The ozone hole over Antarctica is healing

The ozone layer is a region of the stratosphere located between 15 and 30 km above the Earth’s surface, which has a high concentration of ozone gas compared to other parts of the atmosphere.

By absorbing some of the Sun’s harmful ultraviolet rays, it acts as a shield to protect life on Earth. In the 1970s and 1980s, scientists discovered a large hole in the ozone layer caused by chlorofluorocarbons (CFCs) – man-made chemicals once widely used in aerosols, solvents and refrigerants – depleting the layer after rising into the stratosphere.

In 1987, the United Nations adopted the Montreal Protocol, an international agreement to ban CFCs globally, and to set a long-term plan to phase out ozone-depleting substances and slow the expansion of the ozone hole. 197 countries and economies have since ratified the Protocol.

Montreal is considered one of the most successful international agreements in addressing global environmental issues, helping to reach a global consensus to phase out ozone-depleting substances such as CFCs. Research published in 2023 by the University of Otago, New Zealand, showed that the ozone hole over Antarctica has a maximum area of ​​up to 26 million square kilometers, about 3.4 times the land area of ​​Australia, and the amount of ozone in the hole’s core has decreased by 26% since 2004.

However, the ozone layer is 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 in late November.

The hole over Antarctica developed later than usual this year due to disruptions in the polar vortex caused by two sudden stratospheric warming events in July 2024, according to the EU’s Copernicus Atmosphere Monitoring Service (CAMS). It is therefore relatively small for the time of year. However, data shows that the hole is as expected and is recovering.

“From volcanoes to climate change, there are many factors that play a direct or indirect role in the formation of the Antarctic ozone hole. However, none have had as great an impact as man-made ozone-depleting substances. The Montreal Protocol and its 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,” Laurence Rouil, director of CAMS at the European Centre for Medium-Range Weather Forecasts, said in a statement. “This shows that humanity has the power, 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 that caused the ozone hole in Antarctica and spent more than 40 years trying to find a way to “patch” it – also admitted that “the hole is narrowing and the ozone layer will gradually recover”, she told VnExpress and added that it could happen around 2050.