What is the difference between El Niño and La Niña?

The term "El Nino" describes the irregularly occurring, above-average sea surface temperatures in the eastern and central equatorial Pacific. The ENSO cycle's warm phase is represented by it. In the eastern and central equatorial Pacific, there is a periodic decrease of sea surface temperatures known as La Nina.

What is the El Nino and La Nina effect?

El Nino impacts weather systems around the globe, triggering predictable disruptions in temperature, rainfall and winds. La Nina is the opposite – a cooling phase of ENSO that tends to have global climate impacts opposite to those of El Nino.

What are El Nino and La Nina years?

El Nino and La Nina can both have global impacts on weather, wildfires, ecosystems, and economies. Episodes of El Nino and La Nina typically last nine to 12 months, but can sometimes last for years. El Nino and La Nina events occur every two to seven years, on average, but they don't occur on a regular schedule

Is El Niño wet or dry?

• Reduced rainfall. • Warmer temperatures. • Shift in temperature extremes.

Is La Niña warm or cold?

La Nina refers to the periodic cooling of ocean surface temperatures in the central and east-central equatorial Pacific. Typically, La Nina events occur every 3 to 5 years or so, but on occasion can occur over successive years. La Nina represents the cool phase of the El Nino/Southern Oscillation (ENSO) cycle.

How does El Nino affect monsoons?

El Nino disrupts normal ocean temperatures in the Pacific Ocean, which in turn affects global weather patterns, including monsoons in India.

El Nino and La Nina and its Impact on Indian Monsoon in 2023-24

Table of Contents

Context

El Niño is weakening but will continue to influence global climate for months.
The IMD predicts above-normal temperatures across India for March-May 2024.
Potential for normal monsoon rainfall in 2024 if ENSO neutral conditions develop.

El-Nino and Its Impact on India in 2023-2024

El Nino and La Nina are phases of changing sea-surface temperatures in the eastern Pacific Ocean that influence global weather. The current El Nino, ongoing since 2023, is expected to weaken and shift to neutral conditions by April-June 2024, according to NOAA’s Climate Prediction Centre. This change reduces the chances of major effects on the early Indian monsoon season.

Above-Normal Temperatures Forecast:
- India Meteorological Department (IMD) predicts above-normal temperatures until May.
- Both maximum and minimum temperatures expected to be higher than usual across most regions.
Impact on Health and Well-being:
- Heightened risk of heat-related illnesses, especially among vulnerable populations.
- Urgent need for heat preparedness plans to mitigate health risks.
Agricultural Implications:
- Heat stress poses challenges for crop yields, livestock health, and water availability.
- Adaptive strategies like crop diversification and irrigation optimization are crucial for agricultural resilience.
Infrastructure Resilience and Adaptation:
- Infrastructure systems vulnerable to extreme heat events, leading to disruptions in services.
- Investment in climate-resilient infrastructure and heat mitigation strategies essential to enhance resilience.

Predicted Heat Conditions for India in 2024

Summer Heat Forecast: The IMD predicts above-normal temperatures across India for March-May 2024.

Regions Affected

Areas like Ladakh, Himachal Pradesh, Rajasthan, and several others will experience higher maximum temperatures.
Nights will be warmer across most of the country, except in some regions of Eastern India.

Heatwave Predictions:

Central and Northern Peninsular India may face longer and harsher heatwaves, possibly extending to 12-15 days in places like Maharashtra, Telangana, and North Karnataka.
States like Gujarat, Rajasthan, Madhya Pradesh, Uttar Pradesh, and several others are expected to experience heatwaves in the coming months.

El Nino’s Impact on Indian Monsoon

El Niño Phenomenon: El Nino, characterized by the warming of the equatorial Pacific, affects global weather patterns and can lead to temperature increases and droughts.
Influence on Southwest Monsoon: Although there’s no direct correlation, El Nino Phenomenon often coincides with weaker monsoons in India, leading to below-average rainfall.
Current Status of El Nino: The 2023-24 El Nino has peaked and is weakening, impacting global climate, with sea surface temperatures recently reaching 2°C above normal.
ENSO Neutral Conditions: Global climate models indicate a shift to ENSO neutral conditions by April-June, potentially aligning favourably with the onset of India’s southwest monsoon.

Southwest Monsoon Outlook for 2024

Monsoon’s Economic Importance: The southwest monsoon is vital for India, delivering 70% of annual rainfall and sustaining agriculture and water reservoirs.
Forecast Development: MMCFS model forecasts ENSO neutral conditions by May, which may favour the timely onset of the monsoon.
Monsoon Progression: Expected to reach the Andaman and Nicobar Islands by mid-May and mainland India around June 1, the monsoon covers the country by mid-July.
Upcoming Long Range Forecast: The LRF by the IMD, expected in mid-April, will provide more insights, and current predictions suggest the monsoon may not be heavily impacted by El Niño.
Normal Rainfall Potential: If other climatic factors like wind patterns and low-pressure systems are favourable, India could see normal monsoon rainfall this year.

Super El Nino in 2024

The National Oceanic and Atmospheric Administration (NOAA) predicts a 75%-80% chance of a strong El Niño event in the Northern Hemisphere from March to May 2024, with a 1 in 3 chance of it being a “super El Niño.”

A super El Niño happens when sea surface temperatures in the central and eastern equatorial Pacific Ocean are at least 2.5 degrees Celsius above average. These events can significantly impact global weather patterns, including:

Warmer and drier conditions in the southwestern United States and southern California.
Increased rainfall and flooding in the western United States, Alaska, and Hawaii.
Drier conditions in Australia, Indonesia, and Southeast Asia.
Increased rainfall and flooding in South America.
Drier conditions in Africa and India.

Super El Nino Implications For Indian Monsoon

In India, a strong El Nino is associated with reduced rainfall during the monsoon season. This could lead to drought conditions in some parts of the country, and could also impact agricultural production. Here are some of the implications of a super El Nino in 2024 for the Indian monsoon:

Reduced rainfall: A super El Nino is typically associated with reduced rainfall during the monsoon season in India. This could lead to drought conditions in some parts of the country, particularly in the north and east.
Impact on agriculture: Reduced rainfall could have a significant impact on agricultural production, leading to higher food prices and food insecurity.
Water shortages: Reduced rainfall could also lead to water shortages, particularly in areas that rely on monsoon rains for irrigation.
Increased risk of heatwaves: Super El Niños can also lead to increased risk of heatwaves in India. Heatwaves can be dangerous for human health, and can also impact crop yields.
Impact on human health: Heatwaves and drought conditions can have a significant impact on human health, leading to increased cases of heat-related illnesses, malnutrition, and waterborne diseases.

You can check below the complete Phenomenon of El Nino and La Nina in detail.

El Nino and La Nina

El Nino and La Nina are two opposite climate events that affect the global economy, ecosystems, and weather. These events usually occur every two to seven years, though not consistently. El Nino happens more frequent than La Nina. Both are caused by changes in water temperature in the eastern central equatorial Pacific.

El Nino and La Nina Meaning

El Nino

El Nino refers to sporadic climate changes and the warming of ocean surface waters along the coasts of Peru and Ecuador, first noticed by South American fishermen in the 17th century.

During El Nino, the trade winds that usually blow from east to west along the Equator weaken. This causes high air pressure in the western Pacific and low air pressure in the eastern Pacific, pushing warm surface water towards the northern South American coast. This warming lasts about six months and reduces the usual upwelling of cold, nutrient-rich water in the central and eastern Pacific.

The East Pacific Ocean’s warmer waters cause the winds in some areas to change direction.

Usually lasting a few weeks to a few months, the El Nino impact happens around Christmas. Depending on how warm the water is at the moment, it could occasionally last for significantly longer lengths of time.
When a climate like this warms for seven to nine months, it is referred to as El Nino “conditions,” and when it lasts longer, it is referred to as an El Nino “episode.”
The El Nino effect typically happens more often than the La Nina effect. The relationship between the ocean-atmosphere climate interaction and the rise in sea surface temperature in the Central and East-Central Equatorial Pacific can be inferred from fluctuations in ocean temperature.
These complex meteorological conditions develop in the Equatorial Pacific Ocean. El Nino happens regularly, but the “cold phase” of ENSO is infrequent. The Indian monsoon has had a disastrous effect on the nation’s agricultural activity as a result of the El Nino influence.
The El Nino effect is unpredictable; it never follows a set rhythm. El Nino occurs erratically every 2–7 years as well. El Nino is sometimes thought of just a coastal surface water warning, but it is also known to cause significant climate change.

La Nina

La Nina, also known as El Viejo, Anti El Nino, or a “cold occurrence,” means “little girl” in Spanish. It is the opposite of El Nino. During La Nina, stronger trade winds push warmer water towards Asia. This causes cold, nutrient-rich water to rise off the west coast of the United States, leading to more marine life.

The cold Pacific waters push the jet stream north, causing droughts in the southern United States and heavy rain and flooding in the Pacific Northwest and Canada. The South experiences warmer winters, while the North gets colder ones. La Nina can also lead to more hurricanes. The colder waters support more marine life, attracting coldwater animals like squid and salmon to areas like the California coast.

El Nino and La Nina Effect

Since 1950, ten out of India’s thirteen droughts have happened during El Nino years, and one during a La Nina year. This is because El Nino usually brings less rain to India. Indian agriculture relies heavily on monsoon rains, so when there is less rain, crop production often falls below average.

Effect of El Nino

Warmer surface water increases the chance of rain.
In South America, more rainfall has led to erosion and coastal flooding.
Areas hit by natural disasters like floods and droughts are more prone to disease outbreaks.
Many regions believe El Nino flooding has increased the spread of diseases like cholera, dengue fever, and malaria, causing respiratory issues.
El Nino causes dryness in Australia and Indonesia, leading to water shortages as reservoirs dry up and rivers carry less water, threatening agriculture.
El Nino has reduced the number of hurricanes in the Atlantic.

Effect of La Nina

It causes heavy monsoons in Southeast Asia and India.
It creates drought-like conditions in Peru and Ecuador.
It brings cold, wet winters to Southeast Africa and rainy weather to Eastern Australia.
It causes dry winters in the Southern United States.
It makes winters in the northwest United States and western Canada very cold.
It leads to major flooding in Australia.
It raises temperatures in the Western Pacific, the Indian Ocean, and off the coast of Somalia.
It results in intense monsoon rains in India.

El Nino Vs La Nina

El Nino	La Nina
The trade winds, which blow from east to west, weaks during an el nino.	The trade winds that blow from east to west intensify during La Nina.
Warmer than normal sea surface temperatures	Cooler than normal sea surface temperatures
It occur every two to seven years	It occur every two to seven years
El Nino has low wind speeds.	The wind speed is particularly high during La Nina.
Coriolis force strength declines during El Nino.	During La Nina, the Coriolis force becomes stronger.
Reduces rainfall, causes draughts	Increases railfall and can cause flooding
Draughts in Asia and Africa, floods in America	Floods in Asia and Africa, droughts in south america

El Nino and La Nina Facts for UPSC

The trade winds that blow from east to west intensify during La Nina.
The 1997–98 El Nino was the first to be systematically tracked from beginning to end.
The 1997–1998 events had an impact on many areas; Peru and California had significant rain and flooding, whereas the Philippines, Malaysia, and Indonesia experienced drought conditions.
La Nina is primarily brought on by an increase in easterly trade winds.
The El Nino – Southern Oscillation (ENSO) cycle has two opposing phases, El Nino and La Nina.