Study finds climate change not likely to worsen malaria in West Africa

Overall infection rates of malaria are unlikely to increase in West Africa as a result of climate change, according to a study published on Monday in Environmental Health Perspectives.

MIT professor Elfatih Eltahir and graduate student Teresa Yamana combined a new model of malaria transmission with global forecasts for temperature and rainfall to improve predictions of how climate change will impact malaria. The researchers found that while the capacity for malaria transmission will change in some parts of West Africa, overall infection rates were not likely to increase.

"Malaria is one of the world's leading public-health problems, taking a toll not only in lives, but also in economic terms, especially in Africa," Eltahir said. "While other researchers are looking at the global impacts of climate change on broadly defined variables such as global temperature or global sea level, the biggest challenge faced by the global climate-change research community is how to come up with credible predictions for specific variables that are relevant to society, such as malaria incidence, defined at the appropriate regional and local scales."

Eltahir and Yamana found that hotter temperatures on the southern border of the Sahara will become too hot for the survival of some species of mosquitoes. On the other extreme, hotter temperatures in the southern zone close to the Guinean coast will improve environmental suitability for malaria. The opposing impacts of warming temperature and increasing rainfall are likely to cancel each other out along the transitional Sahel zone.

The researchers noted that the study does not take into account potential changes in healthcare, economics, migration, population and other socioeconomic factors.

"Many countries in this region are very underdeveloped and people are much more vulnerable to changes in the environment than people in more developed areas," Yamana said. "If these countries become fully developed and are no longer vulnerable to vector-borne diseases, or malaria is completely eradicated, that would be fantastic news. But I don't think we can count on either of these things happening in the near future."

Malaria infected an estimated 219 million people in 2010 and is the fifth leading cause of death worldwide among children under five years of age.