CAMS estimated the Antarctic ozone hole covered 25 million square kilometers on Sept. 12, 2026, above its seasonal average as scientists monitor atmospheric conditions linked to ozone loss.
The estimate came after the hole passed 15 million square kilometers before August ended, slightly ahead of the seasonal average. The Copernicus Atmosphere Monitoring Service (CAMS) said the pace was similar to 2025, when the area reached that threshold on Aug. 30.
The area rose quickly in the first half of September. During that expansion, minimum temperatures at roughly 20 kilometers above the South Pole fell sharply, the service reported.
Cold stratospheric conditions support the formation of polar stratospheric clouds, CAMS said. During Southern Hemisphere spring, from August through November, sunlight and halogens contribute to chemical ozone removal. The 2026 increase coincided with atmospheric conditions associated with seasonal ozone loss.
The expanding area was not the only measure CAMS monitored. Its ozone-column minimum value within the defined area of the hole and the ozone mass deficit both stayed close to average levels, according to the service’s Sept. 16 update.
CAMS links the long-term thinning of the ozone layer to human-made emissions released over nearly five decades. It says people face risks from harmful ultraviolet radiation, which is a major cause of skin cancers. The service also said global warming tends to lower stratospheric temperatures, favoring the clouds involved in ozone depletion.
CAMS said the hole’s overall development from the second half of August followed a pace typical of the previous 46 years. The ozone hole opens over Antarctica each austral spring, when the region’s polar vortex and stratospheric winds are more stable. In recent years, smaller and shorter-lived holes have indicated recovery, though their development can vary with atmospheric and chemical factors.
The largest area on record was 29.6 million square kilometers on Sept. 9, 2006. In its Sept. 16 update, CAMS said forecasts at the time pointed to a possible further increase in mid-September; the service tracks the hole using daily data.
