Expanding Cities

Humanity is becoming a predominantly urban species.  Cities occupy just 2 per cent of Earth's land surface, but they now house over half the world's population.  Perhaps most alarming of all, they use three-quaters of resources we take from Earth.

The growth of the world's largest cities in particular has been pretty staggering.  The first megacity - with a population of ten million people - was New York, which reached that figure around 1940.  

New York Skyline evolution 

Today there are twenty-two megacities, half of them in Asia, including three in India and two in China. The largest, Tokyo in Japan, has over thirty-five million inhabitants.  Most urban growth from migration.  China, which has ninety cities with populations of more than a million people, has a 'floating population' of more than 100 million people who have moved to cities in recent years.  Its cities expect to welcome another 400 million people from the countryside within the next thirty years.  Perth, WA is set to double its population by 2050.

Cities have become economic powerhouses, providing jobs in manufacturing, transport and wholesaling, as well as service including universities, hospitals, government services, banking, media and culture.  But, despite their attractions, cities can be centres of squalor too.  More than a quarter of all urban inhabitants live in unplanned, overcrowded and often illegal squatter settlements, with no running water.  Cities can also become victims of their size.  Congestion, worsening air pollution, and crime can cause megacities to stop growing, as people and businesses flee to the suburbs surrounding new cities.

The result of this out-migration has been a new geographical phenomenon as the 'polycentric megacity zone' - an urban landscape composed of a number of different centres.  These new zones include Yangtze delta region around Shanghai, southeast England around London, and the Japanese urban corridor between Tokyo and Osaka.

The good news on human population growth is that for the first time since the mid 1900s, the rate of increase in human population is actually decreasing in areas.  The Earth peaked in the late 1980s and has started to generally decrease since then, this is a milestone in human population growth and encouraging.  The role of education has been paramount to the population problem.  As people (particularly women), become more educated, the population growth rate tends to decrease.  As the rate of literacy increases, population growth is reduced.  

Given the variety of cultures, values, and norms in the world today, it appears that our greatest hope for population control is, in fact, education.

Of interest:

http://megacities.nl/?tag=hall

http://www.viewsoftheworld.net/?p=1590

Megacity on the map - source viewsoftheworld.net