Earth’s heat did not ease in 2025. Global temperatures ranked among the three hottest years ever measured, according to major climate-monitoring groups, prompting scientists to call the streak of extreme warmth a “warning shot” from a climate system that keeps shifting toward higher heat and higher risk.
On Jan. 14, 2026, the World Meteorological Organization said its consolidated analysis of eight international datasets put 2025 at about 1.44 degrees Celsius (2.59 degrees Fahrenheit) above the 1850-1900 average — with an uncertainty range of ±0.13°C — and an estimated global average temperature of 15.08°C (59.14°F). Two datasets ranked 2025 as the second-warmest year, while six ranked it third.
The same day,the National Oceanic and Atmospheric Association’s National Centers for Environmental Information said 2025 ranked third-warmest in its 176-year record dating to 1850, coming in 0.12°C behind record-hot 2024 and 0.02°C behind 2023. NOAA estimated 2025 ran about 1.34°C above the pre-industrial 1850-1900 average.
NASA’s Goddard Institute for Space Studies, also reporting Jan. 14, 2026, said 2025 was slightly warmer than 2023 but “within the margin of error,” effectively tying the two years. NASA said 2024 remains the hottest year since recordkeeping began in 1880.
European data tracked the same pattern. ECMWF, which runs the Copernicus Climate Change Service, said on Jan. 14, 2026, that 2025 was the third-warmest year in the ERA5 record, only 0.01°C cooler than 2023 and 0.13°C cooler than 2024. Copernicus put 2025’s global average surface air temperature at 14.97°C, or 1.47°C above the 1850-1900 level.
The rankings differ slightly because each group uses different methods, data inputs and baselines. But the underlying story does not: the last three years — 2023, 2024 and 2025 — sit at the top of every dataset WMO assessed.
Scientists expected some relief because 2025 began and ended with La Niña conditions, which often cool global averages by lowering temperatures in parts of the tropical Pacific. WMO Secretary-General Celeste Saulo said the cooling influence did not offset the buildup of heat-trapping greenhouse gases. “The year 2025 started and ended with a cooling La Niña and yet it was still one of the warmest years on record globally,” Saulo said in WMO’s statement.
Copernicus said weak La Niña or near-neutral conditions persisted for much of the year, helping hold down tropical air and sea-surface temperatures compared with 2023 and 2024. The polar regions moved the other way: Antarctica logged its warmest year in the ERA5 record, and the Arctic saw its second-warmest year.
NOAA’s annual analysis also found pronounced warmth in the Arctic, along with widespread above-average temperatures across most of Earth’s surface.
The burst of heat matters because it crowds up against the Paris Agreement’s 1.5°C target, which aims to limit long-term warming, not a single hot year. Copernicus said several methods place long-term global warming at about 1.4°C above pre-industrial levels and warned that, at the current rate, the 1.5°C long-term limit could arrive by the end of the decade.
WMO’s consolidated numbers show how close the world already sits to that benchmark. The organization said the three-year average for 2023-2025 reached 1.48°C above the 1850-1900 average, again with ±0.13°C uncertainty — the highest such multi-year average in its assessment.
Land temperatures draw headlines, but the oceans hold most of the planet’s extra heat — and they kept setting records in 2025. NOAA said upper ocean heat content hit a record high in 2025 and noted that the oceans store about 90% of the excess heat in the Earth system. WMO pointed to a separate peer-reviewed analysis published in Advances in Atmospheric Sciences that estimated the upper 2,000 meters of global ocean heat content increased by about 23 ± 8 zettajoules from 2024 to 2025.
Rising ocean heat helps drive sea level rise through thermal expansion and can add fuel to extreme weather by providing more energy and moisture to the atmosphere. WMO said the combination of high land and ocean temperatures helped power “heatwaves, heavy rainfall and intense tropical cyclones” in 2025.
Scientists point first to greenhouse gases from human activity as the dominant driver behind long-term warming. Copernicus said the “exceptional warmth” of the past three years stems primarily from rising greenhouse gas concentrations and unusually high sea-surface temperatures, with additional influences from aerosols, low clouds and atmospheric circulation patterns.
Berkeley Earth, an independent research group that compiles global temperature records, said the 2023-2025 “warming spike” deviated sharply from the previous 1970-2019 trend and suggested changes in low cloud cover and reductions in sulfur aerosol pollution likely contributed to the extra warmth on top of greenhouse-gas-driven warming.
As for 2026, Berkeley Earth said early indications point to a year similar to 2025, with a lower chance of a new record unless El Niño conditions return sooner than expected.
But scientists say the larger message does not depend on whether the next year ranks second, third or fourth. The last decade has rewritten the odds, and the climate system now delivers extreme heat more often — a pattern researchers describe as a warning shot with consequences that will grow as temperatures climb.
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