Courtesy of the Center for Climate Analysis. In these maps of four El Niño winters, the orange and red areas illustrate how much warmer (in degrees Celcius) sea surface temperatures were. The birds' excrement (guano) produces deposits on the islands off the Peru coast, which in the form of fertilizers is another important economic asset of Peru. This in turn reduces the number of marine birds who feed on the anchovy. (During the 1972 El Niño, the anchovy population dropped from 20 million to 2 million). The cooler, rich waters drop along with the thermocline, driving the anchovy population down with it, or killing off a large portion. Along the Peruvian coast, warm water builds up, driving the thermocline (the buffer zone between the upper layer of water and the frigid ocean below) down. Warm water sloshes back east in a vast, slow wave. By the time winds reach Micronesia, the sea level has risen about three feet and the water has warmed about seven degrees F.īut during an El Niño, these trade winds relax, or even reverse, as was the case during the devastating 1982-1983 El Niño. In the west, the warm water that's pushed along raises sea levels. The result is some of the coolest water found in the lower latitudes (sometimes dipping to 68 degrees F), and a plentiful plankton-filled feeding ground for the anchovy population on which Peruvians count on for much of their economic survival. These winds travel along the surface of the sea and bring warm surface water along with them to the western coasts.Īs the warm surface water is pushed away from the coasts of Peru, colder, nutrient-rich water rushes up to take its place. Normally the winds blow east to west across the southern Pacific. And it all can be attributed to the same event: the El Niño/Southern Oscillation (ENSO).Įl Niño (meaning "The Little One" in Spanish for its tendency to arrive around Christmas) is characterized by a dwindling, or sometimes even a reversal of trade winds. In fact, it can happen about once every four to seven years-with varying intensity. Could all these events possibly be related?Ībsolutely. Droughts strike Indonesia, Africa, and Australia-all within the period of the same few months. Torrential downpours and mud slides besiege southern California while the Northeast United States has fewer hurricanes and a mild winter. Flooding rains and warm weather in Peru wipe out the anchovy harvest.
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