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El Nino and Monsoon

GS Paper 1

 Syllabus: Important Geophysical Phenomena

 

Source: HT

 Context: According to the India Meteorological Department (IMD), there is nearly a 70% probability of an El Nino developing this monsoon.

el_nino

Understanding La Nina and El Nino:

Normal climatic conditionsWeather depends a lot on sea surface temperature (SST) → warm ocean → more clouds form → more rain falls

 

In the Pacific Ocean, near the equator → warm water on the surface → Normally, a low-pressure system forms in northern Australia and Indonesia and a high-pressure system develops off the Peru coast

 

Trade winds → blow strongly from east to west →  convective storms/thunderstorms over Indonesia and coastal Australia.

El Nino and La Nina are two opposing climate trends that deviate from the normal conditions
El NinoLa Nina
 

It is typically known as the warm phase of ENSO – a band of warmer water spreading from west to east in the equatorial Pacific Ocean → brings rainfall in the central and eastern Pacific, and droughts in Australia, and Asia. El Nino is more frequent than La Nina

 

 

La Nina is identified as the cold phase – a band of cooler water spreads east-west → effects on climate (opposite of El Nino)

 

These are together referred to as the El Nino-Southern Oscillation (ENSO) cycle. These events occur every 2-7 years on average & have global effects on weather, wildfires, ecosystems and economics

 

Summary of the 2023 Southwest Monsoon Season Rainfall:

  • According to the IMD, the country as a whole is likely to receive 96% of the southwest monsoon from June to September and farmers need not worry about deficient rainfall.
  • The monsoon is the lifeblood of the world’s fifth-largest economy.
  • Nearly half of the country’s net-sown area lacks irrigation access, making the rain-bearing system vital → replenishing natural reservoirs → feeding power generation, factories and drinking supply.

 

 

El Nino in India:

  • In 1997, India faced the strongest El Nino ever, but the monsoon was normal.
  • Between 2001 and 2020, India saw seven El Nino years → Of these, 4 resulted in droughts (2003, 2005, 2009-10, 2015-16).
  • These years also saw kharif or summer-sown farm output (accounting for nearly half of the country’s annual food supply) decline by 16%, 8%, 10% and 3%, leading to inflation.
  • The 2023 El Nino is expected to develop following a triple dip La Nina event (2020-22).

 

Threats posed by El Nino:

  • A slippage of one percentage point in monsoon rainfall will mean a below-normal monsoon.
  • Drought drives up inflation, erodes farm incomes, reduces spending on consumer goods and hurts the overall economy.

 

Good news for India:

  • A currently positive Indian Ocean Dipole (IOD) – temperature difference between two spots (western and eastern) in the Indian Ocean – boosts the rains and thwarts an El Nino. IOD is the.
  • Droughts are no longer the disaster they used to be, thanks to a significant leap in farm productivity.
    • The country’s food output has risen sharply from about 50 million tonnes in 1950-51 to 323.5 million tonnes during 2022-23.
  • This will help avoid a scary “Malthusian world” of food production not keeping pace with population growth.

 

Additional steps needed to protect farmers: Setting up a system for specific advisory services and forecasts for all the districts based on different rainfall scenarios.

 

Insta Links:

El Nino

 

Prelims Links: (UPSC 2017)

With reference to the ‘Indian Ocean Dipole (IOD)’ sometimes mentioned in the news while forecasting the Indian monsoon, which of the following statements is/are correct?

  1. The IOD phenomenon is characterised by a difference in sea surface temperature between the tropical Western Indian Ocean and the tropical Eastern Pacific Ocean.
  2. An IOD phenomenon can influence El Nino’s impact on the monsoon.

Select the correct answer using the code given below:

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

 

Ans: 2