Some 770 million people experienced record-warm annual conditions where they live, while no record-cold annual average was logged anywhere, according to Berkeley Earth.
The Antarctic experienced its warmest year on record, while it was the second hottest in the Arctic, Copernicus said.
An AFP analysis of Copernicus data last month found that Central Asia, the Sahel region and northern Europe experienced their hottest year on record in 2025.
Berkeley and Copernicus both warned that 2026 would not break the trend.
If the warming El Nino weather phenomenon appears this year, “this could make 2026 another record-breaking year”, Carlo Buontempo, director of the Copernicus Climate Change Service, told AFP.
“Temperatures are going up. So we are bound to see new records. Whether it will be 2026, 2027, 2028 doesn’t matter too much. The direction of travel is very, very clear,” Buontempo said.
Berkeley Earth said it expected this year to be similar to 2025, “with the most likely outcome being approximately the fourth-warmest year since 1850”.
EMISSIONS FIGHT
The reports come as efforts to cut greenhouse gas emissions – the main driver of climate change – are stalling in developed countries.
Emissions rose in the US last year, snapping a two-year streak of declines, as bitter winters and the AI boom fuelled demand for energy, the Rhodium Group think tank said on Tuesday.
The pace of reductions of greenhouse gas emissions slowed in Germany and France.
“While greenhouse gas emissions remain the dominant driver of global warming, the magnitude of this recent spike suggests additional factors have amplified recent warming beyond what we would expect from greenhouse gases and natural variability alone,” said Berkeley Earth chief scientist Robert Rohde.
The organisation said international rules cutting sulfur in ship fuel since 2020 may have actually added to warming by reducing sulfur dioxide emissions, which form aerosols that reflect sunlight away from Earth.