A recent study has found that nearly half of the global population endured an additional month of extreme heat over the past year due to man-made climate change. The analysis, conducted by scientists at World Weather Attribution, Climate Central, and the Red Cross Red Crescent Climate Centre, reveals the devastating impact of continued fossil fuel burning on health and well-being worldwide.
The study’s findings are stark: approximately four billion people, or 49% of the global population, experienced at least 30 more days of extreme heat than they would have otherwise. The researchers defined “extreme heat days” as those hotter than 90% of temperatures recorded at a given location between 1991 and 2020. By comparing the number of such days to a simulated world without human-caused warming, the team identified 67 extreme heat events during the year and found the fingerprint of climate change on all of them.
The Caribbean island of Aruba was the worst affected, recording 187 extreme heat days – 45 more than expected in a world without climate change. Friederike Otto, a climate scientist at Imperial College London and co-author of the report, emphasized the consequences of continued greenhouse gas emissions: “With every barrel of oil burned, every tonne of carbon dioxide released, and every fraction of a degree of warming, heat waves will affect more people.”
The study follows a year of unprecedented global temperatures, with 2024 being the hottest year on record, surpassing 2023, and January 2025 marking the hottest January ever. The report highlights a critical lack of data on heat-related health impacts in lower-income regions, emphasizing the need for early warning systems, public education, and heat action plans tailored to cities.
To mitigate the effects of extreme heat, the authors recommend better building design, including shading and ventilation, and behavioral adjustments like avoiding strenuous activity during peak heat. However, they stress that adaptation alone will not be enough; rapidly phasing out fossil fuels is essential to halt the rising severity and frequency of extreme heat.
Key Quotes
- “With every barrel of oil burned, every tonne of carbon dioxide released, and every fraction of a degree of warming, heat waves will affect more people.” – Friederike Otto, climate scientist at Imperial College London
- The study highlights the need for “early warning systems, public education, and heat action plans tailored to cities” to address the impacts of extreme heat.
The study’s findings underscore the urgent need for global action to address the climate crisis and mitigate the devastating effects of extreme heat on human health and well-being.