The world is steadily becoming more urban as people move to cities and towns in search of employment, educational opportunities and higher standards of living. They migrate away from areas that can no longer support them due to environmental degradation, unemployment, persecution and conflict. By the year 2005, the UN projects that urban areas will be home to more than half of the world's people, growing to three-fifths by 2025. This is a growth rate three times faster than in rural counterparts.
Already, 74 percent of Latin American and Caribbean populations live in urban areas, as do 75 percent of people in Europe, 68 percent of people in countries comprising the former Soviet Union and more than 75 percent of people living in Canada, the United States, Australia and New Zealand. In both Africa and Asia, urban dwellers represent about a third of the total populations. There is significant variations within regions; Algeria, South Africa and Tunisia are among the African countries with more than 50 percent of their populations in urban areas.
By 2010, it is estimated that eight of the 10 largest cities will be in the developing world, with only two (New York and Tokyo) located in the developed world. A higher proportion of the population in cities of the developing world is under 15 years of age, about 30 percent, in contrast to about 20 percent in cities of the developed world.
There is a continuing trend towards ever-larger urban agglomerations. By the turn of the century, 300 cities in developing countries will have populations over one million, compared with 125 today. In 1992, there were 13 so-called mega-cities, defined as cities with at least 10 million inhabitants, and their number is expected to double by 2010 when most of them will be in developing countries. In 1990, Sao Paulo, Brazil, with its 18.1 million inhabitants, and Mexico City, with its 15.1 million inhabitants, were, respectively, the second and the fourth largest cities in the world. And while London's population of 1 million people took more than 100 years to reach 8 million, the population of Mexico City increased from 1 million to more than 15 million in just 50 years. On average, developing country cities are growing at a rate of 3 percent a year, at which rate they will double in size in less than 25 years.
Rapid urban growth, particularly in developing countries, strains the capacity of local and national governments to provide even the most basic of services, such as water, electricity and sewerage. Two-thirds of housing units in cities in developing countries are without facilities, such as piped water, toilets, electricity or cooking space. Access to education, health care and other human services are also greatly overburdened or non-existent.
In the absence of sufficient housing, squatter and other informal settlements have sprung up, including the famous favelas that cling to the hillsides of Rio de Janeiro and Cairo's City of the Dead tombs used as homes by tens of thousands of urban residents.
The outward growth of urban areas often eats up productive farmland, with further consequences for the health and welfare of urban residents.
United Nations Conference on Human Settlements (Habitat II), and United Nations Centre For Human Settlements are seeking strategies and plans to make urban growth sustainable for the future.
