The two chief chemicals that munch away at ozone are in lower levels in the atmosphere, said Newman, chief Earth scientist at NASA’s Goddard Space Flight Centre. Chlorine levels are down 11.5 per cent since they peaked in 1993 and bromine, which is more efficient at eating ozone but is at lower levels in the air, dropped 14.5 per cent since its 1999 peak, the report said.

That bromine and chlorine levels “stopped growing and is coming down is a real testament to the effectiveness of the Montreal Protocol,” Newman said.

“There has been a sea change in the way our society deals with ozone-depleting substances,” said scientific panel co-chair David W Fahey, director of the US National Oceanic and Atmospheric Administration’s chemical sciences lab.

Decades ago, people could go into a store and buy a can of refrigerants that eat away at the ozone, punch a hole in it and pollute the atmosphere, Fahey said. Now, not only are the substances banned but they are no longer much in people’s homes or cars, replaced by cleaner chemicals.

Natural weather patterns in the Antarctic also affect ozone hole levels, which peak in the fall. And the past couple years, the holes have been a bit bigger because of that but the overall trend is one of healing, Newman said.

This is “saving 2 million people every year from skin cancer,” United Nations Environment Programme Director Inger Andersen told The Associated Press earlier this year in an email.

Loading

A few years ago emissions of one of the banned chemicals, chlorofluorocarbon-11 (CFC-11), stopped shrinking and was rising. Rogue emissions were spotted in part of China but now have gone back down to where they are expected, Newman said.

A third generation of those chemicals, called HFC, was banned a few years ago not because it would eat at the ozone layer but because it is a heat-trapping greenhouse gas. The new report says that the ban would avoid 0.3 to 0.5 degrees Celsius of additional warming.

The report also warned that efforts to artificially cool the planet by putting aerosols into the atmosphere to reflect the sunlight would thin the ozone layer by as much as 20 per cent in Antarctica.