Warming, erratic rainfall push disease into new regions, complicating control efforts
By Bunmi Yekini
Climate change is altering how, where and when malaria spreads across Africa, raising concerns for a continent that already carries the world’s heaviest burden of the disease, according to new research by Uzodinma Adirieje.
The study finds that rising temperatures, shifting rainfall patterns, and more frequent extreme weather events are changing the life cycle of malaria-carrying mosquitoes and the development of the parasite that causes the disease, leading to new transmission patterns across regions.
Africa accounts for the vast majority of global malaria cases, and the research shows that even small climate changes can significantly influence outbreaks. Temperature and rainfall, in particular, remain the strongest drivers of transmission across countries, including Nigeria, Ghana and Mozambique.
In Nigeria, which has the highest malaria burden globally, the disease closely follows seasonal weather patterns. Cases surge during the rainy season from June to October, when stagnant water provides ideal breeding grounds for mosquitoes.
In the country’s north and across the Sahel, cycles of drought followed by sudden heavy rains often leave behind pools of water that trigger outbreaks. Meanwhile, in coastal areas such as the Niger Delta, climate-change-linked flooding is extending the duration of malaria transmission.
Across West Africa, the research highlights a delicate balance: malaria transmission increases when temperatures remain within a favourable range, roughly 15°C to 40°C, and when rainfall is moderate. While extreme heat in the Sahel can limit mosquito survival, irregular rains can still spark epidemics. In contrast, humid coastal countries tend to experience more stable, year-round transmission.
East Africa is emerging as a clear example of climate-driven change. Warmer temperatures are allowing mosquitoes to survive in highland areas that were once too cool for malaria. Countries such as Kenya, Ethiopia, and Uganda are already experiencing increased risks in these areas, where populations often have lower immunity, thereby making outbreaks more severe.
In Central Africa, including Cameroon and the Democratic Republic of Congo, heavy rainfall and flooding are creating more mosquito breeding habitats. In rainforest zones, where malaria persists year-round, unusually wet seasons could further intensify outbreaks.
Southern Africa presents a mixed picture. While extreme heat and drought may reduce mosquito survival in some areas, rising temperatures are making previously cooler regions more suitable for transmission. Countries such as Zambia and Zimbabwe have reported shifting seasonal patterns linked to rainfall variability and cyclones.
Overall, the research suggests that climate change is expanding the range of malaria, prolonging transmission seasons in tropical zones, and making outbreaks more unpredictable.
These changes, experts warn, could strain already stretched health systems unless countries invest in early warning systems, climate-based disease surveillance and stronger community health responses.