This unprecedented increase in urban population will provide new opportunities for improving education and public services in Africa and Asia, as more concentrated populations are easier to reach, says the UN [2011 Revision of the World Urbanization Prospects](http://esa.un.org/unpd/wup/index.htm), launched on 5 April.

However, this will also pose new challenges of providing urban jobs, housing, energy and infrastructure to mitigate urban poverty, expansion of slums and a deterioration of the urban environment.

**Half of Humanity Living in Cities Today**

With half of humanity living in cities today, urbanization is a critical issue for Rio+20—the UN Conference on the Sustainable Development, which takes place on 20-22 June in Rio de Janeiro, Brazil. One of the major challenges faced by cities is the growing number of urban dwellers living in slum conditions, the UN study adds.

“About one third of the world urban population live in slum conditions,” said Sha Zukang, Secretary- General of Rio+20.

“The launch of the World Urbanization Prospects is very timely as the world gathers together to promote sustainable development for the future we want. We expect world leaders to come up with concrete action plans to realize sustainable cities,” he said.

**How to Reduce Poverty, Advance Social Equity in More Crowded Planet?**

At the Rio+20 Conference, world leaders, along with thousands of participants from governments, the private sector, civil society organizations and other groups, will come together “to shape how the world can reduce poverty, advance social equity and ensure environmental protection on an ever more crowded planet.”

The largest increases in urban population are expected in the following countries: India, China, Nigeria, the United States of America and Indonesia, according to the study.

Over the next four decades, (2010 to 2050) India will add another 497 million to its urban population; China – 341 million, Nigeria – 200 million, the United States – 103 million and Indonesia – 92 million.

**200 Million Urban People in Nigeria**

The projected increase in urban population in India and Nigeria, between 2010 and 2050 will be higher than that of the past 40 years.

“This trend is particularly prominent in Nigeria where its urban population grew by only 65 million between 1970 and 2010, and yet it is now projected to increase more than three times between 2010 and 2050, thus by 200 million.”

For the first time, the 2011 Revision of the World Urbanization Prospects includes geographical coordinates for all cities with more than 750,000 inhabitants. This will allow researchers to link estimates and projections of the population in urban agglomerations to various environmental characteristics, such as proximity to coastal areas, earthquake faults, or climate zones.

**Major Risk of Natural Disastre**

An initial analysis found that among 450 urban areas with 1 million or more inhabitants in 2011 (representing 1.4 billion people), 60 per cent, or about 890 million people, are located in regions exposed to at least one major risk of natural disaster, says the UN study.

“Major cities in Europe and Africa are the least exposed overall. Only 26 per cent and 37 per cent of their cities with one million inhabitants or more are living in regions exposed to at least one major risk of natural disaster.” However, cities in Latin America and the Caribbean, in Northern America, and especially in Asia are often located in regions exposed to natural hazards.

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2012 [Human Wrongs Watch](http://human-wrongs-watch.net/)