世界における砂漠化とその研究の現状
1988 年 61 巻 2 号 p. 89-103
詳細
1988 年 61 巻 2 号 p. 89-103
Attention to the problems of desertification by many governments and the scientific communities in many countries has increasingly been paid in the last decade. The drought in the Sahel, which extended from 1968 to 1973, especially focused public attention on the problem of desertification. In response, United Nations Conference on Desertification (UNCOD) was held in Nairobi, Kenya, from August 29 to September 9, 1977.
According to United Nations' definition(Biswas, M. R. and Biswas, A. K., 1980), “desertification is the diminution or destruction of the biological potential of land and can lead ultimately to desert-like conditions: grazing land ceases to produce pasture, dryland agriculture fails, irrigation fields are abandoned owing to salinization, waterlogging or some other form of soil deterioration”.
The purpose of this paper is to make clear the present situation of desertification and its research in the world.
The author explains the present situation and the problems of desertification in the world using distribution map showing the degree of desertification hazards prepared by Hopkins and Jones (1983). Aridlands divided into four types based on the degree of aridity such as hyper arid, arid, semiarid and subhumid regions, and three classes of desertification risk such as very high, high and moderate are shown on the map presented to UNCOD by UNESCO (1977).
Then, the author has described the results obtained from the case study in South-East Spain, and conducted the comparative study on desertification taking place in South-East Spain and in semiarid region of northeastern Brazil.
The author overviewed also the previous researches on desertification from the viewpoint of its definition, causes, reversibility or irreversibility, and degradation of tropical forests.
Lastly, the author has emphasized that the desertification is the subject of interdisciplinary researches which should be faced in collaboration with various fields of science such as geography, politics, economics, cultural anthropology, hydrology, climatology, geomorphology, plant ecology, forestry, agriculture and so on. So, it is of importance to organize an interdisciplinary project team on desertification and to make clear scientifically the causes of desertification.
