This year's Antarctic ozone hole was the seventh largest in 48 years of records, but scientists say the layer is still healing
A large, stubborn polar vortex let ozone loss run longer than usual over Antarctica. NASA and NOAA, whose Boulder lab helps lead the measurements, still expect recovery by the 2070s.
Key takeaways
- The hole peaked at 10.5 million square miles (27.1 million square kilometers) on September 18, 2026.
- It averaged about 9.6 million square miles from September 7 to October 13, seventh largest in 48 years of monitoring.
- Scientists estimate the ozone hole will recover by the 2070s as older chemicals break down.
The hole in the ozone layer over Antarctica was the seventh largest by area in 48 years of monitoring this year, according to NASA and NOAA. It reached its biggest single-day size on September 18, at 10.5 million square miles (27.1 million square kilometers), and averaged about 9.6 million square miles during the peak season from September 7 to October 13, NASA said in a report dated November 4.
Why was it so big this year?
Weather, not a new surge in pollution, is the main explanation. An unusually large polar vortex, the ring of cold winds over the pole, kept conditions right for ozone loss. The planet-scale weather waves that normally break the vortex apart were weak in August and September, NASA said. The hole was not as deep as several other large ones: balloon readings at the South Pole bottomed out at 105 Dobson units on October 17, compared with a record low of 92 in October 2006. Scientists count the hole as the area where ozone falls below 220 Dobson units.
What is the Colorado connection?
NOAA's Global Monitoring Laboratory in Boulder co-leads the yearly measurements, and Boulder-based staff launch balloon-carried instruments called ozonesondes from the Amundsen-Scott South Pole Station, The Colorado Sun reported on November 10. The ozonesonde was invented in Boulder in the 1960s and is still built by Boulder companies, the Sun said.
Is the ozone layer still recovering?
Yes, according to both agencies. "The annual ozone hole has been forming later in the season in recent years, which tells us the ozone layer is healing," Paul Newman, a longtime leader of NASA's ozone research team, said in the NASA report. Chlorine from ozone-depleting chemicals in the Antarctic stratosphere has fallen by about a third from its peak, NASA said, and Newman estimated this year's hole could have been 1 to 2 million square miles larger if those chemicals were as common as in 2000, the record year.
Scientists estimate the hole will recover by the 2070s as long-lived chemicals break down. Thinner ozone lets more ultraviolet light reach the ground, which is linked to sunburn, skin cancer and eye damage, the Sun noted.
Sources
- NASA, “NASA, NOAA Track 2026 Antarctic Ozone Hole,” November 4, 2026
- The Colorado Sun, “Dangerous ozone hole widened by polar vortex in 2026, Boulder researchers say,” November 10, 2026
Written by Action Global News from the sources above; quotations are attributed to the outlet that published them. See our editorial standards and corrections policy.