Climate Change Could Redraw the Malaria Map in Sub-Saharan Africa, Research Finds
Climate change is expected to redraw Africa’s malaria map, increasing childhood malaria risk in cooler highland areas of East and southern Africa while reducing transmission in some of the continent’s hottest. . .
Climate change is expected to redraw Africa’s malaria map, increasing childhood malaria risk in cooler highland areas of East and southern Africa while reducing transmission in some of the continent’s hottest regionsRising temperatures could push malaria-carrying mosquitoes into places such as the Ethiopian and Kenyan highlands, Angola, Zambia and northeastern South Africa, with some southern coastal areas potentially seeing cases rise by as much as 20% by 2100Parts of West Africa and the Sahel could see malaria transmission decline as temperatures become too hot for mosquitoes, but stronger surveillance, control measures and limits on global warming could substantially reduce future childhood casesClimate change is expected to shift childhood malaria hotspots across sub-Saharan Africa by the end of the century. This shift could increase the prevalence of the parasitic disease in normally cool highland areas while reducing transmission in some of the region’s hottest zones, according to a research paper published Wednesday, July 29, by U. S. and African researchers in the scientific journalNature. The paper, titled“The past and future impact of climate change on childhood malaria in Africa,”quantifies the historical and projected effects of climate change on childhood malaria south of the Sahara, where most cases and deaths occur. The disease, transmitted through the bite of an infected femaleAnophelesmosquito, killed about 579,000 people in Africa in 2024, around 75% of them children under the age of 5, according to the World Health Organization. Warming redistributes malaria riskBy analyzing clinical data alongside records of temperature and rainfall changes linked to human-caused climate change, researchers affiliated with the Yale School of Public Health and the University of California in the United States, and the University of Cape Town in South Africa, found that climate change likely contributed to a slight overall increase in malaria prevalence in sub-Saharan Africa over the past century while also shifting the geographic distribution of the disease. They found that transmission of the parasite that causes malaria peaks at temperatures of about 25 degrees Celsius and declines when temperatures fall below 16 degrees Celsius or rise above 34 degrees Celsius. The research also found that episodes of very heavy rainfall were associated with higher malaria prevalence two to three months later. This suggests that mosquito populations may increase following periods of intense rainfall, although the authors stressed that the relationship is complex and remains highly uncertain. These temperature thresholds help explain why warming is making formerly cool regions more suitable for malaria transmission, particularly in southern Africa and the highlands of East Africa. Malaria cases have increased in East Africa, particularly in mountainous regions. The data show that climate change caused an average increase of 0. 32 percentage point in malaria prevalence across the subregion, with increases of 1 to 2 percentage points in parts of the Ethiopian highlands and the Great Rift Valley. West and Central Africa could fare betterIn areas more than 1,000 meters above sea level, malaria prevalence increased by an average of 0. 81 percentage point. At the same time, some low-lying areas of Ethiopia, Sudan, South Sudan, Eritrea and Djibouti experienced small declines, highlighting the contrasting effects of warming across different landscapes. By 2050, rising temperatures are expected to further expand the range of malaria-carrying mosquitoes into cooler parts of southern and eastern Africa. In the highlands of East Africa, including parts of Kenya and Ethiopia, as well as in Angola, Zambia and northeastern South Africa, cases are projected to increase by about 5% on average compared with current levels. In some coastal areas of southern Africa, cases could rise by as much as 20% by 2100. The research found that the opposite trend is expected in some of the continent’s hottest regions. Parts of West and Central Africa, which currently bear the heaviest burden of the disease, could see transmission decline as temperatures rise above the optimal range for malaria transmission. By 2100, transmission is projected to fall by 4. 5% in countries such as Nigeria, Burkina Faso and Mali. In some parts of the Sahel, conditions could even become too hot for malaria-carrying mosquitoes to survive, potentially making sustained transmission impossible in some areas. The researchers stressed that the projected increase in malaria prevalence in parts of sub-Saharan Africa is not inevitable. Limiting global warming to two degrees Celsius could avert about five additional malaria cases per 1,000 children in southern Africa, with even greater benefits in high-altitude areas of East Africa, they conclude. Efforts to reduce greenhouse gas emissions must also be accompanied by stronger malaria surveillance and control measures, particularly in southern and eastern Africa, where malaria-control capacity is weaker, they write. Walid Kéfi