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Seven New Gases Deal Damage to Ozone Layer

Despite a global phase-out of CFCs such as Freon, newly detected gases threaten the ozone layer's recovery.

By Jennifer Draper|Wednesday, November 26, 2014
RELATED TAGS: POLLUTION, EARTH SCIENCE
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On the left, ozone layer over Antarctica in March 1986. On the right, the same view in March 2014. Bluer areas on the maps indicate less ozone; greener areas more.
Molecule, Tim Evans/Science Source; Ozone images, NASA Ozone Watch; Illustration, Dan Bishop/Discover

The recovery of Earth’s protective ozone layer has been hailed as an environmental success story. But the celebration may have been premature: Last spring, scientists discovered new ozone-destroying gases in the atmosphere.

The U.N.’s 1987 Montreal Protocol phased out almost all of the offending gases, and the ozone hole began to shrink. But in March, researchers with England’s University of East Anglia reported finding four new ozone-depleting compounds in the atmosphere — three chlorofluorocarbons (CFCs) and one hydrochlorofluorocarbon (HCFC) — amounting to about 81,000 tons. In June, they found three more — two CFCs and one HCFC — bringing the total to seven.

And more could be discovered, says Johannes Laube, a co-author of the studies. “It could reverse the recovery trend,” he says.

The emissions may have come from the production of insecticides, refrigerants or solvents, he says, either under the treaty’s exemptions or through illegal use.

Overall levels of ozone-harming gases are still lower than before the ban, but since some disintegrate slowly, they’ll continue destroying ozone for decades to come, Laube says.

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