Climate change is already exposing millions of children in Bangladesh to additional dangerous heat stress, with 22 million children aged 0–9.

Around 79% of all children in this age group are experiencing at least one additional month of heat stress every year because of human-induced climate change, according to new research led by Vrije Universiteit Brussel (VUB) and published in Science Advances.

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The analysis also finds that climate change has nearly tripled the number of Bangladeshi children aged 0–9 experiencing at least five total months (150 days) of dangerous heat stress each year, increasing the number from 9 million in a world without climate change to 26 million today which is equivalent to 91% of children in this age group.

The findings place Bangladesh within a wider South Asian crisis.

Across South Asia, 167.4 million children aged 0–9, about 62% of children in the age group are currently exposed to at least one additional month of heat stress attributable to climate change.

Climate change has also doubled the number of children in the region experiencing at least five total months of dangerous heat stress, from 80 million to 156.6 million.

The youngest are facing the greatest risk

Globally, the study estimates that up to 560 million children aged 0–9, 43% of children in this age group are currently experiencing at least one additional month of heat stress each year due to human-induced climate change. This exposure is higher than for any other age group.

Children are particularly vulnerable to extreme heat because their bodies heat up faster than adults, they sweat less efficiently and they depend on adults for protection.

Excessive heat can cause dehydration and heatstroke, aggravate existing health conditions and affect learning and cognitive development.

The study focuses on humid heat, measured using a wet-bulb globe temperature threshold above 28°C in the shade. Humid heat is particularly dangerous because high humidity prevents the body from effectively cooling itself through sweating.

Bangladesh faces an escalating future threat

The analysis shows that Bangladesh's current exposure could become even more widespread under further global warming.

Under a 1.5°C warming scenario, 23 million Bangladeshi children (87%) are projected to experience at least one additional month of heat stress each year, while 25 million (93%) could experience at least five total months of heat stress.

Under a 2°C warming scenario, the share of children exposed to at least one additional month of climate-change-driven heat stress is projected to rise to 98%, with 97% projected to experience at least five total months of heat stress.

These projections underscore the growing importance of preparing Bangladesh's health, education and social protection systems for prolonged periods of extreme heat — while rapidly reducing the fossil fuel emissions driving further warming.

A call for urgent climate and health action

The researchers warn that children in developing countries face disproportionate exposure to climate extremes, while poverty, inadequate housing, limited access to cooling and overstretched health systems can leave children with fewer ways to cope with extreme heat.

“Climate change is already causing hundreds of millions of children to suffer from dangerous heat worldwide, posing severe risks to their health. Children in developing countries face disproportionate exposure to climate extremes now and into the future,” said Rosa Pietroiusti, lead author of the study and PhD researcher at VUB.

Dr. Shimul Mazumdar, Senior Consultant (Child), General Hospital, Comilla said “The impact of intense heat, worsened by climate change is becoming increasingly evident among children. Issues such as sudden vomiting, excessive fatigue, restlessness, and a loss of appetite being observed much more frequently.”

For Bangladesh, the findings make clear that extreme heat is not simply an environmental concern but an increasingly urgent child health, education and development challenge. Protecting children will require stronger heat-health preparedness, targeted adaptation measures, resilient public services and accelerated action to reduce the emissions driving climate change.