El-Nino

El Nino is a shift in ocean temperatures and atmospheric conditions in the tropical Pacific that disrupts weather around the world. It is a poorly understood recurrent climatic phenomenon that primarily affects the Pacific coast of South America, but has dramatic impacts on weather patterns all over the world.

Pronounced ‘El-Ninyo’, it means ‘the boy’ in Spanish and was named so by Peruvian fishermen after the Christ child since its effects are generally first felt around Christmas. It is a periodic warming of the Pacific Ocean that leads to terrible extremes of weather. The precise causes, intensity, and longevity of El Nino are not very well understood. The warm El Nino phase typically lasts for 8–10 months or so.

Normally, trade winds blow towards the west, across the Pacific, pushing warm surface water away from the South American coast towards Australia and The Philippines. Along the Peruvian coast the water is cold and nutrient-rich, supporting high levels of primary productivity, diverse marine ecosystems, and major fisheries. During El Nino, the trade winds relax in the central and western Pacific. This allows warm water to accumulate in the surface, which causes the nutrients produced by the upwelling of cold water to significantly come down, leading to the killing of plankton and other aquatic life such as fish and the starvation of many seabirds. This is called the El-Nino effect, which is also responsible for destructive disruptions of worldwide weather patterns.

A wide variety of disasters have been blamed on the El-Nino effect including a famine in Indonesia in 1983, bush fires in Australia arising from droughts, rainstorms in California, and the destruction of anchovy fishery off the coast of Peru. During 1982/83 it is said to have led to the death of some 2000 people worldwide and caused losses amounting to approximately 12 billion dollars.

The impact of the 1997/98 spell of the phenomena was very damaging. Floods devastated the Americas, storms hit China, drought parched Austria, and forest fires burnt parts of South-East Asia and Brazil. Indonesia experienced the worst drought in the last 50 years and in Mexico, the town of Guadalajara saw snow for the first time since 1881. In the Indian Ocean, it affected the movement of the monsoon winds.

When pressure is high in the Pacific Ocean it tends to be low in the Indian Ocean from Africa to Australia. This was the first recognition that changes across the tropical Pacific and beyond were not isolated phenomena but were connected as part of a larger oscillation.