NAIROBI: The damaged ozone layer — the shield that protects the earth from harmful solar radiation — is showing signs of recovery, according to a new study.

The summary of a report by senior scientists, being made public in Paris on Monday, indicates that levels of ozone-depleting chemicals in the atmosphere have peaked or are on the decline.

However, the report from the Nairobi-based United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) says the ozone layer will remain vulnerable during the next decade or so.

The report comes from a panel that has reviewed the status of the ozone layer once every four years since an international treaty on ozone-depleting substances, known as the Montreal Protocol, came into effect in 1987.

“These results confirm that the Montreal Protocol is achieving its objectives,” said Gerard Megie, one of the report’s authors. “During the next decades, we should see a recovery of the ozone layer.”

Levels of ozone-depleting chemicals in the troposphere (the lower part of the atmosphere) are slowly declining, while levels in the stratosphere (upper atmosphere) are at or near their peak, says the report.

The hole in the ozone layer over the Antarctic has increased in size over the past decade but not as rapidly as during the 1980s, says the report.

Industrialized countries have phased out most substances blamed for depleting the ozone layer, such as chlorofluorocarbons (CFCs), once widely used in aerosol propellants, air conditioners and refrigerators.

The developing countries that have signed the Montreal Protocol are committed to reducing their consumption and production of CFCs by 50 per cent by the year 2005 and by 85 per cent by 2007.

The report warns that if governments fail to meet targets set out in the Montreal Protocol to reduce the use of such chemicals, the ozone layer’s recovery could falter.

“The total atmospheric abundance of ozone-depleting gases will decline to pre-Antarctic ozone-hole amounts only with adherence to the Montreal Protocol’s full provisions on production of ozone- depleting substances,” says the report.

The report’s executive summary is being released on Monday, International Ozone Day, with the full report scheduled to come next year.—dpa