The hole in the ozone layer over Antarctica It has given a small respite again in 2025. According to data recently published by NASA and the US National Oceanic and Atmospheric Administration (NOAA), the size reached this season places it as the fifth smallest since 1992, the year in which the historic international agreement to curb chemicals that damage this natural barrier began to be effectively implemented.
Although the figure still describes a phenomenon of continental dimensionsExperts emphasize that this year's oil hole is smaller than many of those recorded in previous decades. This behavior aligns with the trend toward a slow recovery which has been observed in the stratosphere, as a result of the application of the Montreal Protocol and its subsequent amendments, in which the European Union and Spain also participate.
A still gigantic hole, but smaller than in the worst years
During the period when ozone depletion becomes most intense, known as the season of exhaustionThe hole, which this year ran from September 7 to October 13, registered an average extent of about 18,71 million square kilometersTo give you an idea, it is roughly twice the size of the contiguous United States and a much larger area than all of Europe.
At its peak on September 9, the area affected by the severe ozone depletion It reached 22,86 million square kilometers. Even so, according to the measurements released, this hole is 30% smaller than the historical record observed in 2006, when the destruction of the ozone layer was particularly severe.
The records from 2025 confirm that the hole has not only been contained in area, but also has begun to disintegrate earlier than usual. NASA and NOAA point out that the significant reduction of the hole has occurred almost three weeks earlier than normal over the last decade, a detail that scientists are observing with caution, but which fits with the gradual stabilization of the Antarctic atmospheric system.
Another comparison offered by US agencies refers to the average area of the years in which the hole reached its historical maximum. Compared to values close to 26,6 million square kilometers In the worst episodes, this year's behavior is interpreted as a symptom that international policies are having an effect, even though the recovery is still incomplete.
What NASA and NOAA say about the evolution of the ozone hole
Scientific teams monitoring ozone levels from satellites and ground stations emphasize that holes of recent years They tend to be more moderate than in the early 2000s. Paul Newman, a researcher at the University of Maryland and head of the ozone group at NASA's Goddard Space Flight Center, points out that in this phase the hole is observed to It forms somewhat later in the austral season and it starts to close earlier.
Despite this relative improvement, Newman warns that there is still “a long way to go” to return to pre-pandemic levels. decade 1980This occurred when the destruction of the Antarctic ozone layer had not yet reached the critical levels that triggered international alarm. The scientific community insists that the process of repairing this protective layer is very slow and depends on the gradual elimination of the most harmful chemical compounds.
From NOAA, specialist Stephen Montzka points out that the progress would not have been possible without the rigorous application of the commitments of the Montreal ProtocolThe treaty, signed in 1987 and reinforced in subsequent years, has shown that, according to data from the organization's Global Monitoring Laboratory, since its peak around the year 2000, the amount of ozone-depleting substances in the Antarctic stratosphere has decreased by approximately [a certain percentage]. third compared to previous values to the discovery of the hole.
Scientists point out that, had the use of chlorofluorocarbons and similar gases not been restricted, this year's hole would have been much larger. Newman estimates that, if there were still as much chlorine in the atmosphere as there was about 25 years ago, the affected area could have been more than one million square miles larger than that observed in 2025, which in practice would have meant a new extreme episode.
The role of the Montreal Protocol and its impact on Europe and Spain
The gradual improvement of the situation is understood, in large part, as a direct result of compliance with Montreal Protocol and its amendmentsInternational agreements mandate the phase-out of ozone-depleting compounds. These include many refrigerants, aerosols, and products used in the air conditioning and insulation foam industries.
The European Union, in which Spain actively participates, has been one of the strictest blocs in the application of these restrictions on ozone-depleting substancesThis regulation has promoted the replacement of old gases with less harmful alternatives, both in the domestic sector (refrigerators, air conditioners, sprays) and in industrial areas such as commercial refrigeration or building insulation.
In European countries, the policies derived from Montreal have been combined with other initiatives of energy efficiency and emissions reductionThis has accelerated the replacement of older equipment that could still release compounds harmful to the ozone layer. However, experts point out that materials and devices containing these banned chemicals still remain in use or in landfills, making proper waste management crucial.
For Spain, located in mid-latitudes, ozone depletion in Antarctica does not directly translate into values as extreme as those recorded at the South Pole, but it does have repercussions on ultraviolet radiation which reaches the surface on a global scale. Therefore, health authorities maintain the usual recommendations for sun protection and monitoring of exposure, especially in summer and at high altitudes.
Meteorological factors and recovery horizon until the 2060s
In addition to the presence of chemical substances, the stratospheric meteorology plays a key role in the size and evolution of the ozone hole each year. Factors such as air temperature at high altitudes, atmospheric circulation patterns, and the intensity of the so-called Antarctic polar vortex They influence the degree of destruction suffered by ozone molecules during the austral spring.
In general, when temperatures in the polar stratosphere are very low and the vortex remains strong and stable, the formation of Polar stratospheric cloudswhere chlorine and bromine compounds that damage ozone react. Conversely, seasons with a more disturbed vortex or less extreme temperatures tend to produce somewhat smaller or less persistent holes.
Climate models used by NASA, NOAA, and other research centers indicate that, if the phase-out schedule for the most harmful substances continues to be respected, the ozone hole over Antarctica could to practically close towards the end of the 2060sThis is not an exact date, but an estimate that could vary depending on the evolution of emissions and changes in the global climate.
One of the added complications is that many of the gases that are already banned are still present in old materialsThis includes certain types of building insulation, foams, and refrigeration equipment that have not yet been removed. As these products reach the end of their useful life or are improperly disposed of, they continue to release small amounts of compounds that prolong the presence of chlorine and bromine in the stratosphere, delaying full remediation.
Even so, the overall trend based on three decades of measurements supports the idea that internationally agreed policies are working. Experts continue to monitor the situation to see if, over the years, the ozone hole It becomes not only smaller, but also less deep in terms of ozone concentration, something fundamental to reducing the impact of ultraviolet radiation on ecosystems and human health.
This new report from NASA and NOAA reinforces the view that the ozone layer is in a process of Slow but steady recoveryThis progress is supported by decades of international cooperation and concrete changes in industry and consumption. Although the 2025 ozone hole remains enormous on a planetary scale, its fifth smallest size since 1992 and its earlier closure suggest continued efforts to strengthen chemical control measures and scientific monitoring, aiming for a more protected atmosphere and reduced exposure to ultraviolet radiation in Europe, Spain, and the rest of the world by mid-century.