Modeling the future of rainfed agriculture: Climate change and crop water security in Ethiopia

Study region Ethiopia’s economy and livelihoods rely heavily on rainfed agriculture, yet rapid population growth, shrinking landholdings, low productivity, and land degradation are driving persistent food insecurity and socioeconomic vulnerability. Climate change is expected to compound these challenges through rising temperatures and shifting rainfall patterns, increasing crop water demand and further straining already fragile smallholder farming systems. Study focus This study evaluates the impact of projected climate change on crop water security by assessing the crop water requirement (CWR) defined as the deficit between potential and actual crop transpiration. Using a HYDRUS-1D ensemble modeling framework, CWR was assessed for 36 crops aggregated into five categories: cereals, pulses, oil seeds, vegetables/fruits, and cash crops. A historical baseline (2006–2020) was compared against three climate projections (2021–2070) representing dry (5th percentile), median (50th percentile), and wet (95th percentile) climate scenarios. Cohen’s d metric was employed to distinguish the climate change signal from historical inter-annual variability. New hydrological insights for the region Results indicate a divergent future for Ethiopian agriculture. In the median climate scenario, cereals and pulses exhibit reduced drought stress, particularly in the central highlands, suggesting a potential wetting opportunity. Conversely, cash crops exhibit the highest baseline stress (historical mean CWR ∼585 mm) and highest sensitivity to aridity shifts. Cash crops face a small-to-medium agricultural stress dictated by the Cohen’s metric (d=0.169) under dry projections, even when traditional significance is masked by climatic noise. Spatial mapping identifies the southeastern and northern lowlands as persistent vulnerability hotspots. While staple food production may benefit from increased humidity, high-value perennial sectors require targeted adaptation, such as supplementary irrigation.