Ozone hole reaches notable threshold early again as area increases above average in 2026: Copernicus
The Copernicus Atmosphere Monitoring Service (CAMS) reported that the 2026 Antarctic ozone hole crossed the 15 million sq km threshold earlier than the long-term average, for a second consecutive year
By 12 September 2026, the hole's area had expanded to roughly 25 million sq km, about 5 million sq km above the seasonal average for that date
Other diagnostic indicators, including the ozone column minimum value, remained close to long-term average levels despite the larger area, indicating a mixed recovery picture
The finding was released around the UN International Day for the Preservation of the Ozone Layer (16 September), which marks the anniversary of the Montreal Protocol's signing
The Ozone Layer, Ozone Depletion, and the Montreal Protocol (1987)
The stratospheric ozone layer (roughly 15–35 km altitude) absorbs harmful solar ultraviolet-B (UV-B) radiation. Its seasonal depletion over Antarctica, first identified in the 1980s, is caused by ozone-depleting substances (ODS) — chiefly chlorofluorocarbons (CFCs) and halons — which release chlorine and bromine radicals that catalytically destroy ozone molecules in the presence of polar stratospheric clouds (PSCs) during the austral spring.
Key Details
- The Vienna Convention for the Protection of the Ozone Layer (1985) is the framework treaty; the Montreal Protocol on Substances that Deplete the Ozone Layer (1987) is its binding implementation instrument, and is the only UN treaty ratified by all 198 UN member states
- The Montreal Protocol has been amended multiple times, including the Kigali Amendment (2016), which brought hydrofluorocarbons (HFCs) — potent greenhouse gases though not ozone-depleting — under phase-down obligations; India ratified the Kigali Amendment in 2021
- India's HFC phase-down under Kigali is implemented through the India Cooling Action Plan (ICAP, 2019) and amendments to the Ozone Depleting Substances (Regulation and Control) Rules, 2000 (under the Environment (Protection) Act, 1986)
- UN International Day for the Preservation of the Ozone Layer is observed on 16 September each year, marking the 1987 signing of the Montreal Protocol
The 2026 finding is reported through the same institutional and treaty framework — the ozone hole's annual size is the primary metric used to track whether Montreal Protocol compliance is translating into stratospheric ozone recovery.
Polar Stratospheric Clouds and Meteorological Drivers of Ozone Hole Size
Ozone hole size varies year-to-year primarily due to stratospheric meteorology (temperature and polar vortex strength), not fresh emissions, since ODS emissions have already been sharply curtailed by the Montreal Protocol. Colder-than-average stratospheric temperatures around 20 km altitude favour the formation of polar stratospheric clouds, whose surfaces catalyse the chemical reactions that convert stable chlorine reservoirs into active, ozone-destroying radicals.
Key Details
- The largest ozone hole on record spanned 29.6 million sq km on 9 September 2006
- Copernicus/CAMS uses satellite and atmospheric reanalysis data to track the ozone hole's area, depth (minimum column ozone), and duration each year
- Scientific assessments under the Montreal Protocol (WMO/UNEP Scientific Assessment of Ozone Depletion) project full recovery of the Antarctic ozone layer to 1980 levels by around the 2060s, with the Arctic and global layers recovering earlier
- Natural variability (e.g., colder polar vortex years, volcanic aerosol injections, or wildfire smoke reaching the stratosphere) can cause a large ozone hole even as the underlying chemical trend improves
CAMS explicitly separates the 2026 hole's large area (driven by unusually cold stratospheric temperatures) from its ozone column minimum (near-average), illustrating why a single year's ozone hole size cannot alone be read as recovery reversing — it must be read alongside long-term ODS-driven chemical trends.
- 2026 Antarctic ozone hole area: ~25 million sq km by 12 September 2026, about 5 million sq km above the seasonal average
- 2026 hole crossed the 15 million sq km threshold in late August 2026, earlier than the historical average
- Record largest ozone hole: 29.6 million sq km, recorded on 9 September 2006
- Montreal Protocol (1987): universally ratified (198 parties); Kigali Amendment (2016) added HFC phase-down; India ratified Kigali in 2021
- Full Antarctic ozone layer recovery to 1980 levels projected around the 2060s (WMO/UNEP assessments)
- UN International Day for the Preservation of the Ozone Layer: 16 September