Known as the “Roof of Africa”, the highlands of Ethiopia are a lofty oasis. Though situated near the equator, the region enjoys cool temperatures year-round thanks to its high elevation—about 1200 meters above sea level. But a changing climate could change that over the next century.
Researchers at MIT project that towards the end of the 21st century the Ethiopian highlands in East Africa will be at a significantly high risk for transmitting malaria, transforming this temperate haven into a breeding ground for disease.
The work follows up on the team’s previous research on West Africa. There, the researchers acknowledged, malaria currently poses a big threat. A combination of high rainfall and warm temperatures create the ideal conditions for mosquitos to breed and spread disease. But fast-forward several decades and some subregions of West Africa are projected to become less hospitable to the mosquito; with global warming nudging some of the region out of the optimal temperature zone for supporting the mosquito’s life cycle.
In East Africa, the team predicts the opposite will be true. Bands of warmer temperature will gradually creep up the highlands of Ethiopia to push it into the sweet spot for mosquito breeding.
The researchers arrived at the conclusion using a pair of custom-made computer models. Guided by extensive field campaigns, those models helped them forecast the risk of malaria transmission in the Ethiopian highlands. One predicts future climate by taking recent surface temperature data gathered by satellites and projecting it forward in time, based on the current pace of greenhouse gas emissions. The other combines such climate data with other environmental parameters to project the future success of mosquito breeding.
Results showed that if the current rate of greenhouse gas emissions is left unchecked, the Ethiopian highlands can expect a 4-degree bump in temperature over the next several decades. And that could be enough to turn the region into a place where mosquitos can thrive and spread disease.
That the highlands have, to date, remained relatively malaria-free will only make things worse. The low incidence of malaria in the region means that the more than 30 million people who live in vulnerable subregions of the highlands will likely have little or no immunity to protect them.
This study proposes a framework that reconciles seemingly contradictory conclusions about climate change and disease risk. It also informs strategies for climate change adaptation not only over the Ethiopian Highlands but broadly over Africa. The maps of high-risk areas identified in this study could help guide the implementation of efficient measures to prevent malaria from becoming endemic to this region.