Distribution of world population and location of mega-cities

In 1800 only 3 percent of the worlds total population lived in cities, this figure now stands at 47 percent an increase of 44 percent over 200 years. In 1950, there were 83 cities with populations exceeding one million; New York was recognised as becoming the world’s first megacity. By the year 2007 83 millionaire cities had risen to 468. If this trend continues however the worlds urban population will double every 38 years. This is due to the propelled high rates of natural increase and very high rates of rural to urban migration.

A few of the largest cities have grown to merge with others to form city regions, or agglomerations, such as Tokyo whose region now includes the population of Yokohama. The term megacity is now used to describe these city regions.

A few current megacities according to that of the world gazetteer are that of Cairo in Egypt with a population of 16,794,464, Beijing in China with a population of 13,294,474 and Buenos Aires in Argentina with a population of 14,723,625.

A few countries that have the potential to become megacities within the next 5 years are that of Chicago in the USA with a population of 9,506,302, and Xianggang in China with a current population of 9,565,291.
This image shows the urban population (millions). As the image clearly show there are around 6 mega-city areas in the western hemisphere. The more obvious one being that of the world cities such as New York. As you can see Europe has no strong megacity(s) as the hierarchy of the urban distribution is quite stabilised in turn creating many world cities such as that of London, Paris Frankfurt and Brussels. However in the eastern hemisphere there are around 9 mega cities, this vast expansion could be due to uncontrolled birth rate or by form of city regions (agglomerations). These megacities seem to be