2025 was the third-warmest year on record globally, according to data released Wednesday by the European Centre for Medium-Range Weather Forecasts (ECMWF), which operates the Copernicus Climate Change Service (C3S) and the Copernicus Atmosphere Monitoring Service (CAMS).
Global temperatures were 1.47 °C (2.65 °F) above pre-industrial levels (1850 -1900), slightly cooler than 2023 by 0.01 °C and 0.13 °C below 2024, the warmest year on record.
The World Meteorological Organization (WMO) also confirmed that 2025 was one of the three warmest years on record, saying the global average surface temperature in 2025 was 1.44 °C above the 1850-1900 average, with a margin of uncertainty of ±0.13 °C.
The average temperature from 2023 to 2025 exceeded 1.5 °C above pre-industrial levels, marking the first three-year period to surpass the Paris Agreement’s long-term warming limit.
Meanwhile, the past 11 years, from 2015 to 2025, were the 11 warmest years on record, according to WMO.
Based on the current rate of warming, the agreement's 1.5 °C threshold could be reached by the end of the decade, more than a decade earlier than predicted when the agreement was signed.
Air temperatures over land were the second warmest on record, while the Antarctic recorded its highest annual temperature and the Arctic its second-highest. Sea-surface temperatures were also among the highest recorded.
According to WMO, around 90% of excess heat from global warming is stored in the oceans, making ocean heat a critical indicator of climate change, with ocean temperatures remaining among the highest on record in 2025.
"The report confirms that Europe and the world are in the warmest decade on record," said ECMWF Director-General Florian Pappenberger. "Preparedness and prevention remain possible but only when action is guided by robust scientific evidence."
The extreme warmth in 2025 was driven primarily by greenhouse gas accumulation, continued emissions and reduced carbon uptake by natural sinks. High sea-surface temperatures, influenced by El Nino and other ocean variability, also contributed.
WMO Secretary-General Celeste Saulo noted that 2025 began and ended under cooling La Nina conditions, yet still ranked among the warmest years on record globally.
"The year 2025 started and ended with a cooling La Niña and yet it was still one of the warmest years on record globally because of the accumulation of heat-trapping greenhouse gases in our atmosphere," Saulo said. "High land and ocean temperatures helped fuel extreme weather – heatwaves, heavy rainfall and intense tropical cyclones, underlining the vital need for early warning systems."
While tropical temperatures were slightly lower than in 2023 - 2024, polar regions experienced record warmth.
Europe saw its third-warmest year on record, with an average temperature of 10.41 °C, 1.17 °C above the 1991 - 2020 average. In February, combined polar sea ice cover fell to its lowest extent since satellite records began in the late 1970s.
"Human activity remains the dominant driver of the exceptional temperatures we are observing," said Laurence Rouil, director of CAMS.
"Atmospheric greenhouse gases have steadily increased over the last 10 years,” he said. “The atmosphere is sending us a message, and we must listen."
Half of the global land area experienced more days than average with strong heat stress, defined as a feels-like temperature of 32 °C or above, contributing to extreme wildfires in Europe, North America and other regions. The resulting emissions degraded air quality and posed risks to human health.
