Assessing the Impact of Monsoon Variability and Rising Temperature Extremes on Cropping Pattern Dynamics: A Geographical Perspective from South India

Abstract

South India's agrarian economy is deeply intertwined with the rhythms of the southwest monsoon and the thermal regimes that govern crop growth. Over recent decades, however, both these climatic systems have exhibited pronounced changes: monsoon onset dates have shifted by 3–8 days across peninsular India, inter-annual rainfall variability has intensified, and maximum temperatures have risen at rates of 0.15–0.22°C per decade across Tamil Nadu, Karnataka, Kerala, and Andhra Pradesh. These changes are progressively reshaping the region's cropping calendar, spatial distribution of cultivated crops, and the viability of traditional rainfed systems. This systematic review synthesizes peer-reviewed and authoritative evidence from 2017 to 2026, drawn from 143 studies selected from an initial pool of 2,134 records. The review addresses four central questions: (i) what are the documented temporal and spatial patterns of monsoon variability and temperature extremes in South India? (ii) How have cropping patterns shifted in response? (iii) What are the quantified impacts on agricultural productivity and food security? And (iv) how adequate are existing policy and adaptation frameworks in addressing these dynamics? Key findings include area contraction in traditional crops—paddy (−17 to −26% in Kerala and Tamil Nadu), sorghum (−42%), and groundnut (−29%)—alongside expansion of water-intensive cash crops and drought-tolerant species such as maize (+41%). Yield losses of 5–8% per degree Celsius of warming are documented for major cereals, compounded by drought-stress effects during critical growth stages. Research gaps are identified in integrated modelling, sub-regional vulnerability mapping, and socio-economic impact attribution, and recommendations for policy-relevant research and adaptive management are presented.