What is El Nino? Difference between El Nino and La Nina.

A “El Nino” refers to a specific climate pattern that occurs when the sea surface temperatures in the central-east equatorial Pacific Ocean reach at least 2°C or warmer. This warming leads to various weather patterns and impacts. For instance, classic El Nino events are known to produce stormy weather across the southern tier of the U.S., while the northern part of the country sees less rollercoaster-like conditions.

It’s important to know that Super El Nino's are considered to be rare, as the world has only recorded three of these events since the 1950s. Despite their common appearance, El Nino events are not similar, and the National Oceanic and Atmospheric Administration (NOAA) says the weather patterns can lead to varying impacts.

The El Nino oscillation cycle (ENSO) is divided into two: La Nina, when we experience extreme rainfall, and El Nino, when we experience extreme dry spells. The changes in temperature of the Pacific Ocean bring with it an immediate reaction. El Nino occurs every 2-7 years, usually after La Nina, and can last up to 8 months. As such, it affects agriculture and food security the most.

Difference between El Nino and La Nina

El Nino and La Nina are part of a natural climate phenomenon known as the El Niño Southern Oscillation (ENSO). They represent opposite states of this cycle and significantly alter global weather. 

Here are the key differences between them:

1. Temperature

El Nino is associated with warmer water in the Pacific Ocean along the equator, while La Nina is associated with cooler water.

2. Trade Winds

During an El Nino period, the trade winds that typically push the water towards Asia are weaker. So, the warm water flows back east, towards the west coast of North and South America. In La Nina periods, the normal east-to-west winds become stronger, pushing warmer waters further west.

3. Weather Patterns

El Nino and La Nina have different impacts on global weather patterns. For instance, El Nino often leads to warmer and wetter conditions, while La Nina can cause both warmer and cooler conditions at different points in the year.

4. Global Temperatures

Global temperatures typically increase during an El Nino episode, and fall during La Nina.

Remember, the specific impacts of each can vary widely depending on the event and the regions it affects.

Impacts of El Nino

El Nino can have a wide range of impacts globally

1. Ocean Temperatures and Currents

El Nino results in the rise of sea surface temperatures and weakens the trade winds of the affected region.

2. Weather Patterns

It can trigger extreme weather events globally, from fierce droughts, wildfires, and heatwaves to deadly flooding and tropical storms.

3. Agriculture

In countries like India and Australia, El Niño can bring about drought conditions, affecting crop productivity largely1. However, in some other countries, it may result in excessive rainfall.

4. Economic Impact

The global economic fallout of El Niño can be significant, with a recent study estimating costs as high as $3.4 trillion.

5. Human Health

Changes in weather patterns can also have impacts on human health, potentially influencing the spread of certain diseases.

The impacts of El Nino can vary widely depending on the specific characteristics of the event and the regions it affects.

Can we predict El Nino?

Yes, predicting El Nino events is possible and is a significant area of research due to the global impacts these events can have. Various methods are used for El Nino detection and prediction, including satellites, moored ATLAS and PROTEUS buoys, drifting buoys, sea level analysis, and XBT’s.

The International Research Institute for Climate and Society provides monthly summaries of the status of El Nino, La Nina, and the Southern Oscillation, or ENSO, based on the NINO3.4 index. Almost all the models in the IRI ENSO prediction plume forecast a continuation of the El Niño event during the boreal winter and early boreal spring of 2024, which rapidly weakens thereafter.

Moreover, research conducted at Korea’s Pohang University of Science and Technology suggests that changes in Atlantic Ocean sea surface temperatures can be used to predict extreme climatic variations known as El Nino and La Nina more than a year in advance.

However, it’s important to note that while we can predict the likelihood of an El Nino event, the specific timing and impacts can vary.