Table of Contents
- Could we see an unusually chilly winter due to "La Niña"?
- "El Niño" and "La Niña": What are they?"
- What is the reach of global weather impacts from "El Niño" or "La Niña"?
- What are the potential benefits of "La Niña"?
- What effects do these weather phenomena have on the world economy?
Could we see an unusually chilly winter due to "La Niña"?
- The potential existence of an early winter could be imminent due to La Niña.
While the World Meteorological Organization (WMO) anticipates a global cooling as a result of the meteorological phenomenon known as "La Niña" (meaning "the girl" in Spanish) over the coming months, temperatures have primarily decreased in the opposite hemisphere - specifically, the eastern part of the Pacific Ocean near South America. Recently, the WMO announced that the eastern Pacific has slightly cooled at the surface during the summer and could move into a "La Niña" phase in the fall. In "La Niña" years, global temperatures generally tend to drop.
However, the WMO clarifies that all other oceans remain warmer than usual at the surface at this time, so there is no expectation of unusually low temperatures on the continents except for regions like the eastern Pacific or the southwestern coast of North America. It is also unclear how much of the cooling Germany will experience: Europe is not as heavily influenced by "La Niña" as other landmasses, and global warming appears to have weakened the "girl" in recent years.
"El Niño" and "La Niña": What are they?
The two weather phenomena, "El Niño" (means "the boy" or "the Christ child," as the event takes place around Christmas) and its opposite "La Niña," disrupt air and water circulation in the tropical Pacific. These two extremes are sometimes referred to as an "air pressure seesaw" or "weather swing." Both "Christ child" and "girl" lead to deviations from the usual state of the Pacific Ocean.
Under normal circumstances, consistent trade winds blow from northeast to southwest around the equator and push warm surface water westward towards Southeast Asia - roughly from Peru to Indonesia. In Asia, much of the warm water evaporates and causes heavy rainfall and humidity. At the same time, "missing" seawater off South America causes cold, nutrient-rich water from the depths to rise, benefiting fish populations and the sardine fishing industry in Peru.
During "El Niño" years, the Pacific's climate system loses its natural rhythm due to air pressure fluctuations for multiple months. The trade winds from the east weaken, and the warm water "stagnating" off Asia flows back towards Peru, causing rain and flooding in South America. Meanwhile, Southeast Asia experiences drought. Conversely, during a "La Niña" event, stronger trade winds blow from east to west. They push cold water to the surface off South America and warm water towards Asia, often leading to even more tropical storms in Asia but also cold and drought in South America. Overall, the Pacific cools during a "La Niña" year, in turn cooling the global weather system.
What is the reach of global weather impacts from "El Niño" or "La Niña"?
"El Niño" and "La Niña" have the most significant impacts around the tropical Pacific, but they are among the largest and most powerful weather mechanisms on the planet. Their effects can be detected thousands of kilometers away. Experts believe that the devastating floods in 2023 in the Horn of Africa were driven by "El Niño." On the other hand, "La Niña" shifts the polar "jet stream" to the north, a high-altitude strong wind band that sweeps across Canada, the USA, and Northern Europe, separating the regions into cold and warm weather zones. In a "La Niña" year, for example, the temperature gradient in North America becomes steeper; temperatures drop further in Canada and the northern United States, while it remains warmer in the south. The hurricane season over the Atlantic is often particularly active during a "La Niña" year.
What are the potential benefits of "La Niña"?
Since the summer of 2023, the world has been experiencing a record-breaking heatwave - a combination of climate change and an exceptionally strong "El Niño" season created above-average sea temperatures, fueling the worst drought in decades in the Amazon. Many scientists, farmers, and environmentalists worldwide are now hoping for some cooling and more rain through "La Niña." However, the details are unclear, and it's uncertain which regions will reap the benefits in the end. For example, it's expected that it could rain more in Australia or southern Africa, but extreme weather events are likely to increase in many regions. "La Niña" and "El Niño" have historically been both positive and negative: farmers have longed for rain, only to see their fields flooded and destroyed.
In Peru, people tend to eagerly anticipate the refreshing "La Niña" period, and in 2023, it proved to be even more valuable with a 21% decrease in mango production compared to the previous year. This is because mango trees only bloom in cool and dry conditions, but the moist heat of "El Niño" prevented them from producing many blossoms last year. Additionally, in the sardine and anchovy fishing industry off the Peruvian coast, fishermen hope that "La Niña" will bring easterly winds along the Pacific shore, pushing up nutrient-rich deep water. This abundance of nutrients allows plankton to thrive, which subsequently attracts fish swarms and provides an ample food source for the fishermen. Unfortunately, "El Niño" brought a near-stagnant current, causing a shortage of nutrients, which ultimately led to the death of plankton and fish. Consequently, "La Niña" years prove to be beneficial for fishermen in South America, as their fishmeal factories are integral to the livelihoods of poultry farmers and fish farmers in Europe and China, with sardine fishmeal remaining a crucial component in many animal feeds.
The WMO's prediction of a global cooling due to "La Niña" might not result in unusually low temperatures in all continents, as Europe is not as heavily influenced by this phenomenon and global warming appears to have weakened its effects.
The two weather phenomena, "El Niño" and "La Niña," have significant impacts beyond the tropical Pacific, with "La Niña" shifting the polar "jet stream" to the north, affecting weather patterns in North America and the Atlantic Hurricane season.
