INTRODUCTION

• The monsoons are crucial for the Indian economy, serving as the backbone of the agricultural sector, which employs over half of India's population. They are also vital for managing water resources and generating hydro-based clean energy. However, the variability of Indian monsoons, with their wet and dry spells, directly affects the country's socio-economic aspects, including its GDP.

WHAT IS MONSOON ?

• The monsoon is a seasonal change in wind direction that brings heavy rainfall to India and other South Asian countries.

• The Indian summer monsoon typically lasts from June-September, with large areas of western and central India receiving more than 90% of their total annual precipitation during the period, and southern and northwestern India receiving 50%-75% of their total annual rainfall.

TYPE OF MONSOON IN INDIA

Southwest Monsoon:

1. Timing: Occurs from June to September.

2. Onset:

• Hits Kerala on the southwestern coast around June.

• Proceeds across the country.

3. Significance:

• Primary monsoon affecting India.

• Brings respite from the heat.

• Contributes significantly to the ecosystem and economy.

• Crucial for the growth of kharif crops.

Northeast Monsoon (Retreating Monsoon):

1. Timing: Occurs from October to December.

2. Region Affected: Primarily affects peninsular India.

3. Intensity: Not as intense as the southwest monsoon.

4. Significance:

• Important for the growth of rabi crops.

FACTORS AFFECTING INDIAN MONSOON

• Differential Heating of Land and Sea:

• During summer, the Indian subcontinent heats up significantly.

• This creates low-pressure areas over the land.

• Surrounding oceans maintain relatively lower temperatures, creating high-pressure zones.

• Pressure Gradient:

• The difference in pressure between the heated land and cooler oceans creates a pressure gradient.

• This gradient triggers the southwest monsoon, drawing moist air from the Indian Ocean.

• El Niño-Southern Oscillation (ENSO):

• El Niño: Leads to drier conditions in India.

• La Niña: Enhances the monsoon, bringing more rainfall.

• Indian Ocean Dipole (IOD):

• Positive IOD: Warmer sea surface temperatures in the western Indian Ocean lead to increased rainfall in India.

• Negative IOD: Cooler sea surface temperatures in the western Indian Ocean can result in reduced rainfall.

• Geographical Features:

• Tibetan Plateau: Acts as a heat source, influencing wind patterns.

• Western Ghats: Orographic effect causes heavy rainfall on the western side.

• Himalayan Mountains: Block cold winds from Central Asia, aiding the monsoon's progress.

CHANGING RAIN PATTERN OF INDIAN MONSOON

• A new study “Decoding India’s Changing Monsoon Patterns: A Tehsil-level Assessment” has found that monsoon patterns in India have been fast-shifting and erratic in the past decade. 

• Also the experts opined that the stalled southwest monsoon, which typically experiences break periods every season, is different this time because the monsoon trough has not even reached its normal position.

KEY FINDINGS OF THE REPORT 

• The researchers examined high-resolution meteorological data spanning four decades, from 1982 to 2022, which has been sourced from the Indian Monsoon Data Assimilation and Analysis project (IMDAA).

• The study also found that monsoon patterns in India have been fast-shifting and erratic in the past decade. This has been mainly driven by the accelerating rate of climate change. 

• The Findings:

• Rainfall increases in some of the traditionally drier regions and decreases in some of the high monsoon rainfall areas.

• In the past decade, traditionally drier areas such as Rajasthan, Gujarat, the Konkan region, central Maharashtra, and parts of Tamil Nadu have experienced a more than 30% increase in southwest monsoon rainfall compared to the baseline of 1981–2011.

• Meanwhile, traditionally high monsoon rainfall areas such as Assam and Meghalaya saw a reduction in rainfall, with the study indicating that tehsils in this area received 30% less rainfall compared to the Long Period Average (LPA).

• Regions with heightened rainfall experience more frequent heavy rainfall events:

• Southwest monsoon rainfall increased in 55% of India’s tehsils. The spike, however, has come from short-duration, heavy rainfall, which often results in flash floods, according to the study. 

• “This trend is of particular concern as it is related to the distribution of rainfall within a season and this could be one of the reasons behind the recent occurrences of flash floods, such as in Delhi, Uttarakhand, Himachal Pradesh (in 2023), and Bangalore (in 2022),” the study added.

• Changes in monsoon patterns can affect agriculture output and ecosystems:

• The analysis revealed that southwest monsoon rainfall has decreased in only 11% of tehsils over the past decade; however, a concerning aspect is that a significant number of these tehsils are located in the Indo-Gangetic plain, northeast India, and the upper Himalayan region, which are vital for India’s agricultural output.

• Additionally, these regions contain fragile ecosystems that are particularly vulnerable to extreme climate events such as floods and droughts.

• Rainfall is not distributed evenly throughout the seasons and months:

• Most of the tehsils experiencing decreased southwest monsoon rainfall saw a decline during the initial monsoon months of June and July, which are critical for sowing kharif crops.

• On the other hand, 48% of tehsils in India observed an increase in October rainfall by more than 10%, likely due to the delayed withdrawal of the southwest monsoon from the subcontinent, potentially affecting the sowing of rabi crops.

• Northeast monsoon rainfall also increased in some regions:

• In the past 10 years, the retreating monsoon rainfall spiked by more than 10% in approximately 80% of tehsils in Tamil Nadu, 44% in Telangana, and 39% in Andhra Pradesh. 

• Odisha, West Bengal, Maharashtra, and Goa are also seeing an increase in rainfall during this period.

• IMD OPINION ON STALLED MONSOON PERIOD:

• According to data from the India Meteorological Department (IMD), the Bay of Bengal branch of the southwest monsoon has been stalled since May 31, a day after the onset of the monsoon.

• That is a stalling period of 19 days as of June 19, one of the longest in recent time.

The Arabian Sea branch of the monsoon has been stalled since June 10, which is a stalling period of nine days.

• IMPACT:

• This Led to an all India deficit in monsoon rainfall of 20 per cent between June 1 and June 18, heralding a sluggish start to the season responsible for 70 per cent of the country’s total rainfall.

• It is also one of the reasons for the late heatwaves in most of north India and many parts of west, central and eastern India since the beginning of June. 

• In many places like Delhi, temperatures are also not reducing at night, leading to warm night conditions and no respite for people even at night.

• The east and Northeast India region has received 14.7 percent less rainfall than normal, despite the region suffering from floods since the beginning of the season.

• Southern India has been the only region with ample rainfall during the first three weeks of June. 

• It recorded an excess of 15.7 percent between June 1 and June 18.

BREAK IN MONSOON (GURU prasad Box)

• A "break" in the monsoon refers to a temporary cessation or reduction in rainfall activity during the monsoon season. 

• It is characterised by a period of several days to weeks when the monsoon rains significantly reduce or stop altogether over a particular region or even larger areas of the country. 

• ‘Break periods’ are a normal characteristic for the monsoon. But some of the recent breaks have been much longer than normal. 

• Cause behind break in monsoon:

• The season is usually said to be on a break when the monsoon trough moves towards the foothills of the Himalayas.

• During this period, it starts raining heavily in the Himalayan and the northeastern states while the rest of the country remains dry, especially what the IMD defines as the ‘core monsoon zone’. 

• The core monsoon zone stretches from Gujarat in the west to West Bengal and Odisha in the east.

• Presence of Weather Systems: The influence of weather systems such as cyclones, low-pressure areas, and atmospheric disturbances (western disturbances) can disrupt the monsoon circulation. 

• These systems may alter wind patterns, divert moisture flows, or suppress the development of rain-bearing clouds, contributing to a break in the monsoon.

• Oceanic Conditions: Anomalies in sea surface temperatures in the Indian Ocean and Pacific Ocean, such as El Niño or La Niña events, can influence monsoon dynamics. 

• Warmer sea surface temperatures (El Niño) can weaken the monsoon by reducing moisture availability, while cooler temperatures (La Niña) can enhance it.

• Intraseasonal Variability: The monsoon exhibits intraseasonal variability with active and break phases. These phases are influenced by internal atmospheric processes, interactions between different atmospheric layers, and feedback mechanisms within the monsoon system itself.

• Topographical Features: Geographic features like mountain ranges (e.g., the Western Ghats) and desert regions (e.g., Thar Desert) can influence monsoon circulation patterns. 

• They may act as barriers or triggers for weather systems, affecting the distribution and intensity of rainfall across different regions of India.

• Offshore Trough:It is typically found along the western side of India during the monsoon season.

• India's summer heat drives the formation of a low-pressure zone over land, attracting moisture-laden monsoon winds. 

• As these warm winds encounter the cooler Arabian Sea, they sink and deflect due to the Coriolis effect, creating an offshore trough – a dip in atmospheric pressure. 

• This trough acts like a magnet, drawing in winds and promoting their convergence, which fuels cloud formation and heavy rainfall along India's western coast during the monsoon season.

• If the offshore trough weakens or shifts away from the coast, it could reduce the convergence of moisture and contribute to a decrease in rainfall.

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REASON FOR CHANGING PATTERN (continuation of main topic)

• 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, affecting 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. 

• 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.

IMPACT OF CHANGING MONSOON PATTERN

• 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.

• Increase in natural disasters:

• Erratic Rainfall and Floods: 

• Example- 2018 Kerala floods

• Droughts and Water Scarcity: 

• Example - States like Maharashtra and Karnataka have faced severe drought conditions in recent years due to erratic monsoon patterns.

• Landslides and Soil Erosion:

• Example: Increases the risk of landslides in hilly and mountainous regions, such as in Himachal Pradesh, Uttarakhand, and parts of Northeast India.

 

 HOW CAN INDIA ADAPT TO CHANGE IN MONSOON PATTERN ?

1. Water Management and Conservation:

1. Rainwater Harvesting: Promote and incentivize rainwater harvesting at individual, community, and institutional levels to recharge groundwater and mitigate water scarcity during dry spells.

2. Efficient Irrigation Practices: Encourage the adoption of drip irrigation and other water-efficient technologies to optimise water use in agriculture, reducing dependency on monsoon rainfall.

2. Flood Management and Disaster Preparedness:

1. Early Warning Systems: Strengthen early warning systems for floods and cyclones to enable timely evacuation and minimise loss of lives and property.

2. Floodplain Regulation: Implement and enforce regulations on land use and construction in flood-prone areas to reduce vulnerability to floods and ensure sustainable urban planning.

3. Infrastructure Development:

1. Climate-Resilient Infrastructure: Invest in climate-resilient infrastructure, such as roads, bridges, and buildings, that can withstand extreme weather events associated with changing monsoon patterns.

2. Green Infrastructure: Develop green infrastructure projects like urban parks and green roofs that can absorb excess rainfall and mitigate urban heat island effects.

4. Agricultural Adaptation:

1. Crop Diversification: Promote crop diversification and the cultivation of drought-resistant varieties to enhance agricultural resilience against erratic monsoons.

2. Insurance Schemes: Expand crop insurance schemes to provide financial protection to farmers against crop losses due to monsoon variability.

5. Ecosystem Restoration and Conservation:

1. Watershed Management: Implement watershed management practices to conserve soil moisture, prevent erosion, and enhance natural water storage capacity.

2. Forest Conservation: Protect and restore forest ecosystems, which play a crucial role in regulating water cycles and mitigating the impacts of floods and droughts.

6. Community Engagement and Capacity Building:

1. Public Awareness: Increase awareness among communities about climate change impacts and adaptation measures through education and outreach programs.

2. Capacity Building: Provide training and technical support to local governments, NGOs, and communities to implement climate adaptation strategies effectively.

7. Policy and Governance:

1. Integrated Planning: Integrate climate adaptation considerations into national, state, and local development plans and policies, ensuring coherence and synergy across sectors.

2. Incentive Mechanisms: Establish incentives and subsidies for businesses and industries adopting climate-resilient practices and technologies.

8. Research and Innovation:

1. Climate Research: Support research and innovation in climate science, forecasting, and modelling to improve understanding of changing monsoon patterns and inform adaptive strategies.

2. Technology Transfer: Facilitate the transfer of climate adaptation technologies and knowledge from research institutions to end-users, including farmers and local communities.

HOW WILL INDIAN MONSOON CHANGE IN FUTURE ?

• Projections anticipate an increase in both southwest and northeast monsoon rainfall across India.

• This increase is expected to be accompanied by more frequent heavy rainfall days.

• Climate change projections suggest a substantial 10-14% rise in southwest monsoon rainfall in India by the end of the twenty-first century.

• Increased rainfall can impact various regions differently, potentially affecting agriculture, water resources, and infrastructure planning.

  
  

  SHORT TAKE

  • Intertropical Convergence Zone (ITCZ)

  • It is a low pressure region near the Earth's equator where the trade winds from the Northern and Southern Hemispheres converge. 

  • The ITCZ is typically found around the equator but can shift north or south depending on the season. 

  • Its position is influenced by the thermal equator, which is the latitude where the Earth's surface is the warmest.

  • It forms due to the convergence of the northeast trade winds from the Northern Hemisphere and the southeast trade winds from the Southern Hemisphere.

  • This convergence causes the air to rise, leading to the formation of clouds and precipitation.

  • It is characterised by heavy rainfall and thunderstorms, making it a crucial region for tropical precipitation.

CONCLUSION

The Indian monsoons, which inherently show high variability, are now seeing even more rapid changes across seasons and geographies due to climate change. This poses significant risks to critical sectors such as agriculture, water, and energy. To build res

Tags:
Geography

Keywords:
Monsoon Indian Monsoon Climate