The Scale of Urban Change Worldwide 1950-2000 and its Underpinnings

The world's urban population multiplied ten fold during the 20th century and most of the world's growth in population between 2000 and 2020 is expected to be in urban areas. However, the world was less urbanized and less dominated by large cities by 2000 than had been expected. Most of the world’s largest cities had several million fewer people than had been predicted one or two decades earlier. There were also fewer ‘mega-cities’ with ten million or more people and the year when the world’s urban population is predicted to exceed its rural population has been put back to 2007.

This paper discusses the reasons for this and also why the long-term trend to an increasingly urbanized world has not changed. Lower urbanization levels and fewer large cities also does it alter the fact that many aspects of urban change in the last fifty years are unprecedented, including the size and number of very large cities. But this review of urban change, shows some surprises, including:·
- many of the largest cities now having more people moving out than moving in;
- Asia having most of the world’s largest cities (but this only returns to what has generally been the case). Northern America and sub-Saharan Africa have the most ‘new’ large cities; and·
- How rapid urban change is not confined to low- and middle-income nations, since Northern America has some of the world’s fastest growing cities over the last 50 years.

This paper also outlines what has underpinned the trend towards an increasingly urbanized world, and the economic logic behind it – for instance, how most of the world’s largest cities and fastest growing cities are in the largest national economies. The ending of colonial empires after World War II also had profound effects on urban trends in Africa and much of Asia – and although political changes are still important in underpinning urban change, they are now less important than economic change for most nations. The paper also describes the costs generated by rapid urban growth, and suggests that most are not caused by the urban growth itself but by “poor governance” – the inability of national and local institutions to adapt to the new challenges that rapid urban growth presents. It also describes some of the exceptions – the national and city governments that have managed to adapt.

Finally, the paper stresses that there is no automatic link between rapid urban growth and urban problems. Some of the world’s fastest growing cities are also among the best governed, with some of the best quality of life in their nation. In addition, by concentrating people and enterprises, cities present many opportunities for better services and environmental management. There is no reason why well-governed large cities should not achieve the highest standards in terms of quality of life – and also set high standards with regard to the environment, through efficient resource use, low waste volumes and low per capita greenhouse gas emissions.