By: Pastor C. Paa, Jr.
Tantrums of a Child
El Niño is a term first used by the Peruvian fishermen meaning ‘Christ Child’ to describe the warm current appearing off the western coast of Ecuador and Peru around Christmas time. The result is extra heavy rain, which the coastal inhabitant of those countries have always welcomed for the abundance of crops that it brings, hence the name El Niño (the Christ Child), for the gifts of plenty that it bestows so soon after the Nativity.
However, the event is no longer a blessing in other parts of the world, because today it is associated with severe flooding, severe drought, reversal of normal rainfall pattern and even mass death due to toxic marine harvest during ‘red tide’, a phenomenon caused by excessive toxic algal bloom associated with a rise in sea temperature.
Sir Gilbert Walker, a British meteorologist started the first investigation into this phenomenon while attempting to understand the droughts that caused famine in India in the 1800s. He coined the term ‘Southern Oscillation’ to describe the warm phase of a naturally occurring sea surface temperature oscillation in the tropical Pacific Ocean. The El Niño Southern Oscillation (ENSO) has become one of the most studied phenomena on the planet because it is also one of the most feared.
Normally, a large area of high pressure sits over the eastern edge of the Pacific Ocean. From this high-pressure zone the southern trade winds blow towards a large area of low pressure that is settled over Indonesia, on the other side of the ocean. These strong winds drag the cool water that lies off South America westwards with them, which in turn is warmed up as it makes contact with the atmosphere and by the heat of the sun. This process raises the sea level in the western Pacific by about 40 cm thick of warm water that is brought back gently to the east to cool off by an action known as the countercurrent, and the cycle starts again. This process also brings about the monsoon rains. Further up, the drier air is carried by the fast moving upper level winds to the east, where it cools and comes down producing a high pressure zone off South America where the cycle began. This is called the ‘Walker circulation’ and is the normal cycle.
An El Niño event is different, however. A slight relaxation of the trade winds can start this event. The weaker winds causes the mass of warm water in the west to surge eastward, strengthening the countercurrent and forming a warm layer of warm water much closer to South America than usual. This warm layer of water warms the air above which lowers the pressure of the atmosphere thus weakening the winds even more. So more warm water pushes eastward reversing the flow of the countercurrent. The whole Pacific is effectively covered with an extra layer of warmth and the winds change direction, setting into a new long term pattern in the opposite direction.
The warm air eventually will carry with it moisture evaporating from the ocean resulting to more rain. For the farmers, this is a blessing but for some it is a disaster. Large areas are flooded while those that depend on the harvest from the seas, this event is a disaster.
The warm waters are depleted of nutrients needed by the fish thus fish goes somewhere else to feed.
Tantrums of a Child
El Niño is a term first used by the Peruvian fishermen meaning ‘Christ Child’ to describe the warm current appearing off the western coast of Ecuador and Peru around Christmas time. The result is extra heavy rain, which the coastal inhabitant of those countries have always welcomed for the abundance of crops that it brings, hence the name El Niño (the Christ Child), for the gifts of plenty that it bestows so soon after the Nativity.
However, the event is no longer a blessing in other parts of the world, because today it is associated with severe flooding, severe drought, reversal of normal rainfall pattern and even mass death due to toxic marine harvest during ‘red tide’, a phenomenon caused by excessive toxic algal bloom associated with a rise in sea temperature.
Sir Gilbert Walker, a British meteorologist started the first investigation into this phenomenon while attempting to understand the droughts that caused famine in India in the 1800s. He coined the term ‘Southern Oscillation’ to describe the warm phase of a naturally occurring sea surface temperature oscillation in the tropical Pacific Ocean. The El Niño Southern Oscillation (ENSO) has become one of the most studied phenomena on the planet because it is also one of the most feared.
Normally, a large area of high pressure sits over the eastern edge of the Pacific Ocean. From this high-pressure zone the southern trade winds blow towards a large area of low pressure that is settled over Indonesia, on the other side of the ocean. These strong winds drag the cool water that lies off South America westwards with them, which in turn is warmed up as it makes contact with the atmosphere and by the heat of the sun. This process raises the sea level in the western Pacific by about 40 cm thick of warm water that is brought back gently to the east to cool off by an action known as the countercurrent, and the cycle starts again. This process also brings about the monsoon rains. Further up, the drier air is carried by the fast moving upper level winds to the east, where it cools and comes down producing a high pressure zone off South America where the cycle began. This is called the ‘Walker circulation’ and is the normal cycle.
An El Niño event is different, however. A slight relaxation of the trade winds can start this event. The weaker winds causes the mass of warm water in the west to surge eastward, strengthening the countercurrent and forming a warm layer of warm water much closer to South America than usual. This warm layer of water warms the air above which lowers the pressure of the atmosphere thus weakening the winds even more. So more warm water pushes eastward reversing the flow of the countercurrent. The whole Pacific is effectively covered with an extra layer of warmth and the winds change direction, setting into a new long term pattern in the opposite direction.
The warm air eventually will carry with it moisture evaporating from the ocean resulting to more rain. For the farmers, this is a blessing but for some it is a disaster. Large areas are flooded while those that depend on the harvest from the seas, this event is a disaster.
The warm waters are depleted of nutrients needed by the fish thus fish goes somewhere else to feed.
The rise in the temperature of the environment also changes the normal patterns of the weather. Freak storms and hurricanes appear suddenly while large part of the world experience drought. In the Philippines, the effects of El Niño can be enumerated as:
Environmental effects
- degradation of soil which could lead to desert-like conditions if persistent
- effect on water quality like salt water intrusion
- high forest/grass/bush fire risk
- domestic water supply shortages
Social effects
- disruption of normal human activities
- migration to urban communities
- health problems
Economic effects
- unemployment
- food shortages
- significant reduction in the productivity and subsequent revenue of various industries
In other parts of the world like India, the monsoon rains is always an awaited event but during an El Nino event, this may never happen which will result into a drought that devastates the crops and induce famine.
Elsewhere, the calm weather is deafening!
Reading references
1) Philander, S.G.H., 1990: El Niño, La Niña and the Southern Oscillation. Academic Press, San Diego, CA, 289 pp
2) Lynch, John. 2002. The Weather. Firefly Books Ltd.. Toronto, Ontario. p100-104
3) . 2010 [cited 2010 Jan 27]. GMA News TV. [Internet]. Diliman, QC: GMA. Available from: http://www.gmanews.tv/story/52900/The-El-Niño-Phenomenon
4) . 2010 [cited 2010 Jan 27]. Ww2010. [Internet]. Urbana-Champaign: Department of Atmospheric Sciences-University of Illinois. Available from: http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/eln/home.rxml.
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