Tech – Metro | The largest ozone hole ever recorded is now closed

The biggest documented Arctic ozone hole has vanished again just weeks after it first appeared (Nasa)

Scientists have announced a gigantic hole in the ozone layer over the North Pole has now closed.

The hole had formed earlier this year and reached its maximum size only a few weeks ago in mid-March. It was the largest ozone hole ever recorded and now it appears to have vanished.

Researchers believe the hole was caused by an unusually strong polar vortex and have said its disappearance probably has nothing to do with the drop in air pollution due to the coronavirus lockdown.

The polar vortex is a high altitude current that circulates in an irregular ring-like pattern around the Arctic and helps keep cold air trapped above the pole.

'It is very unusual for such strong ozone depletion to occur in the northern hemisphere, but this year's polar vortex was exceptionally strong and persistent, and temperatures were low enough to allow stratospheric cloud formation for several months,' Antje Inness from the Copernicus' Atmospheric Monitoring Service told Euro News.

Ozone helps filter ultaviolet light from the atmosphere, and when holes appear it means more harmful solar radiation is penetrating the atmosphere and reaching the Earth's surface. 

Ozone protects the Earth from harmful UV radiation (Getty Images/iStockphoto)

Some suggested the rapid disappearance of the ozone hole might have been caused by the radical reductions in air pollution during the worldwide COVID-19 shutdowns but the CAMS team have rejected the idea.

'COVID19 and the associated lockdowns probably had nothing to do with this,' the group wrote in a Twitter post.

'It's been driven by an unusually strong and long-lived polar vortex, and isn't related to air quality changes.' 

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.

More on the NH Ozone hole➡️https://t.co/Nf6AfjaYRi pic.twitter.com/qVPu70ycn4

— Copernicus ECMWF (@CopernicusECMWF) April 23, 2020

Levels of ozone had declined to such a worrying degree that a 1987 agreement known as the Montreal Protocol put a stop to the use of ozone depleting substances (ODSs) around the world.

The scientists are wary of this trend being undone as carbon dioxide emissions continue to spiral out of control and climate change becomes a defining issue.

How that plays out in the wake of the worldwide coronavirus pandemic remains to be seen.

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