Dynamics of the Indian Monsoon System: A Physics-Based Assessment of Agricultural Economic Impact

The Indian Summer Monsoon (ISM) is a coupled atmosphere–ocean–land phenomenon that exerts dominant control over the hydrological cycle of South Asia and forms the backbone of India’s agricultural economy. Variations in monsoon onset, duration, spatial distribution, intra-seasonal oscillations, and extreme rainfall events strongly influence crop productivity, food security, rural livelihoods, and macroeconomic stability. Recent observational and modeling studies reveal a changing monsoon regime marked by increased rainfall variability, weakening large-scale circulation, enhanced moisture availability, and a rise in short-duration extreme precipitation events under anthropogenic warming. This review synthesizes advances in the physical understanding of the Indian monsoon system and critically examines how these physical processes translate into agricultural and economic impacts. Emphasis is placed on land–sea thermal contrast, large-scale circulation, intra-seasonal dynamics, ocean–atmosphere coupling, and monsoon extremes, alongside their implications for crop yields, irrigation demand, price volatility, and policy responses. By integrating atmospheric physics with agricultural economics, this review highlights emerging risks, uncertainties, and future research directions essential for climate-resilient agricultural planning in India.