The role of climate adaptation bundles in enhancing sustainable food security and resilience in Ethiopia

Climate change poses a major threat to food security in Ethiopia, where smallholder agriculture remains highly dependent on rainfall. Although farmers often adopt multiple adaptation practices, evidence on whether joint adoption generates additive, complementary, or sub-additive food-security effects remains limited. This study examines the treatment effects of adaptation combinations among 500 mixed crop-livestock households in Jimma and East Shewa Zones of Ethiopia. Focusing on improved seeds (IV), small-scale irrigation (IR), and crop diversification (CD), a Multinomial Endogenous Switching Regression (MESR) model was employed to estimate the effects of eight adaptation regimes on per capita daily caloric intake while controlling for selection bias. Results from the adoption model show that credit access, extension services, climate information, landholding size, and market access significantly influence adaptation choices. The outcome analysis indicates that adoption of the full three-practice package increases food security by 1170.08 kcal/AE/day relative to non-adoption. However, this effect is significantly lower than the additive benchmark of 1863.41 kcal/AE/day, demonstrating sub-additivity in the complete adaptation bundle. In contrast, the irrigation–crop diversification combination shows positive complementarity, indicating that food-security outcomes depend on the specific composition of adaptation portfolios rather than the number of practices adopted. Qualitative evidence further suggests that farmers perceive adaptation combinations primarily as risk-management strategies under production uncertainty. Overall, the findings highlight the heterogeneous effects of adaptation packages and the importance of understanding interactions among climate adaptation practices.