WEST PALM BEACH, Fla.- El Niño is on the prowl this season in the Pacific Ocean sending its effects in every direction. This natural climate event is often associated with warmer-than-average sea surface temperatures near the equator. After years of back-to-back La Niña, this is Florida’s first El Niño in five years. The last time Florida saw an active El Niño event was in the winter of 2018 and was weaker than the current event.
El Niño and its counterpart, La Niña, are climate phenomena that originated in the equatorial Pacific Ocean. El Niño and La Niña are the most dramatic year-to-year shifts of the Earth’s climate system. It affects agriculture, public health, freshwater availability, power generation and economic activity in the United States and around the globe. Their iconic names come from South American fishermen during the 17th century. The fishermen began to notice the warmer water off the coast at different times during the winter seasons. "El Niño,” which means "little boy" in Spanish. When capitalized, it means "Christ Child," since the event occurred around Christmas. As the opposite of El Niño, they named the second cycle La Niña, which means, “little girl.”
El Niño is the warm phase of a larger phenomenon called the El Niño-Southern Oscillation (ENSO). La Niña is the cool phase of ENSO and describes the cooling of the region’s surface waters. El Niño and La Niña are the parts of ENSO that cause change in the ocean, while the Southern Oscillation causes a change in the atmosphere. Therefore, ENSO heavily affects two things: the pressure of the atmosphere and the surface temperature of the ocean below it.
Researchers and scientists are not exactly sure what jump starts the oscillation cycle. However, they know that the development of El Niño events are directly linked to trade winds that normally blow from east to west. Dr. David R. Legates, climatologist and retired professor of climatology and geography/spatial analysis at the University of Delaware, has extensively researched El Niño and shed light on the complexities of the climate event.
“The wind sets the ocean in motion, so if there were not any winds there would be no global circulation,” said Dr. Legates.
Dr. Christian Batoh, professor of biology at Palm Beach Atlantic University says “[During an El Niño cycle], trade winds in the Pacific weaken and instead of warm water being pushed towards the Western Pacific, it flows back east towards the Americas.”
Winds across the central Pacific ocean constantly push water towards the Indian ocean. When the winds calm down, the water comes back warmer, causing a mass of warm water to form in the ocean that transfers various amounts of heat into the atmosphere through convection. As a result, the heat affects atmospheric circulation in both the east-west and south-north directions. Meanwhile, during a La Niña cycle, the trade winds become stronger and the warm water is pushed to the West and is replaced by colder water in the East. These changes can impact the timing of convection, when heat is transferred by the movement of liquids or gasses, and affect rainfall and temperatures.
Typically, the American West coast tends to experience more rain, whereas places like Indonesia and Australia are faced with a severe drought. This is often related to the position of the jet stream, the winds that cross the planet from west to east. The shifts in atmospheric circulation lead to changes in the weather around the world. In an El Niño cycle, the jet stream shifts to the south, bringing cooler, rainer and stormier conditions to the Southern United States and warmer conditions to the North. Opposite effects can be seen during La Niña.
“As we near the peak of the El Niña cycle in cities like West Palm we can expect an increased risk of flooding and storms,” explained Dr. Batoh.
These are just usual effects; the unexpected patterns of these cycles behave chaotically, making them hard to predict. This behavior is generally unpredictable, even though climate models attempt to predict its tendencies. Due to the chaotic nature of the climate system, scientists still cannot predict when ENSO will occur or the magnitude of the impacts.
With climate change being a top discussion amongst environmental scientists, questions about the impact to oscillation cycles are on the rise.
“It is possible that both El Niño and La Niña coils essentially become more extreme,” mentions Dr. Batoh.
It is uncertain how El Niño and La Niña will change as the planet continues to warm from greenhouse gas emissions. Oceans have been warming steadily and quickly due to climate change. Research suggests that El Niño will increase in temperature, precipitation and frequency.
Daniella Pacheco