Topper’s Copy

GS1

World Geography

15 marks

El Niño is a key driver of global climate variability. Explain the mechanism of El Niño formation and the indicators used to detect it. Analyse its likely global and Indian impacts in the context of early signals of its possible return.

Student’s Answer

Evaluation by SuperKalam

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Score:

9/15

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5
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15

Demand of the Question

  • Explain the mechanism of El Niño formation.
  • Explain the indicators used to detect El Niño.
  • Analyse its likely global and Indian impacts in the context of early signals of its possible return.

What you wrote:

El Nino is a recurring Ocean-atmosphere phenomenon in the equatorial Pacific that disrupts global climate systems, influencing rainfall, temperature and extreme weather events.

El Nino is a recurring Ocean-atmosphere phenomenon in the equatorial Pacific that disrupts global climate systems, influencing rainfall, temperature and extreme weather events.

Suggestions to improve:

  • Can reference recent developments to strengthen context (e.g., "WMO's alert in early 2023 regarding potential El Niño return after three years of La Niña conditions, increasing concerns about food security and climate extremes")

What you wrote:

Mechanisms of El Nino formation
[DRAWING: A diagram illustrating the El Nino phenomenon. On the left is a landmass labeled "America (Peru)" with an annotation "less upwelling". An arrow pointing right is labeled "Trade wind weaken". On the right is a landmass labeled "Asia (India)" with annotations "Drought" and "weak monsoon". The area between the landmasses represents the ocean and is labeled "El Nino". An arrow points east across the ocean labeled "warm water moves east". Below it, another arrow points east labeled "warm water". A text box at the bottom reads: "Warm trade winds shift warm water eastwards, causing rain in pacific and drought/weak monsoon in India."]
1. Weakening or reversal of easterly trade winds over equatorial pacific
2. Eastward movements of warm surface waters from western to central-eastern pacific
3. Suppression of coldwater upwelling off Peru-Ecuador coast
4. Weakening of walker circulation with Pressure reversal
5. Self reinforcing ocean-atmosphere feedback sustaining warming.

Mechanisms of El Nino formation
[DRAWING: A diagram illustrating the El Nino phenomenon. On the left is a landmass labeled "America (Peru)" with an annotation "less upwelling". An arrow pointing right is labeled "Trade wind weaken". On the right is a landmass labeled "Asia (India)" with annotations "Drought" and "weak monsoon". The area between the landmasses represents the ocean and is labeled "El Nino". An arrow points east across the ocean labeled "warm water moves east". Below it, another arrow points east labeled "warm water". A text box at the bottom reads: "Warm trade winds shift warm water eastwards, causing rain in pacific and drought/weak monsoon in India."]
1. Weakening or reversal of easterly trade winds over equatorial pacific
2. Eastward movements of warm surface waters from western to central-eastern pacific
3. Suppression of coldwater upwelling off Peru-Ecuador coast
4. Weakening of walker circulation with Pressure reversal
5. Self reinforcing ocean-atmosphere feedback sustaining warming.

Suggestions to improve:

  • Could add the temperature threshold detail in mechanism point 3 (e.g., "Suppression of cold upwelling—normally 8°C cooler water—leading to 2-3°C warming along Peruvian coast")
  • Can include the thermocline depth change aspect (e.g., "Deepening of thermocline in eastern Pacific by 50-100 meters, restricting nutrient-rich cold water access")

What you wrote:

Indicators used to detect El Nino
1. Sea surface Temperature anomalies (>+0.5°C) in Nino-3.4 region (5°N-5°S, 120°-170°W)
2. Negative Southern Oscillation Index (SOI) ⇒ Tahiti-Darwin pressure difference
3. Weak trade winds or westerly wind burst
4. Increased subsurface Ocean heat content on eastern pacific
5. Outgoing longwave radiation anomalies indicating shifted convection.

Indicators used to detect El Nino
1. Sea surface Temperature anomalies (>+0.5°C) in Nino-3.4 region (5°N-5°S, 120°-170°W)
2. Negative Southern Oscillation Index (SOI) ⇒ Tahiti-Darwin pressure difference
3. Weak trade winds or westerly wind burst
4. Increased subsurface Ocean heat content on eastern pacific
5. Outgoing longwave radiation anomalies indicating shifted convection.

Suggestions to improve:

  • Could add operational forecasting tools (e.g., "NOAA's Climate Prediction Center uses coupled ocean-atmosphere models like CFSv2 for 6-9 month advance warnings, enabling agricultural advisories")
  • Can mention recent monitoring improvements (e.g., "Enhanced Argo float network providing real-time subsurface temperature data up to 2000m depth across Pacific")

What you wrote:

Impacts

Global level
1. Droughts in Australia, South East Asia, Africa (eg Australian Bushfire 2019-2020)
2. Floods in South America & Southern USA
3. Reduced marine productivity and fisheries collapse
4. fewer Atlantic hurricanes, more Pacific cyclones
5. Rise in global mean temperature eg. 2016 warmest year

India
1. Below normal southwest monsoon rainfall (eg 23% in 2002)
2. Increased risk of drought and heatwaves
3. Decline in kharif crop production (eg affected rice, pulses)
4. Water stress, low reservoir levels
5. Food Price inflation & economic slowdown (eg Onion, cereal prices ↑)

Impacts

Global level
1. Droughts in Australia, South East Asia, Africa (eg Australian Bushfire 2019-2020)
2. Floods in South America & Southern USA
3. Reduced marine productivity and fisheries collapse
4. fewer Atlantic hurricanes, more Pacific cyclones
5. Rise in global mean temperature eg. 2016 warmest year

India
1. Below normal southwest monsoon rainfall (eg 23% in 2002)
2. Increased risk of drought and heatwaves
3. Decline in kharif crop production (eg affected rice, pulses)
4. Water stress, low reservoir levels
5. Food Price inflation & economic slowdown (eg Onion, cereal prices ↑)

Suggestions to improve:

  • Could strengthen the linkage to "early signals" as demanded (e.g., "Early detection in 2015 helped India activate contingency farming plans under NMSA, though 2015-16 still saw 12% rainfall deficit highlighting implementation gaps")
  • Can add dimension of cascading impacts (e.g., "Drought-induced rural distress triggering migration—2015-16 saw 8 million people migrate from Maharashtra's Marathwada region due to water scarcity")

What you wrote:

Early El Nino signals demand climate resilient agriculture, water governance and disaster preparedness to protect livelihoods and achieve SDG 13 and SDG 2.

Early El Nino signals demand climate resilient agriculture, water governance and disaster preparedness to protect livelihoods and achieve SDG 13 and SDG 2.

Suggestions to improve:

  • Could emphasize predictive capacity utilization (e.g., "Leveraging 6-month advance El Niño forecasts through IMD's Extended Range Predictions can enable proactive water budgeting, crop insurance activation, and reservoir management—transforming early warning into early action")
  • Can reference recent preparedness initiatives (e.g., "National Crisis Management Committee protocols activated during 2023 El Niño watch demonstrate institutional readiness, yet last-mile community preparedness remains critical")

The answer demonstrates strong conceptual clarity with excellent use of data, examples, and a helpful diagram. The mechanism and indicators are comprehensively covered. However, the analytical connection between "early signals" (as emphasized in the question) and preparedness/impact mitigation could be strengthened throughout, particularly in impacts and conclusion sections.

Demand of the Question

  • Explain the mechanism of El Niño formation.
  • Explain the indicators used to detect El Niño.
  • Analyse its likely global and Indian impacts in the context of early signals of its possible return.

What you wrote:

El Nino is a recurring Ocean-atmosphere phenomenon in the equatorial Pacific that disrupts global climate systems, influencing rainfall, temperature and extreme weather events.

El Nino is a recurring Ocean-atmosphere phenomenon in the equatorial Pacific that disrupts global climate systems, influencing rainfall, temperature and extreme weather events.

Suggestions to improve:

  • Can reference recent developments to strengthen context (e.g., "WMO's alert in early 2023 regarding potential El Niño return after three years of La Niña conditions, increasing concerns about food security and climate extremes")

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