It was also the first time that the average temperature over three years exceeded the limit established in the 2015 Paris Agreement, which limits warming to a maximum of 1.5 degrees Celsius since the pre-industrial era.
Experts stated that keeping the Earth below this limit could save lives and prevent catastrophic environmental destruction worldwide.
The analysis by researchers at World Weather Attribution came after a year in which people around the world were hit by dangerous extremes caused by global warming.
Temperatures remained high despite the presence of the La Niña phenomenon, the occasional natural cooling of the Pacific Ocean waters that influences the climate worldwide.
Researchers have pointed out that the continuous burning of fossil fuels—oil, gas, and coal—which release greenhouse gases into the atmosphere, contributes to global warming.
“If we don’t stop burning fossil fuels very, very quickly, very soon, it will be very difficult to achieve this goal” of reducing global warming, warned Friederike Otto, co-founder of World Weather Attribution and climate scientist at Imperial College London, to the Associated Press (AP).
Extreme weather events kill thousands of people and cause billions of euros in damage annually.
WWA scientists identified 157 extreme weather events as the most severe in 2025, that is, those that met criteria such as causing more than 100 deaths, affecting more than half the population of an area, or leading to the declaration of a state of emergency. Of these, 22 were analyzed in detail.
These included dangerous heat waves, which the WWA classified as the world’s deadliest extreme weather events in 2025.
Researchers stated that some of the heat waves studied in 2025 were 10 times more likely to occur than they would have been a decade ago, due to climate change.
“The heat waves we observed this year are fairly common events in our current climate, but would be almost impossible to occur without human-induced climate change,” Otto emphasized.
Meanwhile, prolonged drought contributed to forest fires that devastated Greece and Turkey. Torrential rains and floods in Mexico killed dozens of people and left many others missing. Super Typhoon Fung-wong struck the Philippines, forcing the evacuation of more than a million people. Monsoon rains battered India with floods and landslides.
WWA emphasised that increasingly frequent and severe extreme weather events threaten the ability of millions of people worldwide to respond to and adapt to these events with sufficient warning, time, and resources—what scientists call “adaptation limits.”