There appears to be an unusually large hole in the ozone layer forming over Antarctica right now

There appears to be an unusually large hole in the ozone layer forming over Antarctica right now

The hole is actually larger than Antarctica itself.

The ozone layer is located in the stratosphere – at an altitude of about 40 kilometers. This protects us from harmful UV rays and is therefore very important. However, every September, during the Australian spring, a “hole” forms in the ozone layer. And this recurring gap is too big this year.

Volume fluctuations
During spring in the Southern Hemisphere, the famous ozone hole forms over Antarctica every year. This isn’t a real hole, by the way, but a continuous thinning of the ozone layer. The crater reaches its maximum size between mid-September and mid-October. Then, as stratospheric temperatures begin to rise in late spring in the Southern Hemisphere, ozone depletion slows and the polar vortex weakens. As a result, the hole in the ozone layer is slowly but surely shrinking, until it disappears completely by December.

Researchers are closely watching the crater’s evolution. And after a fairly record start, the ozone hole has grown significantly over the past week. The hole is now 23 million square kilometres, making it larger than Antarctica itself.

big hole
“At the beginning of the season, the ozone hole developed as we expected,” said Vincent-Henri Beuche, director of the CAMS Copernicus Atmospheric Monitoring Service. “It’s very similar to last year when the hole didn’t have an exceptional start either, but later in the season it turned into one of the longest ozone holes in our database. Our forecast now shows that this year’s hole has evolved into a slightly larger one than usual.” The vortex is quite stable and stratospheric temperatures are lower than last year. We’re looking at a fairly large and possibly deep ozone hole.”

The size of the ozone hole in 2021. Photo:
Contains modified Copernicus Sentinel (2021) data, processed by the DLR

hole last year
So it seems history is repeating itself. He. She Last year’s ozone hole over Antarctica It eventually grew to become one of the largest and deepest in recent years. The gap grew rapidly from mid-August, peaking at about 25 million square kilometers on October 2. The large ozone hole was powered by a strong, stable, and cold polar vortex that keeps the temperature of the ozone layer over Antarctica constantly cool. This was in stark contrast to The unusually small ozone hole formed in 2019. But this year, too, the gap appears to be extraordinarily large. “The trajectory of the ozone hole in the coming months will be very interesting,” notes researcher Antje Ines.

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recovery
However, the hole in the ozone layer appears to be recovering. This is mainly due to the Montreal Protocol, which was established in 1987 and ranked as one of the most successful environmental agreements in the world. The Montreal Protocol – signed by 200 countries – aims to protect the ozone layer by phasing out the production and consumption of harmful substances (see box).

What was that again?
CFCs are long-lived chemical compounds that are widely used in the production of refrigerants, aerosols, chemical solvents and building insulation. When chemicals are emitted they can rise into the stratosphere. Here it is broken down by the ultraviolet rays of the sun, releasing chlorine atoms. These atoms destroy ozone molecules. And that’s bad news, because ozone protects life on our planet by absorbing potentially harmful UV rays. For example, ultraviolet rays can cause skin cancer, cataracts, and damage plants. To deal with CFCs, the Montreal Protocol on Substances that Deplete the Ozone Layer (the acronym of the Montreal Protocol) was created. Governments have promised to reduce the production of substances that damage the ozone layer. Meanwhile, the so-called “hole in the ozone layer” is already recovering.

Since the ban on halogenated hydrocarbons, the ozone layer has shown signs of recovery. But it is a slow process. Scientists predict that it will be at least 2060 or even 2070 before the complete elimination of substances that deplete the ozone layer. That’s because some of the ozone-depleting substances emitted by human activities linger in the stratosphere for decades. Therefore, according to the researchers, it is necessary to continue monitoring to ensure that the Montreal Protocol is enforced.

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