Impacts of climate change on the South Asian monsoon: A comprehensive review of its variability and future projections

Abstract

The South Asian monsoon is a critical climatic phenomenon that sustains the livelihoods of nearly two billion people, who rely on its rainfall for agriculture, water resources, and economic stability. In this context, this paper reviews the impact of climate change on this crucial system, focusing on its dynamics, variability, and future projections. Based on past studies, this study examines observed changes in rainfall during the second half of the 20th century and compares these changes with model projections for the 21st century. The findings suggest that ocean-land temperature gradients, atmospheric circulation, and regional topography interact intricately to influence monsoon behavior. Rising global temperatures are expected to enhance total rainfall due to increased atmospheric moisture, but concerns remain about the potential weakening of monsoon circulation. This raises the critical question of how the projected increase in atmospheric moisture will impact overall rainfall patterns, including intensity, duration, and timing. Another key finding is the role of aerosols in monsoon variability, leading to the question of how aerosol emissions might influence the variability and dynamics of the South Asian monsoon and how these impacts compare to those of greenhouse gases. Given the current limitations in climate models, observational networks, and data analysis, substantial improvements are needed for more accurate future projections of monsoon variability, particularly in terms of monsoon circulation and extreme weather events. Addressing these challenges will be crucial for developing effective adaptation strategies to mitigate the impact of climate change on the South Asian monsoon and to ensure resilience and sustainability in agriculture, water resources, and the regional economy.