Desertification or the problem of intense land degradation is an old concept. Through time, historical awareness has been fluctuating with periods of more environmental concern and moments of less attention. The UN Convention on Desertification has brought to a first level of consideration the global dimension of the issues. There is a common link between a wide variety of places that can be classed as deserts and this link is slight or nil biological production. The word desertification is a label for this low biological production or for the process decreasing it despite the different biophysical landscapes in which it can develop, but mainly dryland areas.