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2003 Antarctic Ozone Hole Grows Fast, But Recovery Forecast

GENEVA, Switzerland, September 5, 2003 (ENS) - The ozone hole over Antarctica that appears every year at the beginning of spring in the Southern Hemisphere has grown more rapidly than usual this year, the World Meteorological Organization (WMO) said today.

The ozone layer provides a protective filter against the Sun's ultraviolet radiation that can cause skin cancer, eye damage, and other health and environmental problems.

At a news briefing in Geneva, WMO spokesperson Carine Richard-Van Maele, said the latest information on the state of the ozone layer appears in the United Nations agency's new bulletin.

She said the bulletin was released in advance of September 16, World Day for the Protection of the Ozone Layer.

In a report issued to coincide with the ozone protection day last year, the UN Environment Programme (UNEP) noted that despite good signs of recovery, the ozone layer will remain vulnerable for the next decade or so, even if countries comply with international agreements to protect it.

"The battle to protect the ozone layer is far from over," said WMO Secretary-General Godwin Obasi of the 2002 report.


The Antarctic ozone hole on September 18, 2001 covers the entire continent. (Photo courtesy European Space Agency)
The concentration of ozone depleting substances in the upper atmosphere is now at or near its peak, scientists believe. As a result, they say human influenced disturbances on Earth's protective shield are now "at or near their largest."

Last year's report showed that the Montreal Protocol on Substances That Deplete the Ozone Layer is working. The world has been making steady progress towards the recovery of the ozone layer, with the latest scientific results showing the total amount of ozone depleting chemicals in the lower atmosphere continuing to decline, if slowly.

Satellite observations made public in July by the U.S. National Aeronautics and Space Administration (NASA) provided the first evidence that the rate of ozone depletion in the Earth's upper atmosphere is decreasing. This may indicate the first stage of ozone layer recovery, NASA said

From an analysis of ozone observations from NASA's first and second Stratospheric Aerosol and Gas Experiment and the Halogen Occultation Experiment satellite instruments, scientists found less ozone depletion after 1997 in the upper stratosphere - 22 to 28 miles above the Earth's surface. The American Geophysical Union's "Journal of Geophysical Research" has accepted a paper for publication on these results.

This decrease in the rate of ozone depletion is consistent with the decline in the atmospheric abundance of chemicals containing chorine and bromine released by human activities as documented by satellite, balloon, aircraft and ground based measurements.

Concerns about ozone depletion in the upper atmosphere or stratosphere led to ratification of the Montreal Protocol on Substances that Deplete the Ozone Layer by the international community in 1987. The protocol restricts the manufacture and use of human made, ozone depleting compounds, such as chlorofluorocarbons and halons.

"Ozone is still decreasing but just not as fast," said Mike Newchurch, associate professor at the University of Alabama, Huntsville, Alabama, and lead scientist on the study. "We are still decades away from total ozone recovery. There are a number of remaining uncertainties such as the effect of climate change on ozone recovery. Hence, there is a need to continue this precise long term ozone data record," he said.

The amount of ozone depleting chemicals such as refrigerant chlorofluorocarbons (CFCs) in the upper stratosphere is declining, but other ozone depleters such as bromine from industrial halons, and CFC substitutes are on the increase, the WMO says.

A joint ozone assessment by the WMO and UNEP published for September 16, 2002, found that ozone depletion and climate change are interconnected and share many physical and chemical processes.

As atmospheric CFCs decline, due to adherence to the Montreal Protocol by signatory countries, their climate warming contributions will also decrease. But, the joint assessment warns, the use of HFCs and HCFCs as substitutes for the banned CFCs will cause the climate warming contributions of those two chemicals to rise.

Because ozone depletion tends to cool Earth's climate system, the agencies said, future recovery of the ozone layer would tend to warm the climate system.

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