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The percentage of the world’s population that lives in urban settings has increased explosively in recent years. In 1950, less than 30 percent of the world’s population lived in urban areas. By the year 2003, that proportion had grown to 48 percent. The year 2008 witnessed a remarkable shift: for the first time, the majority of the world population lived in an urban setting. The Population Reference Bureau (September 2007) predicts that by the year 2030, roughly 60 percent of the world’s population will live in urban areas.
Because urban populations are characterized by much higher densities of people—meaning that more people are sharing the same spaces—diseases are much more easily transmitted.
Urban Population by major development regions (in per cent of total population)
Source: United Nations, Department of Economic and Social Affairs, Population Division:World Urbanization Prospects, the 2009 Revision. New York, 2010
And almost all of the future growth of the world’s urban centers will occur in the developing world, where health response systems are weakest. by the year 2050, the total world population is predicted to increase from 6.9 billion people (world population in 2010) to 9.3 billion people.8 In the same period, the urban populations of less developed regions are expected to grow from about 2.5 billion to 5.2 billion people. The number of urban dwellers in more developed regions will increase by a much smaller amount: 930 million to 1.1 billion.9
This population growth is therefore of particular concern because potential public health problems tend to be exacerbated by poverty in developing countries. Many of these expanding cities are characterized by squalid conditions and sprawling shantytowns.
In 2009, nearly two billion people, the equivalent of 30 percent of the world’s population, still lack access to clean drinking water.10 These high densities of people and these unsanitary conditions make for almost perfect breeding grounds for pathogens.
Of course, globalization cannot be said to have caused the move away from subsistence agriculture toward urbanization and industrialization. However, it may be working to accelerate this process in many countries, as international trade and investment create more formal sector jobs in developing countries. The creation of more jobs tends to lead to rising wages levels and inducing more people to move to cities in search of work.
8 Source: http://esa.un.org/unpd/wpp/index.htm
9 Source: http://esa.un.org/wup2009/unup/index.asp
10 Source: http://www.americares.org/newsroom/news/2008-international-waterday.html
* Picture source: http://www.flickr.com/photos/lecercle/2612761536/
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