One Billion More People Now Exposed to Extreme Heat Stress Than in the 1970s, Study Finds

A new study has revealed that nearly one billion more people across the world are now experiencing at least one day of extreme heat stress every year compared to the 1970s, highlighting the growing intensity, frequency, and duration of dangerous heat conditions globally.

The research, conducted by scientists from the European Centre for Medium-Range Weather Forecasts based in the U.K. and Germany, suggests that governments urgently need stronger heat-health action plans, early warning systems, urban cooling strategies, and improved climate risk assessments to better protect populations from rising heat-related threats.

Heat stress refers to the overall heat burden placed on the human body and is determined by multiple environmental factors, including temperature, humidity, wind speed, and solar radiation. Researchers used the Universal Thermal Climate Index (UTCI), commonly described as a “feels-like” temperature, to evaluate how these combined factors impact human health.

Published in the journal Nature Climate Change, the study examined global heat stress data spanning from 1950 to 2024 and found that both daytime and nighttime temperatures have significantly intensified since the 1970s.

According to the researchers, during the 1970s nearly 55 percent of the world’s population experienced around 90 days of strong heat stress annually. In today’s climate, that figure has increased to 70 percent. Exposure to at least one day of extreme heat stress has also risen from 16 percent to 22 percent globally, translating into roughly one billion additional people being affected.

The analysis further found that nighttime temperatures are rising faster than daytime temperatures. The 10 warmest nights recorded annually have been warming at an average rate of 0.32 degrees Celsius per decade, slightly higher than the 0.27 degrees Celsius increase observed during the 10 hottest daytime periods.

Researchers also noted that extreme “feels-like” temperatures are becoming more frequent across every continent, with subtropical regions witnessing the sharpest rise in heat exposure.

Areas including southern parts of North America, southern Europe, northern and southern Africa, as well as South America, are now facing up to 50 extra days every year of strong to extreme heat stress compared to conditions seen in the 1970s.

The findings add to growing concerns over the accelerating impact of climate change and underline the urgent need for countries worldwide to develop stronger adaptation measures as extreme heat events become increasingly common.

Source: PTI