In India, climate change has rapidly altered monsoon patterns. According to a study by the Council on Energy, Environment, and Water (CEEW), there has been a significant increase of over 10% in southwest monsoon rainfall in 55% of the country's districts over the last decade (2012-2022).
Released under the title 'Decoding India's Changing Monsoon Patterns', this study is the first granular-level analysis of rainfall across over 4500 districts of India spanning 40 years (1982-2022). The study highlights increased precipitation in traditionally dry areas like Rajasthan, Gujarat, central Maharashtra, and parts of Tamil Nadu.
Approximately one-quarter of these districts observed a sharp rise of over 30% in rainfall from June to September. This shift is linked to the fast pace of climate change, which is making the monsoons more erratic and intense.
Source: aajtak
Changes during the Southwest Monsoon (June-September)
Rainfall Increase and Decrease: Over the last decade, there was an increase of more than 10% in southwest monsoon rainfall in 55% of districts, particularly in the arid regions of Rajasthan, Gujarat, central Maharashtra, and Tamil Nadu. In contrast, a decline of over 10% was seen in 11% of districts, especially in the Ganges plains, northeastern India, and Himalayan regions.
Impact on Kharif Crops: Districts with reduced rainfall saw 68% having less rain from June to September, with 87% registering a decrease during June and July, critical months for sowing Kharif crops. Reduced rains could impact agricultural yield.
Increase in Heavy Rainfall: There was a rise in the number of heavy rainfall days in 64% of districts, notably in Maharashtra, Tamil Nadu, Gujarat, and Karnataka, states with significant GDP. These heavy rains, though brief, contribute significantly to the total monsoon rainfall, increasing the flood threat.
District Variability: In the last 40 years, 23% of districts, including New Delhi, Bengaluru, Nilgiri, Jaipur, Kutch, and Indore, experienced both dry and extremely wet years. Nationally, there were 29 normal, 8 above-average, and 3 below-average rainfall years recorded.
Changes during the Northeast Monsoon (October-December)
Increase in Peninsular India: In the last decade, northeast monsoon rainfall increased by over 10% in Tamil Nadu (80%), Telangana (44%), and Andhra Pradesh (39%). Rainfall also rose during this time in the districts of Maharashtra, Goa, Odisha, and West Bengal, which are typically dry.
October Rainfall: 48% of the districts recorded more than a 10% increase in rainfall in October, likely due to the delayed withdrawal of the southwest monsoon.
Impact of Cyclones: Cyclones in the Arabian Sea and Bay of Bengal have amplified northeast monsoon rains.
Source: aajtak
Rise in Monsoon Rainfall: Threat of Brief and Intense Showers
Most of the rainfall increase is manifesting as brief but intense rains, leading to flash floods in these districts. Over the last decade, 31% of districts experienced an increase of four or more heavy rain days during the southwest monsoon compared to the past 30 years.
Globally, 2023 has been declared the hottest year on record, exacerbating extreme weather events. For instance, Chandigarh received half its annual rainfall in just 50 hours, while Kerala recorded a 60% shortfall in June (IMD 2023).
Dr. Vishwas Chitale, Senior Programme Lead at CEEW, emphasized the need to future-proof the economy against increasingly irregular rainfall patterns. The monsoon affects what we eat and drink, marking its significance. Our study provides not only a map of southwest and northeast monsoon variability but also tehsil-level rainfall data aiding policymakers in assessing local risks, ultimately saving lives, livelihoods, and infrastructure.
Source: aajtak
Impact on Agriculture and Economy: Concern in 11% Districts
The monsoon is crucial for the Indian economy, serving as the backbone of the agricultural sector, which employs half of the country's workforce. Yet, the study discovered that rainfall decreased in only 11% of districts over the last decade, although these districts lie in the rain-dependent Ganges plains, northeastern India, and upper Himalayan regions. These areas are vital for India's agricultural output and have fragile ecosystems sensitive to extreme climate events.
Among those districts experiencing decreased southwest monsoon rainfall, 87% (situated in states like Bihar, Uttarakhand, Assam, and Meghalaya) saw less rain in June and July, critical months for the sowing of Kharif crops. Meanwhile, 48% of India's districts experienced more than a 10% increase in rainfall in October, possibly due to the delay in the withdrawal of the southwest monsoon, impacting Rabi crop sowing.
Northeast Monsoon Changes: Focus on Peninsular India
The study further highlights changes in the northeast monsoon (October to December), which are particularly important for peninsular India. Over the last decade, 80% of Tamil Nadu's districts, 44% of Telangana's, and 39% of Andhra Pradesh's districts saw over 10% increases in northeast monsoon rainfall. Similarly, rainfall increased along the eastern coast in Odisha and West Bengal and along the western coast in Maharashtra and Goa.
CEEW's Research Analyst Shravan Prabhu noted that extreme weather events like droughts and floods in India are associated with the Indian monsoon. Our research indicates that the Indian monsoon, inherently marked by high variability, showcased even fiercer changes over the past decade with swapping patterns. To tackle these emerging challenges, it is crucial to map the impact of monsoon variability on key sectors like agriculture, water, and energy, and embed these into climate action policies at every level—from state to district.
40 Years of Analysis: Questioning the Definition of a 'Normal' Monsoon
The study revealed that over the past 40 years, India experienced 29 'normal' southwest monsoons. However, district-level analysis indicates that about 30% of districts saw a high number of dry years, while 38% reported a high number of extremely wet years.
Among these, 23% of districts, such as New Delhi, Bengaluru, Nilgiri, Jaipur, Kutch, and Indore, faced both low and excessive rainfall periods. Therefore, developing district-level climate action plans, which include tehsil-level climate risk assessments, is crucial for implementing national adaptation strategies.
Source: aajtak
Need for Local Action
This CEEW study is a milestone in understanding India's changing monsoon dynamics. Climate change is making monsoons more erratic, affecting agriculture, water resources, and energy sectors. Experts suggest developing hyper-local climate risk assessments, early warning systems, and local action plans.
Using high-resolution data from the Ministry of Earth Sciences' National Monsoon Mission, this study offers open information for policymakers. India's economy and livelihoods must adapt to these changes to alleviate losses and enhance gains from the monsoon.
