Ozone layer hole slightly smaller

The hole in the ozone layer this year will probably be slightly smaller than the all-time largest of 2003, and may last for decades before real healing of the ozone layer's depletion takes effect, according to a UN agency.

"The size of this year's ozone hole is approaching an all-time high, but it will probably not break any records," said Geir Braathen, an ozone specialist at the World Meteorological Organization (WMO).

"It's kind of levelling off, but it's still too early to say that the situation is improving," he said earlier at a news conference.

At present, the hole over Antarctica is about 27 million square kilometres and the WMO expects it to increase to about 28 million square kilometres a notch below its 2003 peak at about 29 million square kilometres.

Based on recent patterns, Braathen expects the ozone holes to hover around this year's size for a few more years before they begin to shrink. Some scientists predict it will take about 50 years for the ozone hole to stop forming.

Chlorofluorocarbons, or CFCs, once widely used in spray cans and refrigerators, deplete the earth's protective layer. The hole has been forming in the extremely low temperatures that mark the end of Antarctic winter every year since the mid-1980s. Generally the hole is the biggest around late September, while the so-called ozone value does not bottom out until mid-October.

The ozone layer keeps out ultraviolet radiation, which is dangerous to humans and animals. Less protection could increase risks of skin cancer and cataracts and affect biodiversity, scientists say.

Nevertheless, Braathen warned it was too early to "sound the all-clear," and said global warming had started to reverse some of the positive developments. "Global warming might actually delay the healing of the ozone layer or altogether worsen the issue," he said.

Source: China Daily