Published on: 2026-09-16
Source: United Nations – United Nations –
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September 16, 2026 Climate and Environment
The ozone hole over Antarctica in 2025 was one of the smallest in recent decades. This indicates the success of international efforts to protect the ozone layer, said the World Meteorological Organization (WMO). The ozone layer plays an important role in protecting people and ecosystems from harmful ultraviolet (UV) radiation from the Sun. Its recovery is especially important in the context of an increasing number of days with a high UV radiation index.
According to WMO data, last year the ozone hole ranked among the five smallest since observations of its significant thinning began in 1992. This is the second consecutive year that its size and depth were significantly below the average levels for 1990-2010.
Annual fluctuations depend on large-scale meteorological processes that determine air mass transport and springtime ozone depletion. These fluctuations occur against the backdrop of a long-term trend of ozone layer recovery, reflecting the successful implementation of the Montreal Protocol on substances that deplete the ozone layer.
In the Northern Hemisphere in 2025, the total ozone content in the atmospheric column was below average in a vast region extending from Greenland and Europe to Central Asia, the northern part of Japan, and the Kamchatka Peninsula in the Russian Federation.
International Day for the Preservation of the Ozone Layer
The new WMO Ozone Bulletin was published on the International Day for the Preservation of the Ozone Layer, celebrated on September 16 and dedicated to the adoption of the Montreal Protocol in 1987. Thanks to this agreement, it has been possible to phase out substances that deplete the ozone layer. This year’s theme for the International Day is “Global Actions to Cool the Planet.” It coincides with the tenth anniversary of the Kigali Amendment, which expanded the scope of the Protocol.
In his message on the occasion of the Day, the UN Secretary-General noted that in 2016, countries opened a new chapter in one of the most remarkable success stories in environmental protection.
“Building on the Montreal Protocol, which initiated the gradual restoration of the ozone layer, countries adopted the Kigali Amendment to combat a new threat: hydrofluorocarbons (HFCs) – highly potent greenhouse gases used for cooling,” the UN chief’s message states.
HFCs are widely used in everyday cooling technologies as a replacement for substances that destroy the ozone layer. Although HFCs do not destroy the ozone layer, some of them trap thousands of times more heat in the atmosphere than carbon dioxide, despite persisting in the atmosphere for a significantly shorter time.
With full implementation of the Kigali Amendment by the end of the century, global warming could be reduced by 0.5 degrees Celsius. Combined with the use of energy-efficient cooling systems, this figure could be doubled.
Ultraviolet radiation
About 90 percent of atmospheric ozone is located in the upper layers of the stratosphere. If all this ozone were collected at the Earth’s surface, the resulting layer of pure ozone would be only about three millimeters thick. Nevertheless, this thin layer blocks almost all dangerous shortwave ultraviolet radiation from the Sun and protects life on Earth.
Despite significant progress in combating ozone layer depletion, measurements in recent decades show a noticeable increase in the number of days with a high UV index. The UV index was developed to monitor ozone layer depletion and is now used as an international standard to inform about the need for ultraviolet protection.
Since the mid-1990s, the level of UV radiation has increased by 20 percent in some parts of Europe. Ground measurements show that this is mainly due to a reduction in cloudiness and an increase in the duration of sunshine throughout the year. More intense exposure to UV radiation raises the risk of skin cancer and other ultraviolet-related diseases.
“In light of this trend, targeted and effective measures to protect against UV radiation are of utmost importance,” the bulletin says.
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