The El Nino is a warm ocean surge of the Peru Current. It recurs every 5 to 8 years in the east pacific off south America. It involves a change in the direction of ocean currents, which prevents the upwelling of cold, nutrient rich waters along the coast of Equadator and Peru. It replaces the cool northward flowing Peru Current by a warmer stream that flows southwards.
The warm sea current drives away many species of fish like the tuna and anchovy, away the coastal fishing grounds. They need to feed on plankton to survive but they are unable to do so as the plankton have left the area for colder waters. The warm ocean current also kills several species of fish and plants.
The El Nino is an important factor in the global weather. The change in the ocean currents is related to two centres atmospheric pressure located near Easter Island in the eastern South Pacific and over Indonesia and northern Australia in the west. This phenomenon disrupts the entire climate of the area.
High atmospheric pressure maintains a hot, dry weather in ht east and a wet, cool condition in the west. The easterly winds blow away the warm waters from the south American coast. The trade winds even out the difference in pressure between the areas. Gradually the winds relax and the warm water - El Nino- flows back to Peru.
El Nino lasts for about 18 months or so. However, occasionally and very unpredictably, its lasts for a longer period with catastrophic consequences around the world. For example, the 1990 occurrence was not fully spent till 1993. the El Nino of 1939 continued to 1941 and caused extensive droughts in Bengal.
The El Nino has had disastrous effects all over the world. It has been the cause of famine in Africa an Indonesia leaving thousands dead. Bush fires broke out in the Galapagos Island. Australia suffered the century's worst drought.
El Nino has resulted in torrential rainstorms in California and South America, which destroyed houses, washed away roads and bridges and harvest and the wildlife, as the sea had become very warm. It brought about an unprecedented number of typhoons in Japan in 1991. There were record snowfalls in the Rocky Mountains.
Earlier scientists felt that El Nino was a consistent phenomenon and could be detected early enough without much trouble. Now however they have concluded that it is quite unpredictable and its cause is still known. Research is still on to unravel this intriguing mystery.
