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Geotimes
 Published by the American Geological Institute
November 2000
Newsmagazine of the Earth Sciences

News Notes

Olympic ozone loss

On Sept. 10, the area of the Antarctic ozone hole set a new record as the largest such area ever observed. The ozone “hole” extended 29.7 million square kilometers, overtaking the previous record of 27.2 square kilometers on Sept. 19, 1998, says Paul A. Newman, an atmospheric physicist at NASA’s Goddard Space Flight Center.

Early spring conditions stimulated the dramatic ozone loss. Ozone’s annual low in the Antarctic region usually coincides with the commencement of spring in the Southern Hemisphere in late September or early October. Very cold temperatures and weaker weather systems in the stratosphere contributed to this year’s extensive ozone loss.


The ozone depletion area on Sept. 10. NASA.

These factors increased the area enclosed by the Antarctic vortex, a jet stream that circles the Antarctic region and isolates it from the mid-latitudes and tropics, thereby increasing the area affected by ozone loss.

“We know that the meteorology this year is different from the last few years, and that this has led to this bigger ozone hole,” Newman says. “But we don’t know why. It’s either natural variability or climate change. If it’s climate change we need to be worried.”

The major factor in ozone depletion rates is the continued presence of ozone-destroying gases such as chlorofluorocarbons in the stratosphere.

Despite international restrictions on the production of ozone-destroying gases, says manager Michael Kurylo of NASA’s Upper Atmospheric Research Program, the lifetimes of the gases will allow them to destroy ozone for many decades to come.
 

Bridget K. Mulvey
Geotimes contributing writer


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