La the ozone layer is located in a clear recovery phase After decades of concern about its deterioration, and following years of continuous monitoring, the scientific community agrees that the most recent data point to a sustained improvement, with the hole over Antarctica becoming smaller and less persistent.
This progress does not mean the problem has disappeared, but it does mean that international policies for the control of harmful substances have taken effectThe behavior observed in 2025, with an earlier closing of the hole and a more contained extension compared to the peaks of the last decades, is interpreted as a sign that the course adopted by the international community is the right one.
Why the ozone layer is so important
The ozone layer forms a natural barrier that filters out much of the ultraviolet radiation (UV) from the Sun. When this protection weakens, the amount of UV rays reaching the Earth's surface increases, with direct effects on human health, ecosystems, and agriculture.
A larger or more persistent hole implies increased exposure to ultraviolet radiationThis is associated with an increase in cases of skin cancer, cataracts, and other eye problems. Furthermore, it can also affect the growth of sensitive crops and damage marine organisms, especially in the early stages of the food chain, such as phytoplankton.
For all these reasons, the scientific community had been warning for decades that continued destruction of this layer could to endanger life on Earth as we know itThe hole in the ozone layer thus became one of the first major symbols of the global environmental crisis.
Originally, much of the problem stemmed from the massive use of chemical compounds present in aerosolsrefrigerants and other industrial productsThese very stable substances remained in the atmosphere for years until they reached the stratosphere, where they released compounds capable of destroying ozone molecules very efficiently.
Among the most vulnerable areas is the Antarctic regionwhere atmospheric conditions and low temperatures favor the annual formation of the so-called “ozone hole”Although this phenomenon continues to occur every year, its extent and intensity are decreasing compared to the 1990s and early 2000s.
The key role of the Montreal Protocol
The turning point came with the Montreal Protocol, signed in 1987, an international agreement that forced the withdrawal from the market of substances that depleted the ozone layer, such as chlorofluorocarbons (CFCs) and halons, widely used in refrigeration and aerosols.
Since its entry into force, signatory countries have been progressively implementing restrictions and prohibitions on these compounds. According to the most recent assessments, Around 99% of the substances with the greatest ozone-depleting potential have been phased out.This outcome is considered one of the greatest successes of modern environmental diplomacy.
The controls established by this agreement have allowed that the concentrations of ozone-depleting chemicals in the atmosphere decrease steadilyAs a direct consequence, the ozone layer has begun to regenerate gradually, reducing both the size and duration of the Antarctic hole.
The experience of the Montreal Protocol is often used as example of effective international cooperationThis demonstrates that, when there is scientific consensus and political will, it is possible to reverse very worrying environmental trends. However, experts insist that relaxing now would be a mistake, as the recovery is not yet complete.
Currently, many countries are still adapting their regulations to the subsequent amendments to the Protocol, like the one in Kigaliwhich also seeks to eliminate refrigerant gases with a high climate impact, thus reinforcing the protection of the ozone layer and contributing at the same time to the fight against global warming.
How is the ozone hole behaving in 2025?
The data collected during 2025 shows a positive change in the behavior of the ozone holeThis year has seen one of the earliest closures in recent seasons, the earliest since 2019, and its size has once again fallen below the highs recorded between 2020 and 2023.
During the month of September, the affected area reached a maximum around 20 million square kilometersand remained at that size until October. Despite being a considerable magnitude, it is considered relatively contained when compared to the large holes of previous years.
Agencies like the NASA and the National Oceanic and Atmospheric Administration (NOAA) They have indicated that the 2025 hole is among the smallest since the early 1990s, a period in which the restrictions of the Montreal Protocol began to be effectively applied.
The observation teams indicate that recent behavior confirms that Controls on ozone-depleting substances are driving a gradual recovery in the stratosphereAlthough the hole continues to appear every austral spring, its duration and persistence have been gradually decreasing.
This pattern reinforces the idea that long-term regulatory efforts are yielding tangible results. According to current projections, most regions of the world could to restore ozone levels similar to those prior to the CFC era by the middle of this centuryprovided that current policies are maintained.
Prospects for full recovery and estimated timeframes
Climate and chemical models used by the scientific community agree that the The recovery of the ozone layer will be uneven depending on the region.In mid-latitudes, where most European territories are located, values close to historical reference levels are expected to be reached in the coming decades.
In the case of the In Antarctica, the process will be considerably slower.Current projections place the complete recovery of the ozone layer over this continent around the year 2066, provided that there are no new episodes of illegal emissions of prohibited substances or drastic changes in atmospheric dynamics.
This relatively long time horizon is due to the fact that ozone-depleting compounds have a very long life in the atmosphereAlthough its emission has been reduced almost completely, the remnants that are already present will continue to exert effects for years until they gradually degrade.
In addition, other factors come into play, such as natural variations in stratospheric circulation and in polar temperatureswhich can slightly accelerate or slow down the recovery. That's why experts insist on the need for constant monitoring through satellites, balloons, and surface observation networks.
In any case, the scientific consensus is that the ozone layer is on its way to return to levels considered safe globally throughout this centuryHowever, this does not mean that the problem of ultraviolet radiation will disappear completely, as it will still be necessary to be careful about sun exposure and continue with health prevention campaigns.
An unexpected consequence: more heat on the planet
The positive evolution of the ozone layer is not without its nuances. study led by the University of Reading, in the United KingdomIt has generated debate by pointing out that the ozone recovery itself could contribute to the planet warming more than initially predicted.
The study suggests that, while the ban on gases such as CFCs has helped repair the ozone layer, its combination with the increased air pollution This could intensify the greenhouse effect. According to their estimates, this process could warm the Earth by up to 40% more than projected in some climate scenarios.
Professor Bill Collins, lead author of the research, argues that countries are acting correctly in Continue to ban ozone-depleting compoundsHowever, it warns that this recovery has an added effect: by strengthening the atmosphere's capacity to retain heat, it could increase global warming if other forms of pollution are not reduced at the same time.
The study notes that the pollution from vehiclesfactories and power plants It also contributes to the generation of ground-level ozone, a type of ozone distinct from stratospheric ozone. This tropospheric ozone is harmful to health, aggravates respiratory problems, and also acts as a greenhouse gas.
Therefore, the authors insist that, although protecting the ozone layer remains essential to reducing ultraviolet radiation and preventing diseases such as skin cancer, It is essential to update climate policies to take into account their impact on the planet's thermal balanceOtherwise, there is a risk of underestimating some future warming.
The challenge of reconciling health, climate, and future policies
Experience accumulated in recent years demonstrates that Protecting the ozone layer and fighting climate change are closely linked.Decisions about which substances are allowed or banned have an impact on both ultraviolet radiation and global temperature.
In terms of health, maintaining a robust ozone layer means reduce the risk of skin cancer, cataracts, and other damage associated with overexposure to the sunIt also helps preserve agricultural productivity and the stability of sensitive ecosystems, including marine ecosystems, which depend on a relatively stable level of radiation.
At the same time, studies that point to a possible additional increase in warming due to ozone recovery These factors necessitate adjustments to climate strategies in the medium and long term. The key lies in strengthening the reduction of traditional greenhouse gas emissions, such as carbon dioxide and methane, and in limiting ground-level ozone pollution.
International institutions and national governments are therefore faced with the task of coordinate environmental policies that integrate both ozone protection and climate change mitigationThe goal is to avoid partial solutions that solve one problem while aggravating another.
Although the current situation is much more favorable than it was three or four decades ago, experts emphasize that It is not enough to celebrate the improvementIt is necessary to consolidate it with continuous controls, updating of regulations and support for scientific research, which allows anticipating possible changes in the atmosphere.
The trajectory of the last few decades shows that the deterioration of the ozone layer was not irreversible and that, with broad agreements and rigorous monitoring, it is possible to reverse very worrying trends; now, the challenge lies in maintaining that effort. to complete the recovery planned for the coming decades and, at the same time, integrate this success into a broader climate strategy that takes into account both the health of people and the stability of the global climate system.
