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The Truth About El Niño and La Niña January 31, 2000 For centuries, fishermen of Peru and Ecuador have observed El Niño, which is Spanish for "the little boy" because of its tendency to arrive at Christmas time. Every few years, the fishermen noticed a warm current that flowed along the Peruvian coast which caused the fish to vanish and thus bring their fishing businesses to a halt. Once thought to affect only the narrow strip of water along the Peruvian coastline, scientists and now the public in general have recognized El Niño as a large-scale oceanic warming that not only affects the tropical Pacific, but the global climate.
While El Niño certainly has a great affect on earth's weather, it is certainly not a new phenomenon, nor is its sister, La Niña. For the first time, more precise information about El Niño's impact on the Earth's weather patterns had been made available because of new tracking and sensing technology that let us actually see El Niño and La Niña in action. As a result, many people were led to believe that El Niño was a uniquely occurring weather event that brought about enormous weather changes on our planet. The truth is that both El Niño and La Niña are part of Earth's normal weather patterns and have been for as long ago as we can tell. Essentially, El Niño is a recurring warming of the tropical Pacific waters along the equator, pushing the colder waters down below the surface and stretching from the shores of equatorial South America west, north and south into the Pacific. This creates significant changes to the weather patterns which are naturally created and affected by changes in sea temperatures.
La Niña is expected to continue for the next few months, having strengthened in the tropical Pacific since November 1999. Sea surface temperatures have dropped more than 1.8?F (1?C) below normal. Such a shift of 1-2? Fahrenheit or Celsius may not be significant in terms of air temperature, but it has a dramatic affect on our weather when it involves ocean temperatures. These cold conditions have existed since June 1998 when the El Niño phase ended. It is unknown exactly when the next El Niño will occur as they are difficult to pinpoint far in advance. However, it is expected to occur sometime within the next two-to-five years. For more information about El Niño and La Niña, you may visit the Climate Diagnostics Center website or the home page for the National Oceanic and Atmospheric Administration. Did you know ... ?
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El Niño and La Niña were introduced as new, major weather occurrences to the general global populace during 1997-1998 when the media began reporting that El Niño was creating havoc with the Earth's weather conditions. There were droughts in Australia, floods in Peru and fires in Indonesia, and the mammals of the eastern Pacific were starving to death due to a severe loss of their food supplies, "all caused by El Niño."
The most recent El Niño was in 1997 - 1998. The average cycle for El Niño is about every three-to-seven years where the surface temperatures can change dramatically from normal to as high as 6?F (3.33?C) above normal. The more rapidly the temperature changes, the more drastic weather conditions may change as well. Previous known El Niño ocean patterns have occurred in 1991-92, 1982-83, 1977-78, 1972-73, 1968-69, 1965-66, 1957-58, and 1951-52. We are currently under the influence of La Niña, which is the opposite of El Niño. La Niña, Spanish for "the little girl," can cool waters as much as 6?F (3.33?C) from normal. While La Niña can cause equally opposite effects as those caused by El Niño, sea mammals and fishermen alike welcome La Niña because the cooler waters bring back the fish and food supplies that the warmer waters of El Niño chase away.
© 2008 ecology.com
