desertification

n. transformation from fertile land to desert terrain (Ecology)

Desertification is the degradation of land in arid, semi arid and dry sub-humid areas resulting from various climatic variations, but primarily from human activities. Current desertification is taking place much faster worldwide than historically and usually arises from the demands of increased populations that settle on the land in order to grow crops and graze animals.
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Noun
1. the gradual transformation of habitable land into desert; is usually caused by climate change or by destructive use of the land; "the dust storms in Korea are the result of rapid desertification in China"
(hypernym) geological process, geologic process

The progressive destruction or degradation of existing vegetative cover to form desert. This can occur due to overgrazing, deforestation, drought, and the burning of extensive areas. Once formed, deserts can only support a sparse range of vegetation. Climatic effects associated with this phenomenon include increased albedo, reduced atmospheric humidity, and greater atmospheric dust (aerosol) loading.

The process through which a desert takes over a formerly nondesert area. When a region begins to undergo desertification, the new conditions typically include a significantly lowered water table, a reduced supply of surface water, increased salinity in natural waters and soils, progressive destruction of native vegetation, and an accelerated rate of erosion.