The hole in the ozone layer is very weird, but in a good way

"This is the season when the ozone hole is growing year by year in the skies over Antarctica. It's still early, but scientists say this year's version behaves unusually and could become the smallest hole seen in more than three decades.

On this International Day for the Preservation of the Ozone Layer, we bring you good news about the atmosphere of the Earth. Recent observations from the Copernicus Atmospheric Monitoring Service (CAMS) – a service run by the European Union that constantly monitors the state of the atmosphere – suggest that the hole in the ozone layer located over Antarctica in 2019 "could have the smallest area of ​​any ozone hole in the Antarctic since the mid-1980s," according to a CAMS press release issued on September 9, 2019. Over the past week, the hole in the ozone layer has continued to behave strangely, but in a manner consistent with a smaller hole than usual, according to CAMS.

The ozone hole is formed each year during the Antarctic spring, from the end of August to the end of December, during which time the amount of ozone in the Earth's stratosphere over Antarctica can be reduced to 60 %. During the first days and weeks of this year's ozone hole, the gap in the atmosphere did not open in the usual way; the hole is well below the size usually seen at this time of year. In addition, the hole is not immediately above the South Pole, but rather closer to South America.

"This year, we found that the hole in the ozone layer was particularly unusual," said Antje Inness, senior scientist at CAMS, in the press release issued today. "Although growth was relatively early, in early September, a sudden warming of the stratosphere disrupted the polar cold vortex at the origin of the hole in the ozone layer."

According to CAMS, the warming of the stratosphere has resulted in a reduction in the number of stratospheric clouds, which has resulted in a decrease in the depletion of the ozone layer. In addition, the unusual orientation of the hole to South America means that the air rich in ozone from outside the vortex can infiltrate, reducing the hole in the ozone layer.

Last week's CAMS observations revealed an ozone-depleting zone extending over approximately 5 million square kilometers (1.9 million square miles), while In 2017, it reached 20 million square kilometers (7.7 million square miles), the BBC reported, noting that there is "a good degree of year-to-year variability".

The hole is currently going through phases of growth and decline, but has stabilized in recent days. CAMS forecasts suggest it will remain small this week and is still on the verge of becoming the smallest hole seen in 30 years, Inness said.

And thank god for that. Ozone is a critically important molecule that protects the Earth's surface from the harmful ultraviolet rays of the Sun. Atmospheric ozone exists in a perpetual cycle of birth and destruction which, under normal circumstances, would be in a state of equilibrium. However, human activities, such as the release of halogenated hydrocarbons, disrupt this happy balance, contributing to the depletion of the ozone layer, located between 20 and 30 km above the surface. .

The world's attention turned to the ozone layer in the mid-1980s, when scientists detected a scary ditch that culminated in the 1987 Montreal Protocol. Hard to believe in today's standards – with our disconcerting inability to reach a global consensus on climate change caused by humans – the world has rallied to reduce halocarbon emissions that deplete the diaper Ozone, from compounds produced by refrigerators and air conditioners. aerosols and medical sterilizers. Today, the Montreal Protocol has 196 signatories and it seems to work. The healing ozone layer is recovering, albeit slowly. According to a United Nations report from last year, the ozone layer is expected to reach its levels before the 1980s in about 40 years.

That said, the unusually small ozone hole observed this year can not be linked to the Montreal Protocol.

"This is not really related to the Montreal Protocol, where we have tried to reduce chlorine and bromine in the atmosphere, because they are still there," said Richard Engelen, CAMS Executive Director, BBC. "It's much more connected to a dynamic event. People will obviously be asking questions about climate change, but we just can not answer that for now. "

That the little hole in the ozone layer is linked to climate change would be, in a word, ironic. Engelen said more research was needed to fully understand the nature of the hole in this year 's ozone layer.

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That said, we must continue to defend the Montreal Protocol and ensure the continued cooperation of the nations of the world.

Last year, for example, scientists detected a mysterious spurt of unauthorized CFC-11 emissions, which would then have been traced back to the east of China. The Chinese government has managed the situation to keep it in compliance with the Montreal Protocol, but the episode has demonstrated the importance of monitoring the environment to detect potential violators. Protecting the planet from those who choose to abuse it requires constant vigilance.