Heat-related childhood deaths have doubled in Africa due to climate change – new study

‘We have high confidence that in many locations around the world, climate change caused by burning fossil fuels is killing people,” said Dr Christopher Trisos, director of the Climate Risk Lab at UCT and co-author of a recent global study. 

The research systematically reviewed and synthesised the strongest scientific evidence linking human health loss directly to climate change, aiming to provide a clearer picture of how human-caused global heating is already affecting health worldwide.

The global study, published in Nature Climate Change last month, estimates that 30,000 deaths occur globally each year due to climate change, with an economic toll of between $100-billion and $350-billion per year. 

The study estimated the value of these lost lives using the “value of a statistical life”, which is a method that incorporates not only healthcare and emergency costs, but lost productivity, welfare losses and the broader social impact of premature death.

And closer to home, the impact is significant - with heat-related deaths among children in Africa having more than doubled in the past two decades.

“And we know that’s a massive underestimate because very few of these studies have been done in low- and middle-income countries, and that’s where most of the world’s people live,” said Trisos.

How scientists know it’s climate change

It’s not a debate, the Intergovernmental Panel on Climate Change (IPCC), the world’s leading authority on climate science, states unequivocally that human activities - primarily through the burning of fossil fuels - have caused global heating. 

As Trisos says, “The IPCC doesn’t even say ‘high confidence’; it says human burning of fossil fuels has caused climate change. It’s just a fact.”

To link specific deaths to climate change, researchers use a method called end-to-end health impact attribution. This compares the real world we live in with a “counterfactual” world, where humans had never emitted large amounts of greenhouse gases.

“It’s kind of like dealing with gravity,” Trisos explains. “You could simulate what your furniture would do without gravity.”

Using global climate models, scientists simulate both the real climate and this counterfactual climate in cities such as Cape Town, Johannesburg, London, Paris and New York. They look at the frequency and intensity of hot days in each scenario.

“We have the counterfactual climate that says no, it wouldn’t have been a hot day even if we hadn’t burned the fossil fuels, and it considers climate variability,” Trisos explains. 

“If the numbers are significantly different, then you can say human-caused climate change has led to this much additional heat death.”

These climate models are very accurate because scientists know exactly how much greenhouse gases have been added to the atmosphere since the Industrial Revolution - thanks to precise measurements from instruments worldwide, and even older data from ice cores, where air bubbles trapped in ancient ice reveal historical carbon dioxide concentrations.

By comparing heat-related deaths from the real and counterfactual worlds, using cause-of-death records, and statistical links between temperature and mortality, researchers can isolate deaths specifically caused by human-induced global heating.

Heat: the deadliest and best-studied killer

Trisos noted that most health impact attribution studies have focused on heat-related deaths. Heat is the best-studied climatic cause of death linked to climate change because temperature and mortality data are widely available, and easier to analyse statistically than hazards such as flooding or storms.

The research found that between 1995 and 2004, an estimated 3,000 to 5,000 heat-related child deaths occurred annually across Africa due to rising temperatures linked to climate change. Between 2011 and 2020, this had soared to between 7,000 and 11,000 deaths per year, illustrating a rapid and deeply concerning increase. Trisos emphasised that heat is the dominant cause of these deaths in the datasets analysed, particularly among children below five years of age.

“When heat increases, death increases,” says Trisos.

The study analysed data from 732 locations in 43 countries (1991–2018) and found more than 271,000 heat-related deaths linked to human-caused global heating - around 37% of all deaths from heat during warm seasons.

Dr Darshnika Lakhoo from the Wits Planetary Health Division explained that children are particularly vulnerable to extreme heat because of both biological and social factors. Her research has found that heat exposure increases the risk of preterm birth and stillbirth, and can worsen pregnancy-related conditions such as hypertension and diabetes.

“Children are more vulnerable to heat than adults - they have a [proportionately larger body surface area to body mass ratio than adults], generate more heat through activity, sweat less and their thermoregulation systems are still developing,” said Lakhoo.
“They’re also dependent on caregivers to dress them appropriately and keep them hydrated, which doesn’t always happen - especially with infants, who are often overdressed.”

Where children live also matters. Lakhoo’s research in Pretoria found that temperatures inside informal homes can be several degrees hotter than outdoors.

“If you live in a house with no roof insulation or ventilation, in an area without shade or greenery, the temperatures you’re exposed to indoors can be far higher than in a well-ventilated apartment surrounded by trees.”

Extreme heat can cause heat exhaustion and heat stroke - as seen in tragic cases like children dying in overheated cars - and indirectly contribute to hospitalisations for asthma and kidney illness, more accidents and drownings, and worsening nutrition as heat affects food security.

The true toll is much higher

Despite these dire figures, Dr Trisos stressed the true toll is likely far greater. Most studies focus on countries with detailed health records, leaving low- and middle-income countries underrepresented.

“Most of these studies focus on heat-related deaths, with fewer studies yet on flooding, storms and drought impacts - especially in low- and middle-income countries. Africa, including South Africa, is underrepresented because of funding and data access challenges,” he said.

Millions of people living in poorer regions where climate hazards are growing rapidly remain largely invisible in the data.

“South Africa is somewhat better represented than many other African countries because of more digitised health records, but we still need more comprehensive data,” Trisos added.

Why Africa’s numbers are underestimated

Despite facing some of the highest exposure to extreme heat, drought and flooding, Africa remains underrepresented in global health attribution studies. Two main factors drive this: limited research funding and scarce access to digitised, anonymised health data.

“Most of the existing studies come from high-income countries because that’s where the data and resources are,” Trisos explains. “We need more locally led research in Africa so we can understand the real toll of climate change on our communities.”

While South Africa has relatively good health records compared with many African countries, gaps remain, meaning many deaths go uncounted.

“Very few of these attribution studies have been done in low- and middle-income countries,” Trisos adds. 

“International funders and national governments should support this to address data gaps and improve climate adaptation policy.”

Treating climate change as a public health emergency

The study’s authors argue that climate change should be considered not just an environmental issue, but a full-blown public health emergency. This requires scaling up early warning systems, improving healthcare capacity during heatwaves and designing cooler urban environments.

For African scientists, there is also a growing push to link specific deaths to major fossil fuel emitters, opening avenues for accountability and climate justice.

“Advanced research is now linking specific health impacts to major emitters,” says Trisos. “That could reshape the conversation around responsibility for climate damages - including in courts.”

The rising heat-related mortality burden, especially among children, reflects broader vulnerabilities tied to poor housing, limited ventilation, food insecurity and overstretched healthcare systems. Trisos stresses the urgency: “These numbers give us a baseline, but they will grow sharply as research improves and warming continues. Policymakers must urgently treat climate change as a health emergency.” DM