Bright spot: Antarctica’s ozone hole is starting to shrink

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 shows that the hole in the ozone layer, Earth’s atmospheric shield that helps protect the planet from the sun’s cancer-causing ultraviolet rays, is getting smaller and forming later in the year. Refrigerants called chlorofluorocarbons, or CFCs, had been eating away at the ozone layer, before the international community took action.

“It isn’t just that the patient is in remission,” said Susan Solomon, MIT scientist and the lead author of the study. “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, she said.

‘A remarkable achievement’

In 1987, countries negotiated the Montreal Protocol, considered the world’s most successful global environmental treaty, to phase out many of the ozone-depleting chemicals. As a result, companies had to develop new products that didn’t harm the ozone layer.

The hole won’t be completely closed until about 2050, but the healing is appearing earlier than scientists expected, Solomon said.

The hole has shrunk by about 4.5 million square kilometers in the key month of September since 2000 — a decline of about one-fifth, the study found.

In the 1970s, scientists warned of potentially catastrophic effects: A depleted ozone layer meant dramatic worldwide increases in skin cancer, crop damage and a host of other problems.

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.

The Antarctic ozone hole was the gaping wound that grabbed the world’s attention.

“So, 28 years after the agreement, the Montreal Protocol shows what the world can accomplish, said Ross Salawitch of the University of Maryland. “I’d say this is a remarkable achievement.”

Today’s chemical refrigerants, hydrofluorocarbons or HFCs, may not damage the ozone layer as much as their predecessors in the 1970s, but they remain potent greenhouse gases. To make air conditioning more efficient and better for the environment, China, India, Canada, Saudi Arabia and the United States are looking to limit HFCs through the Advanced Cooling Challenge.