Social polarization.

Despite the advantages of mixed neighbourhoods, there is some indication that poverty is on the rise. According to a report in 2002 by Toronto's United Way, the number of middle-income families in the city declined by 8.2% in the 1990s, as the percentage of both rich and poor families increased. If that is a trend, then some experts say it becomes even more important for communities to involve all residents, rich and poor, in making decisions about the neighbourhoods they live in. As regional director for Latin America and the Caribbean with Canada's International Development Research Centre, Federico Burone, observed in 2002, some surprising results came from a project in Mar del Plata, Argentina. When community members helped design a waste-removal plan (that encouraged public participation through on-line discussions, and made computer facilities available to people in poor areas) the resulting plan was developed at half the initial estimated cost. The system also better addressed the needs of the community. "Equally important was the message to residents that ... poor citizens had a role in deciding what services the city would provide, and how," said Mr. Burone in a Globe and Mail article.

But, the sad truth is that a lot of people in the world live in slums. The United Nations estimates that somewhere between 835 million and two billion people do, leaving some of the world's largest cities (Mumbai, Bogota, and Cairo, for example) with more slum dwellers than there are people living in more traditional housing. Urban growth plus poverty equals slums: half of the world's population growth in the last 30 years (an increase of 2.4 billion people) has been in cities and, over the next 30 years, global population is expected to increase by another two billion. Demographers think all of that future population growth will end up in developing-country cities because of urban migration (for jobs) and high birth rates, according to an article in World Watch magazine in 2002. The article also cites a World Bank estimate that while the urban share of the world's extreme poverty is currently 25 percent, it probably will reach 50 percent by 2035.