Climate Change Risk Meets Resource Inefficiency: A Multi-method Assessment of Thanjavur's Rice Economy

Abstract

Rice cultivation in Thanjavur district faces interacting climatic, water, labour, and production-efficiency constraints. This study assessed these dimensions through an integrated multi-method framework. Primary data were collected from 120 rice farmers between October 2025 and February 2026. Climatic vulnerability was evaluated using an exposure–sensitivity–adaptive capacity framework; crop water requirements and water footprints were estimated with CROPWAT 8.0; technical and resource-use efficiency were analysed with a Cobb–Douglas stochastic frontier production function; economic water-use efficiency was calculated from output value and irrigation use; and farmer-perceived constraints were prioritised using Garrett ranking. The normalised Climate Vulnerability Index was 0.359, indicating moderate vulnerability. Exposure (0.575) and sensitivity (0.690) were high, while adaptive capacity was moderate (0.442). The total water footprint of rice was 2,154 m³/tonne, of which blue water contributed 66.7%, green water 24.5%, and grey water 8.8%. The stochastic frontier model produced a gamma value of 0.8755, indicating that technical inefficiency accounted for most composite-error variation. Labour had the largest significant elasticity (β = 0.4500), while seed had a smaller significant positive effect (β = 0.0978). Economic water-use efficiency was ₹12.50/m³. Labour shortage ranked first among farmer-perceived constraints, followed by low product prices and delayed input availability. The findings indicate that interventions should jointly address management efficiency, labour scarcity, water use, market conditions, and climate adaptation.