Just as the sea ice around Antarctica waxes and wanes every year, so does the ozone hole above Antarctica. This year, the hole has widened a lot. Observations from the European Space Agency's (ESA) Copernicus Sentinel-5P satellite indicate that on September 16, 2023, the area of ​​the ozone hole reached approximately 10 million square miles (26 million square kilometers), making it one of the largest seasonal ozone holes ever observed.

Ozone hole map on September 16, 2023. (Image source: NASA Ozone Observatory)

The truly largest ozone hole occurred in 2000, when it covered nearly 11 million square miles (28.4 million square kilometers).

Ozone is a natural gas found in the stratosphere that protects us from the sun's ultraviolet rays. In 1985, a hole in the ozone layer was discovered over Antarctica, which was later found to be related to human use of carbon-consuming substances. We have banned these substances since then and have been monitoring the size of the ozone hole.

However, the ozone hole still expands and contracts seasonally due to temperature changes and wind conditions in the stratosphere, reaching a maximum between mid-September and mid-October. Antje Inness, senior scientist at the Copernicus Atmosphere Monitoring Service, said in a statement: "Our ozone monitoring and forecasting services show that the ozone hole in 2023 started early and has grown rapidly since mid-August."

The January 2022 eruption of the Hunga Tonga volcano, which introduced large amounts of water vapor into the air, may have contributed to the above-normal heat growth. "Water vapor may lead to increased formation of polar stratospheric clouds, and chlorofluorocarbons (CFCs) may react in polar stratospheric clouds to accelerate ozone depletion," Innes said.

However, despite the larger seasonal increase this year, the overall size of the ozone hole is still shrinking. Claus Zehner, ESA's Copernicus Sentinel-5P mission manager, said: "Based on the Montreal Protocol and the reduction of anthropogenic ozone-depleting substances, scientists currently predict that the global ozone layer will return to normal conditions around 2050."