Human-driven climate change pushed 2025 into the ranks of the three hottest years ever recorded and, for the first time, the three-year global temperature average crossed the 1.5 degrees Celsius limit set under the 2015 Paris Agreement, scientists said.
The findings by World Weather Attribution researchers, released Tuesday in Europe, came after a year marked by deadly and costly climate extremes across the globe. Scientists said temperatures stayed unusually high despite the presence of La Nina, a natural cooling pattern in the Pacific, pointing instead to continued burning of fossil fuels as the main driver.
“If we don’t stop burning fossil fuels very, very quickly, very soon, it will be very hard to keep that goal,” said Friederike Otto, co-founder of World Weather Attribution and a climate scientist at Imperial College London.
The researchers said extreme weather killed thousands of people and caused billions of dollars in damage in 2025. They identified 157 severe extreme events worldwide and closely examined 22 of them. Heat waves were described as the deadliest disasters of the year, with some events found to be 10 times more likely than they would have been a decade ago because of climate change.
Otto said many of the heat waves seen this year would have been almost impossible without human-caused warming, underscoring how sharply risks have increased.
Other disasters included prolonged drought that fueled wildfires in Greece and Turkey, deadly floods in Mexico, Super Typhoon Fung-wong forcing more than a million people to evacuate in the Philippines, and monsoon-triggered floods and landslides across parts of India. The report warned that the growing frequency and intensity of such events are pushing communities toward what scientists call limits of adaptation, where warning systems, resources and recovery capacity are no longer sufficient.
The study also highlighted how rapidly intensifying storms are complicating forecasting and response, citing Hurricane Melissa, which struck Jamaica, Cuba and Haiti and overwhelmed local response capacities.
Meanwhile, global efforts to curb warming showed limited progress. United Nations climate talks in Brazil ended without a clear plan to phase out fossil fuels, although more funding was pledged to help vulnerable countries adapt. Many experts now acknowledge that global warming is likely to exceed 1.5 degrees Celsius, even as some say reversing the trend may still be possible.
Progress has varied by country. China is expanding renewable energy but continues to rely heavily on coal. In Europe, extreme weather has increased pressure for climate action, though some governments warn of economic costs. In the United States, the Trump administration has shifted policy toward supporting coal, oil and gas over clean energy.
Andrew Kruczkiewicz, a senior researcher at Columbia University’s Climate School who was not involved in the analysis, said communities are increasingly facing unfamiliar and fast-intensifying disasters, requiring earlier warnings and new approaches to response and recovery.
“On a global scale, progress is being made,” he said, “but we must do more.”