Earth’s protective ozone layer remains on track for long-term recovery, despite atmospheric conditions that contributed to a larger Antarctic ozone hole in 2026, NASA and the National Oceanic and Atmospheric Administration (NOAA) reported. The ozone hole ranked seventh largest by area in 48 years of monitoring, but was not as deep as other large holes on record.
From Sept. 7 to Oct. 13, peak ozone depletion season, the average extent of the hole covered about 9.6 million square miles (25 million square kilometers). Scientists continually track the amount of ozone in the stratosphere because it acts as the Earth’s sunscreen that helps shield life from harmful solar radiation. This is distinct from ground level ozone, which is an air pollutant commonly resulting from human activities.
“The annual ozone hole has been forming later in the season in recent years, which tells us the ozone layer is healing,” said Paul Newman, a senior scientist at the University of Maryland, Baltimore County, and longtime leader of NASA’s ozone research team at the agency’s Goddard Space Flight Center in Greenbelt, Maryland. “But an unusually powerful polar vortex has extended ozone depletion in the Antarctic this season, allowing the hole to grow to proportions we haven’t seen in a decade.”
The ozone hole reached its greatest one-day extent for the year on Sept. 18 at 10.5 million square miles (27.1 million square kilometers). For comparison, the largest ozone hole observed since monitoring began reached its maximum extent in September 2000.
“The 2026 ozone hole is large but could have been 1 to 2 million square miles (3.5 million square kilometers) larger if ozone-depleting substances were as prevalent in the atmosphere today as they were at their peak in 2000,” Newman said.
The Antarctic polar vortex helps create the cold conditions that allow chlorine and bromine from human-made compounds to deplete stratospheric ozone.
“The polar vortex was unusually large this year in part because planetary-scale weather systems that typically propagate up from the lower atmosphere and break up the vortex were especially weak in August and September,” said Amy Butler, a research scientist at the NOAA Chemical Sciences Laboratory. “That weak wave action kept the strongest polar vortex winds further from the pole by several degrees of latitude, creating a larger area for conditions ideal for ozone depletion to occur.”
Despite its relatively large area, this year’s ozone hole was not as deep as the record ozone holes observed in previous decades. Using balloon-borne instruments from the South Pole Baseline Atmospheric Observatory, NOAA scientists found that ozone concentrations directly overhead reached their lowest value for the year — 105 Dobson units — on Oct. 17. The Dobson unit is the standard measurement used to express ozone concentration. The lowest value recorded over the South Pole was 92 Dobson units in October 2006.
In addition to NOAA’s balloon- and ground-based observations, satellite data has been integral to monitoring the health of Earth’s protective ozone layer since 1979. Instruments aboard NASA’s Aura satellite, the NOAA-20 and NOAA-21 satellites, and the Suomi National Polar-orbiting Partnership satellite, jointly operated by NASA and NOAA, all contributed to the report.
NASA and NOAA scientists said that the ongoing monitoring shows that controls established by the Montreal Protocol in 1987 continue to drive long-term recovery of stratospheric ozone. As part of that agreement, countries committed to replacing ozone-depleting substances with less-harmful alternatives. From their peak, chlorine levels in the Antarctic stratosphere derived from ozone-depleting substances have since declined by about a third relative to 1980s levels, said Stephen Montzka, senior scientist of the NOAA Global Monitoring Laboratory.
Chlorofluorocarbons and other ozone-depleting compounds were once widely used in consumer goods like refrigerators, air conditioners, and building insulation. They can linger in the atmosphere or leach out of old products and landfills for many decades. As those legacy compounds break down, scientists estimate that the ozone hole will recover by the 2070s.
View the latest status of the ozone layer over the Antarctic with NASA’s Ozone Watch and NOAA’s South Pole Ozone website. Learn more about how NASA studies the ozone hole.
By Sally Younger
NASA’s Earth Science News Team
Media Contact:
Aries Keck
NASA Headquarters
202-604-2356
aries.keck@nasa.gov
Peter Jacobs
NASA’s Goddard Space Flight Center, Greenbelt, Md.
301-286-3308
peter.jacobs@nasa.gov
Theo Stein
NOAA Communications
303-819-7409
theo.stein@noaa.gov
English (UK) 
English (United States)