Air samples collected around the globe show that the threat to the ozone layer fell more than 50% back to levels last observed in 1980 before ozone depletion was significant, said scientists from the National Oceanic and Atmospheric Administration (NOAA).
Early in 2022, the mid-latitude stratosphere's overall concentration of ozone-depleting chemicals had dropped, according to a NOAA news release issued on Aug. 24.
“It’s great to see this progress. At the same time, it’s a bit humbling to realize that science is still a long way from being able to claim that the issue of ozone depletion is behind us,” said NOAA scientist Stephen Montzka, according to the release.
The Montreal Protocol on Substances that Deplete the Ozone Layer's restrictions on the manufacturing and trade of ozone-depleting substances anticipated this gradual but steady development over the past three decades, the release reported.
NOAA’s release said that 90% of the ozone on Earth is found in the stratosphere, which is above the troposphere, the layer closest to the planet's surface. The term “ozone layer” refers to the area of the stratosphere that has the most ozone. All of the biological systems on Earth are shielded from the sun's dangerous ultraviolet rays by the stratospheric ozone layer, which absorbs these rays.
An enormous “hole” in the ozone layer over Antarctica and a smaller, but still concerning depletion in mid-latitudes were caused by a class of man-made substances that the scientific community learned was gravely harming the protective ozone layer in the 1980s. As part of the U.S. response, the 1990 amendments to the Clean Air Act required NASA and NOAA to monitor stratospheric ozone and ozone-depleting compounds, according to the release.
