As the sea ice around the Antarctic continent grows and retreats each year, so does the ozone hole above the region. This year, the ozone hole has expanded significantly.
Ozone is a natural gas found in the stratosphere, the Earth’s second atmospheric layer, which protects us from the sun’s harmful ultraviolet radiation. In 1985, a hole was discovered in its layer above the Antarctic continent, which was later attributed to human use of ozone-depleting substances and regional conditions. Since then, the size of the ozone hole has been monitored.
The size of the ozone hole in the region fluctuates from August to October every year, reaching its maximum around mid-September to mid-October, according to the Copernicus Earth Monitoring Program, a satellite-based Earth monitoring program by the European Union.
Satellite images captured on September 16 last year showed that the ozone hole had reached approximately 26 million square kilometers, nearly three times the size of Brazil.
Annie Innis, a prominent scientist in the Copernicus Atmospheric Monitoring Service, stated that “the ozone hole began early this year and expanded rapidly since mid-August, making it one of the largest ozone holes ever recorded.”
The previous record for the ozone hole in the region dates back to 2000 when it reached nearly 28.4 million square kilometers, meaning that the current hole is approaching the record size.
How Is Ozone Hole Size Determined?
The variation in ozone hole size is largely determined by the strength of strong winds that circulate around the South Pole region. The extent of these strong winds is a direct result of the Earth’s rotation and the significant temperature differences between polar and temperate latitudes.
If the wind’s range is strong, it acts as a barrier, preventing the exchange of air masses between polar and temperate latitudes, leaving the air masses isolated above the polar latitudes, cooling during the winter. Ozone levels usually return to their natural state by mid-December, after the temperature in the stratosphere in the southern hemisphere rises, slowing down ozone depletion and weakening the polar vortex.
This monitoring is carried out by the “Sentinel-5P” satellite, the first satellite dedicated to atmospheric monitoring as part of the Copernicus program. Launched in October 2017, it possesses advanced spectrometry imaging equipment, called “Tropomi,” capable of detecting the unique spectral signatures of atmospheric gases, thus offering a more precise and higher spatial resolution for a wide range of pollutants.
Total ozone measurements from “Tropomi” are processed at the Earth part of the “Sentinel-5P” satellite mission at the German Aerospace Center, using algorithms developed by the German Aerospace Center and the Royal Belgian Institute for Space Aeronomy.
Speculation on Unusual Ozone Behavior in 2023
There’s speculation that the unusual behavior of the ozone layer in 2023 may be a result of the underwater volcanic eruption of “Hunga Tonga” in the South Pacific in January 2022.
Annie Innis suggests that “the massive amount of water vapor injected into the atmosphere due to the volcanic eruption may have just started reaching the South Polar region.” She adds, “Water vapor could lead to increased stratospheric polar cloud formation, enabling chlorofluorocarbon compounds to interact with the ozone, accelerating its depletion.”
The widespread impact of harmful ozone-depleting substances, such as chlorofluorocarbons, emitted from products like refrigerators and aerosol cans in the ’70s and ’80s, had previously led to the depletion of the high ozone layer in the atmosphere, allowing the ozone above the Antarctic continent to open up, according to Copernicus.
Concerns over this issue prompted global efforts and the signing of the “Montreal Protocol,” a United Nations treaty that was universally ratified and entered into force in 1989. This treaty gradually phased out the production of ozone-depleting substances, including chlorofluorocarbons. However, this time, the impact appears to be natural, resulting from the eruption of the “Hunga Tonga” volcano, as predicted by experts in the Copernicus Atmospheric Monitoring Service.
Accumulative Impact
Donald Wuebbles, from the Department of Atmospheric Sciences at the University of Illinois, downplays the significance of the “Hunga Tonga” volcano eruption as a cause of the expanding ozone hole, stating that variations in ozone holes from year to year are related to the strength of the polar vortex. He notes, “This could be the primary factor for this year, and there might be some impact from the ‘Hunga Tonga’ volcano eruption, but I have not seen any evidence of that.”
Stephen Andersen, the Research Director at the Institute for Governance & Sustainable Development, believes that the expanding ozone hole does not diminish the success of the Montreal Protocol but supports a swift move towards full compliance to protect the ozone layer and climate better. The parties to the protocol will convene in Nairobi, Kenya, from October 17 to 23 this year to fund protocol compliance and strengthen monitoring measures.
The expanding ozone hole over the Antarctic region raises concerns about its potential consequences. While there is speculation about the role of the “Hunga Tonga” volcano eruption in this phenomenon, the cumulative impact of decades of ozone-depleting substances remains a significant factor. The world’s commitment to the Montreal Protocol continues to be vital in protecting the ozone layer and the environment.
