The year 2025 will be remembered as one of the hottest and most extreme in recent history, according to data published by the European Center for Medium-Range Weather Forecasts (ECMWF), which manages the Copernicus Climate Change Service (C3S) and the Copernicus Atmospheric Monitoring Service (CAMS) on behalf of the European Commission.
In 2025, global surface air temperature was 1.47°C above the pre-industrial level, an alarming figure, although slightly lower than the record 1.60°C recorded in 2024, the warmest year on record. Current estimates suggest that long-term global warming is already around 1.4°C above the pre-industrial level, meaning that the 1.5°C limit set in the Paris Agreement could be exceeded by the end of this decade, much sooner than originally anticipated.
The data published by the European Center for Medium-Range Weather Forecasts (ECMWF) has been joined by other institutions such as NASA, NOAA, the United Kingdom Meteorological Office, Berkeley Earth and the World Meteorological Organization (WMO), which have agreed to coordinate the publication of the state of the climate that highlights the challenges facing humanity.
Determining factors
This new record is not the result of a coincidence. Experts point to two main factors. The first is the accumulation of greenhouse gases (GHG) in the atmosphere, derived from continuous emissions and the reduction of carbon dioxide absorption by natural sinks. The second, that sea surface temperatures reached exceptionally high levels throughout the ocean, associated with the El Niño phenomenon and other factors of ocean variability, aggravated by climate change.
The consequences of these extreme conditions have been felt throughout the planet. While the tropics experienced somewhat lower temperatures than in previous years, many regions outside these latitudes experienced heat waves and temperature records. Antarctica reached its highest average annual temperature ever recorded, and the Arctic its second highest, while other areas, including the northwest and southwest Pacific, northeast Atlantic, and parts of Europe and Central Asia, also broke records.
Florian Pappenberger, Director General of the ECMPM, highlights the urgency of the situation: “This report confirms that Europe and the world are in the warmest decade on record and that the European Commission’s investment in Copernicus remains essential. “Preparedness and prevention remain possible, but only when measures are based on solid scientific evidence.”
For his part, Mauro Facchini, Head of Earth Observation at the European Commission, underlines the importance of having reliable information: “Exceeding the three-year average of 1.5 °C above pre-industrial levels is a milestone that none of us wanted to achieve, but which reinforces the importance of Europe’s leadership in climate monitoring to inform both mitigation and adaptation.”
Impact on health
The impact on health and daily life is already a palpable reality. In 2025, half of the world’s land surface endured more days than usual with intense heat stress, defined by WHO as perceived temperatures of 32°C or higher, the leading cause of climate-related death globally. In addition, high temperatures and dry conditions led to exceptional wildfires in Europe and North America, which released large amounts of carbon and atmospheric pollutants, degrading air quality and affecting human health.
The year was also marked by extreme events, record heat waves, severe storms in Europe, Asia and North America, and devastating wildfires in Spain, Canada and Southern California. Although the report does not directly attribute these events to climate change, it does place them in a context of increasing risk and public attention on the climate crisis.
For Carlo Buontempo, director of the Copernicus Climate Change Service «The fact that the last eleven years have been the warmest ever recorded provides further evidence of the unequivocal trend towards a warmer climate. We are destined to overcome it; “The choice we have now is how to best manage the inevitable overshoot and its consequences for societies and natural systems,” says the analyst.
Surveillance and monitoring of greenhouse gas concentrations, largely driven by human activities, remains key to guiding mitigation policies. According to Laurence Rouil, Director of the Copernicus Atmospheric Monitoring Service, “the 2025 atmospheric data provide a clear picture that human activity remains the dominant factor in the exceptional temperatures we are observing. For the expert, ‘atmospheric greenhouse gases have increased constantly in the last 10 years, the atmosphere is sending us a message and we must listen to it,’ warns Rouil.