[Geography] El Nino, Its Impact on Indian monsoon, Indian Agriculture (+points from Economic survey)

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Mrunal's Economy Course
  1. Prologue
  2. What happens in a Normal Year?
  3. What happens in La Nina Year?
  4. What happens in an El Nino year?
  5. What is Southern Oscillation?
  6. How does El Nino affect Indian Monsoon?
  7. El Nino 2014 and India
  8. Will El Nino 2014 hurt Indian GDP?
  9. Do we really need to fear El Nino 2014?
    1. Arguments: why we don’t need to fear El Nino?
    2. Arguments: why we should worry about El Nino?
  10. Economic Survey Points on El-Nino


This is an old article from Current Affairs from April Week3 (16th to 22nd). I’ve updated it further with points from Economic Survey Ch.8 on agriculture to create a separate standalone article.

before reading further, practice following questions:
UPSC General Studies (Mains) – Answer following in 200 words each.

  1. (GS1) What is El Nino? How does it affect India and World?
  2. (GS1) Explain in brief, the impact of La Nina on Indian monsoon
  3. (GS3) Discuss the structure and functions of Biodiversity Management Committees under Biodiversity Act 2002? Evaluate their success in India.


  1. The fear about El Nino on Indian Economy is overhyped. Do you agree?

What happens in a Normal Year?

  • Peru Current = Humboldt Current = Cold Current.
  • During normal year two things are “STRONG”
    • Cold Peru Current
    • Trade Winds
  • As a result, cold water is dragged from Peru towards Australia. (observe following image)

El Nino Current during Normal Year

Result of this exchange?

  • In above image, the red (warm) water region around Australia is called Western Pacific Pool (WPP)
  • WPP = low pressure = warm air ascends = cloud formation = rain over North Australia
  • This air also joins walker cell and begins descending near Peru.
  • Descending air = anti-cyclonic condition = high pressure = stability = no cloud/rain = Drought in Atacama Desert.

So in a way two cycles are created

below the water Moving of water from Peru to Australia. @Peru cold water upwelling brings nutrient to surface= more lunch for Plankton= more fishes = good for Peru fishermen.
above water Moving of air from Australia towards Peru. Warm water + low atmospheric pressure = good rainfall over Australia & Indonesia.

Ok, we learned what happens in Normal year. Now let’s check

What happens in La Nina Year?

same things as in a “normal” year, but those two things become even “stronger”

  1. Cold Peru Current
  2. Trade Winds


  • Too many fishes @Peru coast, oversupply of fishes= prices become dirt cheap
  • Too much rain / flood over Australia and Indonesia.

Now coming to the main topic:

What happens in an El Nino year?

Observe following image:
Current during El Nino Year

  • two things become “WEAK”
    1. Cold Peru Current
    2. Trade Winds
  • As result, cold water is not dragged from Peru to Australia.
  • But reverse happens – warm water is dragged from Australia towards Peru.
  • Consequently, warm water + low pressure condition develops in the Eastern Pacific (Peru) and Cold condition + high pressure in Western Pacific (Australia).

Since Pressure is inversely related with amount of rainfall, the results are following

  1. Rain & Floods @Peru, Atkama and even Southern USA
  2. Drought @Northern Australia, Indonesia- even bushfires.
  3. Storms and Hurricanes in East Pacific.
  4. Coral bleaching (high temperature coral dies)
  5. (for MCQ) El Nino decreases earth’s rotation rate, decreases Coriolis force and increases length of day. (La Nina creates opposite). How? Because El Nino changes the wind pattern, hence Earth needs change speed to conserve its angular momentum of Earth-Atmospheric system.

What is El Nino?

  • Warming of Pacific Ocean
  • Near Western coast of Peru and Ecuador.
  • Occurs @every 3-4 years; [In theory, it should occur @every 12 years].
  • Its impact usually lasts for 9-12-18-24 months.
  • It weakens the trade winds and changes in Southern Oscillation, thereby affects the rainfall pattern across the world.

What is Southern Oscillation?

  • Alternating of (tropical) sea level pressure
  • Between the eastern and western hemispheres.

We measure Southern Oscillation by observing the pressure difference between

  1. Tahiti (French Polynesia) and
  2. Darwin (Australia).

Impact of Southern Oscillation (SO)?

Low Index High SO
  • Smaller pressure difference between (tropical) oceans
  • of Eastern vs. Western Hemisphere
Higher pressure difference
associated with El Nino hence the name ENSO = El Nino-Sothern Oscillation La Nina
Weak trade winds Strong trade winds
poor monsoon good monsoon

How does El Nino affect Indian Monsoon?

  • El Nino-Southern Oscillation (ENSO) water circulation happens between Australia and Peru
  • But the wind movement is part of larger atmospheric circulation hence affects the rainfaill over India. But how?

We learned that During normal year, the warm water moves towards Australia, this pool of warm water is called Western Pacific Pool (WPP). From WPP air rises above and moves towards two walker cells

  1. Towards Peru coast = this affects rainfall in South America.
  2. Towards Mascarene High Pressure zone near East Africa. = This affect Indian monsoon.

El Nino and Mascerene High

Mascarene High

  • strong WPP
  • strong trade winds
  • strong Mascarene High
  • Strong push for moisture laden winds towards India
  • good rain
  • weak WPP
  • weak trade winds
  • weakening of winds flowing towards Mascarene high
  • weak push to Monsoon winds towards India
  • Less rainfall / weak monsoon.
During La Nina years, this push is even stronger = heavy rain and floods.
  • El Nino caused severe drought in India (2009-10). Sugar price were highest in 30 year history.
El Nino= Little  boy in Spanish. Hence its opposite is called

  • La Nina (little girl)
  • El Vejo= old man, but La Nina more popular term nowadays.
  • Similar drought situation in Australia, Southeast Asia and Africa. (And floods in Brazil and USA Midwest.)
  • Such condition prevails for 9-24 months.

El Nino 2014 and India

  • India Meteorological Department (IMD) has predicted “below” normal monsoon for 2014.
  • RBI Governor Raghuram Rajan too has warned about the negative impact of El Nino (in his last monetary policy press conference.)
  • Poor monsoon / drought like condition = commodities prices will rise especially sugar, pulses and edible oil. Government needs to stock them up, put restriction on exports, before black marketers start hoarding.
  • Farmers need to device alternate farming strategy, change the seeds and irrigation strategy for the drought like situation.
  • Area without irrigation, and totally dependent on monsoon.
  • Western India region especially oilseeds, pulses and cotton=> high cost of raw material will have negative impact on their manufacturing sectors also.
  • Area depending on Ganga for irrigation. Because so far Ganga’s water is above its 10 year average.
  • Area with alternative irrigation solutions (bore well, watersheds, drip irrigation)
  • Oilseed and pulses- will have to import them.
  • wheat price, because FCI has more than sufficient stock

Will El Nino 2014 hurt Indian GDP?

Merrill Lynch predicated following:

2014 (without El Nino) 2014 with El Nino
good rainfall poor rainfaill / drought like condition
inflation declines to ~7% inflation raises to ~10%
if inflation declines=> RBI will reduce repo rate=>cheaper loans=>more business expansion =>more GDP. To combat inflation, RBI will further increase REPO rate (OR RBI will not decrease REPO Rate) => either way expensive loans => less business expansion => low GDP growth.
GDP growth rate will increase

  • 2013 = 4.7%
  • 2014 = 5.4%
low GDP growth rate

  • 2013 = 4.7%
  • 2014 = ~3.95%

Do we really need to fear El Nino 2014?

answer is both YES and NO.

Arguments: why we don’t need to fear El Nino:

  1. Only “Strong” El Nino affects India negatively. But this time WMO predicted “Weak” El Nino.
  2. Private Weather Agencies predict only 30% chance of El nino.
  3. Not Every El Nino year caused drought in India in the past.
  4. Under British Raj and even in 50s era, a drought under El Nino = Millions would die in starvation and suicide because of moneylenders.
  5. But that’s not the same India we live in today. ~40% of the farmlands are irrigated; FCI has large buffer stock of foodgrains; Government has sufficient money to announce financial packages to drought hit farmers; RBI has sufficient Forex reserve to finance any emergency food imports; we enjoy goodwill among all developed countries for even food-aid free of cost.
  6. Only IF terrorists blowup all FCI godowns, Black maketeers hoard every last gram of remaining onions and foodgrains, RBI’s forex reserve gets completely empty because of Fed Tapering…..THEN and only THEN El Nino can create havoc on India.
  7. El Nino Southern Oscillation = natural phenomenon for redistribution of excess heat. Humans cannot control or modify this cycle. In theory we can stop El Nino by dropping 10m thick iceberg size of a United States, into the Peru coast- but that’s impractical. So, Instead of fearing El Nino, we must learn to predict and adapt to its consequences.

Arguments: why we should worry about El Nino 2014

  • Even if El Nino doesn’t happen, the mere rumor of El Nino drives up the prices in commodity market because of the speculative investors. For example, global prices of Cocoa are high right now- not because of less production but because of El Nino speculation.
  • It is true we enjoy good will among developed countries for getting free food aid. But this time,
    • Australia- second largest export of wheat they’re already facing drought because of Pre-El Nino type condition.
    • US Midwest =called “Granary of the world” for wheat and corn. But they too face flood danger from El Nino.
  • India is second largest producer of sugar, rice and wheat in the world. 90% of Rice comes from Asia.

Combine all these isolated facts with IPCC’s latest report on climate change

Erratic Rainfall, melting of Himalayan glaciers, frequent flooding, draughts, storms and cyclones => Food insecurity for large population.

  • United Nations’ World Meteorological Organization predicted a “weak” El Nino by the middle of 2014.
  • It depends on when exactly during “mid” 2014 this happens because
IF El Nino happens by summer IF El Niño happens by fall season (August to October.)
Then India will be worst affected because of low monsoon during June- September. Then India will escape without injuries.

Economic Survey Points on El Nino

From Ch8. Agriculture

What is El-Nino?

  1. El Niño effect occurs when surface temperatures in the Pacific Ocean continuously rise above average for several months, which in turn adversely affects weather in many parts of the world.
  2. El Nino occurs every 3-5 years.
  3. South-west (SW) monsoon (from June to September) accounts for ~75% rainfall. Any shortage here.
  4. El Nino often begins to form during June-August, and typically lasts 9-12 months.

Where India should worry?

El Nino’s impact will be felt the most at…

  1. rainfed regions of central, south, and north-west India
  2. Maharashtra, Gujarat, Rajasthan, Karnataka, Jharkhand, and Bihar.
  3. rice, soybean, cotton, maize, jowar, groundnut, and sugarcane will be affected.
  4. kharif pulses and oilseed

Why India shouldn’t worry?

  1. While the majority of drought years in India coincide with the occurence of the El Niño, the reverse link is not that strong. (meaning, El nino doesn’t always lead to Drought)
  2. For example, in 1997, when the impact of El Niño was reported to be the worst, India had 2 per cent higher than normal rainfall
  3. In the past decade, the El Niño occurred in 2002, 2004, 2006, and 2009
  4. But 2002-03 was the only year that India showed negative agri sector growth with average rainfall dropping 20 per cent below normal.
  5. The last four occurrences of El Niño reveals that the impact was more in the kharif season.
  6. Government has placed contingency measures in about 500 districts.
  7. Central Water Commission (CWC) reflect a better status of water availability.

Mock question

Q1. What is El Nino? How does it affect India and World? (200 words)

El Nino Indian Monsoon handwritten diagram

  • El Nino is an Oceanic and Atmospheric phenomenon that leads to unusual warming of water in the Peru coast.
  • Consequently, warm water + low pressure condition develops in the Eastern Pacific (Peru) and Cold condition + high pressure in Western Pacific (Australia).
  • Since Pressure is inversely related with amount of rainfall, El Nino causes draught situation in Australia and South East Asia.
  • El Nino also leads to reversal of pressure difference between Indian and Pacific Ocean- known as Southern Oscillation.
  • El Nino Southern Oscillation (ENSO) weakens the Trade winds, consequently less push to the South Western Monsoon Winds from Mascarene High to India, and therefore poor monsoon.

To India

  • Drought condition decreases the agriculture output, leads to food inflation.
  • Declined supply of cotton, oilseeds and sugarcane negatively affects the textile, edible oil and food processing industries respectively.

To World

  • Drought situation over South East Asia and Australia hurts rice and wheat cultivation respectively.
  • Warm condition over Peru coast: unsuitable for Plankton population, thus bad for fishing industry. Birds migrate in search of fishes, thus less guano dropping for Fertilizer industry in Peru and Ecuador.
  • Flood situation in South America & US Midwest lead to decline in coffee-cocoa and corn-wheat production respectively.

~220 words
Q2. Explain in brief, the impact of La Nina on Indian monsoon (200 words)
That’s your homework.

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73 Comments on “[Geography] El Nino, Its Impact on Indian monsoon, Indian Agriculture (+points from Economic survey)”

  1. sir you are great helping candidate in such a manner

  2. great work…..

  3. Hi Mrunal,
    A little correction required in second para under the heading “How does El Nino affect Indian Monsoon?”
    In place of ElNino it should be Normal year or La Nina.
    Thanks for your precious endeavor. :)

    1. agree with you!!!!!@Mrunal ,Sir in that section you have mentioned ‘El Nino = warm water moves towards Australia’;it should be rather ‘warm water moves towards Peru’.Thank you.

  4. sir you are great helping candidate in such a manner
    I am following your blog religious ly

  5. i’m short of words to praise you….

  6. Hi Mrunal
    I think in “How does El Nino affect Indian Monsoon?” part, in third line it should be “towards Peru” in place of towards Australia.
    Thank You for the article.

  7. sir, i have a small question, that can this is economic survey are worth for prelims, or u are writing these for mains

  8. ****very brilliantly explained ..
    thanks sir.

  9. mazaa aa gaya bhaiya

  10. very nicely explained ..one of the best explanation ever seen….

  11. First time i used to express my sincere gratitude to you sir about the whole work u have done for civil service aspirants…I have a good collection of most of your notes. Wide coverage and explanations make this notes an ultimate part of my daily practices. Thanks a lot dear Mrunal Sir

  12. Sir, under your ‘How does El Nino affect Indian Monsoon’ this line “El Nino = warm water moves towards Australia” Is it correct?

  13. GR8888 work.thanks…..

  14. same question here mrunal do we have to call La Nina a normal year? or La Nina relates to very strong rain fall????
    little confused..

    1. La Nina is different from normal monsoon year. La Nina is a counter-El-Nino phenomenon. Means, its gives results opposite to El-Nino.

      La Nina:
      It is the counterpart of El Niño. Both (La-Nina and El-Nino) are part of the broader El Niño-Southern Oscillation climate pattern. El Niño/La Niña combination is also called – ENSO. It is a quasi-periodic climate pattern that occurs across the tropical Pacific Ocean with on average five year intervals.
      La Nina: During a period of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3–5 °C. It is called “anti-El Niño”, because it is the opposite of El Niño. Cold current.
      El Nino :In El Nino there is a higher sea surface temperature by a deviation of at least 0.5 °C, and its effects are often the reverse of those of La-Nina. Warm current.

      Effects of La Niña
      La Niña causes mostly the opposite effects of El Niño, for example, El Niño would cause a wet period in the Midwestern U.S., while La Niña would typically cause a dry period in this area. At the other side of the Pacific La Niña can cause heavy rains.
      For India, an El Niño is often a cause (not always) for concern because of its adverse impact on the south-west monsoon; this happened in 2009. A La Niña, on the other hand, is often beneficial for the monsoon, especially in the latter half.
      The La Niña that appeared in the Pacific in 2010 probably helped that year’s south-west monsoon end on the favourable note. But then, it also contributed to the deluge in Australia, which resulted in one of that country’s worst natural disasters with large parts of the north-east under water. It wreaked similar havoc in south-eastern Brazil and played a part in the heavy rains and consequent flooding that have affected Sri Lanka.

      But, even for El-Nino there are other factors involved too.. Like IOD, EQUINO ( Indian Ocean Dipole, Equatorial Indian Ocean Oscillation ) which leads to the intensity of low-monsoon or not.

  15. correction …El Niño episodes are associated with negative values of the SOI, meaning there is below normal pressure over Tahiti and above normal pressure of Darwin….(wiki)
    Sustained positive SOI values above about +8 indicate a La Niña event while sustained negative values below about –8 indicate an El Niño.

  16. Hi mrunal , there is slight confusion in your article regarding SOI values.
    Sustained negative values of the SOI below −8 often indicate El Niño episodes while Sustained positive values of the SOI above +8 are typical of a La Niña episode. SOI is calculated as T-D. please refer to article http://www.bom.gov.au/climate/glossary/soi.shtml

  17. is the english portion of csat done away with? do we still need to attempt it?

    1. no official notification by UPSC so far.

      1. No notification from UPSC means, its not taken off. Pattern would remain as it is.
        Govt had clearly said in the ambiguous statement that, “…it shouldn’t be counted…. , UPSC may… ” :)

        1. I feel UPSC may swap those question with some other questions for which they dont need to notify anything….in this way UPSC is taking care of both the things i.e. govt instruction and avoiding any litigation which can be cause due to last hour notification.. so better be prepared for surprise in CSAT-paper2…

  18. sir,very nice work….but i have a doubt….positive southern oscillation index is associated with good monsoon or bad monsoon in india??? i.e tahiti-darwin( pressure high in pacific and low in indian ocean)….

  19. I am quiet happy that atleast I have one place (Mrunal.org) where I can get concept building articles that too free of cost.
    From where I can get a soft copy of all your articles

    1. Download as pdf using google chrome…

  20. I rate this article as one of the best article among all that have provided by the organisation till now.

  21. Really indebted to you Sir..
    thank you for the article & concept you provide






    1. Option 3 seems wrong. MGNREGA guarantees minimum 100 days work not maximum 100 days.

    2. As per the question;
      Correct Option c – MNREGA guarantees min 100 days of work ( as in drought conditions in 2012 empowered Group of ministers increased it to 150 days in drought bearing states)

      P.S Option D – this scholarship program is for both SC and ST ; (just for ur info)

  23. option.b ( Vote on account is not passed through an appropriation bill. It is passed after the process of voting on general budget is complete)

    1. @sanat
      Mate any grant whether its an advance grant like “vote-on-account” or others such as “supplementary, additional, excess” are to be dealt in same manner as normal “Demand on grants”. This means that for every grant an appropriation bill is required; in “vote-on-account” case Appropriation (vote on account) bill is introduced in parliament after discussion on “vote-on-account” has taken place.

      here’s is the link
      link 1 – of economic survey (search vote on account in this page) you will know it is always thru appropriation bill. http://indiabudget.nic.in/ub2009-10/keybud/keybud2009.htm
      link 2 – rules of parliament , here also search ” vote on account” and you will get all your answers http://parliamentofindia.nic.in/ls/rules/rulep19.html

  24. i love u mrunal !

    1. Luv u sunny

  25. Super article. I can say with conviction that if this concept is to be taught at Harvard University, even they won`t have much easier and clearer explanation than this. Thanx Mrunal sir.


    1. @sakshi

      I think the answer would be (a. But the question is not much clear
      Last few years we have economic slowdown. Wedge between deposit and credit growth means there is a mismatch. Ideally deposits (savings) should match credit (investments) , whatever deficit being met by foreign investments.
      Last few years, there has been high fiscal deficit, meaning govt is borrowing more to finance its consumption. Hence domestic savings have been used to finance govt consumption leaving less for investments. Also high interest rates by rbi has contributed to liquidity crunch.
      Any case, the savings and investments both have fallen in recent years. Hence option b and c are ruled out. Also, high fiscal deficit means less growth momentum. Hence answer will be (a or this question is faulty.

      1. pls explain like mrunal

    2. Case 1:
      Inflation is high and other macro economic conditions are good.

      People’s expenditure increase—-> less savings——> less deposit in banks ( as bank interest rate is less than the inflation rate) —–> u invest more in some physical items like gold…land…etc( risk is high)——> banks have less money to give credit to companies—–> liquidity deficit.

      In this case deposit growth is less because of inflation and credit growth is more because of good macro economic conditions companies want more credit for expansion….so the gap between both widens….liquidity deficit…

      Case 2:

      Moderate inflation and other macro economic conditions are bad

      People’s expenditure decrease—-> more savings——> more deposits in banks ( as bank interest rate is more than the inflation rate and risk is less) —–> u invest less in some physical items like gold…land…etc(as risk is high)——> banks have more money to give credit to companies—–> liquidity surplus.

      In this case deposit growth increases because of less inflation and credit growth is decreases because of bad macro economic conditions….like economic slowdown….increase in NPA’s…banks are not willing to give credit to companies…so they will invest their surplus liquidity in govt securities as they are gilt edge securities….

      1. Thanks a lott, u explained it like mrunal.:-)

      2. superb explanation :-) spot on

  27. @ Mrunal, I think there should be a CORRECTION.

    Sir, I think high SO index means La Niña conditions and low SO index means El Niño
    High SO = difference between low pressure at WPP and high pressure at east pacific is high = La Niña
    Low SO = low pressure at WPP has moderated and high pressure at east pacific has also been moderated , hence this is El Niño

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