The year 2025 went down in history as third warmest year on record, only narrowly lagging behind 2024 and 2023. According to data from the Copernicus Service (C3S) and the World Meteorological Organization (WMO), the global average surface air temperature reached level 1.47°C above pre-industrial average (1850–1900 period). This analysis confirms that while natural phenomena such as La Niña have had a slight cooling effect, the dominant driver of warming remains the accumulation of greenhouse gases in the atmosphere due to human activity.

Temperature records and exceeding limits

The most disturbing finding of 2025 is the fact that the last 11 years (2015–2025) represent the 11 warmest years in the history of observations. For the first time in history, the entire three-year period (2023–2025) exceeded the 1.5°C warming limit on average above pre-industrial levels. Scientists warn that although the Paris Agreement measures this limit over a long 30-year horizon, the current rate of warming suggests that we will definitely exceed this threshold this decade, more than a decade earlier than predicted in 2015.

While 2024 remains the warmest year on record, 2025 brought extreme temperatures, especially to the polar regions. Antarctica experienced its warmest year on record, while the Arctic recorded its second warmest year on record. On land, where most of the population lives, the warming was even more pronounced – temperatures over land were on average 2°C higher than in the pre-industrial period. The record-breaking warm year was felt by approximately 770 million people, mainly in China and other parts of Asia.

Oceans trapped in heat

While surface air temperatures can fluctuate from year to year, Ocean heat content (OHC) is a more stable indicator of global warming and reached record levels again in 2025. The oceans absorb more than 90 % of the excess energy in the climate system. In 2025 alone the oceans gained 23 zettajoules of extra heat, which is equivalent to approximately 37 times the global energy consumption of humanity in 2023.

Sea surface temperatures were the third highest on record, with extremes recorded in the North Pacific, North Atlantic and Indian Oceans. This increase in heat has direct consequences for storm intensity, melting sea ice and rising sea levels due to thermal expansion of water. The rate of sea level rise has doubled in the last 30 years – while in 1993–2002 it was 2.1 mm per year, in the period 2016–2025 the speed increased to 4.1 mm per year.

Emissions status and carbon budget

Despite global commitments, CO2 emissions from fossil fuels continued to grow in 2025. According to the Global Carbon Budget report, it is expected increase in global fossil emissions by 1.1 %, which represents a new historical record of 10.4 billion tonnes of carbon (38.1 Gt CO2). The concentration of carbon dioxide in the atmosphere reached 425.7 ppm, which is 53 % more than in the pre-industrial era.

These data mean that The remaining carbon budget to keep warming below 1.5°C is almost exhausted.. At current emissions levels, we only have about four years, before we exceed the amount of CO2 that gives us a 50 % chance of maintaining this target. If we wanted to reach net zero by 2050, we would need to reduce emissions by about 4 % each year, a decrease comparable to 2020 during the COVID-19 pandemic.

Cryosphere Decline: Glaciers and Sea Ice

The cryosphere is showing signs of rapid collapse. In the hydrological year 2023/2024 The world's glaciers have lost a record 1.3 meters of water equivalent ice, which is the largest loss since measurements began in 1950. Venezuela became one of the first countries to lose all of its glaciers in modern times. Greenland's ice sheet has been losing mass for the 29th year in a row, losing 105 billion tons of ice in the last 12 months alone.

In the Arctic, sea ice reached its March 2025 extent its lowest recorded winter maximum, while in Antarctica its extent has remained at critically low levels throughout the year. This loss of white surface that reflects sunlight creates a feedback loop that further accelerates ocean warming.

Extreme events and social impacts

The year 2025 was marked by devastating extreme events. Heat waves hit Europe and the Mediterranean, with Turkey setting a national record of 50.5 °C. The California wildfires in January 2025 caused $40 billion in damage, a record for this type of disaster. Extensive fires have also plagued Canada and Brazil, with Canada's emissions from fires in the past three years exceeding the total for the previous 20 years. .

The hydrological cycle is showing increasing instability. While monsoon floods were killing in Pakistan and India, South America and Southwest Asia were enduring catastrophic drought, which has limited food and hydropower production. These events have a disproportionate impact on vulnerable communities and women in developing countries, exacerbating global inequality.

Political Outlook: COP30 and 2026

Climate summit COP30 in Belém, Brazil has yielded mixed results. Although the Tropical Forests Forever Facility was launched and the importance of indigenous peoples' rights was emphasized, attempts to create a clear plan to phase out fossil fuels have failed due to resistance from the petrostates.

Looking ahead, predictions for 2026 suggest that it will be another exceptionally hot year, with an average temperature of around 1.4°C above pre-industrial levels. Although the start of the year may be affected by a weakening La Niña, there is an increasing likelihood that a new El Niño will develop in late 2026, which could lead to 2027 will once again challenge for the title of the warmest year in history.

The conclusion of the 2025 analysis is clear: the climate crisis is no longer a future risk, but a present reality that requires immediate and decisive action to reduce emissions and adapt to irreversible changes. The atmosphere and oceans are sending us a clear signal that we must finally start listening to. JRi&CO2AI