CFC ban 'should close up hole in ozone layer'

The hole in the ozone layer that appears over the polar regions each spring will gradually begin to shrink and should close completely within 50 years, according to new estimates of the impact of a world ban on ozone-destroying chemicals.

The hole in the ozone layer that appears over the polar regions each spring will gradually begin to shrink and should close completely within 50 years, according to new estimates of the impact of a world ban on ozone-destroying chemicals.

A dramatic reduction in the production of chlorofluorocarbons (CFCs), which were widely used in refrigerators, air-conditioners and spray cans, means ozone depletion will eventually dwindle to a point where a complete recovery is possible, scientists announced yesterday at a conference in Buenos Aires.

Although the Montreal Protocol banning CFCs was signed by leading industrial nations in 1987, the protective ozone layer in the upper atmosphere has continued to thin. This is a result of the build-up of existing CFCs and their continued production while countries looked for alternatives.

Scientists attending the conference believe the position is set to improve within the next few years as evidence emerges that levels of CFCs in the atmosphere are finally beginning to drop.

One CFC molecule can spend up to a century in the atmosphere before being broken down. The European Union has managed to cut the amount of CFCs produced from 306,000 "ozone-destroying tons" to 2,500. Japan has cuts its production from 118,000 tons to zero; Russia from 100,000 to 1,000 tons; and the United States from 306,000 to 2,500 tons.

However, some countries actually increased their production during the same period. China raised its emissions from 29,000 tons in 1986 to 51,000 in 1997; South Korea from 8,500 to 9,200 tons and the Philippines from 1,900 to 2,700 tons.

"The ozone hole is a global problem. If a chemical is put in the atmosphere in Argentina, the US or Thailand, it... affects the entire globe," said Professor Marvin Geller, co-chairman of the stratospheric processes and their role in climate group, whose general assembly meets this week in Buenos Aires.