The United Nations says there could be some good news for the ozone layer this year. It says the ozone hole, over the Antarctic, is expected to be smaller this year than last’s. The agency says a ban on harmful substances has stopped its depletion.
But despite the positive news, Reuters reports that the hole is probably larger than in 2010 and a complete recovery is still a long way off.
The ozone layer is the earth’s protective shield against ultraviolet rays.
The U.N. weather agency credits the signing of the Montreal Protocol 25 years ago. The new rules, which phased out chemicals that deplete the ozone layer, reportedly helped prevent millions of cases of skin cancer as well as harmful effects on the environment.
Reuters quotes a statement from the World Meteorological Organization (WMO): “The temperature conditions and the extent of polar stratospheric clouds so far this year indicate that the degree of ozone loss will be smaller than in 2011 but probably somewhat larger than in 2010.”
The Antarctic ozone hole currently measures 19 million square kilometers. The WMO says it most likely would be smaller this year than in the record year of 2006. The annual occurrence typically reaches its maximum surface area during late September. And maximum depth in early October.
But the banned chlorofluorocarbons (CFCs), once used in refrigerators and spray cans, have a long lifeline in the atmosphere. The WMO says it will take several decades before their concentrations are back to pre-1980 levels.
Reuters reports that U.N. weather agency expert, Geir Braathen, believes the Montreal protocol has been a great succes: “This has prevented a major environmental disaster and globally ozone depletion has leveled off. We haven’t really seen any kind of unequivocal ozone recovery yet. Ozone depletion has stopped, leveled off.”