2026 Antarctic ozone hole is biggest in 10 years
NOAA and NASA report the gap reached 10.5 million square miles in September, driven by a strong polar vortex.
By Rebecca Foster ·
The hole in Earth's ozone layer over Antarctica reached its peak size on Sept. 18, covering 10.5 million square miles. According to a new joint report from NOAA and NASA, this marks the largest extent recorded in a decade.
The 2026 measurement ranks as the seventh largest in 48 years of continuous monitoring. Researchers attribute the expansion to an unusually powerful polar vortex. This weather pattern kept the ozone depletion prolonged, allowing the gap to grow larger than typical seasonal averages.
Amy Butler, a research scientist at NOAA's Chemical Sciences Laboratory, explained that planetary-scale weather systems were weak in August and September. These systems normally well up from the lower atmosphere to break up the vortex. Their absence this year allowed the vortex to remain unusually large.
Paul Newman, a senior scientist at the University of Maryland and leader of NASA's ozone research team, noted that the 2026 hole could have been 1 to 2 million square miles larger. He stated that if ozone-depleting substances were as prevalent today as they were at their 2000 peak, the gap would have expanded further.
The 2026 figures stand in sharp contrast to 2025, when the ozone hole was the fifth smallest since 1992. Government data shows the 2026 maximum is about 90% as large as the record set in 2000. Scientists emphasize that the long-term recovery remains on track despite this year's larger size.
Chlorofluorocarbons and other ozone-depleting compounds, once common in aerosol sprays, foams, air conditioners, and refrigerators, caused the initial damage. Researchers estimate the layer will recover by the 2070s as these older compounds disintegrate. Newman added that the annual hole has been forming later in the season in recent years, a sign the ozone layer is healing. The term "ozone hole" refers to a region of the stratosphere with extremely low ozone concentrations, not a literal gap. This layer acts as a planetary sunscreen, shielding life from harmful ultraviolet radiation that can cause skin cancer, cataracts, and crop damage.
