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Ozone Layer Faces Bumpy Return to Health

Emily Sohn, Discovery News

But the increase in greenhouse gasses also speeds up the circulation of ozone through the atmosphere. Normally, ozone forms in the tropics, where it rises to the upper stratosphere and then moves toward the poles. Li wanted to know what a quickening of this process would do to the ozone layer.

With a computer model that looked at how climate change might affect ozone recovery over the next century, his team found that faster circulation through the stratosphere is depositing lots of ozone in mid- and high-latitude regions -- so much so that these areas are "super-recovering" to levels higher than in the pre-CFC era.

Faster circulation, however, is also bringing more ozone-poor air from the lower atmosphere into the stratosphere above the tropics. "This speeding up prevents the full recovery of tropical ozone," Li said. The study appeared in the journal Atmospheric Chemistry and Physics.

The findings may have policy implications, Waugh told Discovery News.

"If all that mattered was the amount of chlorine in the atmosphere, and chlorine is expected to go back to what it was in 1970, then you would expect ozone to go back to what it was in 1970," he said. "Now they're saying there are other things that are going to be impacting ozone."

In that way, he added, the ozone layer's healing process resembles a person's recovery from serious disease.

"If it takes you 30 years to recover from something, you're not going to recover to how you were when you were 20," Waugh said.

Related Links:

NASA: The Ozone Layer

Discovery Earth Pub