The last three years on Earth were the warmest on record

The past three years have been the warmest on record, according to a new analysis of global climate data. They also mark the first three-year period in which the global average temperature exceeded 1.5 degrees Celsius above pre-industrial levels – a threshold associated with increased risks to biodiversity, human health and extreme weather events.

“1.5°C is not a cliff, but we know that every half degree counts,” climate scientist Samantha Burgess said at a Jan. 12 news conference announcing the report. Burgess is the climate policy lead for the European Center for Medium-Range Weather Forecasts, or ECMWF, which released the report on January 14.

Although 2025 was slightly colder than the previous two years, averaging 1.47 degrees above pre-industrial temperatures, the Earth is warming faster than a decade ago. The planet is now on track to regularly exceed the 1.5 degree threshold by 2029.

The year 2024 remains the hottest ever recorded on Earthon average 1.6 degrees above the pre-industrial period, with 2023 still in second place. While the tropics were a little cooler in 2025 than in 2024, Antarctica had its warmest year on record and the Arctic its second warmest year. Sea ice at both poles was also at a record low.

The main driver of these temperatures is the buildup of greenhouse gases in the atmosphere, dominated by the burning of fossil fuels, Burgess said.

Tropical air temperatures in 2023 and 2024 were stimulated by a strong El Niño. But by 2025, the planet entered a neutral or weak La Niña phase of this climate oscillation pattern, generally resulting in cooler temperatures. However, 2025 remains the warmest La Niña year on record, Burgess said.

“There have been historically high sea surface temperatures throughout 2025, despite the absence of El Niño conditions,” she said.

Extreme weather events exacerbated by rising temperatures – including wildfires, heat waves and heavy rains – were widespread in 2025, according to analyzes by the World Weather Attribution, a global consortium of climate scientists. More than half of the planet has experienced an increase in the number of days of heat stress, defined as a temperature above 40°C.

“Will 2026 be more exceptional? It’s too early to tell,” Burgess said. But the overall trend is clear, and there is an 80% chance that at least one of the next five years will replace 2024 at the top, she said.

The last 11 years have been the hottest on record in the world. “I expect next year it will be 12 out of 12.”