New Delhi, March 17: A recent study reveals that monsoon rainfall in India was significantly higher nearly three million years ago compared to today. Conducted by the National Institute of Technology (NIT) Rourkela, this research indicates that future global warming will impact the Indian summer monsoon. It suggests an increase in rainfall due to a warmer climate, with August potentially becoming the month with the highest monsoon rainfall, replacing July.
The findings of this study were published in the prestigious International Journal of Climatology. The Indian summer monsoon accounts for about 80% of the country’s annual rainfall, serving as the backbone for millions of livelihoods, particularly for those dependent on agriculture. Regular monsoon rains are crucial not just for India but for food production, water resources, and economic stability across South Asia. As global temperatures rise due to climate change, various global studies present conflicting results.
Some studies suggest that increasing temperatures could reduce rainfall, while others indicate that monsoon rains may become stronger. Given the profound impact of the monsoon on human life, understanding how the Indian monsoon will respond in the future is essential. To bridge this knowledge gap, NIT Rourkela undertook a specialized study.
The study was led by Assistant Professor Dr. Nagaraju Chilukoti and research graduate Dr. Karishma Dahiya, in collaboration with Associate Professor Dr. Raju Attada from IISER Mohali. They analyzed the behavior of the monsoon during warmer periods in Earth’s past to gain insights into future trends. The research team compared two warm periods using climate models, one of which was the mid-Pliocene epoch, spanning approximately 3.3 to 3.0 million years ago.
Scientists often study this epoch to understand future climate change, as many aspects of the Earth’s climate system during that time resemble the projected future of current global warming. During the mid-Pliocene, global warming was about 4 degrees higher than pre-industrial levels. Current climate projections suggest that temperatures could reach similar levels by the end of this century.
Based on this, researchers examined how the Indian summer monsoon responds when the Earth is warmer. The study indicates that monsoon rainfall was higher during the mid-Pliocene, and a similar increase is expected in the future due to a warmer climate. However, the reasons for increased rainfall in both scenarios differ. During the mid-Pliocene, stronger winds and more active atmospheric circulation led to enhanced monsoon rainfall. In contrast, the future increase in rainfall will primarily result from a warmer atmosphere’s ability to hold more moisture.
Dr. Nagaraju Chilukoti stated, “The past holds the key to understanding the future. By studying the warm climate of the mid-Pliocene, we gain crucial insights into how global warming could affect the Indian summer monsoon. Our team found that a warmer climate may increase moisture in the atmosphere over the Indian Ocean and land, strengthening moisture flow towards India. We also discovered that the month with the highest rainfall may shift from July to August. These findings are vital for climate preparedness, agriculture, and water management in India and surrounding regions.”
According to the researchers, a better understanding of rainfall patterns can aid government officials and forecasting agencies in improving early warning systems for floods and droughts. Changes in the timing and intensity of rainfall could also help farmers plan their crop cycles and irrigation more effectively. Additionally, this study could assist policymakers in better managing water resources in major river systems like the Ganges and Brahmaputra, and strengthen disaster preparedness and urban planning in flood-prone areas.
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