In 2024, half the world's population experienced one more month of summer

2025-05-31 16:46:00, Sociale CNA

Half of the world's population experienced an additional month of extreme heat last year compared to the 1991-2020 average.

According to a study, this happened due to human-caused global warming. The consequences of the continued use of fossil fuels.

The study results highlight how harmful the continued use of fossil fuels is to the health and well-being of people on all continents, with the consequences being particularly unknown in developing countries, according to the researchers.

“With every barrel of oil burned, every ton of carbon dioxide released, and every fraction of a degree of warming, heat waves will affect more and more people,” notes Friederike Otto, a climatologist at Imperial College London and author of the report.

The analysis, conducted by scientists from World Weather Attribution, the non-governmental organization Climate Central and the Red Cross and Red Crescent's Climate Change Directorate, was published ahead of World Heat Action Day on June 2, which this year is dedicated to the risks of heat exhaustion caused by heat waves.

Time period analyzed by researchers

To assess the impact of climate change, the researchers analyzed the period from May 1, 2024 to May 1, 2025.

"Extremely hot days" were defined as those days when the temperature exceeded 90% of the average temperatures recorded at a specific location in the period 1991-2020.

The researchers compared the number of these days to a hypothetical world without anthropogenic warming. The results are indisputable: about four billion people, or 49% of the world's population, experienced at least 30 additional days of extreme heat last year compared to the hypothetical world.

All extreme heat events have the imprint of climate change

The study recorded 67 episodes of extreme heat during the period studied, all of which bear the hallmarks of climate change.

The Caribbean island of Aruba was hit hardest, with 187 days of extreme heat, 45 more than would be expected in a world without climate change.

The year 2024 was the warmest year ever recorded, surpassing 2023, while 2025 began with the warmest January since records began.

On average over the past five years, global temperatures have been 1.3° Celsius above pre-industrial levels. In 2024, it surpassed the 1.5° Celsius threshold – the symbolic upper limit set by the Paris Climate Agreement.

The report also highlights the apparent lack of data on the health impacts of heat in poorer areas.

While Europe recorded over 61,000 heat-related deaths in the summer of 2022, there is little data available for other regions. Many heat-related deaths were wrongly attributed to heart or lung disease./ CNA