Ozone forecast charts produced daily by the Copernicus Atmosphere Monitoring Service show predictions for total vertical ozone column values for the Antarctic region up to five days ahead. European Commission Atmosphere Monitoring Service
An unusual phenomenon happened in March and April when an enormous hole in the ozone layer formed over the Arctic. Last week, though, scientists tracking the hole noticed that it has closed, as CNN reported.
Unlike the infamous hole in the ozone over Antarctica, which was caused by overuse of now illegal chemicals containing chlorofluorocarbons, the hole in the Arctic was caused by a combination of factors, including low Arctic temperatures, sunlight, pollutants and a particularly strong polar vortex, according to the Copernicus’ Atmospheric Monitoring Service (CAMS), as CNN reported.
The unprecedented 2020 northern hemisphere #OzoneHole has come to an end. The #PolarVortex split, allowing #ozone-rich air into the Arctic, closely matching last week's forecast from the #CopernicusAtmosphere Monitoring Service.
— Copernicus ECMWF (@CopernicusECMWF) April 23, 2020
“These two are really different animals,” said Paul Newman, the chief scientist in the Earth Sciences Division at NASA’s Goddard Space Flight Center, as Mashable reported. “This [Arctic ozone hole] is not comparable to the Antarctic ozone hole. If this was happening over the Antarctic we would be shouting for joy.”
The hole over Antarctica opens up every year from August until October. However, it has improved dramatically since ozone-depleting chlorofluorocarbons were banned in the 1994 Montreal Protocol. Last year, the Antarctic ozone hole was at its smallest since it was first discovered, as CNN reported.
While the COVID-19 lockdowns have improved air quality around the world and helped wildlife, the drops in pollution did not cause the ozone hole to close up.
“COVID19 and the associated lockdowns probably had nothing to do with this,” CAMS said on Twitter. “It’s been driven by an unusually strong and long-lived polar vortex, and isn’t related to air quality changes.”
The hole in the ozone above the Arctic started in March when unusual conditions trapped cold air over the North Pole for several weeks in a row. That triggered a circle of cold air, known as a polar vortex, which led to clouds high in the atmosphere. Those clouds interacted with pollutants from human emissions and depleted the ozone gases above the Arctic. The hole it opened up was roughly three times the size of Greenland.
The ozone layer, which sits between 9 and 22 miles from the earth’s surface, shields the planet from the sun’s damaging ultraviolet radiation. The hole above the Arctic would have only posed a threat to humans if it had traveled or expanded farther south, as Euronews reported.
“It’s unusual but not unexpected,” said Newman, of the recent Arctic ozone hole, to Mashable. “It’s unusual in that we only have events like this about once per decade.”
In 1997 and 2011, there were similar ozone depletions of the Arctic, according to Antje Innes, a senior scientist at the European Union’s Copernicus Atmosphere Monitoring Service, who spoke to Mashable. However, the extent of ozone depletion was far greater during this one.
Scientists insist it is too early and too rare to say if the recent ozone depletion portends a new trend. “From my point of view, this is the first time you can speak about a real ozone hole in the Arctic,” said Martin Dameris, an atmospheric scientist at the German Aerospace Center, to Nature.