him by surprise.
Earlier this month New Scientist magazine reported that the authorities in Germany had prohibited the sale of products containing CFC propellants. The ban follows a decision taken last August by German manufacturers voluntarily to stop using CFCs.