Ozone layer could heal by 2050
Copyright 1999, Environmental News Network
December 4, 1999
By Robinson Shaw
More than half a century may pass before the hole in the ozone layer is repaired and the first clear signs of repair may not be apparent for 20 more years, said Dr. Paul Fraser of CSIRO.
The ozone layer shields the Earth from the sun's harmful ultraviolet rays and is part of the Earth's stratosphere, nine to 20 miles above our planet's surface. Chlorine and bromine atoms released from chlorofluorocarbons and halons, cause the depletion of the ozone. CFCs are industrial chemicals used in the past as refrigerants, solvents, pressure packs and foaming agents. Halons were used in fire extinguishers.
Even though the Montreal Protocol, a pact designed to protect the ozone layer, is working well to reduce the use and release of ozone-depleting substances, the life of chemicals already released in the atmosphere will keep the depletion going for years to come, according to a United Nations report.
While the ozone hole over the Arctic appears to have stopped growing, the ozone layer over Antarctica and parts of Australia is thinning. The annual springtime ozone hole over Antarctica peaked in September, covering an area more than three times the size of Australia. Measurements at Halley Bay in Antarctica reveal that October ozone concentrations are now less than half what they were during the 1960s.
The ozone layer over sub-tropical parts of Australia has also thinned, which means that more harmful ultraviolet radiation is reaching the ground today than in the past.
Signatories to the Montreal Protocol met last week in Beijing to discuss funding to help developing countries eliminate the use of ozone-depleting chemicals. The United Nations set up the fund in 1991 and has since invested about $1 billion in projects in 117 countries to phase out the consumption of 122,000 tons and the production of 42,000 tons of chemicals and gases which destroy ozone, reported Reuters Thursday.
"Based on the maximum predicted emissions of ozone-depleting chemicals allowed under the Montreal Protocol, it will be at least the year 2050 before the ozone layer recovers. Global warming may further delay recovery by 10 to 20 years," said Fraser.
The United States, Australia and other developed countries have completely phased out production of CFCs and halons. Under the protocol, developing countries have until the year 2010 before they must completely phase out halon production
"A positive step we could take to reduce emissions would be to expand CFC and halon recovery, recycling or destruction," he said.
Support for CSIRO's research into ozone depletion comes from the Co-operative Research Center for Meteorology at Monash University and from Refrigerant Reclaim Australia.