Study: 3.8 billion people will be exposed to extreme heat waves by 2050

Around 3.8 billion people could be exposed to extreme heat waves by 2050, according to a study published in the journal Nature Sustainability, cited by AFP. Facing dangerous temperatures will not only be a challenge for already affected tropical regions, but will transform the climate and lifestyle in many areas that are currently considered temperate. Researchers modeled the evolution of population exposure to extreme heat according to different global warming scenarios. If global average temperatures rise by 2 degrees Celsius above pre-industrial levels, the number of people exposed to extreme heat could approach 3.79 billion by 2050 - almost double the number in 2010.

The study's lead author, Jesus Lizana of the University of Oxford, points out that most of the effects will be felt this decade, as humanity approaches the 1.5 degrees Celsius threshold for warming. "The need to adapt to extreme heat is more urgent than previously estimated," he says.

• Urgent adaptation: heat-resilient infrastructure

According to the researchers, adapting to heat waves is becoming an immediate necessity. They warn that new types of infrastructure - from passive cooling systems to sustainable air conditioning - must be built in the coming years to protect public health and limit economic losses. Prolonged exposure to extreme heat, often described as the "silent killer,” can overwhelm the body's ability to adapt, causing symptoms such as dizziness, headaches, dehydration, and even death. The risk is particularly high among the elderly, children, and those with chronic illnesses.

• Developing countries hardest hit

The increase in energy demand for cooling systems will be strongest in developing countries, where existing infrastructure is often inadequate. India, the Philippines, and Bangladesh are among the countries with the highest number of people exposed to intense heat waves. Tropical and equatorial regions will see the most significant climate change requiring the use of cooling, especially in Africa. Countries such as Laos, Brazil, the Central African Republic, Nigeria, and South Sudan are among the most vulnerable. "The most disadvantaged are also the ones who will suffer the most from this trend of increasing heatwaves,” explains Radhika Khosla, co-author of the study.

While climate change will make it less necessary to heat homes in some rich countries, they will also see an increase in the number of days with extreme temperatures for which they are not prepared. Regions such as Canada, Russia and Finland are targeted by this trend.