In the previous section, world population has been analysed from a demographic perspective, that is, from the volume’s viewpoint (total number of inhabitants on Earth) and from the structure’s one (basically, sex and age structure).
Obviously, in order to analyse the effects that this population has on the environmental and on the sustainability, it is necessary to carry out this geographical perspective in a geographical way, since it’s territorial distribution is especially important. In other words, at a certain territorial scale, the impact on the environment will not depend only depend on the population volume, but also on its distribution in that space.
As it is said in the module’s introduction, the settlement is the concept that links the population with the territory it occupies and that is used, from the geographical perspective, to refer to the territorial distribution of the population. A first distinction within the settlement of a region is the differentiation between the urban settlement and the rural one.
The urban settlement is, generally speaking, characterised by high density of population and building, as a result of a long process of the territory urbanisation, which can be divided into three stages: a) a first one, linked to the preindustrial cities, which have been created because of military-strategic, administrative-political, economic or religious reasons; b) a second stage, clearly demarcated by the existence of the modern mechanised industry; and c) a third post-industrial stage, characterised by a decrease of the urban growth rhythm and the development of the service sector within the economic activities. Generally, cities tend to create its urban networks in a hierarchical and integrated system manner, where each element, each urban nucleus tends to specialise functionally.
On the other hand, the rural settlement is usually defined as the settlement that doesn’t reach a certain population threshold. Although the fixing of this threshold is subjective and variable within the time, in Spain, it usually reaches 10000 inhabitants.
However, the transformation and the territorial dynamics of the western countries, mainly characterised by the population dispersion and the economic activities distribution, have caused doubts on the traditional dichotomy between the urban and the rural spaces. For this reason, the population density criterion is used, that is to say, the link between the population volume and the territory it occupies. Therefore, there are two types of settlement: concentrated or dispersed settlement. Nevertheless, as it can be deduced, this differentiation is very variable accordingly to the analysis’s scale and it is also very subjective, as it depends on the administrative demarcation of the frontiers and the territorial divisions used for the calculation.