Antarctica’s ozone hole starting to heal

WASHINGTON — Antarctica’s ozone hole finally is starting to heal, a new study finds.

In a triumph of international cooperation over a man-made environmental problem, research from the United States and the United Kingdom shows the September-October ozone hole is getting smaller and forming later in the year.

And the study in Thursday’s journal Science also shows other indications the ozone layer is improving after it was being eaten away by chemicals in aerosols and refrigerants.

Ozone is a combination of three oxygen atoms; high in the atmosphere, it shields Earth from ultraviolet rays.

The hole has shrunk by about 1.7 million square miles in the key month of September since the year 2000 — a decline of about one-fifth, the study found. That difference is more than six times larger than the state of Texas. It also is taking about 10 days longer to reach its largest size, according to the study.

The hole won’t be completely closed until mid-century, but the healing is appearing earlier than scientists expected, said study lead author Susan Solomon of MIT.

“It isn’t just that the patient is in remission,” Solomon said. “He’s actually starting to get better. The patient got very sick in the ’80s when we were pumping all that chlorine” into the atmosphere.

“I think it’s a tremendous cause for hope” for fixing other environment problems, such as man-made climate change, said Solomon, who led two U.S. Antarctic expeditions to measure the ozone layer in the 1980s and has also been a leader in studying global warming.

In the 1970s, scientists suggested Earth’s ozone layer — about 6 to 30 miles high in the stratosphere — was thinning because of chemicals called chlorofluorocarbons from aerosols and refrigerants.

Those chemicals would break down into chlorine that attacked ozone, which at that level protects people from ultraviolet rays linked to skin cancer.

Then in the early 1980s, a hole in the ozone layer over Antarctica started appearing in October — and then, September and October — making the problem more urgent. Ozone thinned elsewhere on Earth and already has begun healing in the middle section of the planet, but the Antarctic ozone hole was the gaping wound that grabbed the world’s attention.

The Montreal Protocol, a 1987 global treaty to phase out many of the ozone-depleting chemicals, led companies to develop new products that didn’t eat away at the ozone layer.

“IT ISN’T JUST THAT THE PATIENT IS IN REMISSION. HE’S ACTUALLY STARTING TO GET BETTER.” – SUSAN SOLOMON, MIT