Smallest, shortest-lived ozone hole in 5 years closes, signifies optimism
The closing of this year's ozone hole over the Antarctic continues the positive trend of smaller gaps in Earth's ozone layer in recent years, perhaps leading to an eventual, full recovery of it in the coming decades
The Earth's ozone layer is on an optimistic trend towards an eventual recovery in the years to come, if it maintains the path it's currently on.
According to the Copernicus Atmosphere Monitoring Service (CAMS), the 2025 Antarctic ozone hole officially closed on Dec. 1, marking the earliest closure since 2019.
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In addition to that, the 2025 ozone hole was also the smallest in five years, the second consecutive, 12-month period that featured "relatively" tiny holes compared to the large ozone craters documented from 2020-23. Also, this year featured higher ozone concentrations, indicating more optimism for a recovery, CAMS said in the news release.
False-colour view of total ozone over the Antarctic pole on Sept. 1, 2025. The purple and blue colors are where there is the least ozone, and the yellows and reds are where there is more ozone. (NASA Ozone Watch)
“The earlier closure and relatively small size of this year’s ozone hole is a reassuring sign, and reflects the steady, year-on-year progress we are now observing in the recovery of the ozone layer, thanks to the ODS (ozone-depleting substances) ban. This progress should be celebrated as a timely reminder of what can be achieved when the international community works together to address global environmental challenges,” said Laurence Rouil, CAMS director, in the news release.
Ozone hole's 2025 size progression
Each year, the ozone hole season, which occurs during the austral spring, is formulated by temperatures and winds in the stratosphere over the Southern Hemisphere, as well as the inclusion of human-emitted ODS, according to CAMS.
The ozone layer shields the planet from the sun's ultraviolet radiation, which can cause skin cancer and other health risks from exposure over time.
It was an early start to the development of the ozone hole in 2025, coming to form through mid-August--a similar path to the large hole in 2023.
In early September, it grew to its maximum area for the season, 21.08 million square kilometres--much below the historical maximum of 26.1 million square kilometres seen in 2023, CAMS said.
However, through the rest of September and October, the hole's size remained notable, covering between 15 million square kilometres--roughly the area of Antarctica--and 20 million square kilometres, the agency added.
More good news was revealed when the ozone hole experienced a quicker decline during the first half of November, a sign that there could be an early closure. But CAMS then pointed out that a "persistent, small area of low ozone" lingered for most of the remainder of the month, until it completely closed on Dec. 1
"Compared to recent years, the 2025 ozone hole showed higher-than-average ozone column minimum and lower ozone mass deficit, indicating higher ozone concentrations in the Antarctic stratosphere," CAMS said in the release.
Without a large, organized effort from countries worldwide to curb ozone-depleting substances, including the creation of the Montreal Protocol and its amendments, the globe could have seen "catastrophic dimensions," according to CAMS, as demonstrated by the bigger, longer-lasting holes documented from 2020-23.
WATCH: NASA ozone minimums 1979 to 2013
Thumbnail courtesy of NASA Ozone Watch.
