El Nino is a weather phenomenon that describes the anomalous warming of surface waters in the eastern tropical Pacific Ocean. It happens more often than La Nina. Fishermen off the coast of Peru noted El Nio as the presence of unusually warm water. El Nino is not a regular cycle or predictable in the same way that ocean tides are. This article will explain to you the El-Nino which will be helpful in Geography preparation for the UPSC Civil service exam.

El-Nino Concept

• El Nino was first identified off the coast of Peru by Peruvian fishermen as the appearance of unusually warm water.
• The Spanish immigrants dubbed it El Nino, which translates as "the little boy" in Spanish.
• El Nino quickly evolved to be used to indicate erratic and extreme climatic changes rather than only the warming of coastal surface waters.
• El Nino events are not a regular cycle; they are unpredictable and occur at two- to seven-year intervals.
• Climate scientists discovered that El Nino occurs together with the Southern Oscillation.
• The Southern Oscillation is a shift in atmospheric pressure across the tropical Pacific Ocean.
• When the eastern tropical Pacific's coastal waters warm (El Nino), the air pressure over the ocean falls.
• Climatologists refer to these interconnected processes as the El Nino-Southern Oscillation (ENSO).

El-Niño - Formation

• During an El Nino year, air pressure falls across broad regions of the central Pacific and along the South American coast.
• In the western Pacific, a weak high replaces the regular low-pressure system.
• Weak Walker Cell trade winds are diminished as a result of this shift in pressure pattern. Walker Cell can even be reversed at times.
• This decrease permits the equatorial countercurrent (current through the doldrums) to amass warm ocean water along the Peruvian and Ecuadorian coasts.
• The concentration of warm water causes the thermocline in the eastern Pacific Ocean to descend, cutting off the upwelling of cold deep ocean water near Peru's coast.
• El Nino weather patterns bring dryness to the western Pacific, rain to South America's equatorial coast, and convective storms and hurricanes to the central Pacific.

El Nino - Impact

• El Nino also has an effect on ocean temperatures, the speed and strength of ocean currents, the health of coastal fisheries, and local weather patterns from Australia to South America and beyond.
• Increased precipitation is caused by convection above warmer surface waters.
• Rainfall in South America is increasing dramatically, contributing to coastal floods and erosion.
• Diseases thrive in areas that have been ravaged by natural disasters such as flooding or drought.
• In some regions of the world, El Nino-related flooding has been linked to a rise in cholera, dengue fever, and malaria, whilst dryness can cause wildfires that cause respiratory difficulties.
• El Nino, which gives rain to South America, also causes dryness in Indonesia and Australia.
• As reservoirs dry up and rivers transport less water, the region's water resources are jeopardized. Agriculture, which relies on water for irrigation, is also in jeopardy.
• Warm surface water is pushed westward by these winds, where it meets Asia and Australia.
• Due to the mild trade winds, the sea surface in Indonesia is typically 0.5 meters higher and 4-5° F warmer than in Ecuador.
• Warmer seas migrate westward, causing colder waters to rise to the surface off the shores of Ecuador, Peru, and Chile. This is referred to as upwelling.
• Upwelling transports cold, nutrient-rich water to the euphotic zone, the ocean's top layer.
• It can also have a beneficial effect; for example, El Nino lessens the frequency of hurricanes in the Atlantic.

El Nino - Impacts on India

• El Nino and the Indian monsoon have an inverse relationship.
• Since 1871, the most notable droughts in India — six of them – have been El Nino droughts, including the most recent ones in 2002 and 2009.
• However, not all El Nino's years in India resulted in a drought. For example, although 1997/98 was a significant El Nino year, there was no drought. It is due to the Indian Ocean Dipole.
• A mild El Nino in 2002, on the other hand, resulted in one of the worst droughts on record.
• El Nino has a direct influence on India's agricultural sector since it reduces the output of summer crops such as rice, sugarcane, cotton, and oilseeds.
• The ultimate impact is apparent in the form of high inflation and low GDP growth, as agriculture accounts for around 14% of the Indian economy.

El Nino-Southern Oscillation (ENSO)

• Normally, while the tropical south Pacific ocean gets high pressure, the tropical Indian ocean experiences low pressure.
• However, these pressure conditions can be reversed, resulting in low pressure in the Pacific and high pressure in the Indian Ocean.
• This is the Southern Oscillation, which is a periodic fluctuation in pressure conditions.
• These variations in pressure conditions developing in the Pacific and Indian seas are linked to the El Nino phenomenon.
• This linked phenomenon is known as the El Nino Southern Oscillations, or ENSO.

El Nino Modoki

• El Nino Modoki is a tropical Pacific ocean-atmosphere linked event.
• It differs from El Nino, another linked event in the tropical Pacific.
• Conventional El Nino is distinguished by significant anomalous warmth in the eastern equatorial Pacific.
• El Nino Modoki, on the other hand, is connected with significant anomalous warming in the central tropical Pacific and cooling in the eastern and western tropical Pacific.
• El Nino Modoki is defined by an anomalously warm central equatorial Pacific surrounded by anomalously chilly zones to the west and east.
• As a result of such zonal gradients, the tropical Pacific experiences an unusual two-cell Walker Circulation, with a wet zone in the central Pacific.

El Nino - Measuring Technique

• A buoy is a form of floating item that is used as a locator or warning point for ships in the middle of the oceans. They are usually brightly colored (fluorescent).
• Temperatures, currents, winds, and humidity are all measured by these buoys.
• The buoys provide data to academics and forecasters all across the world on a regular basis, allowing scientists to more correctly anticipate El Nino and visualize its evolution and influence around the planet.
• The Oceanic Nino Index (ONI) is a tool for calculating departures from normal sea surface temperatures.
• The Oceanic Nino Index, a measure of the deviation from normal sea surface temperature in the east-central Pacific Ocean, is the primary method for determining, gauging, and forecasting each El Nino episode.
• El Nino occurrences range in severity from mild temperature rises (about 4-5° F) with only minor local impacts on weather and climate to extremely severe increases (14-18° F) connected with global climatic shifts.

El Nino - Previous Events

• The El Nino occurrences of 1982-1983 and 1997-1998 were the most severe of the twentieth century.
• During the 1982-83 episode, sea surface temperatures in the eastern tropical Pacific ranged from 9 to 18 degrees Fahrenheit above normal.
• The 1997-98 El Nino event was the first to be systematically tracked from start to finish.
• Drought conditions prevailed in Indonesia, Malaysia, and the Philippines as a result of the 1997-98 event. Heavy rainfall and flooding were reported in Peru and California.
• During "the year without a winter," the Midwest saw record-breaking warm temperatures.

Conclusion

El Nino refers to the occurrence of warm ocean surface waters off the coasts of Ecuador and Peru. When this happens, the normal upwelling of cold, nutrient-rich deep ocean water is greatly decreased. El Nino generally happens around Christmas and lasts a few weeks to a few months. El Nino is not a regular cycle that can be predicted in the same way that ocean tides can.

FAQs

Q1: What is El Niño?

Q2: How does El Niño affect the Indian monsoon?

Q3: What is the difference between El Niño and La Niña?

Q4: How frequently does El Niño occur?

Q5: What are the global impacts of El Niño?

MCQs

1. What is a key characteristic of El Niño?

(a) Cooling of the Atlantic Ocean

(b) Warming of the Pacific Ocean

(c) Formation of cyclones

(d) Increase in snowfall over Europe

2. Which ocean region experiences temperature changes during El Niño?

(a) Indian Ocean

(b) Pacific Ocean

(c) Atlantic Ocean

(d) Arctic Ocean

3. How does El Niño influence the Indian monsoon?

(a) Enhances rainfall

(b) Reduces rainfall

(c) Has no impact

(d) Increases snowfall

4. What climatic pattern is opposite to El Niño?

(a) Cyclone

(b) La Niña

(c) Monsoon

(d) Heatwave

5. How does El Niño affect fisheries in South America?

(a) Increases fish population

(b) Reduces fish population

(c) Has no impact on fisheries

(d) Encourages migration of whales

GS Mains Questions and Model Answers

Q1: Examine the impact of El Niño on global climate patterns.

Answer: El Niño significantly impacts global climate patterns by altering the atmospheric circulation, leading to extreme weather events worldwide. In the tropical regions, it causes reduced rainfall and droughts, as seen in India and Australia. Conversely, it triggers heavy rainfall and floods in South America. El Niño events also disrupt ocean currents, affecting marine ecosystems and fisheries. For instance, the warming of Pacific waters reduces nutrient availability, impacting fisheries along the Peruvian coast. Additionally, El Niño influences global temperature trends, contributing to warmer-than-average years. Its widespread effects necessitate international cooperation for climate monitoring and disaster preparedness to mitigate the socioeconomic impact.

Q2: Analyze the impact of El Niño on agriculture in India.

Answer: El Niño adversely impacts Indian agriculture by weakening the monsoon rains, which are crucial for kharif crops like rice, pulses, and oilseeds. With delayed or deficient rainfall, crop yields decline, leading to lower agricultural output and food inflation. States highly dependent on rainfed agriculture, such as Maharashtra and Karnataka, are particularly vulnerable to El Niño-induced droughts. This can exacerbate the agrarian crisis, affecting rural incomes and increasing farmer distress. Moreover, water-intensive crops like sugarcane and cotton also suffer, further straining water resources. Thus, the agriculture sector needs robust contingency planning, including drought-resistant crops and irrigation support, to mitigate El Niño's impact.

Q3: Critically assess the measures taken by India to mitigate the impact of El Niño.

Answer: India has adopted several measures to mitigate the impact of El Niño on agriculture and water resources. Weather forecasting models, such as those developed by the Indian Meteorological Department (IMD), provide early warnings to farmers, enabling them to plan agricultural activities better. The government promotes crop insurance schemes like Pradhan Mantri Fasal Bima Yojana (PMFBY) to protect farmers from financial losses due to erratic weather. In addition, states have been encouraged to develop drought contingency plans and implement water conservation programs such as rainwater harvesting. Despite these efforts, challenges remain, particularly in reaching small and marginal farmers, making it essential to enhance awareness and promote sustainable agricultural practices.

Previous Year Questions on  El-Nino

1. UPSC CSE Prelims 2022

Question:  Which of the following statements is correct regarding El Niño?

a) It leads to excessive rainfall in India.

b) It strengthens the Indian monsoon.

c) It causes drought conditions in India.

d) It has no impact on the global climate.

Answer: c) It causes drought conditions in India.

Explanation: El Niño disrupts the monsoon winds, leading to reduced rainfall over India. This often results in drought conditions, particularly in areas reliant on monsoon rains for agriculture. El Niño's impact extends beyond India, affecting weather patterns globally.

2. UPSC CSE Mains 2020 

Question: Discuss the significance of forecasting El Niño events in managing agricultural production in India.

Answer: Forecasting El Niño events is crucial for managing agricultural production in India, where the monsoon plays a pivotal role in farming activities. Early predictions allow farmers to adjust cropping patterns, such as opting for drought-resistant varieties and modifying sowing schedules. Government agencies use forecasts to plan contingency measures like water resource management and distribution of drought relief. Weather-based crop insurance schemes also benefit from such forecasts, providing timely support to affected farmers. However, the effectiveness of these forecasts depends on their accuracy and the dissemination of information to farmers at the grassroots level. Strengthening weather forecasting systems and enhancing awareness among farmers is essential for mitigating the adverse impact of El Niño on agriculture.