Climate change: Ozone hole over Antarctic ‘largest and deepest’ in recent years, scientists warn
Freezing polar vortex driving depletion of vital protective layer, but enforcing bans on damaging chemicals remain essential, experts say
Your support helps us to tell the story
From reproductive rights to climate change to Big Tech, The Independent is on the ground when the story is developing. Whether it's investigating the financials of Elon Musk's pro-Trump PAC or producing our latest documentary, 'The A Word', which shines a light on the American women fighting for reproductive rights, we know how important it is to parse out the facts from the messaging.
At such a critical moment in US history, we need reporters on the ground. Your donation allows us to keep sending journalists to speak to both sides of the story.
The Independent is trusted by Americans across the entire political spectrum. And unlike many other quality news outlets, we choose not to lock Americans out of our reporting and analysis with paywalls. We believe quality journalism should be available to everyone, paid for by those who can afford it.
Your support makes all the difference.The ozone hole over the Antarctic has reached its maximum annual size and is one of the largest and deepest in recent years, scientists monitoring the protective shield have warned.
The ozone layer, in the upper part of the Earth’s atmosphere, absorbs most of the incoming ultraviolet radiation from the sun that would otherwise be damaging to life on our planet.
Concentrations of ozone, also known as trioxygen, fell to “near zero values” over Antarctica at around 20 - 25km altitude, according to scientists at the Copernicus Atmosphere Monitoring Service (Cams).
The large hole comes after an “unusually small and short-lived” ozone hole in 2019, due to particular atmospheric conditions, Cams said, and highlighted the need to enforce bans on human-made chemicals such as chlorofluorocarbons (CFCs), which are known to contribute to ozone depletion.
The scientists said this year’s large hole in the layer was being driven by a “strong, stable and cold polar vortex” - a persistent region of low pressure, usually found over the edge of the enormous Ross ice shelf, where temperatures can plunge to almost -80C.
“There is much variability in how far ozone hole events develop each year. The 2020 ozone hole resembles the one from 2018, which also was a quite large hole, and is definitely in the upper part of the pack of the last fifteen years or so”, said Vincent-Henri Peuch, director of Cams.
“With the sunlight returning to the South Pole in the last weeks, we saw continued ozone depletion over the area.
“After the unusually small and short-lived ozone hole in 2019, which was driven by special meteorological conditions, we are registering a rather large one again this year, which confirms that we need to continue enforcing the Montreal Protocol banning emissions of ozone depleting chemicals.”
The scientists explained that the hole in the ozone layer is formed as chlorine and bromine-containing substances accumulate within the freezing polar vortex, where they remain inactive in darkness.
But when the sun rises over the pole following the winter darkness, the energy it releases causes the temporarily inert bromine and chlorine atoms to become chemically active, and they rapidly destroy ozone molecules, depleting the layer.
At ground level, ozone - a pungent gas which smells similar to chlorine - is considered a pollutant as it is a powerful oxidant, which causes damage to mucous and respiratory tissues in animals, and can also impact plants.
However, its presence in the stratosphere is beneficial due to its ability to absorb medium-frequency ultraviolet light. The ozone layer absorbs around 97-99 per cent of all UV light, preventing skin cancer and other conditions.
Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies
Comments