News

2025 Season Shows the Smallest Ozone Hole in Five Years, According to CAMS and NASA

The ozone hole over Antarctica reached its smallest extent and duration since 2019 in 2025. According to consolidated data from the Copernicus Atmosphere Monitoring Service (CAMS), NASA, and NOAA, the phenomenon ended on December 1, approximately one month earlier than observed in the previous four years.

The reduction is due to two factors: the continued decline of Ozone-Depleting Substances (ODS), in line with the Montreal Protocol, and meteorological conditions less favorable to ozone destruction.

Leading indicators of the 2025 season

The 2025 season was marked by a significant reduction in both the area and duration of the ozone hole. The maximum area was reported at two different values, depending on the monitoring method used: CAMS reported 21.08 million km², while NASA reported 22.86 million km². This discrepancy is due to differences in the instruments and algorithms used by each institution, but both confirm the same trend: the smallest ozone hole since 2019.

The phenomenon's closing date was recorded on December 1, the earliest since 2019, when a sudden stratospheric warming led to an even earlier closure. In comparison, in the years 2020 and 2023, the ozone hole persisted until the end of December.

The minimum ozone concentration was recorded at 147 Dobson Units (DU) on October 6 (a unit that measures atmospheric ozone density). Although this value still represents a significant decrease, it is above the minimum levels observed between 2020 and 2023, when values frequently fell below 100 DU. According to NASA, the 2025 ozone hole was the fifth-smallest since 1992.

These data confirm that the 2025 season represents a positive deviation from recent years' patterns.

Meteorological dynamics of 2025

The main atmospheric characteristic of 2025 was the instability of the Antarctic polar vortex. The weakening of this structure allowed the mixing of ozone-rich air masses, raising stratospheric temperatures and inhibiting the formation of Polar Stratospheric Clouds (PSCs).

Without PSCs, there is no significant activation of chlorine, which reduces the efficiency of chemical ozone destruction.

In comparison:

• 2020–2023: strong and stable vortex, favoring destruction.

• 2025: unstable vortex, with moderate dynamic warming and reduced atmospheric isolation.

Residual impact of the Hunga Tonga-Hunga Ha’apai volcano

Despite the record water-vapor injection in 2022 (~150 million tons), the direct impact of Hunga Tonga is declining. In 2025, the effects of the vapor plume were moderated by more dominant atmospheric dynamics.

• Water vapor still cools the stratosphere, but planetary wave activity had a greater influence on the behavior of the vortex.

• The decay rate of the volcanic plume is estimated at 3 years. Projections indicate normalization by 2030.

Structural chemical reduction: recovery data

Stratospheric chlorine and bromine concentrations continue to fall, according to NOAA monitoring:

• Since the peak in the early 2000s, levels have dropped by about 30%.

• HCFCs (hydrochlorofluorocarbons), temporary substitutes for CFCs (chlorofluorocarbons), peaked in 2021 and are already in decline.

This process confirms the effectiveness of international policies to eliminate ODS (Ozone-Depleting Substances), with direct impact on ozone hole metrics.

Counterfactual simulations

NASA modeling indicates that if chlorine levels from 2000 were still present, the 2025 ozone hole would have been 2.5 million km² larger, even with favorable meteorology.

Emerging climate challenges

Complete recovery of the ozone layer is projected for 2066, but faces new pressures:

• Stratospheric cooling induced by greenhouse gases, which favors PSC formation.

• Smoke from extreme wildfires, with potential for chlorine activation similar to volcanic particles.

• Climate geoengineering proposals, such as stratospheric sulfate injection, may compromise the progress achieved.

Regional implications

• The earlier closing of the ozone hole resulted in lower UV radiation levels in regions such as South America, New Zealand, and Australia.

• The climate pattern of the Southern Hemisphere tends toward normalization regarding the Southern Annular Mode (SAM), affecting rainfall and temperature regimes.

Technical conclusion

The 2025 Antarctic ozone season showed clear signs of progress in the atmospheric recovery process:

• Smaller extent and duration of the ozone hole in five years;

• Meteorological conditions less favorable to chemical ozone destruction;

• Confirmation of the effectiveness of the Montreal Protocol.

The result is a direct consequence of the global reduction of ODS, supported by high-resolution meteorological and satellite monitoring.

Continuous monitoring of stratospheric indicators will be necessary to assess the stability of this trend in the coming years.

Video

The Efficient Megalopolis That Reveals the Human Exhaustion Behind Urban Order

Tokyo is considered a global model of efficiency. Its transportation system is one of the most punctual in the world, public spaces are organized, and the city operates with almost mechanical precision. For many, this exemplary functioning is synonymous with urban success.

But this appearance of perfection hides deep contradictions.

What is seen in the streets of the Japanese capital is the result of decades of an economic project that prioritized accelerated industrial growth. Since the post-war period, Tokyo has been shaped to serve a productive logic. Urban planning did not focus on comfort or the well-being of the population, but rather on the city’s ability to sustain an economy based on high performance.

This created an urban structure in which every element (transportation, housing, services) is designed to ensure that millions of workers are available, punctual, and operating at full capacity. Micro-apartments and 24-hour convenience networks became solutions to optimize the time and energy of people whose lives are organized around work.

This model, which for decades symbolized progress, now shows clear signs of strain. Social problems such as extreme isolation, mental exhaustion, and a drastic decline in birth rates indicate that the city’s technical efficiency is being sustained at the expense of the health and vitality of its own population.

More than an isolated case, Tokyo becomes a mirror of a global dilemma: how do we reconcile urban development, productivity, and quality of life?

Want to dive deeper into the topic?

Check out the full video on the subject and understand how the historical and economic construction of Tokyo’s urban model reveals the human impacts of this productive machinery!

Disclaimer: The video is in Brazilian Portuguese, but simultaneous translation and subtitles are available in multiple languages.

Opinion

The Privatization of Subways: Good or Bad?

The way subways and urban trains are operated directly affects the functioning of cities, access to services, and quality of life in urban areas. In recent years, the debate over the privatization of these systems has gained strength in different regions of the world, especially in contexts of fiscal crisis or the pursuit of greater efficiency. But the results vary widely.

There are different management models around the world (public, private, and hybrid), and their experiences in operational efficiency, financial sustainability, and social inclusion vary from country to country.

Hong Kong: transportation integrated with real estate

MTR Corporation, a mixed-capital company, operates Hong Kong’s subway based on the “Rail plus Property” model. The government grants the company land around stations, which is developed into residential and commercial projects. The profits generated finance network expansion and subsidize operations.

The system achieves high levels of punctuality, maintenance, and quality, without relying on direct subsidies for daily operations. The economic logic is based on the urban value generated by transportation, aligning efficiency with financial sustainability.

Japan: privatization with economic diversification

The privatization of Japan National Railways (JNR) in 1987 divided the network into regional companies. After restructuring, productivity increased and costs decreased. The operators began investing in non-fare revenue sources such as hotels, shopping centers, and developments connected to stations.

Diversification was essential to maintain the financial stability of the systems and ensure ongoing investments in speed, safety, and comfort, especially on routes that compete with air and road transport.

United Kingdom: fragmentation and state takeover

The United Kingdom implemented public-private partnerships in the London Underground between 1999 and 2010. Operations remained public, but maintenance was outsourced to private consortia. The contracts failed due to poor management and high costs. After Metronet’s bankruptcy, the government regained control of the infrastructure.

In the case of railways, the privatization of British Rail led to fare increases, network fragmentation, and a decline in user satisfaction. Some lines, such as ScotRail, were renationalized, and public management showed improvement in passenger evaluations.

France: state-owned companies with corporate governance

Public companies such as RATP (Paris Metro) and SNCF (national railways) operate with corporate structures and work internationally through subsidiaries like RATP Dev and Keolis. These operators meet performance contract requirements in various countries and demonstrate positive financial results.

The French experience shows that public companies can be efficient, provided they operate with technical autonomy, clear targets, and professional governance.

Latin America: concessions with regulatory challenges

In Latin America, railway concessions were largely motivated by fiscal constraints. However, the absence of strong regulation and balanced contractual models has produced uneven results.

In Brazil, MetrôRio and SuperVia face constant criticism for infrastructure problems and fares. SuperVia filed for bankruptcy protection, claiming financial imbalances. In São Paulo, Line 4–Yellow (privately operated) has good evaluation scores, but its contract guarantees a minimum revenue per passenger, while public networks assume greater operational risk.

In Chile, the state-run Metro de Santiago maintains high performance levels, with technical and financial autonomy. In Buenos Aires, the concession of the “Subte” system lost efficiency after the 2001 economic crisis, with fare freezes and increased dependence on state subsidies.

Efficiency, contracts, and regulation

The efficiency of private operations is directly linked to how contracts are structured. Models that include performance indicators (such as punctuality, cleanliness, and user satisfaction) tend to align the operator’s interests with service quality. On the other hand, contracts with guaranteed revenue or without effective oversight may lead to a decline in quality.

The presence of complementary revenue sources, such as commercial developments or urban value capture, contributes to the system’s economic sustainability, as shown by the cases of Hong Kong and Japan.

Even in privatized systems, the State remains responsible for ensuring access, monitoring quality, planning network expansion, and, in many cases, financing part of operational costs. There is no significant urban rail operation anywhere in the world that functions without some level of public participation.

Conclusion

The privatization of metro-rail systems is not, in itself, an indicator of success or failure. Performance depends on contract quality, incentive structures, the State’s regulatory capacity, and the existence of complementary funding mechanisms.

Cases such as Hong Kong and Japan show that it is possible to achieve efficiency and financial sustainability with innovative and well-structured models. In contrast, experiences such as those of the United Kingdom and Argentina highlight the risks of poorly planned processes and regulatory failures.

The State’s role is essential—whether as operator, regulator, or financier. It must ensure that urban transport serves the public interest, guarantees accessibility, and functions as an integrated part of the urban and environmental policy of cities.