Modeling the impact of climate change on maize (Zea mays L.) production at the county scale in Kenya

Global climate change is projected to disproportionately impact cereal crop yields in developing regions, such as Kenya, due to increased vulnerability and limited adaptation capacity of the population. This study examines the current and projected influence of climate change on maize yields in two major maize-producing counties of Kenya. Utilizing the calibrated and evaluated DSSAT-CERES-Maize model (where DSSAT is Decision Support Systems for Agrotechnology Transfer and CERES stands for Crop and Environment REsource Synthesis) for the H614 maize cultivar, we investigated the projected impact of climate change on maize production with reference to a baseline period (1984–2013). Simulations were conducted for the mid-century period (2041–2070) and end-of-century period (2071–2100) using projected climate data from regional climate models (RCMs) under two Representative Concentration Pathways (RCPs; 4.5 and 8.5) scenarios. Our findings indicate a substantial decline in maize yields, ranging from 7 to 20% for the mid-century period and between 22 and 41% for the end-of-century period, with increased temperature during critical growth phases identified as the primary driver. Spatial clustering and hotspot analysis reveal differential climate impacts across the region. In the end-of-century period, both scenarios revealed that the counties will be marked by hotspots and adaptation spots, areas where climate change adaptation should be intensified. The study underscores the urgency for tailored, location-specific adaptation measures such as maize-legume intercropping, drought-resistant crops, soil water conservation and optimum sowing to mitigate future yield losses and adapt maize production to climate change.