Earth’s protective ozone layer is slowly but noticeably healing at a pace that would fully mend the hole over Antarctica in about 43 years, a new United Nations report says. “In the upper stratosphere and in the ozone hole we see things getting better,” said Paul Newman, co-chair of the scientific assessment. Natural weather patterns in the Antarctic also affect ozone hole levels, which peak in the fall. 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 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% in Antarctica.

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