The ozone layer in Earth’s stratosphere is slowly getting healthier and could fully recover in about 50 years, according to a recent review by NOAA scientists.
In early 2022, NOAA’s Ozone Depleting Gas Index announced that the concentration of ozone-depleting chemicals in the mid-latitude stratosphere had dropped over 50 percent, returning to levels observed in 1980. The ozone layer can be defined as the region of the stratosphere between 15 and 30 kilometers (9.3 to 18.6 miles) from the Earth’s surface that has a high concentration of gaseous ozone compared to other parts of the atmosphere.
This layer acts as a shield for life on our planet, absorbing most of the Sun’s harmful ultraviolet rays. However, in the second half of the 20th century it became clear that human activity began to destroy this invaluable atmospheric shield. The ozone layer was once degraded after being blown into the stratosphere by chlorofluorocarbons (CFCs), man-made chemicals commonly used in aerosol sprays, solvents and refrigerants.
But humanity quickly took action. By 1987, just seven years after scientists discovered that CFCs were eroding the ozone layer, production of such compounds began to be phased out under the Montreal Protocol. For the first time in thirty-five years, we’re seeing solid progress, as the latest NOAA review has shown.
It should also be noted that the giant “hole” in the ozone layer over Antarctica is still there. The size of the hole can change with the seasons. Because the air in the Antarctic stratosphere is older than that in the mid-latitudes, progress in correcting the hole is slower than in mid-latitudes. Since its peak in the 1990s, the concentration of ozone-depleting chemicals has dropped by just 26 percent in this region.
But if this progress continues, NOAA estimates that we could see full recovery of the Antarctic ozone layer around 2070.
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