Fact check: Unprecedented Arctic ozone hole has healed itself

The claim: A record-breaking Arctic ozone hole appeared and healed itself
Scientists at the Copernicus' Atmospheric Monitoring Service tracking the "rather unusual" ozone hole announced April 23 on Twitter that it had healed. The CAMS said the hole was caused by a polar vortex and closed when that vortex split.
The CAMS is one of the European Union’s six Earth observations programs.
“Although it looks like the #PolarVortex has not quite come to an end yet and will reform in the next few days #ozone values will not got back to the very low levels seen earlier in April,” the CAMS replied to its own tweet.
An abnormally strong polar vortex caused the hole
A polar vortex is a large area of cold air high in the atmosphere that normally spins over the North Pole. An ozone hole is a dramatic thinning of the ozone layer that's typically boosted by colder temperatures.
Ozone holes have formed annually for the past 35 years in the Antarctic because of human-made chemicals migrating into the stratosphere and accumulating inside a strong polar vortex, the CAMS reported. Because of unusually high temperatures high above Antarctica, the ozone hole shrank to its smallest size on record last October.
In the Arctic, however, polar vortexes are much weaker, meaning the conditions needed for such strong ozone depletion aren't normally found, making this ozone hole "unprecedented."
“The ozone hole we observe over the Arctic this year has a maximum extension of less than 1 million sq km," German Aerospace Center's Diego Loyola said. "This is small compared to the Antarctic hole, which can reach a size of around 20 to 25 million sq km with a normal duration of around 3 to 4 months.”
Ozone depletion over the Arctic in 2020 has been so severe that most of the ozone at an altitude of around 11 miles had been depleted, according to the CAMS.
Researchers say this has occurred only two other times since ozone observations began in the 1970s. The first time was during the winter of 1996-97 and the second was during the winter of 2010-11. In both cases, the extreme ozone depletion was caused by unusual weather patterns that kept the Arctic colder for longer periods than most years.
The ozone layer is important because it acts like a sunscreen, blocking potentially harmful ultraviolet energy from reaching our planet's surface. Without it, humans and animals may experience increased rates of skin cancer and other ailments such as cataracts.
The naturally occurring ozone high in the atmosphere is the "good" ozone and is in contrast to the "bad" ozone near the surface, which is man-made pollution that can cause respiratory problems.
“For me there is 100% surety contributed by the lockdown in the healing process of Ozone layers,” Lijan Lotha commented on Facebook. “Lockdown definitely has played a great role in bringing ecology back to normalcy to a great (extent).”
“The ozone hole had appeared during the lockdown,” Anubhav Singh responded to Lotha. “I think just about two or 3 weeks ago. So ... most probably not by humans but you never know.”
Our ruling: True
We rate the claim that the Earth healed a unprecedentedly large ozone hole above the Arctic to be TRUE because experts have confirmed it. The record-breaking hole was caused by an unusually strong and enduring polar vortex and healed when the vortex split – not because of COVID-19 closures.