Previous methods have used rainfall totals to indicate the presence of surface water suitable for breeding mosquitoes, but the new research used several climatic and hydrological models to include real-world processes of evaporation, infiltration and flow through rivers. This groundbreaking approach has created a more in-depth picture of malaria-friendly conditions on the African continent.
It has also highlighted the role of waterways such as the Zambezi River in the spread of the disease with almost four times the population estimated to live in areas suitable for malaria for up to nine months of the year than was previously thought. Malaria is a climate-sensitive vector-borne disease that caused 608,000 deaths among 249 million cases in 2022.
The new hydrology-driven approach also shows that changes in malaria suitability are seen in different places and are more sensitive to future greenhouse gas emissions than previously thought. "What is surprising in the new modelling is the sensitivity of season length to climate change -- this can have dramatic effects on the amount of disease transmitted."
The researchers hope that further advances in their modelling will allow for even finer details of waterbody dynamics which could help to inform national malaria control strategies.