Introduction
A recent study published in the journal Nature Climate Change reveals that the number of people exposed to at least one day of extreme heat stress has increased significantly since the 1970s. According to the research, the percentage of people affected has grown from 16% to 22%, meaning that one billion more people are being affected by extreme temperatures due to the increase in the global population.
The Impact of Extreme Heat
Heat is the leading cause of climate-related mortality on a global scale. The study, conducted by scientists at the European Centre for Medium-Range Weather Forecasts (ECMWF), shows that in the 1970s, 55% of the global population faced at least 90 days of “strong” heat stress. Today, that number has increased to 70%. Additionally, the number of days of heat stress has also increased, with regions experiencing up to 50 additional days of “strong” heat stress per year and a longer season.
Understanding Heat Stress
Heat stress is the physiological overload that occurs when the body is exposed to extreme temperatures (especially intense heat) and cannot dissipate that heat to maintain its ideal temperature. Besides temperature, other factors must be considered, such as humidity, wind, solar radiation, and the response of each individual's body. Therefore, the Universal Thermal Climate Index (UTCI), used in the research, categorizes ten levels of heat stress, from cold to extreme heat, based on the impacts on the human body.
Consequences and Affected Regions
The study highlights that the warmest nights of the year are warming faster than the hottest days, with an increase of 0.32°C and 0.27°C per decade, respectively. And the combination of days and nights of heat stress is becoming more frequent and severe, mainly in Europe and Africa. In South America, the maximum thermal sensation on the hottest days has risen by 2°C to 4°C since the 1970s, and the minimum has increased by 1°C to 3°C.
Conclusion
The increase in heat stress is a direct consequence of climate change and has significant implications for public health and human well-being. It is essential that measures are taken to mitigate the effects of global warming and protect the most vulnerable populations.
Source / Reference
Original URL: https://climainfo.org.br/2026/06/23/calor-extremo-atinge-1-bilhao-de-pessoas-a-mais-do-que-na-decada-de-1970/