The ozone hole over Antarctica could completely heal by 2066, the UN says

The ozone hole over Antarctica could completely heal by 2066, the UN says

(DENVER) — Earth’s protective ozone layer is slowly but noticeably healing at a pace that would completely close the hole over Antarctica in about 43 years, according to a new United Nations report.

A scientific assessment conducted every four years found a recovery is underway, more than 35 years after all the world’s nations agreed to stop producing chemicals that attack the ozone layer in the Earth’s atmosphere, which protects the planet from harmful radiation, associated with skin cancer, cataracts and crop damage.

“In the upper stratosphere and in the ozone hole, we’re seeing things getting better,” said Paul Newman, co-chair of the scientific assessment.

Progress is slow, according to the report, presented Monday at the American Meteorological Society meeting in Denver. The global average amount of ozone at an altitude of 18 miles (30 kilometers) in the atmosphere will not return to pre-depletion 1980 levels until about 2040, the report said. And by 2045, things won’t be back to normal in the Arctic.

Antarctica, where it’s so thin that a huge gaping hole yawns in the stratum every year, won’t be fully repaired until 2066, the report said.

Scientists and environmentalists around the world have long credited the effort to cure the ozone hole — which grew out of a 1987 agreement called the Montreal Protocol that banned a class of chemicals commonly used in refrigerants and aerosols — as one of the greatest ecological achievements of mankind celebrated .

“Ozone action sets a precedent for climate action. Our success in phasing out ozone-depleting chemicals shows us what can and must urgently be done to move away from fossil fuels and reduce greenhouse gases, thereby limiting temperature rise,” World Meteorological Organization Secretary-General Prof. Petteri Taalas said in an explanation.

Signs of healing were reported four years ago but were minor and rather preliminary. “These recovery numbers have become very solid,” Newman said.

The two main chemicals that eat up ozone are in lower concentrations in the atmosphere, said Newman, senior Earth scientist at NASA’s Goddard Space Flight Center. Chlorine levels have fallen 11.5% since their peak in 1993, and bromine, which is more efficient at depleting ozone but is in lower amounts in the air, has fallen 14.5% from its peak in 1999, they said in the report.

That bromine and chlorine levels “have stopped rising and falling is real testament to the effectiveness of the Montreal Protocol,” Newman said.

Natural weather patterns in Antarctica also affect ozone hole levels, which peak in the fall. And in the last few years, the holes have been a little bigger because of it, but the general trend is toward healing, Newman said.

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

A few years ago, emissions of one of the banned chemicals, chlorofluorocarbon-11 (CFC-11), stopped declining and were increasing. Rogue emissions were spotted in parts of China but have now receded where expected, Newman said.

A third generation of these chemicals called HFC was banned a few years ago not because it would deplete the ozone layer, but because it is a heat-trapping greenhouse gas. The new report says the ban would avoid 0.5 to 0.9 degrees (0.3 to 0.5 degrees Celsius) of additional warming.

The report also warned that efforts to artificially cool the planet by forcing aerosols into the atmosphere to reflect sunlight would thin Antarctica’s ozone layer by up to 20%.

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