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EL NINO IMPACT ON MONSOON

1st September, 2023

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Context

India's monsoon weather patterns and their impact during the months of August and September.

Details

  • India experienced above-average rainfall in July despite the emergence of El Nino.
  • August, however, saw the adverse impacts of El Nino, making it the driest August in over a century.
  • The outlook for September is uncertain, with hopes of a revival in monsoon activity.

Driest August on Record

  • August is typically the second rainiest month in India, accounting for about 22% of the annual rainfall.
  • August 2023 is set to be the driest since 1901, with a deficit of about 33%.
  • States like Gujarat and Kerala had nearly 90% rainfall deficit, while others like Karnataka, Telangana, and Andhra Pradesh had over 50% deficiency.
  • Tamil Nadu, relying on winter rainfall, had a shortfall of 23%.

El Nino Impact

  • El Nino, the warming of the equatorial Pacific Ocean, suppresses monsoon rainfall in India.
  • The Indian Ocean Dipole (IOD) didn't compensate for El Nino's impact this year.
  • The relationship between IOD and the Indian monsoon remains uncertain.

Regional Variances

  • East and northeast India received good rainfall in August after deficits in June and July.
  • However, this rainfall couldn't fully offset the seasonal deficit.

Possible Monsoon Revival

  • Experts predict a potential monsoon revival in the first or second week of September.
  • It's uncertain how much rainfall this revival will bring, but El Nino's influence may still lead to a deficiency in September.

Reservoir Levels and Concerns

  • Monsoon provides 75% of India's annual rainfall, crucial for reservoirs.
  • As of last week, major reservoirs were at 94% of normal levels, but this may decline.
  • Some states already have critically low reservoir levels (e.g., Kerala, Tamil Nadu, Bihar).
  • A dry September could worsen the situation.

Impact on Crops

  • Winter crops and standing kharif crops are under stress due to inadequate rainfall.
  • Soybean, a relatively low water-intensive crop, requires immediate rain for sustainability.
  • The extent of yield loss will depend on the monsoon's behavior in the next 45 days.

About El Nino

  • El Nino, Spanish for "the boy child," is a climate phenomenon characterized by the abnormal warming of sea surface temperatures in the equatorial Pacific Ocean.
  • It is part of the broader El Nino-Southern Oscillation (ENSO) climate pattern, which also includes La Nina.

Causes of El Nino

  • El Nino occurs irregularly, typically every 2 to 7 years, and is driven by complex interactions between the ocean and the atmosphere.
  • It is triggered when the trade winds that usually blow from east to west weaken or reverse direction, allowing warm water to move eastward.

Key Characteristics of El Nino

  • Elevated Sea Surface Temperatures: The central and eastern Pacific Ocean experiences unusually warm sea surface temperatures during El Nino events.
  • Disruption of Normal Weather Patterns: El Nino disrupts typical climate patterns worldwide, affecting weather systems and precipitation.
  • Global Impact: The effects of El Nino are felt globally, influencing weather events, agriculture, ecosystems, and economies.

Impacts of El Nino

On Weather Patterns

  1. Reduced Rainfall: El Nino tends to suppress rainfall in regions that normally receive it, leading to droughts and water shortages.
  2. Increased Rainfall: Conversely, it can result in excessive rainfall and flooding in other areas.

On Agriculture and Food Security

  1. Crop Failures: Droughts or floods caused by El Nino can lead to crop failures, impacting food production.
  2. Food Price Volatility: Reduced agricultural output can cause food prices to rise, affecting food security.

On Ecosystems

  1. Marine Ecosystems: El Nino can disrupt marine ecosystems, leading to coral bleaching and changes in fish migration patterns.
  2. Terrestrial Ecosystems: Forest fires and altered vegetation patterns may occur due to changed precipitation patterns.

On Economics

  1. Economic Disruption: Industries such as agriculture, fisheries, and insurance can be negatively affected by El Nino-induced weather extremes.
  2. Costly Disasters: The economic costs of responding to El Nino-related disasters, such as floods and wildfires, can be substantial.

El Nino's Counterpart: La Nina

  • La Nina is the opposite phase of ENSO, characterized by cooler-than-average sea surface temperatures in the equatorial Pacific.
  • It often leads to contrasting weather patterns, such as increased rainfall in some regions and more active hurricane seasons.

Prediction and Monitoring

  • Scientists use various tools, including ocean buoys and climate models, to monitor and predict El Nino events.
  • Early detection and prediction are essential for preparedness and mitigation efforts.

PRACTICE QUESTION

Q) Discuss the causes, characteristics, and global impacts of El Nino, and elucidate the strategies that governments and organizations can adopt to mitigate its adverse effects. (150 words)

https://indianexpress.com/article/explained/explained-climate/staring-at-driest-ever-august-8915316/