World Meteorological Organization data released this week show that the Antarctic ozone hole recorded in 2024 was the fourth to fifth smallest since systematic monitoring began in 1992, and for the second consecutive year it fell well below the 1990‑2010 average. The finding confirms that the protective ozone layer, which has been slowly rebuilding since the turn of the millennium, is on track to recover fully within a few decades.

Nevertheless, the same report flags a growing public‑health concern: several parts of the Northern Hemisphere, including large swathes of Europe, are experiencing more days with an elevated UV index. The UV index, an internationally recognised scale, measures the intensity of solar ultraviolet radiation that reaches the ground.

Why UV levels are climbing despite ozone gains

Since the mid‑1990s, scientists have documented a rise of up to 20 percent in UV radiation in some European locations. The increase is linked mainly to clearer skies and longer periods of sunshine rather than to any reversal in ozone recovery. Less cloud cover lets more ultraviolet light penetrate to the surface, raising the risk of skin cancer, cataracts and other health problems.

"Atmospheric monitoring is essential for protecting the ozone layer and, by extension, life on Earth," said Laurence Rouil, director of the Copernicus Atmosphere Monitoring Service at the European Centre for Medium‑Range Weather Forecasts. She added that the 2026 ozone hole's area expanded earlier than usual in September, even as most other diagnostics remained close to historical norms. "No single diagnostic can tell the whole story," Rouil warned, underscoring the need for a comprehensive data set.

Monitoring capacity under pressure

Accurate tracking of ozone and UV trends depends on a dense network of ground‑based spectrophotometers. Europe enjoys one of the world's most extensive arrays, with the EuBrewNet consortium coordinating roughly 50 instruments and a regional calibration centre in Spain ensuring consistency across the network. However, the global picture is less reassuring: the total number of ozone‑monitoring stations worldwide has fallen from about 130 in the early 2000s to roughly 110 today, as many sites close in regions where data were already scarce.

Reduced coverage could hamper early warning systems and limit the ability to detect regional anomalies. Experts stress that sustained investment in monitoring infrastructure is vital, especially as climate‑related shifts in cloud patterns may further alter UV exposure.

Policy background and future challenges

The long‑term recovery of the ozone layer owes much to the 1987 Montreal Protocol, which mandated the phase‑out of chlorofluorocarbons (CFCs) used in refrigeration, aerosol propellants and fire‑fighting foams. The treaty is widely hailed as a successful example of coordinated international action, and its legacy is now evident in the shrinking size of the Antarctic ozone hole.

Yet the protocol does not address the drivers of climate change, which stem from rising concentrations of carbon dioxide and other greenhouse gases. While the ozone issue and climate change are distinct, both affect public health and require robust regulatory frameworks. Some observers note pressure from the United States for the EU to relax certain chemical‑control measures, a development that could undermine the precautionary approach that has protected the ozone layer.

For European citizens, the practical implication is clear: even as the ozone layer heals, sun‑related health risks are not disappearing. Public health agencies are urged to maintain, if not strengthen, skin‑cancer prevention campaigns, promote the use of sunscreen, and encourage protective clothing during high‑UV days.

Unions and consumer groups have called for greater transparency around UV forecasts and for workplaces, especially those outdoors, to adopt safety guidelines that reflect the latest scientific data. Meanwhile, the European Commission is expected to review funding for atmospheric monitoring programmes in its upcoming budget cycle, with environmental NGOs lobbying for increased resources.

In sum, the ozone layer's gradual rebound is a cause for cautious optimism, but the rise in UV exposure across Europe underscores the need for continued vigilance, investment in monitoring, and public‑health measures that protect ordinary people from the sun's hidden dangers.