ENSO is a phenomenon of climate variability. Due to the two phases: El Niño or La Niña, they produce various effects, sometimes unexpected, in different regions of the continent and the world. Knowing the climatic disturbances associated with each phase allows intelligent decisions to be made, aiming for a planned development that protects communities and their means of subsistence.
* This article was published in Geociências SURA Magazine | Issue 1 | November 2016.
ENSO: manifestations and characteristics
The El Niño Southern Oscillation (ENSO) or the EL Niño Southern Oscillation (ENSO) is a phenomenon of climate variability that has a significant impact on the dynamics of atmospheric winds and precipitation patterns in the tropics, caused by the rise or fall of the average surface temperature of the Equatorial Pacific Ocean.
ENSO is a phenomenon that occurs due to the interaction between the ocean and the atmosphere in the Equatorial Pacific. Depending on the season, certain regions of the Equatorial Pacific Ocean increase their surface temperature, producing a rise in heat in the atmosphere, which, if condensed, can cause a considerable increase in chuvas in certain regions.
The intensity of ENSO can be classified into three levels: weak, moderate and strong. To estimate each level of intensity, there are different macroclimatic indices that are built from the comparison of climatic variables observed in various regions of the Equatorial Pacific Ocean, such as ocean surface temperature, atmospheric pressure, surface wind speed and cloud cover.
Since each index is built from the observation of different climatic variables, the values obtained can vary from one to another, so that the final intensity of each ENSO event is defined by a consensus made by specialists from entities such as the Administração Nacional Oceânica e Atmospheric Institute of the United States (NOAA), or the El Niño Research Center (CIIFEN) and the International Institute for Climate and Society Research (IRIS), among other entities worldwide, coordinates of the World Meteorological Organization .
Suramericana carries out constant monitoring of the seasonal (quarterly) ENSO forecast generated by international and national agencies in charge of the World Meteorological Organization (WMO), in order to promptly inform its clients of the probability of occurrence of the phenomenon.
Why do the effects of ENSO in different regions of Latin America vary so much?
ENSO is a macroclimatic phenomenon that, combined with other climatic, geographical and topographical variables, such as the proximity of a specific place in the tropics, the orographic configuration, the proximity of the Amazon Basin, and the ocean currents of the Pacific, affects behavioral dynamics. local climate.
This phenomenon is quite complex and, it affects its probability of occurrence and can be predicted, as duration and intensity are difficult to foresee. Its impacts depend on the specific climatic conditions of each country.
It is important to be aware of the two climatic effects that this phenomenon causes in each region and its probability of occurrence. To do this, the responsible agencies constantly monitor the atmospheric-oceanic state and have communication channels to inform and offer the fundamental elements that allow us to plan the actions to follow for different sectors, in the case of El Niño or La Niña, in order to reduce your impacts.
Why is this phenomenon called “El Niño”?
During the current phase of ENSO (El Niño), surface temperatures along the Equatorial Pacific Ocean reach their apex in December. This fact directly affects the thermal structure of the ocean, especially in the eastern Pacific, on the Peruvian coasts, where it inhibits both surface and deep waters, or prevents nutrients from emerging in the surface layers from the seabed. For this reason, a large part of the marine fauna migrates to other regions looking for food.
We will first notice this situation for the fishermen on the Peruvian coast, who associate the phenomenon with the birth of Jesus (The Child God) Due to the time in which this anomaly occurred, reason why we began to refer to the phenomenon as “El Niño”. The scientific community adopted this name for the current phase of ENSO, and called the other part of the phenomenon (cold phase) as “La Niña”.
What are the characteristics of ENSO?
ENSO shows its first signs in the variation in surface temperature of the Equatorial Pacific Ocean, approximately in the March-April-May quarter (MAM), consolidates between June and November, and reaches its maximum intensity approximately no more than December, when I started to lose strength.
The variation of the average temperatures mentioned in the Equatorial Pacific Ocean does not immediately affect the climatic disturbances of each region where the effects of this phenomenon are perceived. Decreases or increases in average precipitation may take several months after the ENSO signals in the ocean, depending on the geographic location of each region.
ENSO exhibits an irregular cycle, which means that its phases do not always alternate, that is, an El Niño phase does not necessarily have to be followed by a La Niña phase and vice versa. An example of irregularity that can occur in each of its phases is the La Niña period that occurred between 2010-2011, of moderate intensity, or which was followed by another La Niña period between 2011-2012, with weak intensity.
ENOS or climate change
Oceanographer Rodney Guillermo Martínez Güingla, director of the International Center for Research on the El Niño Phenomenon (CIIFEN), explains that the scientific community still maintains an open debate on the behavior of ENSO not referring to Climate Change, and places as an example latest discussions of the Government Panel on Climate Change (IPCC, acronym in English).
However, A tangivel fact that makes us more aware of the effects of the phenomenon — and that makes us more vulnerable to its effects — is the unplanned development of society.
Extensive livestock farming, population settlement in cities in a disorganized manner and in high-rise areas, as well as misinformation, among other aspects, mean that, having seasons of intense rainfall or prolonged dry periods, have more consequences.
Variability of effects
When we look at ENSO, we realize that each event related to its hot or cold phase can present various characteristics associated with its duration and severity, due to the climatic repercussions of a season, such as the development of the El Niño phase in certain region, only as we could generate another season associated with the same phase.
It does not refer to its impacts, or the phenomenon presents a differentiated behavior by region, even within the same country. For example, the El Niño phase causes excessive precipitation on the Peruvian coast and an increase in air temperature in the Andean region. In Colombia, its behavior is also differentiated, since in the Andean region there is a marked decrease in precipitation in comparison with other areas of the country.
We mention countries such as Argentina, Uruguay, Chile or Brazil, we must explain that, due to their geographical characteristics, the weakening of two trade winds is expected to occur more coldly when we are in the current phase (El Niño).
“The effects of ENSO are felt more intensely in the north of South America than in the south. Depending on the geographic region, the effects may vary. In Colombia, La Niña causes an increase in precipitation that causes flooding and landslides; “While in Chile and in large areas of the basins of the Paraná River and the La Plata River, dryness intensifies,” explains Dr. Germán Poveda, Specialist in hydroclimatology and climate change and research professor at the National University of Colombia.
Who are the sectors most affected by ENOS?
According to Dr. Poveda's observation, all productive sectors can be impacted positively or negatively by this phenomenon; For example, the agricultural, fishing, energy, tourism and health sectors, among others.
Therefore, it is very important to know in real time the state of the climatic variables that define El Niño or La Niña, to mitigate their negative effects through urban planning and implementation of protective measures and to enhance the positive effects in business opportunities. and economic development.
Smart hydroclimatic decisions
Oceanographer Martínez highlights that it is essential to assimilate the concept of climate-intelligent development. “This is why hydroclimatic information is an additional input for the decision-making process of national and local governments, and also for business leaders who want to maintain their competitiveness in the market and sustain economic activities. Of course, this implies being informed to make decisions in time.”
The objective is to look for solutions that allow us to make timely decisions, because Latin America must go in the direction of strategic planning, “on the contrary we will be improvising all the time and, from a productive point of view, this would imply losses and poor resilience in activity. economic,” he explains.
A challenge: managing two risks and opportunities
According to oceanographer Martínez, it is necessary to acquire knowledge not to mention respect for prognosis, mitigation and preparation for these types of events. “We have the challenge of adequately preparing ourselves for the effects of ENSO, this is the concept of risk management, even more so when we are also vulnerable.” Its logic is simple: “We will act with this precautionary principle in mind, we will be prepared in case something happens or there is no phenomenon, and we will have a territory ready to face its consequences.”
The different productive sectors must seek to act in advance in order to be able to mitigate the negative impacts that any phase of ENSO may cause. However, these measures should not be limited only to managing the risk of direct material damage, but also consider the risk of supply networks (that we open suppliers, infrastructure, logistics, customers, among others) to make preventive decisions and guarantee sustainability of two businesses.
An interesting point in discussing what None of the impacts of ENSO are negative, such as the case of El Niño for the Caribbean tourism industry., due to the diminution of furacões, which encourages reflection on the way in which these conditions can be taken advantage of “and not only to anticipate for possible losses, but also to benefit from the foresight of the phenomenon”, as mentioned by Dr. Germán Poveda .
Consequently, it is possible to make intelligent decisions not only in terms of how to manage businesses, but also in the possibility of dealing with climatic disturbances in each phase of ENSO.
Sources
- Rodney Guillermo Martinez Güingla. Oceanographer, international director of CIIFEN, International Center for Research on the El Niño Phenomenon, Equador Marine Officer in passive service.
- German Poveda Jaramillo. Doutor in Water Resources Engineering at the National University of Colombia and the University of Colorado. Professor at the Faculty of Mines of the National University of Colombia.