WIREDGOV

The three-year run of record warmest years saw 2025 conclude at 1.41±0.09°C above the 1850-1900 global average, according to the HadCRUT5 temperature series, collated by the Met Office, the University of East Anglia and the National Centre for Atmospheric Science. 2025 is the third warmest year on record and is the third calendar year exceeding 1.4°C.

Commenting on the three warmest year series, Professor Stephen Belcher CBE – the Met Office Chief Scientist – said: “From 2023 the globe has seen a surge in average annual temperatures. The three-year average global temperature from 2023 to 2025 has been 1.47°C above the average for 1850-1900.”

Professor Tim Osborn is the Director of the Climatic Research Unit at the University of East Anglia. He said: “Our global temperature observations show that the world is continuing to warm in line with predictions made by climate scientists worldwide.

“A natural climate variation in the Pacific Ocean, known as the El Niño-Southern Oscillation, temporarily added about 0.1°C to the global temperature in 2023 and 2024, contributing to the abrupt onset of the recent temperature surge. This natural influence weakened by 2025 and therefore the global temperature we observed in 2025 provides a clearer picture of the underlying warming.

“Sharp and sustained reductions in greenhouse gas emissions would slow, and eventually stop, further human-caused changes in the world's climate.”

Human-induced greenhouse gas rise 

Climate scientist Colin Morice of the Met Office said: “The long-term increase in global annual average temperature is driven by the human-induced rise in the concentration of greenhouse gases in the atmosphere. Fluctuations in the year-to-year temperature largely result from natural variation in the climate system.”

Using a combination of observations from the last decade and projections for the next ten years (2015-2034), the World Meteorological Organization estimated last year in the State of the Global Climate  report that the current long-term global warming level (more relevant than the average for a single or small number of years when considering the Paris Agreement on climate change) is 1.37°C with a range of 1.34°C to 1.41°C above the average of the period from 1850-1900. 

Climate scientists from the Met Office and other organisations are examining the rise in annual global mean surface temperatures; this includes the significant recent increase seen in 2023 and 2024. The scientists confirm the main cause of climate warming is increasing greenhouse gas concentrations driven by rising emissions. The experts also cite a number of factors for the recent surge, including: the rapid transition to El Niño conditions in 2023; the accumulation of ocean heat due to the high value of Earth’s Energy Imbalance; and reductions in anthropogenic aerosol emissions.

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