Climate change exposes up to 560 million children worldwide to extreme heat for at least one month longer each year

26/08/2026

A new analysis shows that children today – and in the future – are disproportionately affected by heat stress resulting from climate change. This poses serious risks to their health and development.

New research from the Vrije Universiteit Brussel (VUB) shows that up to 560 million children aged between 0 and 9 years worldwide experience at least one extra month (30 days or more) of heat stress per year due to human-induced climate change. This corresponds to 43 per cent of all children in this age group. This additional exposure exceeds that of any other age group and is almost three times higher than the 190 million people (30 per cent) aged between 60 and 69 who experience this additional health threat. Children are therefore already disproportionately exposed to high levels of dangerous humid heat, driven by human-induced climate change, and this exposure is expected to increase further as global warming continues.

Under the projected climate change scenarios of 1.5°C and 2°C of global warming – which are highly likely to be exceeded if countries continue with their current policies – the number of children exposed to an additional month of extreme heat is expected to rise to 620 million (49 per cent) and 650 million (59 per cent) children aged 0 to 9, respectively.

The study was carried out by an international research team led by the VUB and is published today in the scientific journal *Science Advances*. It is the first analysis to quantify, on a global scale, how heat resulting from climate change affects different age groups, both today and in the near future. To this end, the researchers combined population data with advanced climate models and attribution science, a method that assesses the extent to which climate change contributes to extreme weather conditions. The results show that the health risks of climate change are already a reality today and, moreover, are unevenly distributed across generations and regions.

Children affected by climate-driven heat stress around the world: The colour of the map indicates the number of additional heat stress days per year occurring today due to human-induced climate change; the size of the circle indicates the percentage of the population aged 0–9 in each AR6 land region. © Pietroiusti et al. 2026

Key findings:

Current impact: Climate change has almost tripled the number of children worldwide who are exposed to at least five months (150 days) of heat stress each year. In a world without climate change, this figure would be an estimated 120 million children (9 per cent), compared with 350 million children (27 per cent) today. That is almost three times as many children as there are adults aged between 60 and 69 who are exposed to at least five months of heat stress each year (120 million or 18 per cent).
Geographical differences: The greatest increase in humid heat due to climate change is occurring in tropical regions and poorer countries where the population is younger, which explains why more children are affected. South Asia, South-East Asia and West Africa are the regions with the highest number of children currently exposed to dangerous heat stress.
Future scenarios: Children will be disproportionately affected compared with all other age groups, regardless of global population ageing:
- In a world with 1.5°C of warming: it is expected that 620 million children (49%) aged 0–9 will experience at least one additional month of heat stress per year, and 390 million (31%) will experience at least five full months of heat stress.
- In a world with 2°C of warming: it is projected that 650 million children (59%) aged 0–9 years will experience at least one additional month of heat stress per year, and 420 million (37%) will experience at least five full months of heat stress.

Extreme heat disrupts the normal functioning of the human body, exacerbates underlying health conditions and can lead to serious complications such as heatstroke, dehydration and organ failure. Dangerous heatwaves are becoming more frequent and intense due to climate change, which is primarily driven by the burning of fossil fuels such as oil, coal and gas.

The study focuses on humid heat, which is more dangerous than dry heat. Humid heat impairs the body’s ability to sweat and cool down, leading to dangerous levels of heat stress.

Children are particularly vulnerable to extreme heat: their bodies heat up more quickly than those of adults, they sweat less efficiently and they are dependent on adult care. Overheating can lead to serious health risks, including dehydration and life-threatening heatstroke, as well as impacts on learning and cognitive development.

The findings come at a crucial moment for climate policy. The ongoing energy crisis has once again highlighted the risks of dependence on fossil fuels, and by 2026 the world had already experienced some of the most severe heatwaves ever recorded, some of which would have beenpractically impossible without the influence of climate change.

Rosa Pietroiusti, lead author of the study and a PhD student at the VUB: “Climate change is already causing hundreds of millions of children worldwide to suffer from dangerous heat, posing serious risks to their health. Children in developing countries are disproportionately exposed to climate extremes, both now and in the future, despite having contributed the least to historical greenhouse gas emissions. At the same time, poverty, inadequate housing, limited access to cooling and overburdened health systems mean that many children have few options for protecting themselves from the heat. Young people are not only the hardest hit by climate change; they are also at the forefront of the fight against it, from leading school strikes for the climate to bringing important climate cases before national and international courts. We need governments to step up and take serious and immediate action to respond to young people’s calls for climate justice.”

Wim Thiery, lead author of the study and professor at the VUB: “Our research emphasises that, in order to protect future generations, policymakers must urgently and drastically reduce fossil fuel emissions and limit global warming in line with the Paris Agreement to halt the most catastrophic consequences of the climate crisis. At the same time, a massive increase in climate finance for developing countries and targeted adaptation measures worldwide, such as heat action plans and improved public health systems, will be essential to protect younger generations in a rapidly warming world.”

Via this link, you will find a complete press pack containing: the press release in other languages, the research article, the results broken down by region/country, and a supplementary document with detailed results for countries/regions where many children have been affected by this situation, additional quotes from civil society representatives, health experts and affected parents and children, and a world map illustrating the results.

Additional information and definitions used:

Heat stress days are defined here as the number of days of humid heat stress (i.e. with a WBGT index — wet bulb globe temperature — in the shade > 28°C), representing conditions in which protective measures such as reduced activity or structured rest periods are recommended to prevent heat-related illnesses.
Additional heat stress days are defined here as the number of heat stress days attributable to human-induced climate change, i.e. days that would not occur without climate change. This is estimated using attribution methods applied to observation-based reanalysis data or to global climate model data. The results cited here are estimated using state-of-the-art global climate model data, which enable us to make consistent comparisons between current and future conditions; the full article also includes results from reanalysed data and therefore contains a broader range of quantitative estimates that confirm the differences between age groups.
Total heat stress days include both those attributable to climate change and those that would have occurred without climate change. They therefore represent the total exposure to humid heat stress conditions.
Population exposure to heat stress today is estimated using population data from 2023. Projections of population exposure in a world with +1.5°C and +2°C of global warming take into account climate change as estimated by global climate model projections, and demographic changes under a medium scenario for socio-economic development.
The results presented here relate to humid heat stress. Additional results using alternative heat metrics (e.g. daily maximum temperature > 99th percentile) are available in the appendices to the article. Regardless of the heat metric used, all results show that children worldwide are disproportionately exposed.
The research was carried out by an international team of researchers led by the Water and Climate Department at the VUB, with colleagues from ETH Zurich, the University of Oxford, the University of Waikato and the Potsdam Institute for Climate Impact Research.
The findings of this study also contributed to a recent UNICEF report, which shows that 550 million children worldwide are exposed to extreme heat attributable to human-induced climate change.
The current research provides further evidence of the well-documented impacts of climate change on public health. The Lancet Countdown 2025 report on Health and Climate Change highlights the damage being inflicted on people’s health worldwide: from extreme heat and extreme weather events to drought and increasingly widespread infectious diseases, the climate crisis is affecting every aspect of people’s lives and placing an extreme strain on healthcare systems.
The authors of the current study at the VUB also contributed to a recent report by Save the Children, which found that around 100 million of the 120 million children born in 2020 will face unprecedented exposure to heatwaves.

Contact

Lead author: Rosa Pietroiusti, Department of Water and Climate, Vrije Universiteit Brussel; rosa.pietroiusti@vub.be, +32 496 83 66 63.
Senior author: Prof. Dr Wim Thiery, Department of Water and Climate, Vrije Universiteit Brussel; wim.thiery@vub.be, +32 2 629 30 29.
Valorisation Manager: Dr Marie Cavitte, Department of Water and Climate, Vrije Universiteit Brussel; marie.cavitte@vub.be, +32 470 19 24 15.