Earth’s ozone layer is slowly healing, UN report says

“It’s really good news,” said report co-chairman Paul Newman, chief Earth scientist at NASA’s Goddard Space Flight Center.

“If ozone-depleting substances had continued to increase, we would have seen huge effects. We stopped that.”

High in the atmosphere, ozone shields Earth from ultraviolet rays that cause skin cancer, crop damage and other problems. Use of man-made chemicals called chlorofluorocarbons (CFCs), which release chlorine and bromine, began eating away at the ozone. In 1987, countries around the world agreed in the Montreal Protocol to phase out CFCs and businesses came up with replacements for spray cans and other uses.At its worst in the late 1990s, about 10 per cent of the upper ozone layer was depleted, said Newman. Since 2000, it has increased by about 1 to 3 per cent per decade, the report said.This year, the ozone hole over the South Pole peaked at nearly 24.8 million square kilometres. That’s about 16 per cent smaller than the biggest hole recorded — 29.6 million square kilometres in 2006.The hole reaches its peak in September and October and disappears by late December until the next Southern Hemisphere spring, Newman said.The ozone layer starts at about 10 kilometres above Earth and stretches for nearly 40 kilometres; ozone is a colourless combination of three oxygen atoms.WATCH BELOW: Online map shows impact of climate change on Canada’s boreal forests If nothing had been done to stop the thinning, the world would have destroyed two-thirds of its ozone layer by 2065, Newman said.But it’s not a complete success yet, said University of Colorado’s Brian Toon, who wasn’t part of the report.“We are only at a point where recovery may have started,” Toon said, pointing to some ozone measurements that haven’t increased yet.WATCH BELOW: 2030 declaration calls for stronger climate change targets Another problem is that new technology has found an increase in emissions of a banned CFC out of East Asia, the report noted.And the replacements now being used to cool cars and refrigerators need to be replaced themselves with chemicals that don’t worsen global warming, Newman said. An amendment to the Montreal Protocol that goes into effect next year would cut use of some of those gases.“I don’t think we can do a victory lap until 2060,” Newman said. “That will be for our grandchildren to do.”