Coastal megacities

Posted: 6 March 2007

Coastal cities are getting bigger on virtually all continents. Of the world's 17 megacities in 2006 - those with over 10 million inhabitants - 14 are coastal1.

The other, less noticed trend, is that most of these cities are growing by much faster rates than other cities further inland. In 1990, coastal megacities contained 160 million people. By 2001 that figure had climbed to 238.6 million. And by 2015, a projected 340.5 million people will reside in 21 megacities - 18 of them in coastal areas. These ever-growing conurbations will contain close to 5 per cent of the global population within 12 years.

Coastal cities are also turning into what one expert calls "megalopolis's". Already along the North-east coast of the United States there is virtually one continuous urban area stretching from Boston to New York to Washington DC, containing 50 million people. Similarly, Hong Kong, Shenzhen and Guangzhou are well on their way to becoming one continuous urban area containing over 20 million people. And by 2010, Brazil's two largest cities - São Paulo and Rio de Janeiro - will be one huge conurbation containing some 40 million people.

Sources:Urban Agglomerations 2005, UN Dept of Economic and Social Affairs, Population Division, (UN, NY, 2007).World Population Prospects, the 2006 Revision, UN Population Division, 2007.