New Copernicus data shows 2025 was the third warmest year on record globally
The three-year period from 2023 to 2025 averaged above 1.5°C over pre-industrial levels for the first time
Scientists warn the world is nearing a sustained breach of the Paris Agreement temperature limit
The year 2025 has been the third warmest on record, according to new data, completing a three-year period that has, for the first time, consistently exceeded a critical global warming threshold.
The Copernicus Climate Change Service’s (C3S) annual temperature data has confirmed that the average temperature for 2023-2025 was more than 1.5 degrees Celsius (°C) above pre-industrial levels (1850-1900).
This pace suggests the Paris Agreement’s goal of limiting long-term warming to 1.5°C could be breached by 2030 — a decade earlier than envisaged when the accord was signed in 2015.
C3S figures show the global average surface air temperature in 2025 was 1.47°C above the pre-industrial baseline, marginally cooler (0.01°C) than 2023’s 1.48°C. The record remains with 2024, which saw an anomaly of 1.6°C.
Last year, surface air temperatures over land areas were the second highest ever recorded.
Polar regions experienced particularly excessive warming: 2025 was the warmest year on record for Antarctica and the second warmest for the Arctic. Global oceans were also the third warmest on record with average annual sea surface temperature of 20.73°C.
Arctic sea ice extent also hit record lows for January, February, March and December, and was the second lowest in June and October. In February 2025, the combined sea ice extent for the Arctic and Antarctica was the lowest since satellite records began in the 1970s.
The data also noted that the last 11 years rank as the warmest on record.
C3S cited two primary reasons for the unprecedented three-year heat:
The accumulation of greenhouse gases in the atmosphere from ongoing emissions, coupled with a reduced capacity of natural environments to absorb carbon dioxide.
Exceptionally high sea-surface temperatures linked to an El Niño event and other ocean variability factors, which were amplified by climate change.
“The first is the build-up of greenhouse gases in the atmosphere, from continued emissions and reduced uptake of carbon dioxide by natural sinks. Secondly, sea-surface temperatures reached exceptionally high levels across the ocean, associated with an El Niño event and other ocean variability factors, amplified by climate change. Additional factors include changes in the amounts of aerosols and low cloud and variations in atmospheric circulation,” stated a C3S press release.
Intense warming in the polar regions drove the rise in the global average temperature, as warming in the tropical regions was not as pronounced as in 2023 and 2024, according to the press release. The comparatively lower temperatures in the tropical regions were due to the presence of El Niño Southern Oscillation (ENSO)-neutral or weak La Niña conditions in the equatorial Pacific Ocean.
El Niño is the warmer-than-normal phase of the ENSO phenomenon and is generally associated with higher-than-average global surface temperatures, especially in the tropical regions. La Niña is the cooler-than-normal phase of ENSO and has the opposite effect to El Niño.
Beyond the poles, record annual temperatures were observed in the northwestern and southwestern Pacific, the northeastern Atlantic, parts of Europe, and Central Asia.
The report highlighted that half of the global land area experienced more days than average with “strong heat stress”—a “feels-like” temperature of 32°C or above. “Heat stress is recognised by the World Health Organization as the leading cause of global weather-related deaths,” it stated.
Dry, windy, and hot conditions fuelled extensive wildfires, notably in parts of Europe, which saw its highest wildfire emissions on record in 2025. Significant wildfires also occurred in North America. These fires emit carbon, particulate matter, and ozone, degrading air quality.
Conversely, some regions were notably cooler than average, including most of India, parts of southern Africa, and northern Australia. Aerosol pollution may have contributed to cooler conditions in India, but this requires further study. As air quality improves and aerosol levels fall, warming in such regions could accelerate rapidly.
C3S underscored that human activity remains the dominant cause of long-term warming. “Rising concentrations of greenhouse gases in the atmosphere — mainly a direct consequence of human activities — are the primary driver of the observed long-term increase in the global mean temperature,” stated the press release.
“The fact that the last eleven years were the warmest on record provides further evidence of the unmistakable trend towards a hotter climate,” stated Carlo Buontempo, director of the C3S.
“The world is rapidly approaching the long-term temperature limit set by the Paris agreement. We are bound to pass it; the choice we now have is how to best manage the inevitable overshoot and its consequences on societies and natural systems,” he added.