Potential impact of Stratospheric Aerosol Injection on horticultural crop suitability in Africa

Abstract

Global warming will be devastating for agriculture in Africa, impacting food security throughout the continent. Stratospheric Aerosol Injection (SAI), which involves the injection of sulphur into the stratosphere to reduce incoming solar radiation to Earth's surface, has been proposed as a strategy to reduce the global warming rate; however, there is a knowledge gap on how this may affect horticultural crops including mango, orange and tomato in Africa. Our study examines the effects of climate change due to Greenhouse Gases (GHG) and SAI on horticultural crop suitability in Africa using datasets from the Stratospheric Aerosol Geoengineering Large Ensembles (GLENS) project for the periods 2011–2030 and 2070–2089 as inputs into the Ecocrop model. Our findings show GHG may lead to an increase of 3–4°C in temperature and a 5–10 mm increase in total monthly rainfall in West, Central and East Africa, but a decrease (10 mm) in southern Africa. SAI intervention is projected to induce cooling of up to 3°C in both minimum and mean temperature and may also lead to a decrease of 10–20 mm in total monthly rainfall in Africa by the end of the century. The intervention may lead to an increase (~0.2) in the Suitability Index Value (SIV) of mango and tomato over West and Central Africa. However, a projected decrease (~0.3) in SIV is projected for mango and orange from Angola extending to northern Mozambique in southern Africa. In addition, no change in SIV is projected for the three crops in North Africa. SAI intervention may lead to a 2% increase in highly suitable areas for tomato and about a 7% increase in unsuitable areas for the three crops. The results should be interpreted with caution as they are particular to this Solar Radiation Management approach and modelling experiments in the GLENS project.