Data-driven evaluation of constraints and adaptation priorities in Asian and African rice systems: outcomes from the PAiCE toolkit

Context Rice systems across Asia and Africa face persistent production constraints and rising climate-related stresses. Yet adaptation planning remains fragmented, with limited comparability across locations and insufficient integration of stakeholder perspectives. Decision makers increasingly need transparent, data-driven tools capable of identifying locally relevant but cross-comparable adaptation priorities. Objective This study systematically quantified major agronomic and climatic constraints in the Mekong Delta and West African Sahel rice systems and prioritised adaptation options using a structured, participatory, multi-criteria framework. Methods We applied the PAiCE (Prioritising Agronomy in Changing Environments) toolkit through 11 workshops in six countries, engaging 100 experts from 59 organisations. PAiCE integrates system characterisation, estimation of production and climate losses, adaptation longlisting and shortlisting, and multi-criteria evaluation of adoptability, implications, support requirements, economic performance, and uncertainty. In total, 99 adaptation options underwent full assessment across 5.6 million ha of rice production. Results and conclusions In the Mekong Delta, losses were driven by suboptimal planting practices, water deficits, and poor fertility and residue management. Mechanised direct seeding and in field Trichoderma straw management were consistently identified as high priority adaptations. In contrast, the West African Sahel showed highly heterogeneous constraints (e.g. temperature extremes, climate induced biotic stresses, and soil limitations) resulting in location specific adaptation priorities such as varietal change and SRI in Mali and Senegal, residue retention in Burkina Faso, and staggered planting in Nigeria. High ranking adaptations often exhibited trade offs between economic benefit and farmer adoptability or institutional support. Data certainty averaged 38%, underscoring evidence gaps, particularly for climate-related impacts. Significance As the first multi continent, comparable multi-criteria assessment of rice system challenges and adaptations, this work demonstrates the value of structured, participatory processes for identifying high impact, context sensitive adaptation pathways and supporting more effective climate resilient agricultural planning.