Super El Nino, Causes, Development, Global Effects, Impact

Super El Nino is an informal term for an exceptionally strong El Nino event, characterised by unusually high sea-surface temperatures in the central and eastern equatorial Pacific Ocean. The impact of Super El Nino can extend far beyond the Pacific, influencing global temperatures, rainfall, agriculture, water security and extreme weather events.

Super El Nino Meaning 

Super El Nino is not an officially recognised scientific category with a universally accepted definition. It generally refers to an exceptionally strong El Nino, often associated with sea-surface temperature anomalies of around +2°C or more in the Nino 3.4 region, along with a strong atmospheric response.

• El Nino is the warm phase of the El Nino-Southern Oscillation (ENSO), which also includes La Nina and neutral conditions.
• “Godzilla El Nino” is an informal popular term used to describe an exceptionally powerful El Nino event.

Why Is Super El Nino Called “Godzilla El Nino”?

The term “Godzilla El Nino” is a popular nickname used to highlight the exceptional strength and widespread effects of a major El Nino event. 

• It became particularly popular during the 2015-16 El Nino, one of the strongest events recorded. 
• The name compares the enormous scale of the climate event with the fictional monster Godzilla.
• It is not an official scientific classification used by the World Meteorological Organization or meteorological agencies.

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How Does Super El Nino Develop?

Super El Nino develops when weakening Pacific trade winds allow warm surface water to move eastwards, triggering major changes in oceanic and atmospheric circulation.

• Normally, easterly trade winds push warm surface water towards Indonesia and Australia.
• Warm water accumulates in the western Pacific, while cold, nutrient-rich water rises near the eastern Pacific through upwelling.
• When trade winds weaken, warm water moves towards the central and eastern Pacific. This raises sea-surface temperatures in the Nino regions and weakens normal upwelling.
• The main zone of rising, moisture-laden air and rainfall shifts eastwards.
• When these oceanic and atmospheric changes become exceptionally strong, the event is informally described as a Super El Nino.

Role of the Walker Circulation: The Walker Circulation is a large-scale east-west circulation of air over the tropical Pacific.

• Under normal conditions, warm, moist air rises over the western Pacific and air sinks over the relatively cooler eastern Pacific.
• During El Nino, warming in the central and eastern Pacific shifts the main zone of rising air eastwards.
• This alters atmospheric pressure, winds and rainfall patterns across the tropics.

These changes can influence distant regions through teleconnections.

Super El Nino Historical Events

Only a few El Nino events have reached exceptionally strong levels in the modern instrumental record.

• 1982-83: One of the strongest El Nino events of the 20th century, associated with major disruptions in global rainfall and temperature patterns.
• 1997-98: A particularly powerful event associated with widespread floods, droughts, heatwaves and disruptions to agriculture and marine ecosystems.
• 2015-16: One of the strongest El Nino events on record, associated with severe drought conditions in several parts of Asia and exceptionally high global temperatures.

These events show that the impact of Super El Nino depends not only on its intensity but also on its interaction with other climate drivers and regional weather systems.

Super El Nino Impact on Global Climate

The impact of Super El Nino on global climate is significant because it disrupts normal atmospheric circulation and produces contrasting weather conditions across different regions.

• Extreme heat: It can add natural warming to the atmosphere and intensify heatwaves. The 2015-16 El Nino contributed to exceptionally high global temperatures.
• Drought: It can suppress rainfall in some regions, increasing the risk of water shortages and agricultural losses. Australia and parts of Southeast Asia, for instance, often face increased drought risk during El Nino events.
• Heavy rainfall and floods: Altered atmospheric circulation can produce excessive rainfall and flooding in other regions, including parts of South America.
• Agriculture and food security: Erratic rainfall and extreme temperatures can reduce crop yields and increase food-price pressures.
• Marine ecosystems: Reduced upwelling of nutrient-rich water near the coasts of Peru and Ecuador can affect fisheries.
• Coral bleaching: Warmer ocean temperatures can increase stress on coral ecosystems.
• Water security: Drought can reduce river flows, groundwater recharge and reservoir levels, while intense rainfall can damage infrastructure.

Thus, the same Super El Nino event can produce drought in one region and excessive rainfall in another

Super El Nino Impact on India

The primary impact of Super El Nino on India is an increased likelihood of a weaker and more uneven southwest monsoon. However, the actual outcome depends on the interaction between El Nino, the Indian Ocean Dipole and regional weather systems.

• El Nino weakens the large-scale atmospheric circulation that supports the Indian summer monsoon, reducing moisture transport towards the Indian subcontinent.
• Its influence is generally stronger during the latter half of the monsoon season, making July-September more vulnerable than the onset phase in June.
• The greatest concern is often not merely lower seasonal rainfall but its uneven spatial and temporal distribution, with prolonged dry spells proving more damaging than moderate rainfall deficits.
• Delayed rainfall and long breaks in the monsoon can adversely affect kharif sowing, crop growth and agricultural productivity, particularly in rain-fed regions.
• Reduced rainfall lowers reservoir storage, groundwater recharge and hydroelectric generation while increasing the risk of heatwaves and agricultural stress.
• Lower agricultural production may create supply shortages and contribute to food inflation.
• Since 1950, nearly three-fifths of El Nino years have experienced below-normal monsoon rainfall, and several major drought years including 1972, 1982, 2009 and 2015 coincided with El Nino events.
• Nevertheless, El Nino increases the probability of a weaker monsoon rather than guaranteeing drought across the entire country.

Why Doesn’t Every Super El Nino Cause Drought in India?

Although a Super El Nino increases the probability of a weaker southwest monsoon, it does not invariably lead to drought. The eventual monsoon outcome depends on the interaction between the Indian Ocean Dipole (IOD) and regional atmospheric systems.

• A positive IOD, characterised by warmer waters in the western Indian Ocean than in the eastern Indian Ocean, enhances moisture transport towards India and can partly or substantially offset El Nino-induced rainfall suppression.
• The 1997-98 Super El Nino is the best example, when a strongly positive IOD helped India receive about 2% above-normal monsoon rainfall despite one of the strongest El Nino events on record.
• Conversely, a weak or neutral IOD provides little support against El Nino-induced monsoon weakening, increasing the likelihood of below-normal seasonal rainfall.

Why Can India Experience Cloud Cover and Heavy Rainfall Despite Super El Nino? 

El Nino primarily influences the seasonal probability of rainfall, whereas day-to-day weather is governed by regional atmospheric systems.

• Low-pressure systems, upper-air cyclonic circulations and a favourable monsoon trough can transport abundant moisture from the Arabian Sea and the Bay of Bengal, leading to widespread cloud cover and rainfall.
• Heat-driven convection and the interaction between Western Disturbances and monsoon winds can further enhance rainfall, particularly over northern and central India.

Consequently, episodes of widespread rainfall can occur even during a Super El Nino without contradicting the broader seasonal outlook.

However, short periods of heavy rainfall do not necessarily indicate monsoon recovery, as the overall performance of the monsoon depends on the June-September seasonal rainfall and its spatial and temporal distribution.