Mega Regions

The UN said that urbanisation is now "unstoppable".
.
Just over half the world now lives in cities but by 2050, over 70% of the world will be urban dwellers.
.
By then, only 14% of people in rich countries will live outside cities, and 33% in poor countries.
.
The development of mega-regions is regarded as generally positive
.
They [mega-regions], rather than countries, are now driving wealth
.
Research shows that the world's largest 40 mega-regions cover only a tiny fraction of the habitable surface of our planet and are home to fewer than 18% of the world's population [but] account for 66% of all economic activity and about 85% of technological and scientific innovation
.
The top 25 cities in the world account for more than half of the world's wealth
.
And the five largest cities in India and China now account for 50% of those countries' wealth
.
The migration to cities, while making economic sense, is affecting the rural economy too:
.
Most of the wealth in rural areas already comes from people in urban areas sending money back
.
The growth of mega-regions and cities is also leading to unprecedented urban sprawl, new slums, unbalanced development and income inequalities as more and more people move to satellite or dormitory cities.


Cities like Los Angeles grew 45% in numbers between 1975-1990, but tripled their surface area in the same time.
.
This sprawl is now increasingly happening in developing countries as real estate developers promote the image of a 'world-class lifestyle' outside the traditional city," say the authors.
.
Urban sprawl, they say, is the symptom of a divided, dysfunctional city
.
It is not only wasteful, it adds to transport costs, increases energy consumption, requires more resources, and causes the loss of prime farmland
.
The more unequal that cities become, the higher the risk that economic disparities will result in social and political tension.
.
The likelihood of urban unrest in unequal cities is high.
.
The cities that are prospering the most are generally those that are reducing inequalities.
.
In a sample survey of world cities, the UN found the most unequal were in South Africa.
.
Johannesburg was the least equal in the world, only marginally ahead of East London, Bloemfontein, and Pretoria.
.
Latin American, Asian and African cities were generally more equal, but mainly because they were uniformly poor, with a high level of slums and little sanitation.
.
Some of the most the most egalitarian cities were found to be Dhaka and Chittagong in Bangladesh.
.
The US emerged as one of the most unequal societies with cities like New York, Chicago and Washington less equal than places like Brazzaville in Congo-Brazzaville, Managua in Nicaragua and Davao City in the Philippines.
.
The marginalisation and segregation of specific groups [in the US] creates a city within a city.
.
The richest 1% of households now earns more than 72 times the average income of the poorest 20% of the population. 
.
In the 'other America', poor black families are clustered in ghettos lacking access to quality education, secure tenure, lucrative work and political power," says the report.
.
Cities are pushing beyond their limits and are merging into new massive conurbations known as mega-regions, which are linked both physically and economically.
.
Their expansion drives economic growth but also leads to urban sprawl, rising inequalities and urban unrest.
.
The biggest mega-regions, which are at the forefront of the rapid urbanisation sweeping the world, are:
.
• Hong Kong-Shenhzen-Guangzhou, China, home to about 120 million people;
.
• Nagoya-Osaka-Kyoto-Kobe, Japan, expected to grow to 60 million people by 2015
.
• Rio de Janeiro-São Paulo region with 43 million people in Brazil.
.
The same trend on an even larger scale is seen in fast-growing "urban corridors":
.
• West Africa: 600km of urbanisation linking Nigeria, Benin, Togo and Ghana, and driving the entire region's economy;
.
• India: From Mumbai to Delhi
.
• East Asia: Four connected megalopolises and 77 separate cities of over 200,000 people each occur from Beijing to Tokyo via Pyongyang and Seoul.