Projected climate change impacts on Potato yield in East Africa

This study examines the impacts of climate change on potato production in East Africa. To assess these impacts, we utilised the WOFOST crop model to simulate both potential yield (Yp) and water-limited yield (Yw) for the present-day (1981–2010), near-future (2036–2065), and far-future (2066–2100) under two climate scenarios (SSP3.7 and SSP5–8.5), using a five-member General Circulation Model (GCM) ensemble from the ISIMIP project. The simulations consistently reveal a substantial decline in both Yp and Yw across all future periods. Specifically, without CO2 fertilisation, potential yields are projected to decrease by 37–71 %, and water-limited yields by 25–57 % during the Long Rain season (LRS), while during the Short Rain Season(SRS), these declines range from 39–75 % for potential yields and 32–60 % for water-limited yields, with variations depending on elevation and scenario. Even when accounting for elevated CO2 levels, Yp still decline by 23–57 %, and Yw by 20–49 % in LRS, and by 21–60 % and 20–48 % in SRS. Furthermore, the projected decline in land suitability for potato cultivation is stark, with 82 % of land becoming unsuitable by 2050 and 89 % by 2080, particularly during the LRS. Although elevated CO2 and slight increases in rainfall may provide some limited benefits, these are insufficient to counteract the detrimental effects of rising temperatures, which remain the primary constraint on potato productivity. Consequently, these findings suggest that conventional potato cultivation may become unsustainable by the end of the century due to climate change. The study underscores the pressing need for effective adaptation strategies, including the implementation of Climate Smart Agriculture (CSA) practices, to sustain potato production in the medium term. It further highlights the potential necessity of transitioning to alternative crops in regions that may become unsuitable for potatoes under future climate conditions. By offering region-specific insights based on relatively high-resolution CMIP6 data and the WOFOST crop model, this research provides actionable guidance for the development of adaptation strategies, reinforcing the importance of integrating climate change mitigation and adaptation into agricultural planning to ensure food security and protect rural livelihoods in East Africa.