North Pole's Largest Ozone Hole Closes Thanks to a Strong Polar Vortex


A massively large and “rather unusual” hole in the ozone layer that opened up above the Arctic this spring has closed, scientists said.

Copernicus’ Atmosphere Monitoring Service (CAMS) first made note of hole in early April, and said that ozone columns in the area had reached record-breaking low values — and that most of the ozone typically found around 11 miles into the stratosphere had been depleted.

The last time a hole that strong opened in the ozone layer, which sits above Earth’s stratosphere and absorbs ultraviolet radiation from the sun, was spring 2011.

Late last week, however, CAMS said on Twitter that the “unprecedented” hole had come to an end.

“The Polar Vortex split, allowing ozone-rich air into the Arctic,” CAMS explained. “Although it looks like the Polar Vortex has not quite come to an end yet and will reform in the next few days, ozone values will not go back to the very low levels seen earlier in April.”

Despite the fact that air pollution has fallen due to global coronavirus lockdowns, CAMS said that COVID-19 and its subsequent quarantines likely had nothing to do with the hole’s closure.

“It’s been driven by an unusually strong and long-lived polar vortex, and isn’t related to air quality changes,” CAMS wrote on Twitter.

While the hole was unusual for the Arctic, such ozone holes have developed over the Antarctic each year for the last 35 years.

Those holes are caused by an accumulation of man-made chemicals like chlorine and bromine during the winter that build up inside the polar vortex and become chemically active once sunlight returns to the area, according to CAMS.

The Arctic stratosphere is usually less isolated than its Antarctic counterpart because the presence of nearby land masses and mountain ranges disturbs the weather patterns more than in the Southern Hemisphere,” CAMS said in a release. “This explains why the polar vortex in the Northern Hemisphere is usually weaker and more perturbed than in the Southern Hemisphere, and temperatures do not fall so low.”

Even so, CAMS said that 2019’s was one of the smallest on record.

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