Everything Everywhere Daily: History, Science, Geography & More - El Niño and La Niña

Episode Date: October 18, 2021

Weather systems on Earth aren’t stable. There are cycles that weather patterns go through which can have enormous effects around the globe. There is probably no more important weather cycle than the one meteorologists called the Southern Oscillation. This cycle can have dramatic implications for temperatures and rainfall all over the world. Learn more about El Nino and La Nina and the Southern Oscillation on this episode of Everything Everywhere Daily. Learn more about your ad choices. Visit megaphone.fm/adchoices

Weather systems on Earth aren't stable. There are cycles that weather patterns go through, which can have enormous effects around the globe. And there is probably no more important weather cycle than the one meteorologists have called the Southern Oscillation. This cycle can have dramatic implications for temperatures and rainfall all over the world. Learn more about El Nino, La Nina, and the Southern Oscillation on this episode of Everything Everywhere Daily. Do you ever climb into bed ready to sleep only to have your mind start racing the moment your head hits the pillow? thoughts bouncing around, replaying the day or jumping ahead to tomorrow? That is exactly why Catherine Nicolai created Nothing Much Happens.

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all one word at checkout, and say 15% on your next order. Once again, go to scotivest.com and use coupon code everything everywhere, all one word to say 15% on your next purchase. The El Nino phenomenon was originally named by Peruvian fishermen back in the 17th century. They noticed that sometimes the waters would often get warmer around Christmas time. They named this effect El Nino, which means little boy in Spanish. When capitalized, El Nino refers to the Christ child and it gets its name from the fact that it happened at Christmas. In the 1930s, a meteorologist by the name of Sir Gilbert Walker realized that a meteorological phenomenon called the Southern Oscillation always occurred with what the locals called El Nino.

To understand what happens during an El Nino, it's necessary to understand the circulation of water in the Pacific Ocean. Under normal conditions, cold water will come up to the surface off the western coast of South America. This cold water is great for fishing as it brings up nutrients and plankton, and it's one of the reasons why the Pacific waters off of South America are so good for fishing. This cold water begins to warm up as it reaches the surface, and it is transported roughly along the equator towards Asia and Australia. Along the way, the heat of the sun and the Pacific Ocean warms this water, and it's one of the reasons why parts of Asia along the same latitude, such as Indonesia, are so hot. This current will then take the warm water down

the eastern coast of Australia, down to Antarctica, where it will work its way back to South America and start all over again. This is how it normally works. Ocean currents can change, however. Every few years, the transport of warm water from east to west can sometimes reverse. Warm water from the equator will move eastward towards South America. This is the warm water phenomenon that the 17th century fisherman off Peru found and named, and this is El Nino. Because the Pacific Ocean is so big, this change in warm water currents can change weather patterns globally. The reason why the fishermen recognized and named this phenomenon is that it was horrible for fishing. The nutrients which came up to the surface with the cold water were no longer coming up with warm water.

The areas which see the largest weather changes are in the Americas. On the west coast of South America, they'll see more rainfall with the moist hot air hitting its coast. Chile will tend to have milder winters, and across the Andes into the Amazon basin, there will usually be less rain. During an El Nino event, northern states in the United States and Western Canada tend to have warmer winters, southern states tend to have more precipitation, and the eastern part of the United States tends to be drier. In Antarctica, the Ross Sea, which is south of the Pacific Ocean, will see less ice formation and higher temperatures, whereas the Weddell Sea, roughly south of the Atlantic Ocean, will see lower temperatures and increased ice form. In Asia, El Nino will reduce precipitation and can cause droughts. The driest February is in

recorded history in Singapore, where weather records have been kept the longest, all coincide with El Nino's. Australia likewise sees lower rainfalls with cooler temperatures in northern latitudes and higher temperatures in the southern latitudes. There is a third phenomenon that can also happen in this region, and it's known as the anti-Linio, or as it is colloquially known as La Nina, which just means little girl, signifying it as the opposite of an El Nino. It is also sometimes known as El Viejo or the old man. During a La Nina event, the cold water from the west coast of South America gets pushed up further than normal. The result is usually the opposite of what would happen during an El Nino event. Precipitation on the coast of Peru and Chile is usually

less, but rainfall in the Andes can be more. In North America, Canada and northern states tend to have colder winters. Southern states tend to be much drier than normal, and the eastern part of the country tends to be wetter. In Asia, cyclones can be pushed further west, threatening mainland Asia. Likewise, there can be increased rainfall in Indonesia, the Philippines, and Malaysia. Eastern and Northern Australia likewise see more rainfall as well. The average length of time for an El Nino event is seven months to two years, and the average length of time for a La Nina event is five months to a year and a half. While these events do occur, every several years, they aren't really predictable. You can't pencil it in on your calendar.

There is a period of almost 20 years from the early 1920s to the early 1940s where there were no El Nino events at all. The period coincided with the Dust Bowl. They will usually appear between two and seven years. On the other hand, there have been cases of El Nino events happening within a year of each other. Likewise, not every El Nino or La Nina event is the same. Some are stronger than others. The El Nino events of 1982 and 1983 and 1997 and 1998 were the strongest recorded. Others tend to be rather weak. The coldest temperatures I've ever personally experienced were in 1996 in Minnesota. Temperatures reached minus 40 in the Twin Cities where I was living, and that's so cold that it's the same temperature in both Fahrenheit and Celsius. The record low temperature for the state

of Minnesota was set that year at minus 60 Fahrenheit. Sure enough, when I I checked, it was a La Nina winter. As far as researchers can tell, these cycles of El Nino and La Nina have been going on for thousands of years, at least since the end of the last ice age. Once the El Nino-Lanina cycles were figured out, and we knew what they did to the weather, it wasn't too hard to go back and see just how they affected history. Much of this could be told through the story of dendrochronology or tree rings. A fishery collapsed in 1972 off the coast of South America, and it was due to an El Nino event. When the fisheries collapse, it can result in fewer seabirds feeding, which can affect guano and fertilizer production.

El Nino events may have resulted in droughts and famines, which caused the collapse of some pre-Columbian cultures in Peru. Cyclones and droughts in India may have been caused by El Nino and Lan Nino events. A strong El Nino between 1789 and 1793 might have caused poor harvest in Europe, which was one of the sparks for the French Revolution. In 1998 and 2015, low rainfall in Panama led to reductions in the size of some ships which could go through the Panama Canal. And in 1876, famine in northern China killed up to 13 million people, and it was in part due to an El Nino event. As I'm recording this, weather services are reporting that for the second year in a row, a La Nina event is forming. That will probably mean low temperatures this winter where I live,

More rain in places like Seattle, and less rain in Arizona and Southern California. Depending on where you live in the world, the El Nino-L-Nino-Lanini cycles might be responsible for much of the weather you experience. The Earth has an interconnected web of weather, and one of the biggest drivers of that weather, all has to do with cold water currents off of the western coast of South America. The associate producers of Everything Everywhere Daily are Peter Bennett and Thor Thompson. If you'd like to support the show, please join the list of patrons over at patreon.com. And also remember, if you leave a review or send me a question, you two can have it read on the show.