An Overview of Urbanization, Internal Migration, Population Distribution and Development in the World

The distribution of humanity on the earth’s surface has always responded to
the opportunities that different territories provide. After the invention of
agriculture, the availability of arable land largely determined the place where
most people settled. The practice of agriculture also permitted the accumulation
of food surpluses and the differentiation of productive activities that led to the
emergence of more complex settlements generically identified as “cities”. In
modern history, cities have played key roles as centres of Government,
production, trade, knowledge, innovation and rising productivity. The changes
brought about by the industrial revolution would be unimaginable in the absence
of cities. The mechanization of production made necessary the concentration of
population. Rapid industrialization was accompanied by increasing urbanization.
In 1920, the more developed regions, being the most industrialized, had just
under 30 per cent of their population in urban areas. As industrialization
advanced in the developing world so did urbanization, particularly in Latin
America where 41 per cent of the population was urban by 1950. In Africa and
Asia levels of urbanization remained lower, although the urban population
increased markedly, particularly in Asia. Between 1920 and 2007, the world’s
urban population increased from about 270 million to 3.3 billion, with 1.5 billion
urban dwellers added to Asia, 750 million to the more developed regions, just
under 450 million to Latin America and the Caribbean, and just over 350 million
to Africa. These changes foreshadow those to come. Between 2007 and 2050, the
urban population is expected to increase as much as it did since 1920, that is, 3.1
billion additional urban dwellers are expected by 2050, including 1.8 billion in
Asia and 0.9 billion in Africa. These powerful trends will shape and in turn be
shaped by economic and social development.

Urbanization has been driven by the concentration of investment and
employment opportunities in urban areas as well as by the transition from lowproductivity
agriculture to more productive mechanized agriculture that has
produced labour surpluses in rural areas. Productive activities in industry and
services cluster in cities. By one estimate, 80 per cent of the world’s GDP is
generated by urban areas. As cities attract businesses and jobs, they become
magnets for migrants seeking better opportunities and they congregate both the
human and the entrepreneurial resources to generate new ideas, innovate and use
technology in increasingly productive ways. In OECD countries, for instance, 81
per cent of patents are filed by applicants residing in urban regions (OECD,
2006a). Cities also facilitate social change, particularly through the educational
and cultural opportunities they provide. Thus, in virtually every country, the
transition to lower fertility started and has advanced further in urban areas.