Did you know that the period between November 1997 and November 1998 was the hottest year recorded on earth? In fact, six of the first eight months of the year were the warmest since humans began recording temperatures on earth in 1866.

Weather experts say one of the causes behind the warming of the earth’s atmosphere, or global warming, is El Nino, a water current in the Pacific Ocean.

But why should a water current create heat in the earth’s atmosphere, one would ask.

Actually, water currents could be hot or cold depending on their origin, their speed and the pull of gravity at a particular point in the sea. Swimmers say that they have come across places which are distinctly hot, or cold in different parts of the same sea.

The Baby Current Which Destroys
The Baby Current Which Destroys [Illustration by Sudheer Nath]
El Nino is a very powerful current. It flows from New Guinea and the Micronesian islands some 14,000 km across the Pacific to coastal regions of Peru. It usually lasts between fourteen and eighteen months, and may vanish for three to eight years.

But when it flows, it moves huge amounts of really warm water. As it does so, it heats the water above. The heated water shifts to the north and south. It piles up off South America, leaving colder currents in the western Pacific. The warmth of the water actually affects the weather of the place it reaches.

Besides, the Pacific Ocean is equal in area to all the landmasses on earth combined. Naturally, whatever happens here can influence the world weather. And El Nino’s role in changes in weather has already been proved. In February 1992, there were floods in southern California. Satellite images showed that there was a clear link between El Nino and the floods.

The origins of El Nino are not really known. It is said that it is caused by volcanoes on or just below the sea bed. It is believed that the 1991 eruption of Mt. Pinatubo, in the Philippines, triggered El Nino that year. But no one really knows for sure.

EL Nino was first discovered by fishermen based at Spanish ports along the Pacific coast of South America in the 17th century. They named it El Nino, which means Christ child, because it flows during Christmas time. But not every year.

El Nino is not the only water current which creates havoc on the weather. Another water current called La Nina is believed to have caused fierce storms in northern Europe, a deluge in Australia and a drought in parts of South America. But, unlike El Nino, La Nina is a cold Pacific current. La Nina is believed to be the sister of El Nino.