# Is the Antarctic Ozone Hole Healing? What the Latest Evidence Shows
Yes—the weight of evidence indicates that the Antarctic ozone hole is beginning a slow, uneven recovery. Large holes can still occur in individual years because weather, volcanic material, wildfire smoke and the polar vortex strongly affect each Antarctic spring. Those short-term swings do not erase the long-term decline in human-made ozone-depleting chemicals.
The World Meteorological Organization reported that the 2024 ozone hole was smaller and less deep than the large holes observed from 2020 to 2023. If current international controls remain in place, Antarctic ozone is projected to return to roughly 1980 levels around 2066, with a wide range of possible dates.
Key facts
- The ozone layer absorbs much of the Sun’s biologically harmful ultraviolet-B radiation.
- Human-made chlorofluorocarbons and related chemicals drove severe Antarctic ozone depletion.
- The Montreal Protocol has phased out more than 99% of controlled ozone-depleting substances by production and consumption, according to WMO.
- The 2024 Antarctic ozone hole was below the 1990–2020 average in depth and smaller than the holes from 2020–2023.
- Recovery is a multi-decade trend; one unusually large or small year cannot establish or disprove it.
What did scientists observe in 2024?
The Antarctic ozone hole forms during Southern Hemisphere spring when sunlight returns to the cold polar stratosphere. In 2024, its onset was relatively slow. WMO reported a maximum ozone mass deficit of 46.1 million tonnes on 29 September, below the 1990–2020 average.
The hole was also smaller than the relatively large, persistent holes between 2020 and 2023. WMO identified the tendency toward a later onset as a robust early signal of recovery.
That does not mean the hole has closed. Severe seasonal depletion still develops over Antarctica, and the polar vortex persisted unusually late in 2024. “Recovery” means the long-term statistical direction is improving as ozone-depleting chlorine and bromine decline—not that every annual measurement must improve.
Why did a 2023 study question the recovery?
A 2023 study in Nature Communications examined ozone at different altitudes and stages of the Antarctic spring. The researchers found a 26% reduction from 2004 to 2022 in an October partial-column measurement at the core of the hole. They connected the decline to changes in air descending through the polar vortex.
The result was important, but narrower than headlines claiming that the entire ozone layer was “not healing.” The study also found signs of early-spring recovery. It focused on a particular region, altitude range and time of year during a period ending with three unusually large holes.
The UN-backed 2022 scientific assessment evaluated a broader body of observations, chemistry and modelling. It concluded that the Antarctic ozone hole has generally diminished in size and depth since 2000, while emphasizing large year-to-year variability. A 2026 analysis of Antarctic column ozone from 1979–2023 likewise reported signs of sustained recovery since 2000 and examined how the unusually low values from 2020–2022 affect trend estimates.
The studies are therefore not a simple contradiction. They examine different metrics and time windows. The October core can worsen over a selected period even while the broader, chemically driven recovery signal emerges most clearly in September.
How do scientists measure an ozone hole?
There is no single “ozone-hole number.” Scientists combine several measurements:
| Measurement | What it tells scientists | Important limitation |
|---|---|---|
| Total column ozone, in Dobson units | All ozone above a location | Does not show which altitude changed |
| Ozone-hole area | Region below a defined ozone threshold | Strongly affected by polar-vortex shape and weather |
| Ozone mass deficit | How much ozone is missing relative to a reference | Depends on both depth and area |
| Vertical ozone profiles | Which atmospheric layers gained or lost ozone | Requires instruments or satellite retrievals with altitude resolution |
| Ozone-depleting gas concentrations | Progress in removing the chemical cause | Ozone responds slowly because these gases persist for decades |
Researchers use satellites, ground-based spectrometers, weather balloons and atmospheric models. Agreement across independent methods is more informative than any single day’s maximum area.
Why does Antarctic ozone recovery take so long?
Many chlorofluorocarbons remain in the atmosphere for decades or longer. Even after production stops, old equipment, foams and other stored sources can continue releasing them. The gases must also travel into the stratosphere before sunlight releases chlorine or bromine that can destroy ozone.
Antarctica creates especially effective conditions for that chemistry. During the dark winter, a strong polar vortex isolates extremely cold air. Polar stratospheric clouds form, enabling reactions that prepare chlorine for rapid ozone destruction when sunlight returns.
The Montreal Protocol removed the main human cause, but the atmosphere cannot respond instantly.
When will the ozone layer recover?
The 2022 WMO–UNEP assessment projected a return to 1980 ozone values around:
- 2040 for the near-global average between 60°N and 60°S
- 2045 over the Arctic
- 2066 over Antarctica
These are modelled central estimates, not deadlines. The Antarctic projection spans roughly 2049–2077 across models because atmospheric circulation varies and future emissions are uncertain.
Continued compliance matters. Unexpected emissions of controlled chemicals, uncontrolled short-lived chlorine compounds, major volcanic eruptions, intense wildfires and proposed stratospheric aerosol interventions could alter the timetable.
The evidence-based conclusion
The Antarctic ozone hole is not healed, and large seasonal holes will continue for years. But the latest assessment does not support the claim that recovery has failed. Declining ozone-depleting chemicals, improving September trends and the smaller 2024 hole together support slow long-term healing with substantial annual variability.
Update note: This article was substantially revised and fact-checked on August 23, 2026, to incorporate the 2024 WMO assessment and distinguish annual variability from long-term recovery.
Sources
- World Meteorological Organization, WMO Bulletin shows recovery of ozone layer, driven by science (2025)
- WMO and UNEP, Scientific Assessment of Ozone Depletion: 2022
- Kessenich, Seppälä and Rodger, Potential drivers of the recent large Antarctic ozone holes, Nature Communications (2023)
- Zhang et al., Analysis of Antarctic ozone trends from 1979 to 2023, Atmospheric Chemistry and Physics (2026)