Climate change fuelled severe heatwaves, floods, storms and wildfires worldwide in 2025, hitting vulnerable communities hardest.
Scientists found 17 of 22 analysed extreme events were made more likely or intense by global warming.
The report warns continued fossil fuel reliance is driving temperatures past 1.5°C and pushing millions to the limits of adaptation.
Climate change fuelled extreme weather across the world in 2025, worsening heatwaves, droughts, storms and wildfires and pushing millions close to the "limits of adaptation", according to the World Weather Attribution's annual report.
Scientists have called for a rapid reduction of fossil fuel consumption to avoid the worst consequences of climate change, it said.
A multinational partnership called World Weather Attribution examines and disseminates information about the potential impact of climate change on extreme weather occurrences, including heat waves, droughts, storms, and heavy rainfall.
The paper claims that since the Paris Agreement was signed, heatwaves have gotten demonstrably more extreme, with some occurrences now up to ten times more frequent than in 2015.
It noted that although natural modes like El Niño Southern Oscillation were in a cooler phase, global warming made 2025 one of the warmest years on record.
"Extreme weather disproportionally affects vulnerable groups and marginalised communities. This inequality is also seen in climate science, where lack of data and limitations in climate models constrain analyses for Global South events," the report said.
The experts said reducing vulnerability and exposure of the population saves lives, but some extreme events in 2025 showed that climate change is already pushing millions close to the "limits of adaptation".
"Each year, the risks of climate change become less hypothetical and more brutal reality," Friederike Otto, professor in Climate Science at the Centre for Environmental Policy at Imperial College London, said.
"The report shows that despite efforts to cut carbon emissions, they have fallen short in preventing global temperature rise and the worst impacts. Decision-makers must face the reality that their continued reliance on fossil fuels is costing lives, billions in economic losses, and causing irreversible damage to communities worldwide," Otto, who is also the co-founder of World Weather Attribution, added.
According to the analysis, 2025 will be among the hottest three years ever recorded even though it has La Niña conditions, which are typically linked to colder equatorial Pacific ocean waters and milder global temperatures.
"The three-year average will also cross the 1.5 degrees Celsius threshold for the first time. The rapid studies conducted by World Weather Attribution this year highlight the consequences of this warming. Most extreme weather events analysed by the group showed the fingerprints of climate change.
"The analyses also show that for every extreme event, vulnerable populations are systematically the hardest hit," the report noted.
157 extreme weather occurrences that satisfied a set of humanitarian impact criteria were found by World Weather Attribution in 2025. With 49 occurrences apiece, floods and heatwaves were the most common, followed by storms (38), wildfires (11), droughts (7), and cold spells (3).
Twenty-two of those events—three in Africa, seven in the Americas, five in Asia, six in Europe, and one in Oceania—were thoroughly examined by the researchers.
Of those, 17 were made more severe or more likely by climate change, while five produced outcomes that were not conclusive, primarily because of weather data gaps and climate model constraints.
For a paper, the scientists also reviewed six prior heat events to examine how the frequency and intensity of extreme heat had increased since the Paris Agreement was signed.
According to the analysis, there has been an increase in global warming since 2015, but some heatwaves are now nearly ten times more likely. This is further proof that every degree matters when it comes to climate change.
"Heatwaves were the deadliest extreme weather events of 2025. While most heat-related deaths remain unreported, one study estimated that 24,400 died from a single summer heatwave in Europe this year," the report said.
Tropical cyclones and storms were also among the deadliest events of the year. One of the worst examples happened recently, when several simultaneous storms hit Asia and Southeast Asia, killing more than 1,700 people and causing billions in damages.
