ABSTRACT
Acknowledgments .................................................................................................. 321 References .............................................................................................................. 321
According to estimations of UN-HABITAT (2011), the number of people living in urban areas worldwide will increase from 3.5 billion in 2010 to 4.9 billion in 2030. This is equivalent to an urbanization rate of 1.81% per year from 2010 to 2020 and 1.60% per year between 2020 and 2030, respectively. That is, on average, the number of people living in urban areas worldwide is increasing per year by 1.71%. The largest portion of urbanization will take place in developing countries: from 2010 to 2020, the rate will be at 2.21% per year and from 2020 to 2030, it will decrease to 1.92% per year. From the group of developing countries, the African continent will have the highest urbanization rates: 3.21% per year for the period from 2010 to 2020 and 2.91% per year from 2020 to 2030, of which the largest portion belongs to sub-Saharan Africa with 3.51% per year (2010 to 2020) and 3.17% per year (2020 to 2030). Irrespective of the reasons for such enormous migration movements, these numbers indicate that cities in the developing countries, especially the subSaharan countries, will face an enormous increase in population pressure. Following UN-HABITAT (2007), among the “nearly one billion people alive today one in every six human beings are slum dwellers, and that number is likely to double in the next thirty years.” This number is estimated to be 2 billion by 2030. That is, besides a general increase in urbanization, the portion of the urban population living under slum conditions will increase from 28.57% from now to 40.82% in 2030. This means that by 2030 there will be 2 billion people in urban areas lacking access to safe water, improved sanitation, and secure tenure living in overcrowded and unsecure housing structures with environmental degradation. “Alarmingly, there is currently little or no planning to accommodate these people or provide them with services” (UN-HABITAT 2007). With this background, programs such as the “United Nations Millennium Development goal to improve the lives of at least 100 million slum dwellers by 2020” (UN-HABITAT 2007) were started. However, regarding the increase in rates of slum dwellers, it is obvious that global and local policies and instruments are necessary to improve the living conditions in informal settlements and to fight poverty at all. “Much more political will is needed at all levels of government to confront the huge scale of slum problems that many cities face today, and will no doubt face in the foreseeable future” (Anna Kajumulo Tibaijuka, Executive Director of UN-HABITAT, in UN-HABITAT 2007). The described situation makes it clear that there is an increasing need to detect informal settlements at least for inventory reasons but also for continuous monitoring, mapping, and finally upgrading in terms of providing a minimum standard of housing conditions.
