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A “record level” ozone hole over the Arctic, the largest since 2011, has been closed, the UN World Meteorological Organization (WMO) said on Friday.
The phenomenon was fueled by substances that deplete the ozone layer that are still in the atmosphere and a very cold winter in the stratosphere, the layer of the Earth’s atmosphere that is between 10 and 50 kilometers (six to 31 miles) above the ground. land, reported WMO spokeswoman Clare. Nullis said at a UN briefing in Geneva.
“These two factors combined to give a very high level of depletion that was worse than what we saw in 2011. It has now returned to normal … the ozone hole has closed,” he said.
Scientists monitoring the hole at the Copernicus Atmospheric Monitoring Service (CAMS), a European Union Earth observation program, announced the closure last week.
‘Not related to COVID’
Despite the coronavirus blockages resulting in a significant reduction in air pollution, Nullies said the occurrence of the hole healing “was not entirely related to COVID.”
CAMS also announced that the phenomenon probably had nothing to do with the pandemic.
“Actually, COVID19 and the associated locks probably had nothing to do with this,” CAMS tweeted. “It has been powered by an unusually strong and long-lived polar vortex, and is unrelated to changes in air quality.”
Ten times the size of Greenland
A German scientist had detected depletion just a month ago in what he said was the largest hole in the ozone layer above the North Pole.
“In areas where the thickness of the ozone layer is maximum, the loss is around 90%,” the German press agency dpa Markus Rex, head of the atmospheric physics department of the German Alfred-Wegener Institute, was quoted in March . . It is equivalent to an area three times larger than Greenland.
read more: What happened to the ozone layer?
In total, an area of 20 million square kilometers, or 10 times the size of Greenland, is affected, even though ozone loss is sometimes less.
Scientists from the European Space Agency (ESA) said they had predicted the hole would heal as temperatures rose, breaking the Arctic polar vortex and allowing ozone-depleted air to combine with ozone-rich air from higher altitudes. low.
According to recent data from the National Aeronautics and Space Administration (NASA), ozone levels over the Arctic reached a record low in March.
Separated from the Antarctic ozone hole
The discovery of an ozone hole over Antarctica in 1985 led to the adoption of the Montreal Protocol two years later, in which 197 countries agreed to phase out chemicals such as chlorofluorocarbons to protect ozone from further damage and decrease the size of the hole. .
In 2019, it reached its smallest extension in about 30 years.
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