The ozone layer returns to 1980 levels: the estimate is now 2040

The stratospheric ozone layer, which filters ultraviolet radiation harmful to human health and ecosystems, is recovering according to an increasingly precise timeline. The latest four-yearly scientific assessment, conducted jointly by the World Meteorological Organization and the United Nations Environment Programme, indicates that, if current policies are maintained, the global average at mid-latitudes will return to 1980 values around 2040. For the Arctic the estimate is 2045, for Antarctica 2066.

The benefit concerns the entire world population, because the ozone layer protects uniformly against the excess ultraviolet radiation that increases the risk of skin cancer and eye damage, in addition to affecting marine and terrestrial ecosystems. The mid-latitude band, where the majority of the planet’s population is concentrated, is also the one with the nearest recovery horizon. The polar regions, where the ozone hole phenomenon manifests with greater seasonal intensity, will instead require a few decades longer.

The underlying data supporting this trajectory is the reduction of ozone-depleting substances in the Antarctic stratosphere: since the peak reached around 2000, their quantity has decreased by about a third compared to levels before the hole formed. This is the cumulative effect of years of implementation of the Montreal Protocol, the international agreement regulating the production of industrial substances once widespread in refrigeration, propellants and solvents. According to the same assessment, the measures adopted through the Protocol would also have prevented, as a side effect, global warming estimated at between 0.5 and 1°C by mid-century, because many of the banned substances were also potent greenhouse gases.

The source of the data is the WMO-UNEP four-yearly scientific assessment, the reference report that periodically measures the state of the stratospheric ozone layer through satellite and ground-based observation networks. The same assessment is careful to make one point clear: the recovery is not linear. In 2026 the seasonal hole over Antarctica nonetheless reached, on September 12, an extent of 25 million square kilometers, five million more than the seasonal average recorded in recent years. The underlying trend remains one of measurable improvement, but the year-to-year pattern continues to depend on the meteorological conditions of the polar stratosphere, which can temporarily speed up or slow down the process.