Understanding El Niño

What causes El Niño?

Picture the equatorial Pacific, the large stretch of ocean with South Asia and Australia to the west, and South America to the east.

The Pacific trade winds that blow over the region usually move from east to west, pushing the water on the ocean’s surface toward South Asia and Australia. As the warmest water evaporates, the air fills with moisture and contributes to the monsoon seasons in Asia and Australia.

El Niño occurs when the trade winds stop moving. Scientists have been unable to immediately pinpoint the cause of this shift. A variety of factors can start the cycle in motion at any given time. But once these conditions begin to unfold, they go through a life cycle that usually lasts around 7-12 months, but can, like in the case of last year’s El Niño, go on for longer.

What are the effects of El Niño?

Scientists do know what happens after the winds stop blowing. The weather reverses: Australia and South Asia experience drought instead of rain, and the Pacific Coast of South America is drenched by a rainy season. The paths of other winds, known as jet streams, are altered. One of themdrivespacificstormstocalifornia.el Niño years are typically those in which the monsoon fails in India.

And why is it called El Niño?

According to the US National Oceanic and Atmospheric Administration (NOAA), El Niño was originally recognised by fishermen off the coast of South America in the 1600s, with the appearance of unusually warm water in the Pacific Ocean around the time of Christmas. They called the phenomenon El Niño, which means Little Boy in Spanish, and refers to the birth of Christ.

Is El Niño caused by climate change?

Evidence suggests El Niño has been happening for thousands of years. That said, three of the strongest events in the historical record, which goes back about 120 years, have taken place in the last 30 years. Scientists are studying the possibility of a link between climate change and stronger El Niño events.

THE NEW YORK TIMES