Climate change is bad news for the planet, including the mosquitoes living in West Africa. Reduced rainfall will make it hard for mosquitoes to thrive and lead to lower rates of malaria in parts of the region, shows new research. It overturns earlier assumptions that malaria will get worse due to climate change.
By looking at rainfall data from 1970 to 2005, researchers Teresa K. Yamana, Arne Bomblies and Elfatih A. B. Eltahir, were able to make models for 2070 to 2100. Assuming that the world will not slow down the pace of global warming, the team determined which parts of west Africa would experience changes in rainfall. Countries to the east are expected to see declines, which will also help reduce the malaria burden. Countries in the central and western parts of the region would experience more rain, but the malaria burden would hold steady.
West Africa is home to some of the most malaria-endemic countries in the world. Nearly 400,000 people died from malaria across the continent in 2015. In Nigeria alone, 120,000 people died, and tens of thousands died in other countries in the region. By projecting the burden of the parasite, scientists hope to control its spread.
“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,” said Yamana, in a 2013 interview about the research. “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.”
Overall, research on the future burden of malaria is mixed. Another recent study that looked at the global burden estimated a net increase in malaria risk between 2050 and 2080. The authors admitted that choice in which malaria impact model to use had a significant impact on the projections. Their findings show that the regions at the greatest risk of an increased burden are the ones already saddled with high rates of malaria – highlands in Africa, parts of South America and southeastern Asia.
The new models based on West Africa represent a sort of step forward that the global study recognized was necessary. Looking at smaller regions requires better data that can yield improved predictions. More information about the spread of malaria and rainfall rates at the village and district levels would further improve the ability to know what changes are already taking place and may occur in the future.
And even if malaria is decreasing in some part of the world, it is not exactly great news. Lower rainfall makes for poor crop growth. Parts of Ghana, for example, are already adapting farming techniques and changing crop choices because of shorter rain seasons. Fewer mosquitoes to spread malaria is certainly a welcome development, but it may not end up making too much of a difference overall if the livelihoods of subsistence farmers are worse off.