You can call it a comeback: The ozone layer is slowly recovering, scientists say, with a significant increase in stratospheric ozone, which protects the planet from solar radiation.
A United Nations scientific panel found that between 2000 and 2013, ozone levels went up 4 percent in mid-northern latitudes at 30 miles up. In the 1980s, scientists issued a dire warning about CFCs, man-made chemicals found in aerosol cans and refrigerants that released chlorine and bromine into the air, destroying ozone. In 1987, countries agreed to a treaty that phased CFCs out. "It's a victory for diplomacy and for science and for the fact that we were able to work together," Mario Molina, a chemist who co-wrote a 1974 study forecasting ozone depletion, told The Associated Press.
"More than 98 percent of ozone-depleting substances agreed over time have actually been phased out," says Achim Steiner, executive director of the U.N. Environment Program. If that hadn't happen, "we would be seeing a very substantial global ozone depletion today."
It's not all good news, though. MIT atmospheric scientist Susan Solomon told AP the chemicals that replaced CFCs contribute to global warming and are expected to increase significantly by 2050.