Home South pole ice There’s an Antarctic-sized hole in the ozone

There’s an Antarctic-sized hole in the ozone


A visualization of satellite data from the 2020 ozone hole.

Last year’s ozone hole, not terrible either!
Picture: ESA

The quintessential 1980s ozone hole problem is still present today. And in bad news, this year’s ozone hole is bigger than usual and has spread across all of Antarctica and beyond.

The European Union’s Copernicus atmosphere monitoring service released the results on Thursday, marking the second consecutive year of a large ozone hole is formed at the South Pole. Just two years ago, the region saw its smallest hole in the ozone layer ever recorded.

This year’s hole is in the top quarter of the record books and the biggest since 2010 for this time of year. It covers an area of ​​around 8.5 million square miles (22 million square kilometers), more than double the size of Europe. He could still grow in the coming weeks; the annual peak is generally at the end of September or the beginning of October.

The gash in the ozone layer is due to decades of using ozone-depleting chemicals known as chlorofluorocarbons (CFCs, if you prefer a simple acronym) in things like refrigerators and air conditioners. This is important because the ozone layer blocks harmful ultraviolet rays that can cause skin cancer and have other harmful effects.. CFC were gradually phased out as part of the Montreal Protocol, an international treaty signed at the end of the 1980s which, in the opinion of all, has been a resounding success. The hole in the ozone layer should heal in the decades to come, and the treaty was just amended to phase out CFC replacements, which are a powerful greenhouse gas. (CFCs also warm the planet, and recent research shows how important the Montreal Protocol has been in saving us time to tackle other greenhouse gas emissions.)

But this year’s cavernous hole in the ozone layer shows that recovery takes time. Local weather conditions play a major role in determining the size of the ozone hole in any given year. And the conditions this year have unfortunately triggered the ozone depletion system to shift into high gear.

A graph showing the area of ​​the ozone hole.  A red line shows the extent of this year, which is the largest on record for this time of year since 2010.

Picture: CAM

Vincent-Henri Peuch, director of the Copernicus Atmosphere Monitoring Service, said in an email: “So far this season, the stratosphere over the South Pole has been very cold, the polar vortex is strong, and it seems that this will continue. for a moment.”

Cold weather and the strong polar vortex (the southern hemisphere version, which is a cousin of the one you may be more familiar with) is basically a punch to the ozone layer. The cold allows the formation of polar stratospheric clouds, which contain ice crystals. These crystals affect atmospheric chemistry, triggering a series of reactions when sunlight hits them, causing rapid destruction of ozone. It all happens at this time of year as it is the onset of the southern summer, when sunlight shines on the South Pole after a long, dark winter.

While a monster ozone hole may look like its own long, dark winter, Peuch nonetheless noted that ozone recovery is a “slow, long-term” process. A few bad years for the ozone layer do not mean that our overall progress is on track.

Molly Taft contributed reporting for this article.