By Julio César Centeno
It tends to modify weather patterns in various parts of the world and increase the average temperature of the planet, immediately after the hottest year of the Christian era: 2014 (2014: THE HOTTEST YEAR).
Since the beginning of 2014, several Kelvin waves have been detected: currents of warm water moving under the surface of the Pacific Ocean from Asia to South America in the tropical belt. They take about two months to cross the ocean.
These waves have contributed to generating one of the conditions necessary for the presence of El Niño to be declared: the average temperature on the surface of selected regions of the eastern Pacific must exceed the normal temperature by at least 0.5 ° C during five overlapping periods of three months. .
It also requires the weakening of the trade winds in the lower atmosphere that move in the equatorial belt from South America towards Asia (from east to west).
Under neutral conditions, these winds displace warm surface water westward, causing sea levels to be about 50 centimeters higher in Indonesia than in Ecuador.
Part of this difference is due to thermal expansion: surface water temperatures can be up to 8 ° C higher in the west (approximately 30 ° C) than on the coasts of South America (22 ° C). The colder deep waters move in the opposite direction, towards the East, emerging near the coasts of South America.
During El Niño, the surface winds weaken and the warmer and higher surface waters in the western Pacific drift toward South America, as if collapsing to the east.
Precipitation follows warmer waters. The effects are varied, although it usually causes droughts in Indonesia, Australia, India and northern South America, while unleashing rains and floods in the south-eastern region of South America, in the equatorial east of Africa and in the southern United States .
The coasts of Ecuador and Peru tend to receive higher rainfall.
El Niño and La Niña are the warm and cold phases of an oscillation in the tropical Pacific known as the Southern Oscillation, with a variable period of 3 to 7 years. This oscillation generates a huge redistribution of heat energy in the surface layer of the ocean.
The excess heat energy on the coasts of South America associated with the 1998 event is estimated to be equivalent to that generated by one million electricity generating plants of 1000 MW each, operating for a whole year.
Due to its initial characteristics, this time is not expected to be as devastating as 1998, when it contributed to making it the only one of the 15 warmest years recorded to date that does not correspond to the 21st century. However, you could attend to make 2015 the hottest year in centuries.
* Engineer graduated from New York University; postgraduate degrees at the University of California, Berkeley. Professor at the University of Los Andes, Venezuela.
Advisor to the Secretariat of the United Nations Conference on Environment and Development [UNCED].
Executive Director of the Latin American Forest Institute. Invested by Prince Bernhard of the Netherlands with the Order of the Golden Ark. Vice President of the TROPENBOS Foundation in the Netherlands. Member of the Board of Directors of the Forest Stewardship Council, FSC. Member of the Board of Directors of SGS-Forestry, Oxford. Visiting Professor at the Department of Forest Policy and Economics, University of Vienna, Austria. International advisor.