The Antarctic ozone hole closed on December 1 this year, weeks earlier than usual.
Copernicus says the 2025 hole was the smallest in five years.
It peaked at just over 21 million sq km, well below the 2006 record.
Scientists credit the global ban on ozone-depleting substances for the trend.
The closure offers a rare environmental bright spot during a year of record heat.
The Antarctic ozone hole has fully closed earlier than usual this year, offering a rare moment of optimism amid record global temperatures and climactic doom and gloom.
Copernicus, the European Earth observation agency, confirmed that the hole that formed in August had completely healed by December 1, 2025. October 2025 was 1.55 degrees Celsius (°C) warmer than the pre-industrial average (1850-1900), yet the ozone layer showed one of its strongest signs of recovery in recent years.
The 2025 ozone hole is “the smallest in five years, marking the second consecutive year of relatively small holes compared to the series of large and long-lasting ozone holes from 2020-2023, and had higher ozone concentrations, fueling hopes for recovery,” according to Copernicus.
While ozone holes are common in the stratospheric realm, the most severest form of hole develops over the Antarctic region, and the season usually happens during the austral spring season of the southern hemisphere, which is September to November.
The 2025 ozone hole followed a similar trajectory to the 2023 episode, which was the largest in the last five years, according to Copernicus.
In September, the hole reached its maximum area of over 21 million square kilometres (sq km) before it started shrinking. Historically, the largest ozone hole area ever recorded was over 29 million sq km in 2006.
“The earlier closure and relatively small size of this year’s ozone hole is a reassuring sign and reflects the steady year-on-year progress we are now observing in the recovery of the ozone layer thanks to the ozone-depleting substance ban,” Laurence Rouil, director of the Copernicus Atmosphere Monitoring Service, observed in the report.
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, Rouil underlined.
The ozone hole — a seasonal thinning of the stratospheric ozone layer particularly in the southern polar region — was first discovered in 1985. It is caused primarily by human-induced emission of chemicals like chlorofluorocarbons that destroy ozone molecules and allow more harmful ultraviolet radiation to reach the Earth’s surface.
While ozone depletion occurs globally, the most severe thinning develops over Antarctica due to the extreme cold temperatures and unique chemical reactions in the region’s stratosphere during the southern hemisphere spring.