Climate change may alter where and when malaria transmission is possible, but the relationship is more complicated than a simple rule that warmer weather always means more malaria.
Malaria is caused by Plasmodium parasites transmitted through infected Anopheles mosquitoes. Temperature, rainfall and humidity can influence mosquito survival, parasite development and breeding conditions, so changing climate patterns can alter the geography and seasonality of transmission.
In some places, warming may make conditions more suitable for transmission; in others, very high temperatures or changing rainfall could reduce suitability. WHO notes that evidence on the direct long-term effect of climate change on malaria transmission remains mixed and that areas at the margins of transmission may become either more or less suitable.
Higher-altitude areas are one concern because warming can create conditions that allow transmission in places that were previously cooler. But climate is only one part of malaria risk. Housing, access to prevention and treatment, health-system capacity, mosquito control, drug and insecticide resistance, conflict and population movement also matter.
For public-health planning, the practical lesson is not that malaria will simply move north, uphill or away from the hottest regions. It is that surveillance and prevention need to adapt to changing local conditions and uncertainty.
For further context, see the World Health Organization’s discussion of climate and malaria.
