Impacts of Climate Change and Adaptation Strategies on Maize Yield in Kenya and Northwest China

Climate change poses growing risks to maize-based food systems, yet comparative evidence across climatically similar regions on different continents remains limited. This study compares climate change impacts and adaptation responses in rainfed maize systems in Nakuru County, Kenya, and Northwest China-two geographically distant but climatically similar regions. The CERES-Maize model (DSSAT v4.7), the latest version available when this study was conducted, was calibrated and validated using observed phenology and grain yield data (2005-2009) from Agricultural Meteorological Experimental Stations. Independent evaluation confirmed excellent model performance, with a normalized root mean square error (NRMSE) of less than 10%. The model was driven by bias-corrected climate projections under RCP4.5 and RCP8.5 for the 2030s (2021-2040) and 2050s (2041-2060), relative to the 1986-2005 baseline. Changes in climate, maize phenology, and yield were quantified, and adaptation strategies were evaluated against the baseline. Warming and increased precipitation accelerated maize development, causing yield declines of 3-27% in Nakuru County and 5-22% in Northwest China, with larger losses under RCP8.5. Adaptation measures-including planting-date adjustments, supplemental irrigation, and late-maturing cultivars-increased yields by up to 39% in Kenya and 29% in Northwest China, with combined strategies outperforming individual measures. Coordinated, multi-strategy adaptation can offset a large share of projected yield declines, offering practical pathways to sustain maize productivity under future climate change.