The Antarctic ozone hole in 2026 was the seventh largest by mean size in 48 years of satellite monitoring, according to NASA. The large area was driven by an unusually strong polar vortex that created ideal conditions for ozone depletion during the peak season.
By its mean size during the peak ozone depletion season from September 7 to October 13, the 2026 hole ranked as the seventh largest on record. The hole reached its annual maximum area on September 18.
While large in area, the hole was not as deep as other large holes on record. The lowest ozone concentrations on record were measured in 1994, when they fell to 73 Dobson units.
Human-made chemicals, including chlorofluorocarbons (CFCs) historically used in aerosol sprays and refrigeration, contribute to the Antarctic ozone hole. The 1987 Montreal Protocol is a treaty phasing out the consumption and production of ozone-depleting chemicals.
In 2018, scientists reported a 20 percent decrease in ozone depletion during Antarctic winter months from 2005 to 2016. Scientists estimate the Antarctic ozone layer will return to 1980 levels in the 2070s. Year-to-year fluctuations in the hole’s area and depth are caused by variations in stratospheric temperature and circulation.
Analysis
Why This Matters
- The size of the 2026 hole demonstrates that natural weather patterns can still create severe ozone depletion even as the underlying chemical cause recedes.
- Ozone layer health directly affects UV radiation reaching the surface, impacting both human health and ecosystems.
- The Montreal Protocol is the benchmark for international environmental cooperation; the 2026 data shows its long-term impact while highlighting the decades-long timeline for full recovery.
Background
The Antarctic ozone hole was first detected in 1985, caused by chlorofluorocarbons (CFCs) and other human-made chemicals destroying stratospheric ozone. The Montreal Protocol of 1987 phased out these chemicals. Recovery is a slow process because CFCs linger in the atmosphere for decades. The annual hole fluctuates in size depending on stratospheric weather conditions.
What to Watch
- Future polar vortex strength and its interaction with a changing global climate, which could alter the expected recovery path.
- Annual measurements from NASA and NOAA to track whether the long-term healing trend continues despite year-to-year variability.
Checked
12 claims in this story checked against 1 source: 12 supported.
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- SupportedNASA said the 2026 Antarctic ozone hole ranked seventh largest by mean size in 48 years of monitoring.NASA: “Measured by its mean size from September 7 to October 13, which is peak ozone depletion season, the 2026 hole was the seventh largest in 48 years of monitoring.”
- SupportedAn unusually strong polar vortex created conditions for ozone depletion over a large area during the peak season.NASA: “That was the case in 2026, when an unusually strong Antarctic polar vortex created ideal conditions for ozone depletion over a large area.”
- SupportedThe mean-size assessment covered September 7 to October 13, the peak ozone depletion season.NASA: “Measured by its mean size from September 7 to October 13, which is peak ozone depletion season”
- SupportedThe hole reached its annual maximum area on September 18.NASA: “The map at the top of this page shows the hole on September 18, the day of its annual maximum area.”
- SupportedAlthough large in area, the hole was not as deep as other large holes on record.NASA: “However, it was not as deep as other large holes on record.”
- SupportedThe lowest ozone concentrations on record were measured in 1994, at 73 Dobson units.NASA: “The deepest ozone hole occurred in 1994, when concentrations fell to just 73 DU on September 30.”
- SupportedHuman-made chemicals including CFCs contribute to the Antarctic ozone hole.NASA: “When they reach the stratosphere, however, their behavior changes. In the upper stratosphere (beyond the protection of the ozone layer), ultraviolet light causes CFCs to break apart, releasing chlorine, a very reactive atom that repeatedly catalyzes ozone destruction.”
- SupportedCFCs were historically used in aerosol sprays and refrigeration.NASA: “chlorofluorocarbons (CFCs)—long-lived chemicals that had been used in refrigerators and aerosol sprays since the 1930s—”
- SupportedThe 1987 Montreal Protocol is a treaty phasing out the consumption and production of ozone-depleting chemicals.NASA: “The global recognition of the destructive potential of CFCs led to the 1987 Montreal Protocol, a treaty phasing out the consumption and production of ozone-depleting chemicals.”
- SupportedIn 2018, scientists reported a 20 percent decrease in ozone depletion during Antarctic winter months from 2005 to 2016.NASA: “In 2018, scientists reported the first direct satellite evidence of ozone recovery, observing a 20 percent decrease in ozone depletion during the Antarctic winter months from 2005 to 2016.”
- SupportedScientists estimate the Antarctic ozone layer will return to 1980 levels in the 2070s.NASA: “Scientists estimate that the Antarctic ozone layer will return to 1980 levels in the 2070s.”
- SupportedYear-to-year fluctuations in the hole’s area and depth are caused by variations in stratospheric temperature and circulation.NASA: “Year-to-year fluctuations in area and depth are caused by variations in stratospheric temperature and circulation.”
