Summary
African farming relies heavily on rain and is very vulnerable to climate change. This study shows that reflecting sunlight can lower temperatures but disrupts rainfall patterns across the continent. Specifically, injecting aerosols may help the Sahara but could reduce rainfall in Central Africa, risking food security. Many regions would face shorter growing seasons and less total annual rain. Ultimately, while these methods provide cooling, their complex agricultural side effects require careful consideration alongside cutting emissions.
Abstract
Africa’s agriculture, largely rain-dependent, is exceptionally vulnerable to the impacts of climate change, with projected shifts in temperature and precipitation patterns posing significant challenges for crop production, water availability, and food security. This study investigates the potential of two solar radiation modification (SRM) approaches, stratospheric aerosol injection (SAI) (Gsulfur) and solar dimming (Gsolar) in modifying precipitation dynamics and agro-climatic indices across the African continent under future climate scenarios.Utilizing datasets from the Coupled Model Intercomparison Project Phase 6 and Geoengineering Model Intercomparison Project, we analyze alterations in key agro-climatic indices under SSP2-4.5 and SSP5-8.5 scenarios.
The results showed that while both Gsolar and Gsulfur demonstrate the capacity to attenuate temperature increases associated with global warming, their influence on precipitation is heterogeneous, with significant potential for both beneficial and adverse impacts. SAI may enhance rainfall in Sahara (SAH) and North Africa while it reduces rainfall in the Central Africa (CAF) and Central East Africa (CEAF) region, thereby introducing potential risks for agricultural productivity and water availability. SAI and standard deviation contribute to the higher frequency of wet days under the two emission scenarios but are likely to reduce total annual rainfall and heavy rainfall which can complicate water resources.
This study further examines how growing season length (GSL) in Africa changes under SSP245 and SSP585 scenarios. The impact of G6sulfur (Gsolar) interventions relative to SSP2-4.5 may leads to a GSL decrease about 5–15 (1–16) days over the region while an increase of similar magnitude is expected over Madagascar, (MDG), CEAF. With higher emission, the impact of G6solar intervention relative to SSP5-8.5 may lead to an increase of about (5-15 days) over the region except but a decrease over MDG, Southeast Africa (SEAF) and CEAF. The projected trends in agroclimatic indices were found to be similar under greenhouse gas (GHG) and geoengineering at CAF, CEAF, and SWAF during growing season period. In these regions, CDD declined between 2070 and 2099 while consecutive wet day and PRCPTOT increased. This has implications for the economies based on agricultural production in Africa. Our study has helped improve our understanding of how global warming and SRM approaches can impact agricultural production in Africa and inform policymakers about the trade-offs between SAI and other GHG adaptation strategies.
