El Niño is one of the most interesting weather spectacles that occurs on the planet Earth. While it is a source of a great deal of fascination in the scientific community, its effects can be devastating.
Despite the fact that people have observed El Niño since the 1600s, very little is known about what actually causes it.
In fact, most people who are even aware of the term know it because of the particularly large instances of it happening in 1982 and 1997. However, El Niño actually occurs fairly frequently and varies in size.
This variance cannot be explained, but it is crucial for forecasters to be aware of an oncoming El Niño so the global community can prepare for its effects.
Here we take a look at what is currently known about this climate cycle and some of the issues that it can cause throughout the world.
Explaining El Niño
El Niño is best described as a climate cycle in the Pacific Ocean. It has a huge impact on weather patterns, with its influence being seen across the globe.
This climate cycle starts when warm waters that find their origins in the Pacific Ocean start moving towards the South American coast. While these waters will occasionally pool and dissipate near Indonesia, an El Niño occurs when the warmest of the surface water ends up sitting offshore in north-western South America.
Forecasters look at both the ocean temperatures and the rainfall generated by storms that move east before declaring an El Niño. The phenomenon also leads to trade winds weakening and even reversing direction.
This cycle will usually last somewhere between nine and twelve months. However, there have been rare occasions where the phenomenon occurs over the course of a number of years, causing vast disruption in many cases.
El Niño will typically cause tropical storms to shift eastward for the duration of the cycle. This is due to the fact that the warm waters that pool during the cycle lead to a greater amount of evaporation, creating atmospheric moisture that encourages the generation of thunder storms.
Alongside La Nina, which generally acts in the opposite way, El Niño is part of greater oscillations in the ocean’s atmospheric system that are collectively known as the El Niño-Southern Oscillation, or the ENSO cycle.
What Causes The Phenomenon?
Despite the fact that we have known about El Niño since the 1600s, when its effects were first spotted by Peruvian fishermen, we still don’t fully understand what actually causes it.
It is believed that the phenomenon occurs as a result of extensive interactions between the ocean and the surrounding atmosphere. This means that there are likely a lot of little things that add up to the creation of an El Niño, rather than one specific cause.
The issue is complicated further by the fact that not all occurrences of El Niño are the same. The El Niño that occurred between 1982 and 1983 is particularly considered to be one of the largest instances of the cycle, as is the one that happened in 1997, but there have been a number between those years and since that have been much smaller.
Furthermore, the ocean and surrounding atmosphere also have varying patterns between El Niño occurrences. This makes it even more difficult to predict when they will happen and what their effects will be.
Thankfully, there is still some predictability, as scientists can monitor the ocean temperatures in the upper 656 feet of the water. They do this to look for temperature shifts from the western through to the eastern Pacific.
However, this is not a foolproof method and doesn’t provide the actual explanation for why El Niño happens. In some cases, these temperature shifts occur but are not followed by the storms and trade wind shifts that characterize an El Niño.
When Do They Happen?
While an El Niño cycle can last for a year or more, the cycles are fairly irregular in occurrence. The general pattern suggests every three to five years, but gaps between El Niño cycles have been as short as two years or as long as seven.
When they do occur, they will usually form at some point during the spring. This leads to them attaining peak strength right around the winter months of December and January.
This tendency to arrive around the Christmas period is what led to the cycle being given the El Niño name in the 1600s. Back then it was referred to as El Niño de Navidad, which literally translates to ‘The Christmas Child’.
The cycle will not end right then though, as it usually takes another four of five months for the conditions to revert back to pre-El Niño states.
What is known is that El Niño has been happening for millions of years. Evidence of the cycle can be seen in deep sea muds and ice cores in the ocean.
Typically, the occurrences of El Niño are more frequent than its sister cycle, La Nina.
The Known Effects of an El Niño
Scientists are so keen to keep track of the El Niño cycle because it can have rather drastic effects on weather conditions. The previously mentioned increasing occurrences of storms are an obvious problem, but there are also a number of other issues that El Niño has a hand in.
For example, the El Niño that occurred between 1982 and 1983 is believed to have caused somewhere around $10 billion in weather-related damage throughout the world.
While El Niño makes it harder for hurricanes to form over the Atlantic Ocean, due to the creation of stronger wind shears and formation of stable air, the issue is transferred elsewhere by the cycle. Specifically, eastern Pacific hurricanes become a major problem and have the potential to batter parts of Peru, the southern United States and the surrounding regions.
El Niño also leads to higher amounts of rainfall across the southern United States and in Peru. Conversely, rainfall tends to lower in the Pacific Northwest and in Ohio and Tennessee during a cycle, which can cause issues for farming communities.
This issue is exacerbated elsewhere too, as the cycle can also lead to widespread droughts in other areas. Africa, India, Southeast Asia, Australia and the Pacific Islands have all been known to experience severe water shortages during an El Niño.
The cycle also has adverse effect on the economy. Fishing communities in South America, in particular, tend to struggle as an El Niño causes a lot of marine life to migrate north and south in search of cooler waters.
Despite the fact that El Niño has been occurring since before the dawn of humanity, we still know so little about this phenomenon.
In particular, scientists are struggling to find specific reasoning behind the occurrences. This means that in most cases the best we can do is track various changes in weather and ocean conditions and hope that forecasts that result from this data offer accurate representations of what will happen should El Niño occur.
The cycle is amongst the most interesting ocean-based natural phenomena around, due to its great potential for causing damage and its effects on weather conditions. Over time and with more research we may begin to develop a greater understanding of how it all happens.
Hopefully we have offered you some useful information about El Niño here. Please don’t hesitate to share this article on social media if you feel others may find it useful, or continue the discussion below in the comments section.
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