The ozone hole over Antarctica is shrinking and is expected to fully recover by 2066.
The ozone layer is a region of the stratosphere located between 15 and 30 kilometers above the Earth’s surface, with a higher concentration of ozone compared to other parts of the atmosphere.
By absorbing some of the Sun’s harmful ultraviolet rays, it acts as a shield protecting life on Earth. In the 1970s and 1980s, scientists discovered a large hole in the ozone layer caused by chlorofluorocarbons (CFCs)—synthetic chemicals that were widely used in aerosols, solvents, and refrigerants—that degraded the layer after being released into the stratosphere.
3D map of the ozone hole on September 10, 2024. (Source: CAMS/ECMWF).
In 1987, the United Nations adopted the Montreal Protocol, an international agreement that globally banned CFCs and laid out a long-term plan to phase out substances that deplete the ozone layer, thereby slowing the expansion of the ozone hole. Since then, 197 countries and economies have ratified this protocol.
The Montreal Protocol is regarded as one of the most successful international agreements in addressing global environmental issues, achieving worldwide consensus to gradually eliminate ozone-depleting substances like CFCs. Research published in 2023 by the University of Otago, New Zealand, indicates that the Antarctic ozone hole reached a maximum area of 26 million square kilometers, approximately 3.4 times the size of mainland Australia, and the amount of ozone in the core of the hole has decreased by 26% since 2004.
However, the ozone layer is very complex, and its health is influenced by many factors. The size of the hole fluctuates seasonally, appearing in August and reaching its maximum size in October before closing by the end of November.
According to the European Union’s Copernicus Atmosphere Monitoring Service (CAMS), the Antarctic hole developed later than usual this year due to disruptions in the polar vortex caused by two sudden warming events in the stratosphere in July 2024. As a result, it is relatively small for this time of year. Nevertheless, data indicate that the hole remains on track and is recovering.
“From volcanoes to climate change, many factors play a direct or indirect role in the formation of the Antarctic ozone hole. However, no factor has as significant an impact as human-made ozone-depleting substances. The Montreal Protocol and subsequent amendments have created enough space for the ozone layer to begin to recover, and we can expect clearer signs of recovery in the next forty years,” stated Laurence Rouil, Director of CAMS at the European Centre for Medium-Range Weather Forecasts. “This shows that humanity has the ability, through international cooperation and science-based decisions, to change our impact on the planet’s atmosphere.“
Professor Susan Solomon (Massachusetts Institute of Technology)—the scientist who discovered the mechanism behind the Antarctic ozone hole and has been working for over 40 years to find ways to “repair” it—also acknowledged “the hole is shrinking and the ozone layer will gradually recover,” she told reporters, adding that this could happen around 2050.
