The original definition was actually "land degradation" and not the spread of natural deserts to new areas, as is the case with the Sahara Desert. However, until recently the term “land degradation” had referred to processes in arid and dry sub-humid regions and processes caused by man. Between 35-42% of the earth’s land mass can be defined as "dry lands" and 35% of the population - about two billion people - live in these areas. In Israel, for example, 95% of the land is considered "semi-arid."
Speaking of the subject, Israel expert Professor Safriel suggested that desertification should be defined by "lack of soil productivity" to enable us to focus on possible solutions for seemingly contradictory situations. For example, in South Africa, in areas with similar rainfall, white farmers evidence higher NPP (net primary productivity) than black farmers. This means that we need to focus not only on climatic conditions, but also on monitoring land usage without destroying its productivity. In fact, overuse of land resources often inspires ingenuity that promotes sustainable use of lands and biological activity.