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What is El Nino?

Matt Brady
Matt Brady

El Niño is a weather phenomenon characterized by abnormally high surface temperatures in the tropical Pacific Ocean, and weaker trade winds, which have been known to cause a global ripple effect of turbulent and unusual weather. The effect is caused in large part by the weakening of trade winds, which normally push the warmer surface water of the Pacific westward. As these winds grow weaker, they allow warm surface water to change course and ebb eastward. As sea and sky encourage different behavior in one another, jet streams change course, causing storm systems to show up in locations they normally don't. This weather condition can often cause fishing populations to die off, as they are unable to cope with drastic changes in sea temperature. It also tends to make hurricane season around Central and North America less fierce.

Scientists aren't exactly sure what causes El Niño conditions, but they are quite good at anticipating them. Buoys placed throughout the Pacific Ocean detect water levels and temperatures, letting researchers know of any abnormal conditions. Although the weather ramifications from one El Niño to the next aren't exactly the same, researchers forewarned by data about an upcoming El Niño season are able to give the public a general idea of what to expect. More research is being conducted in the attempt to understand exactly what causes periodic and drastic changes in the Pacific Ocean's climate.

El Niño has caused unusually wet winters in much of South America.
El Niño has caused unusually wet winters in much of South America.

El Niño conditions in the Pacific are something of a climate flip-flop. In normal conditions, eastern countries in the South Pacific, such as Australia and Indonesia, experience heavy rainfall. During seasons with strange weather patterns, however, these countries often experience drought-like conditions. Conversely, western countries around the South Pacific experience abnormally high precipitation. Peru, for instance, experiences heavy rainfall and flooding. Temperatures in the United States plummet far below standard temperatures in certain areas of the country, causing severe winter weather systems, while other states experience less precipitation. This topsy-turvy reversal is known as the El Niño southern oscillation (ENSO), as it resembles a kind of see-saw of weather patterns.

El Niño is Spanish, and literally means "the boy," but it's better understood in its colloquial use in South America, where it often refers to the baby Jesus. South American fisherman came up with this name because the strange weather patterns they witnessed tend to occur around Christmas. It was also fitting that researchers gave weather patterns opposite to El Niño the name La Niña.

Frequently Asked Questions

What exactly is El Niño?

El Niño is a climate phenomenon characterized by the warming of sea surface temperatures in the central and eastern tropical Pacific Ocean. This warming can disrupt normal weather patterns, leading to extreme weather events around the globe, such as heavy rainfall, floods, and droughts. According to the National Oceanic and Atmospheric Administration (NOAA), El Niño events typically occur every 2-7 years and can last anywhere from nine months to two years.

How does El Niño affect global weather patterns?

El Niño influences global weather by altering the jet streams and atmospheric circulation, which can lead to unusual weather in various parts of the world. For instance, it often causes wetter conditions in the southern United States and Peru, while leading to drier conditions in Australia and Southeast Asia. The impacts are far-reaching, affecting not just local climates but also global agricultural production and ecosystems.

Can El Niño be predicted?

El Niño events can be predicted to some extent. Scientists use a combination of oceanic observations and computer models to forecast the onset of El Niño several months in advance. The accuracy of these predictions has improved over time, but uncertainties remain due to the complex nature of the climate system. The Climate Prediction Center (CPC), a division of NOAA, regularly issues El Niño forecasts and updates.

What is the difference between El Niño and La Niña?

El Niño and La Niña are opposite phases of the El Niño-Southern Oscillation (ENSO) climate pattern. While El Niño is associated with warmer-than-average sea surface temperatures in the tropical Pacific, La Niña is characterized by cooler-than-average sea surface temperatures in the same region. These phases have contrasting effects on global weather patterns, with La Niña typically promoting cooler and wetter conditions in the northern hemisphere.

How does El Niño impact marine life?

El Niño can have significant impacts on marine life due to changes in water temperature and nutrient availability. Warmer waters can lead to coral bleaching and the migration of fish to cooler areas, disrupting local fisheries and ecosystems. Additionally, the reduced upwelling of nutrient-rich waters during El Niño can diminish food sources for marine organisms, affecting the entire food chain.

What are the economic consequences of El Niño?

The economic consequences of El Niño can be substantial, affecting agriculture, fisheries, and infrastructure. Crop yields may suffer due to droughts or floods, leading to food shortages and higher prices. Fisheries can be hit by changes in fish populations, impacting livelihoods and food supplies. Furthermore, extreme weather events associated with El Niño can cause damage to buildings, roads, and other infrastructure, necessitating costly repairs and recovery efforts.

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    • El Niño has caused unusually wet winters in much of South America.
      By: Iryna Volina
      El Niño has caused unusually wet winters in much of South America.