Climate Stresses and Adaptation Pathways under Changing Climate for South Asian Oilseed Systems

Climate stressors pose increasing risks to major oilseed cropping systems of groundnut, mustard, and soybean across South Asia, a region where these crops are critical for food security, livelihoods, and edible oil supply. Existing assessments often rely on aggregated climate indicators or generalized crop responses. This limits their usefulness for identifying suitable crop-specific adaptation options. This study advances current understanding of climate–oilseed interactions by adopting a physiology-based, adaptation-oriented framework that explicitly links biologically relevant climate stressors to the suitability of adaptation interventions under current and future climates.

We quantify multiple heat and rainfall-related stressors using crop-specific physiological thresholds and analyse their intensity and frequency under historical conditions and CMIP6-based future scenarios for the 2050s and 2080s. The analysis distinguishes between stress exposure over the full crop (cardinal) cycle and stress occurring during sensitive phenological windows, particularly the reproductive and pollination phases. Stressor projections are then linked to adaptation options using a logical, expert-reviewed heuristic framework that evaluates the feasibility and expected effectiveness of genetic, management, structural, irrigation, and financial interventions under increasing climate stress.

Our results show that the intensity of all heat-related stressors and the crop water deficit index is projected to increase substantially across oilseed-growing regions in South Asia. Rainfall-related stressors display mixed and spatially heterogeneous responses, reflecting uncertainty and regional differences in future precipitation patterns. Importantly, heat stress during the full crop cycle and during critical reproductive phases exhibits contrasting behaviour. Critical-phase heat stress is projected to increase mainly in frequency, implying more frequent exposure to damaging conditions during short, sensitive windows, whereas full-cycle heat stress is projected to majorly intensify in the future.

These changes have direct implications for adaptation planning. Genetic interventions and financial risk-transfer mechanisms emerge as the most consistently robust options across crops, regions, and emission pathways. In contrast, structural measures, nutrient management, and irrigation-based interventions progressively lose effectiveness as future heat and moisture stresses exceed the thresholds these measures can realistically buffer, with outcomes strongly dependent on emission trajectories.

By mapping transitions in stressor regimes and adaptation suitability, this study provides a first-order, spatially explicit basis for climate-smart adaptation planning in South Asian oilseed systems. The findings highlight the need for innovation focused on protecting critical phenological processes under future climate change.