Antarctica’s ozone hole among smallest in decades, study finds

The ozone hole over Antarctica in 2025 is among the smallest observed since the early 1990s , reflecting steady progress under the Montreal Protocol, according to NASA and NOAA scientists.

The 2025 ozone hole ranks as the fifth smallest since 1992 , when the Montreal Protocol began reducing ozone-depleting chemicals. Researchers say this trend indicates the ozone layer is gradually recovering and could return to pre-ozone hole levels later this century.

During the peak season from September 7 to October 13 , the ozone hole averaged 7.23 million sq miles (18.71 million sq km) and started breaking apart three weeks earlier than usual, suggesting improving atmospheric conditions. Paul Newman, NASA senior scientist, noted that ozone holes are now forming later and dissipating earlier compared with the early 2000s.

The largest single-day size on September 9 was 8.83 million sq miles (22.86 million sq km) , around 30% smaller than the record 2006 hole, which spanned 10.27 million sq miles (26.6 million sq km). In the 46-year satellite record dating back to 1979, 2025 ranks as the 14th smallest ozone hole.

Scientists attribute the smaller size to declining chlorine levels , warmer stratospheric temperatures , and a weaker polar vortex , which reduce ozone-destroying chemical reactions. Ozone above the South Pole dropped to 147 Dobson Units on October 6, compared with the record low of 92 DU in 2006.

The reduction of ozone-depleting substances like CFCs , widely used in aerosols, refrigeration, and foam products, has been key. Levels in Antarctica have fallen by about one-third since 2000 . While most chemicals are now banned, some legacy sources in insulation and landfills continue releasing them slowly. Scientists expect the hole to recover by the late 2060s.

The ozone layer, located 7–31 miles above Earth , shields life from harmful UV radiation , protecting against skin cancer, cataracts, and crop damage . Ongoing monitoring uses satellites, weather balloons, and ground instruments to track atmospheric changes and assess the long-term success of global policies.