Abstract
The exceptionally oceanic warm current, known as El Niño,
which abnormally extends southward along
South American coasts is a regional repercussion of a much wider
phenomenon called El Niño Southern
Oscillation (ENSO). It manifests itself every 3 to 7 years. There
has been a tendency for this length of time to
become shorter since 1970. ENSO is a system of complex
interrelations gathering the dynamic of the Pacific
Ocean hydrosphere with aerological dynamic symbolised by the
Southern Oscillation. This SO corresponds to a
variation of the pressures' differential between the East and
West of the Pacific area, whose appearance is due to
a change of conditions of the general atmospheric circulation
impulsed by the Arctic's drop in temperature.
Those recurrent aperiodic fluctuations of the general circulation
together with a faster meridian transfer of
energy predetermine the arrival of an ENSO period. They are in
parallel with the origin of many hydrometeorological
and environmental anomalies, which form an interconnected chain
of hazards. This succession of
climatic incidences and induced effects will also provoke a
multitude of consequences over societies, either
immediately or in the long run. Far from being systematically
harmful, on the contrary, certain effects can be
considered as good opportunities. However, in many cases,
anthropogenic actions over the environment
contribute to an increase of dangerous situations as well as to
vulnerability of human communities. Furthermore,
numerous factors of vulnerability are also to be searched in the
foundations of societies themselves (such as
institutional and political factors). The purpose of this French
Geography DEA thesis centred on Andean
countries and more precisely, on Ecuador -deeply affected by El
Niño- is to establish a theme work programme
to be studied thoroughly in a PhD thesis. A detailed analysis
will lead to the discovery of improvements in order
to minimise danger due to physical hazards and to protect peoples
within the frame of a concerted planning of
the territory as well as a lasting development of societies.
Key words: El Niño, ENSO, Southern Oscillation, anomalies,
physical hazard, immediate consequences, long
term consequences, societal impacts, anthropogenic actions,
vulnerability, Andean countries, Ecuador.
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REMERCIEMENTS
Je tiens à adresser mes sincères remerciements plus
particulièrement aux personnes suivantes,
certaines pour m'avoir aidé dans l'élaboration de
ce mémoire et d'autres pour m'avoir soutenu
lors de mon séjour en Equateur :
Robert D'Ercole, maître de
conférences à l'Université de Savoie
Marcel Leroux, professeur à
l'Université Jean Moulin, Lyon III
Patrick Pigeon, maître de
conférences à l'Université de Savoie
Jean François Dumont, géologue de
l'IRD, en poste à Guayaquil et Sahlia, sa femme
Francis Kahn, représentant IRD à
Quito
Robert Hoorelbeke, hydrologue de l'IRD à
Quito
Jean Louis Perrin, hydrologue de l'IRD à
Quito
Kevin Pedoja, CSN géologue à
Guayaquil
Cristina Carrión, documentaliste de l'IRD
de Quito
Claudine Misson, responsable de la base Em-Dat
au CRED-UCL - Bruxelles
Balbino Fernandez et Céline Milani, mes
irremplaçables traducteurs
et puis les locataires de la Casa Lortic, Axel, Guillaume, Picou,
Séverine, Orane,
Vincent, Benoît, Marisa, Manue, sans oublier Mouic et
Noémie
ma famille.
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