European and U.S. agencies report the 2025 Antarctic ozone hole was notably smaller and shorter‑lived than in recent years. Copernicus called it the smallest since 2019; NOAA and NASA said it was the fifth‑smallest since 1992. Scientists attribute the improvement to sustained reductions in ozone‑depleting substances under the Montreal Protocol, and they project full recovery of the ozone layer by the end of this century. Experts also note a climate benefit because many phased‑out ODS are potent greenhouse gases.
Scientists Praise Sharp Shrinkage of 2025 Antarctic Ozone Hole as Reassuring Progress
Scientists in Europe and the United States have reported encouraging signs that the Antarctic ozone hole shrank substantially in 2025, closing earlier and lasting for a shorter period than in recent years. Data from the European Union's Copernicus Atmosphere Monitoring Service, together with NOAA and NASA, show measurable year-on-year recovery attributed to international controls on ozone‑depleting substances (ODS).
Copernicus said the 2025 ozone hole was the smallest observed since 2019 and was unusually short‑lived. In a separate assessment, NOAA and NASA reported the 2025 hole was the fifth‑smallest since monitoring began in 1992, the year nations started implementing the treaty to phase out the chemicals that damaged the ozone layer.
"The earlier closure and relatively small size of this year's ozone hole is a reassuring sign," said Laurence Rouil, Director of the Copernicus Atmosphere Monitoring Service. "It reflects the steady year‑on‑year progress we are now observing in the recovery of the ozone layer thanks to the ODS ban."
Paul Newman, Chief Scientist for Earth Sciences at NASA's Goddard Space Flight Center, noted that the timing and size of ozone holes are trending in the expected direction: holes are forming later in the season and breaking up earlier. "This year's hole would have been more than one million square miles larger if there was still as much chlorine in the stratosphere as there was 25 years ago," he said.
NOAA and NASA scientists say the recovery will continue as countries replace harmful substances with safer alternatives; full recovery of the ozone layer is projected by the end of this century. Stephen Montzka of NOAA's Global Monitoring Laboratory added that levels of ozone‑depleting substances in the Antarctic stratosphere have declined by roughly one‑third since peaking around the year 2000.
Why it matters: The ozone layer, located in the stratosphere roughly 7 to 31 miles above Earth, acts like a global sunscreen by absorbing harmful ultraviolet (UV) radiation. A weakened ozone layer increases UV exposure, raising risks of skin cancer and cataracts, and damaging crops and ecosystems.
The Montreal Protocol — the global treaty that phased out many ODS — is widely credited with enabling the observed recovery and is often cited as a rare diplomatic success in international environmental cooperation. UN Secretary‑General António Guterres described the Protocol as a "powerful symbol of hope," while experts have emphasized an important climate co‑benefit: many ozone‑depleting chemicals are also potent greenhouse gases, so phasing them out has helped slow global warming.
In a UNEP report, Nobel laureate Mario Molina and Durwood Zaelke wrote: "The ozone layer is healing, and is likely to recover in several decades... phasing out those chemicals has contributed significantly to slowing global warming."
Takeaway
The 2025 observations provide a concrete example that sustained international action can restore planetary systems. While progress is encouraging, scientists stress continued monitoring, adherence to the Montreal Protocol and its updates, and vigilance against illegal or unintended emissions of ODS to ensure full recovery this century.
What you can do: Support policies that reduce harmful emissions, stay informed about sunscreen and UV safety, and encourage international cooperation on environmental treaties.
