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Changing Monsoon Patterns in India

Why in the news?

The Indian subcontinent, in the recent past, has witnessed erratic changes in monsoon patterns.

Brief

Once a year, from early June onwards, the water vapours collected from over the Indian Ocean arrive in India in the form of South West Monsoon Winds bearing rain clouds and replenishing the lands parched from the hot summer months. More than a billion people depend upon this precise timing of Monsoons based on vast global systems of winds. We have no control over it, but unfortunately, in recent times, human beings, by their folly, have managed to disturb the very system that made Monsoons predictable.

Importance of the Indian Monsoon

• The Monsoon is crucial for agriculture because about 60% of India's net arable land lacks irrigation.
• The Monsoon is responsible for over 70% of India's annual rainfall and influences the yield of a wide range of cereals and pulses, including rice, wheat, and sugarcane.
• Agriculture employs more than half of India's people, and monsoon rains directly impact their wages and well-being.
• Agriculture contributes to more than 15% of India's GDP. Hence, crop failure due to a lack of rain negatively impacts the Economy.
• Monsoonal rainfall helps with water storage for irrigation, electricity generation, and drinking.

Mechanism of Indian Monsoon

Modern theory: Air Mass Theory

According to this view, the Monsoon modifies the tropics' planetary winds. The notion is based on the seasonal migration of the ITCZ.

Role of ITCZ [Inter-Tropical Convergence Zone]

• Near the equator, the southeast trade winds of the southern hemisphere and the northeast trade winds of the northern hemisphere meet.
• The Inter-Tropical Convergence Zone is where these winds collide (ITCZ).
• This is the area of ascending air, the greatest clouds, and heavy rainfall.
• During the changing seasons, the ITCZ's location varies north and south of the equator.
• The sun shines vertically over the Tropic of Cancer during the summer, and the ITCZ shifts northward.
• Under the influence of the Coriolis force, the southern hemisphere's southeast trade winds cross the equator and begin blowing southwest to northeast.
• As these displaced trade winds blow over the Indian subcontinent, they are known as southwest monsoons.
• The Monsoon Front is the boundary between the southwest monsoons and the northeast trade winds (ITCZ). Along this front, rain falls.
• The ITCZ shifts to 20°- 25° N latitude in July, positioned in the Indo-Gangetic Plain, and the southwest monsoons blow from the Arabian Sea and the Bay of Bengal. The ITCZ is the Monsoon Trough [highest rainfall] in this position.
• Because of the seasonal change of the ITCZ, the notion of Northern Inter-Tropical Convergence Zone (NITCZ) in summer (July – rainy season) and Southern Inter-Tropical Convergence Zone (SITCZ) in winter has emerged (Jan – dry season).
• The NITCZ is the cloud and rainfall zone that affects India.
  
  
  

Changing patterns

• Erratic Monsoon: It is observed that there has been a shift in the recent period toward more frequent dry spells and more intense wet spells during the summer monsoon season.
• Delayed monsoon withdrawals:
• In recent years, monsoon withdrawal commencement has been delayed, mostly towards either the end of September or early October. The normal date for the commencement of the withdrawal is September 17.
• According to IMD records for 2012-2022, monsoon withdrawal from northwest India took place only for three years in the first half of September.
• If global warming continues unchecked, summer monsoon rainfall in India will become stronger and more erratic. This is the central finding of an analysis that compared more than 30 state-of-the-art climate models worldwide. 
• The study, published by Earth System Dynamics, predicts more extremely wet years in the future — with potentially grave consequences for the well-being, Economy, and food systems of more than a billion people.
• For every degree Celsius of warming, monsoon rainfalls will likely increase by about 5%," said lead author Anja Katzenberger from the Potsdam Institute for Climate Impact Research (PIK)

Factors Influencing Monsoon in India

• Changing climate: The entire northern hemisphere, including the oceans, has remained warm from January through October 2021, with the only exception of the Siberian High. This warming leads to the formation of local low-pressure systems, which are attributed to the delayed monsoon withdrawals.

• Madden-Julian Oscillation (MJO): La Niña conditions prevail over the equatorial Pacific Ocean, and neutral Indian Ocean Dipole (IOD) conditions over the Indian Ocean. During La Nina conditions, rainfall is normal or below normal during the northeast Monsoon in southern Peninsular India. Nevertheless, this time, rainfall is higher because of the favourable location of MJO.

• Arctic sea-ice loss: This year's Arctic sea-ice loss led to high sea-level pressure over western Europe and northeastern China, which steered planetary waves southeastward instead of their eastward trajectory. These
•  Waves, which produce circulation anomalies in the upper atmosphere, entered India late in the season and delayed the Monsoon.

• La-Niña: During which the sea surface temperatures over the eastern and central Pacific Ocean remain cooler than average, affects the trade winds which carry this weather disturbance across the world. In India, La-Niña generally triggers the formation of low-pressure areas, contributing to increased rainfall. Thus, a moisture-laden
•  The atmosphere combined with La Niña conditions will likely create conducive conditions for forming more low-pressure areas and rainfall events.

• Warming Arabian Sea: The other reason for the unusual rains is the warming up of the Arabian Sea over the past decade. This causes higher evaporation which increases the chances of forming a low-pressure area. On some occasions, the pairing of these low-pressure systems resulted in the formation of troughs (elongated regions carrying winds and rain) over the Indian landmass, and it resulted in widespread rainfall.

Cyclones 

Cyclones are rapid inward air circulation around a low-pressure area. The air circulates in an anticlockwise direction in the Northern hemisphere and clockwise in the Southern hemisphere.

How can cyclones impact the Monsoon?

• Enhancement of rainfall: Cyclones often form over the warm waters of the tropical oceans, such as the Bay of Bengal and the Arabian Sea, which also source moisture for the Monsoon.
• When a cyclone interacts with the monsoon winds, it can enhance the overall rainfall in the region.
• The strong winds associated with cyclones help pull in more moisture from the ocean, leading to increased rainfall during the monsoon season.
• Disruption of monsoon flow: Cyclones can disrupt the normal flow of the monsoon winds. As a cyclone develops, it generates circulation and draws in air from surrounding regions. This can divert the monsoon winds and affect their overall distribution and strength. Depending on the proximity of the cyclone to the region, it can cause variations in the onset, intensity, and duration of the monsoon rains.
• Break in the monsoon progression: The occurrence of a cyclone can lead to a temporary break in the progression of the Monsoon. A cyclone approaching the coastal areas brings heavy rainfall and strong winds. This can interrupt the monsoon rainfall for a few days or more, causing a temporary lull in the overall monsoon activity.
• Flooding and damage: Cyclones often accompany intense rainfall, flooding low-lying areas. The heavy downpour from cyclones can exacerbate flooding during the monsoon season.
• Additionally, strong winds associated with cyclones can cause damage to infrastructure, houses, and agricultural fields, affecting the overall socioeconomic conditions of the region.

Impact of Changing Monsoon

• Depletion of Water Table: In India, a little over 50% of India's net sown area is under rainfed farming, and a large part of the irrigated area depends on groundwater extraction through borewells, which needs to be recharged with the groundwater.
• These aquifers may need to be adequately recharged in a poor monsoon, leading to a water crisis.
• Further, according to a NITI Aayog's report, nearly 21 Indian cities — including New Delhi, Hyderabad and Chennai — could run out of groundwater by 2020.
• Fiscal Burden: Multiple crop failures may require the government to support farmers actively. It likely prompts the government to raise minimum support prices for the current season's crops to help support farmers' incomes.
• This will have a diminishing effect on investments into agricultural investments.
• Impacting Electricity Generation: Monsoon rains can be harnessed as hydro power, a valuable energy resource. Hydropower currently provides 25% of India's electricity.
• Reservoirs are filled during the southwest monsoon rains, and then the water is gradually released through dams, turning turbines to create electricity year-round.
• During years when there is little monsoon rainfall, the reservoirs are not replenished, limiting the amount of hydroelectric power produced during the year.
• Impacting Inflation: Normal monsoon rains keep a check on food inflation due to the availability of food products. However, in a situation of drought, prices soar significantly.
• Also, if poor monsoon results in less crop output, the country may need to import.
• It also impacts as many as a dozen sectors that depend on Monsoons directly or indirectly.

Way Forward

Since Monsoons play such a crucial role in the subcontinent impacting the Economy, geography and society.

Major steps need to be taken to foresee the changing trends in the pattern of the Indian Monsoon.

1. Mitigating Climate Change:

• Transition to renewable energy sources: Encourage using renewable energy like solar and wind power, reducing dependence on fossil fuels and lowering greenhouse gas emissions.
• Energy efficiency: Promote energy-efficient practices in industries, buildings, and transportation to reduce energy demand.
• Reforestation and afforestation: Support efforts to plant trees and restore forests, as they absorb carbon dioxide and help mitigate climate change.

     2. International Cooperation:

• Global climate agreements: Advocate for international cooperation and adherence to agreements like the Paris Agreement, which aims to limit global temperature rise.
• Emissions reduction targets: Encourage countries to set and achieve ambitious emissions reduction targets to mitigate climate change on a global scale

3. Other important areas

• Infrastructure development: Design infrastructure, such as flood control systems and drainage networks, to better withstand extreme weather events and minimize damage during monsoons.
• Agricultural adaptation: Promote climate-smart agricultural practices resilient to changing monsoon patterns, such as crop diversification, water-efficient irrigation methods, and improved soil management.
• Education and awareness: Raise awareness about climate change and its impact on monsoons through education campaigns, engaging communities, and empowering individuals to take sustainable actions.

Conclusion

It is important to note that controlling the impact of climate change on monsoons requires long-term, sustained efforts from governments, international organizations, communities, and individuals. Collaboration and collective action are key to achieving meaningful results in mitigating climate change and adapting to its consequences.