Environment

Ozone Hole Healing Stalls

The hole in stratospheric ozone over Antarctica has remained stubbornly large in recent years despite a worldwide ban since 1987 on the chlorine emissions that created it, according to NASA.

While this year’s maximum expanse of the ozone hole, reached on Sept. 9, was about 9 percent less than the record set in 2000, its coverage was about the same as in 2010, 2012 and 2013.

Earth’s ozone layer helps shield life on the surface from potentially harmful ultraviolet radiation that can cause skin cancer, cataracts and plant damage.

The reason the hole isn’t closing up despite no new chlorofluorocarbons being released into the atmosphere is clouded by a complex interaction between it and climate change, scientists say.

“The ozone hole itself is affecting the climate of Antarctica and Australia, and is being affected by it. It is changing the wind systems,” said Jonathan Shanklin of the British Antarctic Survey, one of the three scientists who discovered the hole in the 1980s.

He tells The Guardian he expects the ozone hole to gradually fill in even as the effects of climate change increase over the next 50 years or so.

The U.N. Environment Program and the World Meteorological Organization announced last month that while there were “positive indications” that the ozone layer is recovering, it could take another 35 years to get back to 1980s levels.

The ozone hole over Antarctica two days after it reached its greatest size this year.