Shifting Climate Zones: Sahel might get 50 % more rain by 2040

09/22/2022 - Climate change could turn one of Africa's driest regions into a very wet one by boosting the Monsoon circulation. New computer simulations show a significant future increase in seasonal rainfall in the Sahel under the current trend of global warming. A major increase in average rainfall might kick-in by 2040 already, which means that it is inevitable regardless of how future greenhouse gas emissions develop. Although crossing this new tipping point is potentially beneficial, it comes with substantial unknowns. The change could in fact be so big, it would be a major adaptation challenge for an already troubled region.
Shifting Climate Zones: Sahel might get 50 % more rain by 2040
Burkina Faso, seen here, is one of the countries to receive more rain in the future (photo: Yoda Adaman/Unsplash)

“More rain in a dry region can be good news,” says lead-author Jacob Schewe from the Potsdam Institute for Climate Impact Research (PIK). “Climate change due to greenhouse gases from burning fossil fuels really has the power to shake things up. It is driving risks for crop yields in many regions and generally increases dangerous weather extremes around the globe, including drought risks. Now, for the dry Sahel, the most advanced climate simulations are predicting up to 50 per cent more rain. This would enhance water availability for farming and grazing. Being a researcher investigating mostly dire climate impacts, it’s great to at least once in a while be able to present a positive finding.”

Co-author Anders Levermann from PIK and Columbia University’s Lamont-Doherty Earth Observatory adds: “We don’t know what the impacts on the ground will be, this is beyond the scope of our study; but imagine the chance of a greening Sahel. Still, the sheer size of the possible change is mindboggling – this is one of the elements in the Earth system that we might witness tipping soon.”

“Yet a hopefully positive change in the Sahel unfortunately cannot outbalance negative change elsewhere in Africa and the world,” says Levermann.

Huge adaptation challenge for an already troubled region

Regions like the central parts of Mali, Niger, and Chad – which are practically part of the Sahara desert – could receive as much rainfall as is today registered in central Nigeria or northern Cameroon which boast a richly vegetated tropical climate, according to the study.

“The enormous change that we might see would clearly pose a huge adaptation challenge to the Sahel,” says Levermann. “From Mauritania and Mali in the West to Sudan and Eritrea in the East, more than 100 million people are potentially affected that already now are confronted with a manifold instabilities, including war. Particularly in the transition period between the dry climatic conditions of today and the conceivably much wetter conditions by the middle of this century, the Sahel might experience years of hard-to-handle variability between drought and flood. Obviously, agriculture and infrastructure will have to meet this challenge.”

“As great as it hopefully were for the dry Sahel to have so much more rain,” concludes Levermann, “the dimension of the change calls for urgent attention.”


Jacob Schewe, Anders Levermann (2022): Sahel rainfall projections constrained by past sensitivity to global warming. Geophysical Research Letters [DOI: 10.1029/2022GL098286]


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