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Cities and Global Population

September 13, 2011

For thousands of years, people lived in the countryside.  Slowly people started to aggregate into villages, then towns and cities.  Then, in 2008, the number of people living in cities was over half of the world’s population [i] (UN, 2008).  By 2050, when the global population is expected to be nine billion, urban dwellers will exceed six billion.  Most of these will be in smaller cities, but projections based on UN forecasts for 2025 suggest there could be 500 million people living in 20 mega-agglomerations with populations over 20 million by 2050, [ii] (UN, 2007) and http://www.skyscrapercity.com.

Currently, vast cities in the poor nations are seen as centres for the epidemic diseases arising from poverty, with crime and ideologically-inspired violence are fuelled by poor governance.  And many cities are near the sea or in river valleys subject to flooding, with the consequent exposure to extreme weather events: and despite this, suffering water shortages, [iii] (WWF, 2011).  But there is also evidence that concentrating people in one place increases economic activity, return on infrastructure investment and social vitality: if the population of a city is doubled, there is an average 15% increase in the wages and the patents produced compared with two cities of the original size.  There is also an inverted effect in terms of infrastructure – if the population of a city doubles it needs 15% less physical infrastructure than two cities [iv] (Bettencourt, 2011).

Technology exploitation tends to occur in cities.  It requires many types of infrastructure if it is to be effective: not just adjacent technologies, but law, designers, accountants, transport systems.  For example, Scherngell et al. [v] (Scherngell, 2007), estimate that knowledge has a predictable and extremely local affect on efficiency growth.  Cities however have another spinoff, which is changing society.  When people move to cities, women tend to become educated [vi].  And this leads to smaller families as children are often a cost rather than a labour pool.  This is one of the factors leading us to think that the global population may not rise much above nine billion.

Written by Gill Ringland, CEO at SAMI Consulting

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[ii] UN Population Division, DESA, World Urbanization Prospects, 2007 revision

[iii] World Wildlife Fund report, Big Cities, Big Water, Big Challenges”, see http://www.wwf.org.uk/what_we_do/press_centre/?uNewsID=5202 , 2011

[iv] Bettencourt, Luis M. A., and Geoffrey B. West, “Bigger Cities Do More With Less”, Scientific American, 305, 3, September 2011

[v] Scherngell, T., Fischer M.M., and Reismann, M., “Total factor productivity effects of interregional knowledge spillovers in manufacturing industries across Europe”, Rumanian Journal of Regional Science 1, 2007, http://www.rrsa.ro/rjrs/N1-FISCHER.pdf

 [vi] Kavita Ramdas in Whole Earth Discipline, Penguin, 2010

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