Maize Yields Set to Drop 20% as Climate Worsens

Maize is the most widely harvested agricultural product in Africa and is grown by small farmers who rely heavily on rainwater rather than irrigation. The crop is therefore extremely sensitive to drought, and since 2015 its production has fallen dramatically as a result of record-setting drought conditions across southern and eastern Africa.

Now MIT scientists have found that climate change will likely further worsen drought conditions in parts of the continent, dramatically reshaping the production of maize throughout sub-Saharan Africa as global temperatures rise over the next century.

In a paper published online this week in the journal Earth's Future, the researchers report that, if the world's average temperatures rise by 4 degrees Celsius by the year 2100, much of southern Africa and the Sahel region just south of the Sahara desert—regions that contribute a significant portion of Africa's maize production—will experience increased aridity, which in turn is predicted to decrease maize crop yields in some nations by over 20 percent.

"[Maize] is a relatively drought-sensitive crop in a region where agricultural production is mostly rainfed," says lead author Amy Dale, a postdoc in MIT's Department of Earth, Atmospheric and Planetary Sciences (EAPS). "If under climate change we have changes in temperature and precipitation, this is arguably one of the worst areas of the world where we're going to see really negative impacts on crop production and malnourished populations."

Daniella Van Leggelo-Padilla / World Bank