Earth's ozone layer is recovering, a bit of good news on the environment as the huge hole in the atmospheric layer protecting us from the sun's ultraviolet rays has stabilized, scientists report.
The news comes from a panel of 300 scientists that issues a report every 4 years for the United Nations.
Since ozone-destroying chemicals found in air conditioners, refrigerators and aerosol cans were banned in the late 1980s, the ozone layer is showing sings of becoming thicker after years of depletion, the report says.
Scientists realized in the 1970s that chlorofluorocarbons (CFCs) had thinned the ozone layer above Antarctica, creating a hole; that led to calls for the chemicals to be phased out, finally agreed to by world leaders as part of the 1987 Montreal Protocol.
"It's a victory for diplomacy and for science and for the fact that we were able to work together," says chemist Mario Molina, who was awarded a Nobel Prize for his studies of the ozone layer.
While the ozone hole which appears every year over Antarctica is stabilized, it will need at least 10 years before any shrinkage will occur, the U.N. report says.
Still, computer models suggest that by 2050 the ozone layer in Earth's mid-latitudes will have returned to its healthier 1980 levels, it says.
For Antarctica, which has seen the worst affects of CFCs, such healing will probably take until 2075, scientists say.
The Antarctic "hole" was at its largest in 2006, at around 12,000 square miles, but has since stabilized at around 8,000 square miles.
"International action on the ozone layer is a major environmental success story," says Michel Jarraud, secretary-general of the World Meteorological Organization, which contributed to the report. "This should encourage us to display the same level of urgency and unity to tackle the even greater challenge of tackling climate change."
Despite the good news on the ozone front, the greenhouse gases that drive climate change -- such as carbon dioxide -- remain a concern, with the WMO reporting this week that levels of those gases had reached a record high.
Part of the problem is that replacement chemicals for CFCs known as hydrofluorocarbons or HFCs, although they do not deplete atmospheric ozone, are in themselves greenhouse gases, powerfully trapping the sun's heat and contributing to the greenhouse effect.
Safer replacements that are less effective greenhouse gases do exist, and turning to them would essentially erase HFCs contribution to climate change, experts involved in the U.N. report say.
