The Antarctic ozone hole has fully closed earlier than usual this year, creating an unexpected moment of environmental optimism despite record global temperatures and continuing climate risks. Copernicus, the European Earth observation agency, confirmed that the ozone hole, which formed in August, had completely healed by December 1, 2025.
The early closure comes at a time when October 2025 recorded a temperature 1.55 degrees Celsius higher than the pre-industrial average of 1850 to 1900. Yet, according to scientists, the ozone layer displayed one of its strongest signs of recovery in recent years.
Copernicus reported that the 2025 ozone hole was the smallest in five years. It was the second consecutive year in which the ozone hole remained relatively limited in size when compared with the unusually large and long-lasting ozone holes observed from 2020 to 2023. Higher ozone concentrations recorded during this period have strengthened hopes that the recovery is gaining momentum.
Although seasonal thinning of the ozone layer is a regular stratospheric event, the most severe ozone depletion typically occurs over the Antarctic region. This thinning process usually takes place during the austral spring of the southern hemisphere, between September and November.
The 2025 ozone hole followed a similar pattern to that seen in 2023, which Copernicus noted was the most extensive in five years. At its peak in September, the ozone hole covered more than twenty-one million square kilometres before gradually shrinking. By comparison, the largest ozone hole ever recorded reached over twenty-nine million square kilometres in 2006.
Laurence Rouil, director of the Copernicus Atmosphere Monitoring Service, described the latest development as encouraging. “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,” Rouil said. She added that this progress should be recognised as evidence of what can be achieved when the global community works together on environmental protection.
The ozone hole, which refers to the seasonal thinning of the stratospheric ozone layer in the southern polar region, was first detected in 1985. It is caused mainly by human-produced chemicals such as chlorofluorocarbons that break down ozone molecules and allow more harmful ultraviolet radiation to reach the Earth’s surface.
While ozone depletion occurs across the world, scientists say the most dramatic thinning happens over Antarctica due to extremely cold temperatures and unique chemical reactions in the stratosphere during the southern spring. Environmental agencies continue to monitor global ozone levels as the long-term recovery process moves forward.