Taking Our Temperature

El Niño: Sneak Preview of Our Future?

Every few years, a weather pattern called El Niño appears off the coast of Peru. It turns the world's climate topsy-turvy. El Niño may be a sneak preview of our future. Why? Because global warming also brings extreme weather changes.

El Niño is the best model we have of what global warming may bring. By studying its effect on weather patterns and human health, scientists hope to predict climate change how major will affect future generations.

  • Both can produce extreme weather conditions.
  • Both can seriously damage our health.
  • El Niño happens quickly.
  • Global warming is slow and steady.

El Niño is an abnormal warming of the ocean's surface. It's caused by an unusually warm current flowing eastward across the Pacific Ocean. Because the Pacific is so large, this current is huge too. Sometimes, in fact, it's wider than the U.S.!


These computer images show the Pacific Ocean during normal conditions (above) and an El Niño event (below). North America appears in dark brown in the upper right corner of each picture. Source: NOAA: El Niño Theme Page


This surge of warm water has a tremendous impact. The extra heat within the water interacts with the atmosphere above, shaking up weather patterns. Dry places get drenched, and wet places turn arid. These dramatic changes can cause significant health and environmental effects.


click to enlarge image
Red, orange, and yellow represent areas that experience unusually warm winters during an El Niño event.
Source: NOAA:
El Niño Theme Page


Written records about El Niño date back to 1525, and geological evidence shows that the phenomenon is at least 13,000 years old. Yet El Niño didn't attract serious scientific attention until about 30 years ago.


In the 1970s, fishermen found that their catches off the west coast of South America had turned from great to bad. This seemed to occur every few years around Christmas, so the fishermen connected it with the birth of Christ. They named the event El Niño ("little boy" in Spanish). El Niño's full name is El Niño Southern Oscillation (ENSO).


Scientists say the 1982-83 El Niño event may have been the worst in history. Red and orange show where the ocean turned abnormally warm.
Source: NOAA


Things heated up in 1982-83. Peru's rainfall nearly doubled. The southwestern United States also got far more rain than usual. The extra moisture meant more plants. That, in turn, meant more food for mice and rats—plus outbreaks of disease carried by the rodents. At the same time, droughts, dust storms, and forest fires swept ordinarily wet Northern Australia, Indonesia, and parts of Africa. Altogether, El Niño was blamed for 2,000 deaths and $13 billion in losses worldwide.

video_iconSee how El Niño brought the African nation of Zimbabwe to its knees—literally.
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Source: Journey to Planet Earth

Many factors in the ocean and atmosphere combine to cause El Niño. It seems to be coming more frequently, which has climate experts worried.

You can learn more about El Niño from the National Oceanic and Atmospheric Administration.


health_iconHow can El Niño affect human health?

science_iconCan we predict El Niño events?



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