In what was probably his last paper published during his lifetime, the late Constantinos A. Doxiadis (1975) formulated the main danger of extreme urbanization in the following way:
As soon as commercial forms of energy and machines enter our settlements, they start to expand at a much greater rate than does the growing settlement’s population and economy. As the growing settlements need to add a lot of industry and many big buildings, their expansion is not directed towards mountainous areas but occurs chiefly on the plains. It is here that the best soils usually lie: thus urban growth means profligate elimination of agricultural land.
This is not an immediate problem for tomorrow, in terms of days; but it is a very big problem in terms of years and decades, as agricultural land covers a very small percentage of the global surface and we cannot afford to lose it. The danger is very great and we must act quickly if we are to avoid it. (Ibid., p. 13.)