Half the global population experienced an additional month of extreme heat over the past year as a direct result of manmade climate change, according to a new study released Friday.
The findings highlight how the continued burning of fossil fuels is damaging health and well-being across all continents, with the impacts especially under-recognised in developing nations, the researchers said.
The analysis — carried out by scientists from World Weather Attribution, Climate Central, and the Red Cross Red Crescent Climate Centre — was published ahead of global Heat Action Day on June 2, which this year draws attention to the dangers of heat exhaustion and heat stroke.
To measure the effect of global warming, the researchers examined data from May 1, 2024, to May 1, 2025. They defined “extreme heat days” as days hotter than 90 percent of all recorded temperatures at a given location between 1991 and 2020.