Climate change exposes 580 million children to 20 extra ‘heat-stress days’ every year

More than 40% of children under the age of 10 globally are already experiencing at least 20 additional “heat-stress days” due to climate change. This is according to a new attribution study, published in Science Advances, which combines climate models with demographic data to assess the age groups and regions that are exposed to the most hot, humid days. The study finds that children up to the age of nine already face more additional heat-stress days globally as a result of climate change than any other age group.  It adds that south Asia, southeast Asia and west Africa are recording the greatest childhood exposure to dangerous levels of humid heat – largely because these regions have a rapidly growing population with the highest proportion of young children. As the climate warms, children will continue to be more exposed to heat stress than any other age group, the paper warns. The lead author of the study tells Carbon Brief that the findings should inform discussions about climate justice, noting that children in developing countries “have contributed the least to historical greenhouse gas emissions”.  Humid heat High temperatures can be deadly. For example, the heatwaves that swept across Europe in the summer of 2026 have been linked to tens of thousands of “excess deaths”. A prominent 2021 study found that children born in the 21st century will be exposed to more extreme weather events in their lifetimes than their parents and grandparents.  Four years later, a study conducted 2020 – around 62 million people – will experience “unprecedented lifetime exposure” to heatwaves, even if warming is limited to 1.5C. Now, the latest research from the same team finds that children already face greater  exposure to dangerous levels of humid heat than adults as a result of human-caused climate change. Extreme heat is particularly dangerous when combined with high humidity. In hot weather, the human body produces sweat to cool itself down. However, as humidity increases, sweating becomes less effective. The study uses indoor wet-bulb globe temperature – a measure of temperature that takes humidity into account – to calculate heat stress. It defines a “heat-stress day” as any day with a wet-bulb globe temperature above 28C, as this is considered the threshold for “moderate heat stress” The authors then use climate models to simulate global temperature patterns in the present-day climate. (The authors use the climate of 2023, in which human activity has caused 1.3C of warming, to represent the “present-day”.) They then count the number of heat-stress days that each country records on average, per year.