Scientists have warned that climate change driven by human activity made 2025 one of the three hottest years ever recorded, underscoring the growing urgency of global climate action.
For the first time, the three-year average global temperature exceeded the 1.5°C warming limit set under the 2015 Paris Agreement, a threshold scientists say is critical to saving lives and preventing catastrophic environmental damage.
According to an analysis by World Weather Attribution (WWA), global temperatures remained exceptionally high in 2025 despite the presence of La Niña, a natural phenomenon that typically cools the planet. Researchers attributed the persistent heat mainly to continued fossil fuel use, including oil, gas and coal, which release heat-trapping greenhouse gases into the atmosphere.
WWA scientists identified 157 severe extreme weather events worldwide in 2025, of which 22 were closely analysed. These included deadly heat waves, floods, droughts, storms and wildfires. Heat waves were described as the world’s deadliest climate events this year, with some found to be 10 times more likely due to climate change than they would have been a decade ago.
Extreme conditions were reported across the globe, including drought-fuelled wildfires in Greece and Turkey, deadly floods in Mexico, Super Typhoon Fung-wong in the Philippines, and monsoon-related floods and landslides in India. Rapidly intensifying storms such as Hurricane Melissa overwhelmed response capacities in parts of the Caribbean, highlighting what scientists describe as the “limits of adaptation.”
Experts warn that increasingly frequent and severe climate extremes are stretching the ability of communities, particularly in vulnerable countries, to respond with adequate warning, resources and recovery capacity.
Meanwhile, global climate negotiations continue to face challenges. United Nations climate talks held in Brazil in November ended without a clear commitment to phase out fossil fuels, despite increased pledges for climate adaptation funding. Scientists caution that while global warming is likely to overshoot the 1.5°C target, reversing the trend may still be possible with swift and decisive action.
Researchers say progress varies widely between countries, with some expanding renewable energy while still investing in fossil fuels. They stress that earlier warnings, improved disaster preparedness and stronger global cooperation are essential to confront the accelerating impacts of climate change.
