Ozone layer shows strong signs of recovery, scientists confirm
The ozone layer is on track to recover within four decades, with the global phaseout of ozone-depleting chemicals already benefitting efforts to mitigate climate change.
What you need to know:
- New data from the Copernicus Atmospheric Monitoring Service shows that the 2025 Antarctic ozone hole was the smallest and shortest-lived in five years, closing earlier than expected on December 1.
- Once widely depleted by chlorofluorocarbons (CFCs), Earth’s ozone layer has been healing steadily since the 1987 Montreal Protocol phased out nearly all ozone-destroying chemicals.
- The latest findings offer renewed evidence that global environmental agreements can reverse severe atmospheric damage.
Ozone is the second layer of planet Earth’s atmosphere scientifically known as stratosphere. The naturally occurring layer of gas plays a fundamental role in protecting life on the surface of the Earth by absorbing nearly all the harmful ultraviolet solar radiation (UVB).
In the absence of the ozone layer, deadly UV sun rays would soar to severe extremes, damage DNA, exposing humans to chronic health complications such as sunburn and cancer of the skin. In 1985, Jonathan Shanklin, a British meteorologist, discovered a gaping hole in the ozone layer, which had started diminishing in the 1970s.
Scientists attributed the creation of the ozone hole to humans through releasing chemicals into the atmosphere notably (chlorofluorocarbons, CFCs). In concerted efforts to end CFCs and other ozone-depleting substances (ODS) production, the world-shaking discovery culminated in an international agreement, Montreal Protocol, signed in December 1987.
Through the Montreal Agreement, 99 per cent of all ODS have since been phased out, with the upper atmosphere of the Earth harbouring the remaining one per cent, experts explain. A large pillar of icy cold rotates above the Antarctic Ocean during winter in the Southern hemisphere, concentrating the remaining CFCs where they can deplete the ozone gas layer with the support of solar radiation and cold conditions.
The bigger the ozone hole, the more humans are exposed to increased amounts of UV radiations reaching the surface of the Earth through the hole in the ozone layer. In new evidence that has been hailed as “reassuring”, scientists have found that the hole in the layer is healing and it could actually be closed totally by 2050 and 2066.
According to the Copernicus Atmospheric Monitoring Service (Cams), the ozone hole, which appears over Antarctica annually, closed earlier than expected on December 1 this year. This marked the earliest closure in over five years since 2019, explained the Cams in a statement released this month, titled ‘Copernicus: Smallest and shortest-lived ozone hole in 5 years signals hope for recovery’.
The 2025 ozone hole was also the smallest for the second consecutive year within the same duration of five years. The promising update reviving hope for full recovery of the ozone layer within the next few decades is a stark contrast to a series of large, long lasting holes with higher ozone concentrations reported between 2020–23. “The Copernicus Atmosphere Monitoring Service (Cams) today confirms that the 2025 Antarctic ozone hole has come to an end on November 30, marking the earliest closure since 2019,” the report read.
The ozone hole, scientists explain, is not technically a hole with no ozone, rather it refers to an area over the Antarctic where the ozone layer is intensely depleted. It opens in August until September when it attains maximum size before closing in late November or early December. This year (2025) registered an early trajectory of the ozone hole (mid-August) similarly to the ozone hole development in 2023.
Its size slightly reduced towards the end of August this year before increasing to a maximum size in early September (8.13 million sq miles/21.08 million km2). “Through September and October its size remained considerable, between 15 million km2 – roughly the area of Antarctica – and 20 million km2,” the team explained.
“The area of the ozone hole declined quickly during the first half of November, indicating the possibility of an early closure. However, a persistent small area of low ozone persisted through the second half of the month, until it fully closed on the xxth.”
Compared to recent years, scientists say, “The 2025 ozone hole showed higher than average ozone column minimum and lower ozone mass deficit, indicating higher ozone concentrations in the Antarctic stratosphere.”
The Montreal Protocol and subsequent amendments regulates ODS consumption and production linked to about 100 chemicals that damage the ozone hole. Without global action, experts warn that ozone decline could have reached catastrophic levels reported between 2020–23.
However, experts have expressed optimism that the Earth’s atmosphere could finally be rid of CFS despite their chemical stability delaying the process. It is estimated that the ozone layer will achieve full recovery by 2050–60, thanks to the pact.
During this year’s International Day for the Preservation of the Ozone Layer, United Nations Secretary General António Guterres stated, “The Vienna Convention and its Montreal Protocol became a landmark of multilateral success. Today, the ozone layer is healing.”
He urged nations to ratify and implement the Montreal Protocol Kigali Amendment, which commits to reducing HFCs and greenhouse gases used mainly in cooling technologies.
