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(CNN) – The weather phenomenon called El Niño became part of the vernacular language more than 20 years ago. In 1997, it caused devastating floods in the western United States and a drought in Indonesia. Deadly viral epidemics in Africa and rising world coffee prices have also been blamed.
El Niño even became Chris Farley's character in "Saturday Night Live".
Pure chaos. But what is El Niño? Let us explain.
What is El Niño? And what is the cause?
El Niño is a warming of the east Pacific Ocean, mainly along the equator.
These warmer waters are generally confined to the western Pacific by winds from east to west, pushing the warmer waters to Indonesia and Australia.
But during an El Niño, winds slow down and can even reverse direction, allowing warmer water to spread eastward to South America.
El Niños occurs every two to seven years with variable intensity and eastern Pacific waters can reach 4 degrees Celsius (7 degrees Fahrenheit) warmer than usual.
What happens when there is an El Niño?
An El Niño fort warms the atmosphere and alters circulation patterns around the world, particularly the jet stream over the Pacific, which is gaining strength and causing more frequent and intense storms in the western United States , especially in California. It also means more rain for the west coast of South America.
But the atmosphere is in a way a zero sum game. More rainfall in North and South America is at the expense of normally rainy South Asia and Australia, which are becoming unusually dry and experiencing drought.
A strong El Niño also influences the hurricane seasons around the planet. The warmer the East Pacific, the more hurricanes there are. The Atlantic Ocean sees less cyclones, however, due to the increasing winds at altitude that prevent these storms from developing. This proved true for the Hurricane Season 2015 – The Atlantic has had a relatively calm year while the Pacific has broken several records.
The weather is not the only thing that is affected. The warmer surface waters in the eastern Pacific are chasing the cold-water fish that are the backbone of the fishing industry in most Latin American countries. It is here that the phenomenon was first noticed by the fishermen, who called it "El Niño" – which means "little boy" or "Christ child" in Spanish – because it often appears around Christmas.
Which areas are usually affected?
Like snowflakes, no two El Niños are alike, and this is just one of the many large-scale weather patterns that work together to influence the global climate. The presence of "The Blob", as it is now called – an area of warmer waters in the North Pacific during the 2014-2016 event – was not present at the El Niño from 1997
Nevertheless, generally during the El Niño years – more rain falls in the southwestern and southeastern United States – while the north experiences much drier and warmer weather.
It has been known to cause intense floods in eastern Africa, causing landslides, an increase in water-borne diseases and even food shortages, while northern and southern parts of the continent are experiencing severe drought.
El Niño is also known to leave much of the West Pacific, Australia and Asia warmer and drier than usual.
An El Niño will reduce the development of hurricanes in the Atlantic by creating more wind shear in the region. However, this has the opposite effect on the Western Pacific, allowing for further development of the typhoon.
Does climate change have anything to do with that?
The influence of climate change on El Niño is the subject of debate. Some research suggests that while it is unlikely that the total number of El Niños will increase, the number of "super" El Niños is twice as likely.
Other recent studies show that climate change could worsen the impact of El Niños.
One of the most likely by-products of global warming is the increase in extreme precipitation, as warmer temperatures can retain more water vapor in the atmosphere. This could make the floods caused by El Niño even more devastating.
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