The largest observed hole in the ozone layer over the Arctic has finally closed up, according to scientific reports.
“The unprecedented 2020 northern hemisphere #OzoneHole has come to an end,” read a tweet by the Copernicus Atmosphere Monitoring Service, an organization implemented by the European Centre for Medium-Range Weather Forecasts. “The #PolarVortex split, allowing #ozone-rich air into the Arctic, closely matching last week's forecast from the #CopernicusAtmosphere Monitoring Service,” it continues.
Contrary to popular opinion, the ozone layer healing itself was not caused by a decrease in air pollution due to the global coronavirus lockdown. Instead, as mentioned by CAMS’ Twitter post above, it’s believed to be the result of the warming of the stratosphere.
Euro News explains, “It’s down to the polar vortex, the high-altitude currents that normally bring cold air to the polar regions. This has split in two giving the Arctic region a relative heatwave, with temperatures up to 20ºC higher than is normal for this time of year.”
The one million square kilometer hole over the Northern Hemisphere was first detected by scientists early this month. Worries grew at the possibility of it reaching the Southern Hemisphere where it could have caused actual threats to human life.
As to how the layer drastically thinned in the first place? Science News best explains, “A powerful polar vortex has trapped especially frigid air in the atmosphere above the North Pole, allowing high-altitude clouds to form in the stratosphere, where the ozone layer also sits. Within those clouds, chlorofluorocarbons and hydrochlorofluorocarbons already high in the atmosphere—gases used as refrigerants—react with ultraviolet rays from the sun to release chlorine and bromine atoms, which in turn react with and deplete the ozone.”
Note that use of the aforementioned CFC gases were already banned by the 1987 Montreal Protocol, a.k.a. the agreement to cease the production of ozone depleting substances.
The ozone layer, found in the lower portion of the stratosphere, protects humans from ultraviolet rays, which are usually the cause of skin cancer and other immune deficiency disorders.