期刊名称：Science et changements planétaires / Sécheresse
印刷版ISSN：1147-7806
电子版ISSN：1777-5922
出版年度：1990
卷号：1
期号：3
页码：187-195
出版社：John Libbey Eurotext
摘要：Author Monique Mainguet Laboratoire de Géographie Physique Zonale, université de Reims, 57 rue P Taittinger, 51000 Reims, France. Page(s) : 187-95 Published in: 1990 Once the problem of defining desertification, its existence, reversibility, and localization, has been raised, the first point to be made is that a climatic crisis will reveal underlying desertification. Paleoaridity in tropical Africa and droughts in history are considered. A second point stresses the overload on the carrying capacity and imbalances in production along with the collapse of traditional production systems, the relentless increase of herds, and administrative failings. The third point concerns an environmental crisis due to the disastrous activities of man - the effects of which can be seen in the latest upsurge of drought. The Sahel-Sudan ecosystem sits on the 800 mm isohyet fence where degradation is most important and where populations of man and livestock are of the highest concentration and where the greatest amounts of wood and water are consumed. Evaluating this ecological phenomenon - ecological since it concerns a disruption in the man-environment equilibrium - is justified at a time when a precise knowledge of its nature, causes, mechanisms, consequences as well as the means available to man to avoid or correct it before the critical level of soil degradation has been reached. The satisfying effect of the last good rainy seasons in regions believed - too soon - to be desertified are encouraging. However, the threat still remains since neither responsibility is accepted nor genuine remedies are taken; and media sidestepping is still kept alive by various myths of which the most caricatural is «the ineluctible spread of the deserts».
