Millions of Kenyans face malaria threat as climate change pushes disease into highlands

Malaria is estimated to account for 30 per cent of visits to hospitals in Kenya. [Getty]

For generations, many families in Kenya's cool highland counties have regarded malaria as someone else's problem. Unlike communities along the Lake Victoria basin and the Coast, where the disease has remained endemic for decades, people living in higher-altitude regions have largely escaped sustained malaria transmission.

But scientists now warn that this may no longer be the case. A landmark study published in Nature has found that human-caused climate change is gradually shifting malaria into cooler parts of East Africa, including Kenya's highlands, exposing millions of people who have historically faced little risk to a disease that remains one of Africa's biggest child killers.

The researchers say climate change is not simply increasing malaria across Africa. Instead, it is redrawing the disease's map. As temperatures rise, some of Africa's hottest malaria hotspots are becoming too warm for optimal mosquito transmission, while cooler highland regions are becoming increasingly suitable for the mosquitoes and parasites that spread the disease.

The findings could have profound implications for Kenya, where tea-growing highlands, farming communities, schools and health facilities in counties that have not traditionally battled malaria may increasingly have to prepare for outbreaks.

The study analysed more than 50,000 geolocated childhood malaria surveys collected across sub-Saharan Africa over more than a century, making it the most comprehensive effort yet to determine how much human-caused climate change has influenced malaria transmission. Researchers combined the historical health data with climate models that compared today's world with a simulated world without greenhouse gas-driven warming.

 Their conclusion settles a scientific debate that has lasted decades. Across Africa, climate change has caused an estimated one additional malaria case for every 1,000 children aged between two and 10 years. But the continental average masks sharp regional differences. East Africa and southern Africa have experienced some of the largest increases as warming temperatures make cooler regions more favourable for malaria transmission.

 The study identifies Kenya's highlands among the regions already experiencing the effects. Researchers found robust evidence that human-caused climate change has contributed to malaria resurgence in high-altitude areas of Kenya and neighbouring Ethiopia, supporting earlier local observations that warming temperatures have expanded conditions suitable for mosquitoes.

 "Human-caused climate change has contributed to an increase in malaria in the highlands of Kenya and Ethiopia," said Christopher Trisos, a co-author of the study and Director of the Climate Risk Lab at the African Climate and Development Initiative, University of Cape Town.

"Future climate change is projected to cause further increases in malaria in these regions. Kenya and Ethiopia and their global health partners must start adapting their health systems for this increase in risk."

The research suggests the implications extend beyond hospitals. Children could become increasingly vulnerable as malaria spreads into communities where immunity is lower because exposure has historically been limited. Schools in cooler counties may face more illness-related absenteeism, while pregnant women, who already face heightened malaria risks, could require expanded prevention programmes.

Tea-growing regions could also find themselves confronting an unfamiliar public health challenge. Many of Kenya's tea estates sit in cooler highland environments that have historically experienced relatively low malaria transmission. As temperatures continue to rise, workers and surrounding communities could face growing exposure during periods that were previously considered low risk.

Unlike communities in western Kenya that have lived with malaria for decades, highland populations may have less experience recognising symptoms early, seeking prompt treatment or consistently using preventive measures such as insecticide-treated mosquito nets. According to the researchers, this changing geography means governments must rethink where malaria control resources are directed.

"Climate change isn't just making malaria worse or better—it's moving it," said Tamma Carleton, Faculty Head of Research at the Climate Impact Lab and Assistant Professor at the University of California, Berkeley.

"Whether a place sees elevated malaria risks or reduced burdens under climate change depends on how hot it is today. We see relief in the current hotspots and new risk nearly everywhere else.

" The study projects that the shift will continue through the century. While average malaria prevalence across sub-Saharan Africa could decline later this century as temperatures become too high for efficient mosquito transmission in some of today's worst-affected regions, high-elevation East Africa is expected to experience continued increases in risk.

Under an intermediate emissions scenario, malaria prevalence could increase by as much as 20 percent in parts of the Rift Valley by the end of the century.

The researchers say limiting global warming to below 2 degrees Celsius could prevent additional malaria cases in East African highlands and southern Africa by 2100. Kenyan doctors say the findings should serve as an early warning rather than a prediction of inevitable crisis. Dr Victor Mwaka Wauye, a consultant physician at Longisa County Referral Hospital in Bomet, said the research demonstrates that climate change is altering where  malaria should be expected to occur.

 "This reminds us that climate change is changing where we should expect the disease to occur, particularly in cooler parts of Kenya where health systems and communities may not have faced the same burden before," he said.

 "We must anticipate these changes by strengthening surveillance, investing in resilient health services and ensuring every child has timely access to prevention, diagnosis and treatment. Preparing for tomorrow's malaria burden starts with acting today."

 Consultant paediatrician Dr Reign Mwendwa echoed those concerns, warning that more Kenyan children could be exposed as temperatures rise.

"This study is an alarming reminder that climate change is already reshaping health risks for children across Africa," she said. "In Kenya, particularly in our cooler and highland regions, rising temperatures could allow malaria to spread into communities that have historically faced a much lower risk, putting more children in harm's way."

Despite the warning, the researchers stress that climate change is not the dominant force determining malaria trends.

They found that decades of malaria control programmes, including improved healthcare, insecticide-treated nets, vector control and economic development, have reduced malaria far more than climate change has increased it. The study argues that stronger surveillance, sustained investment and adapting malaria programmes to changing climate conditions can continue to offset the additional risks created by global warming.

 Experts observe that Kenya's greatest challenge is not an immediate explosion in malaria cases, but preparing for a disease whose range is steadily expanding into cooler, highland communities. They say health systems must adapt as climate change redraws the country's malaria map.