Generally, our increasing knowledge has allowed us to refine the definition over the years, such that it has become more specific over time. An early attempt was simply "the spread of desert like conditions", which has since been replaced many times, up to the one in present usage, finally adopted by UNCED in 1992/3; "desertification is land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and adverse human impacts". By introducing "land degradation" it was implicitly understood that desertification leads to long lasting and possibly irreversible desert-like conditions. This definition also brings to play the relative contributions of human and natural factors, which themselves are causes of much controversy, as well as the spatial extent of desertification, which is now known not only to occur on desert borders, but in a number of dryland environments.

             However, in spite of the effort put in, and continuing to be donated, to the resolution of all definitional controversies, there are still commentators who disagree with the need for a separate term to cover what they think, is covered by the term "land degradation". Le Houerou (1959) preferred to use "desertisation" as a term to describe the extension of the desert into areas previously not desert as a result of adverse human actions. El Baz (1983) said further that both the terms desertification and desertisation were "vague and unnecessary", and recommended the universal use of the already defined term "land degradation", which could be tailored to each individual user. (Verstraete, 1983). This would be one way, he said, to avoid the definitional controversies of desertification. However, this may lead to further confusion, as people are forced to disaggregate human and natural factors. "I have regarded rainfall fluctuations as contributing to desertification, although I viewed the degradation as mainly man-made.