Scientists have reported a significant and encouraging milestone in the planet's environmental health: the hole in the ozone layer over Antarctica this year was the smallest and shortest-lived observed since 2019. Data from the European Union's Copernicus Atmosphere Monitoring Service (Cams) reveals a clear trend of recovery, hailed as a direct result of global cooperation to phase out harmful chemicals.
A Smaller, Shorter-Lived Gap in Planetary Protection
According to the latest satellite data, the annual gap in the Earth's protective ozone layer – often described as a planetary sunscreen – peaked at an area of 21 million square kilometres in September. This maximum size is notably smaller than the 26 million square kilometre peak recorded in 2023. The hole then continued to shrink, closing earlier than usual on a Monday in November.
This marks the second consecutive year of relatively small ozone holes, following a concerning series of larger and more persistent holes that spanned from 2020 to 2023. Laurence Rouil, the director of Cams, described the development as a reassuring sign, stating it reflects the steady year-on-year progress we are now observing in the recovery of the ozone layer.
The Montreal Protocol: A Blueprint for Global Success
The ozone layer is a crucial stratospheric shield that absorbs harmful ultraviolet (UV) radiation from the sun, protecting life on Earth. Its depletion was driven for decades by human-made ozone-depleting substances (ODS) like chlorofluorocarbons (CFCs).
The turnaround began with the landmark 1987 Montreal Protocol and its subsequent amendments, which successfully phased out the production and use of these damaging chemicals. A 2023 study in Nature Climate Change confirmed the protocol's effectiveness, noting it also led to the peak heating effect of these gases occurring five years earlier than previously forecast.
The World Meteorological Organization projects that, thanks to the ban, the ozone layer over the Antarctic should recover to 1980 levels by approximately 2066.
Understanding Recent Fluctuations and Future Vigilance
Scientists are still analysing the reasons behind the unusually large and long-lasting ozone holes between 2020 and 2023. A leading hypothesis points to the 2022 eruption of the Hunga Tonga volcano, which injected vast amounts of water vapour and ash high into the stratosphere, potentially exacerbating the 2023 hole.
Cams experts have warned that the severe holes of recent years demonstrate how global stratospheric ozone decline could have reached catastrophic levels without international agreements. This progress should be celebrated as a timely reminder of what can be achieved when the international community works together to address global environmental challenges, emphasised Rouil.
Separate data from NASA and the US National Oceanic and Atmospheric Administration ranks the 2025 ozone hole as the fifth smallest recorded since 1992. Paul Newman, leader of NASA's ozone research team, confirmed the changes are following scientific predictions: They're forming later in the season and breaking up earlier. But we still have a long way to go before it recovers to 1980s levels.
The continued recovery of the ozone layer remains vital for human and planetary health, reducing risks associated with increased UV radiation, such as skin cancer, cataracts, and damage to ecosystems and agriculture.
