Désertification au Sahel: Historique et perspectivesOzer, Pierre ; Hountondji, Yvon ; et alin Bulletin de la Société Géographique de Liège (2010), 54 Over the last decades, the Sahel of West Africa has suffered two dramatic contiguous droughts. Currently, and since the late 1980s, rainfall amounts tend to catch up with the pre-1970 levels. However ... [more ▼] Over the last decades, the Sahel of West Africa has suffered two dramatic contiguous droughts. Currently, and since the late 1980s, rainfall amounts tend to catch up with the pre-1970 levels. However, this improvement seems to occur through increased rainfall intensities but the duration of the rainy season did not significantly change since the 1970s and the 1980s. On the other hand, the Sahelian population has tripled since 1950 and it is foreseen to be multiplied by 10 by the second half of the 21st century. Increasing urban population levels are still much more impressive and cause profound environmental degradation. Such an increasing human pressure leads to uncontrolled deforestation in order to satisfy the needs in fuel and construction wood and to make place for shifting cultivation. In addition, larger and larger herds occupying contracting pasture areas leads to overgrazing and trampling. All these processes provoke the degradation of the vegetation cover, a constant diminution of crop yields, and a strong reduction of the biodiversity. This article provides a state of the art of recent findings and controversy that surround the desertification processes. We conclude that, if the droughts of the 1970s and 1980s have had dramatic consequences for the population of the Sahel, the future very high human pressure on the environment will most likely enhance the desertification of the southern fringe of the Sahara, especially in the case of the alarming climate change scenarios forecasting rainfall decrease all over the Sahel. [less ▲] Detailed reference viewed: 927 (79 ULg) La désertification est-elle en recul au Sahel ?Ozer, Pierre ; ; Hountondji, Yvon et alin Bois et Forêts des Tropiques (2007), 293 Land degradation trends in arid, semi-arid and subhumid areas are such that the General Assembly of the United Nations has declared 2006 the International Year of Deserts and Desertification. Surprisingly ... [more ▼] Land degradation trends in arid, semi-arid and subhumid areas are such that the General Assembly of the United Nations has declared 2006 the International Year of Deserts and Desertification. Surprisingly, a global review carried out for the Millennium Ecosystem Assessment concluded that existing data do not support the claim that the African Sahel is a desertification hotspot. Here, we try to understand the reasons why such conclusions were drawn. [less ▲] Detailed reference viewed: 146 (22 ULg) Boat people d’aujourd’hui; ; Ozer, Pierre ![]() Article for general public (2006) Detailed reference viewed: 23 (2 ULg) Nous ne pouvons ajourner la réforme des politiques d'aide au développementGemenne, François ; ; Ozer, Pierre ![]() Article for general public (2006) Barça ou Barzakh, un autre monde ou l'autre monde, Barcelone ou l'au-delà. Voici le leitmotiv de tous ces candidats à l'exil qui s'entassent quotidiennement dans des cayucos, ces grandes pirogues colorées ... [more ▼] Barça ou Barzakh, un autre monde ou l'autre monde, Barcelone ou l'au-delà. Voici le leitmotiv de tous ces candidats à l'exil qui s'entassent quotidiennement dans des cayucos, ces grandes pirogues colorées utilisées pour la pêche, en direction des îles Canaries. Après les départs massifs observés à partir de Nouadhibou, en Mauritanie septentrionale, les départs s'étalent vers le sud, du Sénégal, de Guinée-Bissau et même de Guinée-Conakry, soit des traversées de plus de 2000 kilomètres. Depuis le début de l'année, ils sont plus de 25 000 à avoir atteint les côtes espagnoles, largement plus que le « record » établi à 9929 pour toute l'année 2002. Mais combien y ont laissé la vie ? Il est malaisé de répondre à cette question. [...] [less ▲] Detailed reference viewed: 181 (17 ULg) |
||