Climate stressor projections inform adaptation needs in South Asian oilseed systems.

Climate stressors impact major oilseed crop systems of groundnut, mustard, and soybean in South Asia. Our analysis shows that the intensity of all heat-related and water stresses is projected to rise by the 2050 s and 2080 s, while rainfall-related stressors show mixed and uncertain responses. We also find that heat stress effects during the full crop cycle and the reproductive phases are different in nature. Critical-phase heat stress is likely to increase mainly in frequency rather than intensity, whereas full-cycle heat stress is likely to intensify in the future. These shifts in climate stressors have direct implications for the suitability of adaptation interventions for oilseed systems. Genetic options, such as stress-tolerant varieties, and financial instruments, such as crop insurance, emerge as consistently robust across scenarios. In contrast, structural, nutrient, and irrigation-based interventions lose effectiveness as climate stressors exceed their adaptive limits. By mapping these future suitability transitions, this study provides a first-order basis for tailored adaptation planning and climate-smart oilseed systems in South Asia.