The Ozone Hole Is the Largest It’s Been in a Decade. The Reason May Surprise You

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1. 55m ago

   Antarctic ozone hole reaches largest size in a decade at 10.5 million square miles

   The 2026 ozone hole over Antarctica peaked at 10.5 million square miles on September 18, making it the largest reading in ten years and the seventh largest since monitoring began in 1978. Scientists attribute the expansion to an unusually powerful polar vortex that prolonged ozone depletion, not to increased emissions of ozone-depleting substances. Despite the annual fluctuation, long-term recovery of the ozone layer remains on track following the global phase-out of CFCs under the Montreal Protocol.

   Why it matters

   The ozone layer protects Earth from harmful ultraviolet radiation, and its hole over Antarctica typically peaks each Southern Hemisphere spring. Year-to-year variations in the polar vortex—a ring of cold air that isolates the stratosphere—can significantly alter hole size. The Montreal Protocol's successful phase-out of ozone-depleting chemicals has driven a gradual healing trend, with the hole shrinking on average over the past two decades despite occasional larger-than-average years.

   What is confirmed

   • The ozone hole measured 10.5 million square miles on September 18, 2026.
   • The 2026 ozone hole ranked as the seventh largest in 48 years of monitoring.
   • The hole was not as deep as other large holes on record.
   • The polar vortex was unusually large this year in part because planetary-scale weather systems that typically well up from the lower atmosphere were especially weak in August and September.
   • Long-term recovery of the ozone layer remains on track following the Montreal Protocol.

   What to watch next

   • The September 2026 ozone hole extent compared to the September 2025 reading to confirm the year-over-year change.
   • Monitoring of polar vortex strength during the 2027 Antarctic spring to assess whether the 2026 expansion pattern repeats.
   • Evaluation of ozone concentration profiles to determine if the 2026 hole was less deep than previous large-hole years.
   Sources used for this update (14)

   1. science.nasa.gov — NASA Science
   2. Newser — Antarctica Ozone Hole Grows, but Prognosis Remains Good
   3. NASA Science (.gov) — NASA, NOAA Track 2026 Antarctic Ozone Hole
   4. Gizmodo — The Ozone Hole Is the Largest It’s Been in a Decade. The Reason May Surprise You
   5. ABC News - Breaking News, Latest News and Videos — Ozone hole in 2026 is largest in a decade, but long-term recovery remains on track: Report
   6. NOAA (.gov) — NOAA, NASA release measurements of 2026 ozone hole
   7. gizmodo.com — The Ozone Hole Is the Largest It's Been in a Decade - Gizmodo
   8. WeatherNation — Weather Leads to Hole in Ozone Layer
   9. Yahoo — The Antarctic Ozone Hole Is the Largest It’s Been in 10 Years
   10. www.yahoo.com — The hole in our ozone layer got larger in 2026; biggest in a ...
   11. www.yahoo.com — Ozone hole is largest in a decade, but long-term recovery ...
   12. digital.abcaudio.com — Ozone hole in 2026 is largest in a decade, but long-term ...
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