THE CHILD (PHENOMENON): CAUSES, CONSEQUENCES, ADVANTAGES, DISADVANTAGES - ENVIRONMENT - 2024

The El Niño phenomenon is an exceptional increase in the temperature of the waters of the central and eastern Pacific Ocean off the Peruvian coast. It is a climatic phenomenon product of the interaction of the hydrosphere and the atmosphere that causes serious imbalances.

This weather phenomenon occurs with an irregular frequency that varies from 1 to 6 years, developing over a period of 8 to 13 months. Its name was given by the Peruvian fishermen referring to the baby Jesus, because it reaches its greatest intensity around Christmas.

Sea level during the 1997 El Niño phenomenon. Source:

It has also been called the warm phase of the Southern Oscillation, due to the variations in atmospheric pressure in the southern subtropical Pacific. Collectively it is referred to as the El Niño-Southern Oscillation (ENSO) phenomenon.

The Earth's climate is a complex system and therefore the consequences of the El Niño phenomenon are reflected in various places on the planet. In general terms, it causes exceptionally high rainfall in the areas close to the phenomenon and severe droughts in other areas.

There has been knowledge of the El Niño phenomenon since the 16th century, having occurred events classified as very strong in at least 10 years. The first phenomenon of the very strong child occurred in 1578, and more recently in the years 1877-1878, 1982-1983 and 1997-1998.

Causes of El Niño

It is the product of the interrelation of several phenomena including equatorial tidal currents, upwelling weakening, and the Walker cell.

Regime of regular winds and currents

Normally in the subtropical Pacific Ocean the rotation of the Earth pushes the trade winds from the southeast to the northwest (Coreolis effect). These winds generate ocean currents from the east to the west, which then drift south.

When these winds reach the western Pacific with warmer waters, they rise and the water vapor they carry condenses and precipitates. Once dry they return to the east, towards South America, forming this cycle the Walker cell.

Normal movement of the winds in the Pacific. Source: Fred the Oyster

The marine current that comes from the southwest to the east, is of denser cold waters and when it collides with the coast of South America, it moves in a south-north direction (Humboldt or Peruvian current). At the height of the Peruvian coast, the current of deep cold waters collides with the continental shelf and rises.

These waters are cold and lower the surface temperature by 7 to 8 ºC, in addition to providing nutrients from the seabed. This phenomenon is known as upwelling of marine waters or upwelling.

This determines a water temperature imbalance between the western and eastern Pacific. In the west the waters are warmer, with temperatures above 30 ºC and in the east they are colder, between 17 and 19 ºC.

In addition, high pressures are generated in the east and low pressures in the west, defining the strength of the trade winds.

Alteration of the tidal pattern

In the occurrence of the El Niño phenomenon, the regular imbalance between the western and eastern Pacific is broken. This is due to the unusual warming of surface waters (first 100 m) in the central and eastern Pacific off the Peruvian coast.

One of the causes of this phenomenon is the alteration of the equatorial tidal currents that transport a greater quantity of warm water from Panama to Peru. Those warm waters overlap the cold waters of the Humboldt Current, weakening the deep cold water outcrop.

This illustration shows the increase in temperatures in the Pacific Ocean during the 2006 El Niño

Global warming

Currently the effect of global warming is added due to the increase in the greenhouse effect, due to the anthropic emission of gases that promote it. The increase in the average temperature of the planet also affects ocean temperatures.

Similarly, the melting of ice in Antarctica adds water and affects the Humboldt current.

Breakdown of normal water temperature imbalance

All these factors cause the surface waters of the eastern Pacific to heat up, altering the normal pattern of the 20 ºC thermocline. This is the imaginary line that separates the warm water zone from the cold one depending on the depth.

In general, in the western Pacific the waters are warmer even deeper, while in the east the waters are cold. During the El Niño phenomenon, the 20 ºC thermocline achieves an equilibrium that is almost symmetrical between the West and the East, which is why both regions present warm surface waters.

Weakening of the Walker cell

As surface waters in the eastern Pacific warm from inputs from the north, the air above the sea warms and rises. This produces a zone of low atmospheric pressure, which weakens the trade winds that blow from this zone to the west.

These winds are the ones that regularly carry hot surface waters to the west (Indonesia), so that when they weaken, a calm zone is formed and the water warms up even more.

Kelvin waves

Under regular conditions, the high water temperatures in the western Pacific cause the water to expand, increasing its level. In other words, the water level in the western Pacific is higher than on the South American coasts, approximately 60 cm higher.

As the thermocline is altered by the warming of the eastern Pacific waters, the water level in this area rises. This, together with the weakening of the trade winds, causes part of the warm waters from the west to move towards the east.

Therefore, water waves are produced in a west-east direction, which are called Kelvin waves. This in turn contributes to a further increase in water temperature in the eastern Pacific.

Consequences

Alterations in the effects of the Peruvian current and decrease in fishing

The Peruvian coasts are among the richest fishing areas on the planet, related to the outcrop of cold waters. The Humboldt or Peruvian current drags cold waters from the south pole to the equator.

Also, the currents of deep cold waters that rise, increase the nutrients deposited in the seabed. For this reason, the superficial layers are enriched with nutrients that promote the arrival of large schools of fish.

In these areas the warming of the waters in this area is generated and therefore the effect of the upwelling of deep waters decreases. This in turn decreases the food supply and shoals move away from the area, affecting fishing.

Exceptional rains and floods

The warming of the eastern Pacific waters off the Peruvian coast causes an increase in evapotranspiration in the area. This in turn results in an increase in the amount and intensity of rainfall.

Exceptionally heavy rainfall causes landslides and floods, which even result in the death of humans and animals. Similarly, wild plants and crops and infrastructure such as roads and buildings are affected.

Beneficial rains

In some areas, the excess of exceptional rains as a consequence of the El Niño phenomenon reduce the effects of droughts. This brings benefits to agriculture and the availability of drinking water.

Public health problems

Excessive rains and floods favor the outbreaks of certain diseases, such as cholera and diarrhea, among others.

Droughts

Exceptional drought occurs in some regions, for example Australia and India. This also implies loss of crops, sources of drinking water, increased desertification and the occurrence of fires.

Forest fires

A correlation has been established between the El Niño phenomenon and the increase in the frequency of forest fires, as well as their intensity. This is associated with the severe droughts that this climatic phenomenon produces in some regions.

Sea level variations and changes in sea temperatures

The warming water expands and therefore the sea level in the eastern Pacific increases in relation to the rest of the ocean. In the 1997 El Niño event, the sea level in the equatorial zone increased to 32 cm.

Temperature rise and loss of coral reefs

The temperature of the water in the ocean can rise up to 2ºC above normal maximums. This, among other things, negatively affects the survival of coral reefs, especially in the Pacific Ocean.

Agriculture and farming

Agricultural and livestock activities are among the most affected by the occurrence of El Niño, given the dependence on cyclical factors of these activities. Crops and animals are affected by both the deficit and the excess of water as the case may be.

This causes crops to be lost due to delayed rains or torrential rains that alter flowering or pollination.

Loss of agricultural land

On the other hand, torrential rains provoke the dragging of the surface layer of the soil, eroding it and causing its loss.

Economic imbalances

This climatic phenomenon causes heavy economic losses in several countries, but can bring benefits in others. In the first case, floods and landslides cause the destruction of communication routes and infrastructure.

In the same way, health problems related to these catastrophes and the rebound in plagues and diseases are increasing. Also the loss of crops implies important economic losses, which in turn impacts towards the rise in the prices of the products.

For example, drought implies a decrease in milk production, determining the increase in the price of milk and its derivatives. On the other hand, in some regions that benefit from a greater supply of water, agricultural activity is boosted.

Advantage

The El Niño phenomenon can bring some advantages that are related to the alteration of various factors at the local level. For example, for some areas it implies an increase in the supply of water with the favorable consequences that derive from this.

There are also some diseases and pests that can reduce their incidence by reducing or increasing the humidity.

Water supply

In some areas where droughts are frequent, the El Niño phenomenon can produce an excess of rains that bring benefits to agriculture and breeding. Similarly, diminished aquifers are recharged by this unexpected supply of water.

Diseases and pests

The development of diseases and pests depends on certain environmental factors, in terms of humidity, temperature and others. In such a way that the alteration of these factors can cause both an increase and a decrease in their occurrence.

Positive climatic changes

Climate conditions for people may improve as a result of the Child. For example, less severe and more humid winters, as it happens in some areas of the United States, implying savings in heating in this country.

Likewise, rains that break a prolonged drought as happened in California with the child of 2015, promoting agriculture.

Disadvantages

In general, this climatic phenomenon produces many disadvantages for people, particularly because it occurs irregularly. This determines the difficulty of adapting human activities to their occurrence, especially in the agricultural and livestock fields.

Among the disadvantages that the child entails are economic losses, increased food prices, increased diseases and loss of water sources.

Negative climatic changes

In most regions, the El Niño phenomenon negatively alters regional weather patterns. Such is the case of the droughts in northern South America, Africa, Australia and India, and the increase of hurricanes in the Pacific.

The Strongest Boys in History

The phenomenon of El Niño has been known since the 16th century, including the occurrence of an event classified as very strong in 1578. As outlined in the document “Probanzas de indios y Spaniards referring to the catastrophic rains of 1578 in the Corregimientos of Trujillo and Fury".

Water temperature at the surface of the Pacific Ocean during the 1997 El Niño phenomenon. Source: Maulucioni based on a NOAA image

Since then, at least 10 events classified as very strong have occurred, those of 1877-1878, 1982-1983 and 1997-1998 being extremely strong. In this century, the 2015-2016 El Niño event also reached considerable intensity.

Increasing intensity

Data obtained from paleoclimatic information and records of current conditions show that the events of the El Niño phenomenon have become more marked in the last 30 years.

El Niño in Peru

Peru suffers strong consequences due to this climatic phenomenon, due to an increase in rainfall in quantity and intensity. This causes frequent and devastating landslides and floods with human and economic losses.

Flood in Peru due to the El Niño phenomenon. Source: Gallery of the Ministry of Defense of Peru, Lima-Peru.

The Peruvian fishing industry was seriously affected during the 1972-1973 El Niño, almost collapsing. While in the events of 1982-1983 and 1997-1998, it incurred economic losses of more than 3,000 million dollars in each period.

As a positive effect, the increase in humidity favors the regeneration of coastal forests in the north of the country.

El Niño in Ecuador

Ecuador, located north of Peru, suffers similar effects from the El Niño phenomenon, that is, a considerable increase in rainfall. It is enough to point out that the average rainfall in Ecuador is around 1,000 to 1,200 mm per year, while in the Niño years it doubles.

Even in very strong El Niño events, such as 1982-1983, annual precipitation almost triples (3,500 mm). In the events classified as extremely strong (1982-1983 and 1997-1998), the average temperature of the ocean in the Ecuadorian coasts reached 35 ºC.

During this period of El Niño, the socio-natural disasters resulting from the torrential rains and the landslides caused were considerable. On the other hand, the rise in ocean temperatures also affects fishing activities, as happens with its neighbor Peru.

El Niño in Colombia

Colombia is located in the northwest of South America, an area where the El Niño phenomenon causes droughts. These droughts are generally very severe, even with a moderate El Niño event.

In the case of strong events such as 2015-2016, the consequences are serious, causing a reduction of up to 60% in rainfall. Among others, we can mention the drastic decrease in the flow of rivers in the 2015-2016 period, the Cali, the Manzanares and the Combeima were severely affected.

Another problem that increases during the occurrence of the El Niño phenomenon in Colombia is forest fires. For example, in the protected natural areas of the Magdalena and Urabá departments, almost 3,000 forest fires occurred during 2015-2016.

Agricultural pest

The main pest of coffee cultivation in the country is a beetle known as the coffee borer (Hypothenemus hampei). It has been determined that its incidence increases after extreme droughts caused by the phenomenon of El Niño.

El Niño in Venezuela

In Venezuela, the El Niño phenomenon causes severe droughts that affect its entire surface. Therefore, there is a decrease in agricultural harvests and livestock production.

However, the greatest impact is on the production of electrical energy, which is obtained by hydroelectric plants. Therefore, the particularly intense drought generated by El Niño causes a substantial decrease in electricity supply.

This negative effect was particularly strong in the 2015-2016 El Niño, when the level of the reservoirs reached historic lows. As a consequence of this, there was a strong crisis in the country's electricity supply, which affected economic and social aspects.

El Niño in Mexico

In Mexico, the El Niño phenomenon causes rainier winters and drier summers, the latter being the most problematic. More than 50% of the Mexican territory is arid or semi-arid, facing serious problems of desertification.

The dry periods caused by the El Niño effect represent a serious threat to this country. In general, there is a great imbalance in the rainfall regime in Mexico during the years with the El Niño phenomenon.

In these winter events, the rains decrease substantially in the south of the country, while they increase towards the north. Temperatures are also affected, causing colder winters and warmer summers.

The 1997-1998 El Niño was particularly strong for Mexico, causing a prolonged and severe drought, reducing rainfall by up to 50%. Especially in the northern states of Mexico El Niño of those years forced to declare a state of disaster due to the droughts.

On the other hand, in Mexico there is also an increase in forest fires during periods of the El Niño phenomenon. Strong summers, as a result of this phenomenon, increase with the increase in the incidence of solar radiation due to the decrease in cloud cover.

Another effect of the Niño in the Mexican territory is the increase in the strength of the trade winds over its territory. This in turn slows down the entry of moisture along the Mexican Pacific coast, reducing orographic rains in those regions.

References

1. Angulo-Fernández, F. and González-Álvarez, L. (2008). The El Niño phenomenon in Mexico, a case study: the Papaloapan basin, Veracruz. In: Lammel, A., Goloubinoff, M. and Katz, E. Aires and rainfall. Anthropology of climate in Mexico.
2. Andean Development Corporation. (s / f). El Niño phenomenon 1997-1998. Memory, challenges and solutions volume IV: Ecuador.
3. SDC (2016). The El Niño phenomenon and its associated impacts . Nexus Report, No 2. Climate change and the environment.
4. Freund, MB, Henley, BJ, Karoly, DJ, McGregor, HV, Abram, NJ and Dommenget, D. (2019). Higher frequency of Central Pacific El Niño events in recent decades relative to past centuries. Nat. Geosci.
5. Gasparri, E., Tassara, C. and Velasco, M. (1999). The El Niño phenomenon in Ecuador 1997-1999. From disaster to prevention.
6. Maturana, J., Bello, M. and Manley, M. (2004). Historical background and description of the El Niño phenomenon, Southern Oscillation. In: Avaria, S., Carrasco, J., Rutllant, J. and Yáñez, E. (Eds.). El Niño-La Niña 1997-2000. Its Effects in Chile. CONA, Chile, Valparaíso.
7. Pan American Health Organization (2000). Chronicle of Disasters. El Niño phenomenon, 1997-1998. Emergency Preparedness and Disaster Relief Coordination Program.