Date posted: October 21, 2008

Science Special Issue On Cities

Some months ago, in a special section of its 8 February 2008 issue, the journal Science explored the various ramifications of urban transformation. It's an excellent introduction to urbanization and the challenges facing the emerging global mega-cities.

Last year the fact that more than half of the world's population now live in cities made news headlines. In recent years cities have also been the subject of numerous exhibitions, from the 2006 Venice Architecture Biennal to the Talking Cities exhibition which opened the Zeche Zollverein.

In a series of short news and review articles Science offers a survey of the various challenges faced by cities around the world, from the provision of clean water and sanitation to pollution and traffic jams.

Michael Batty gives a brief overview of his complex systems approach to urbanization. Nancy Grimm and her colleagues look at the ecology of cities. Christopher Dye discusses the comparative health benefits of urbanization while Ruth Mace takes a more detailed look at fertility and mortality rates in cities. Until the 18th century cities could only grow because of a steady inflow of immigrants from the countryside. The spread of diseases such as cholera, smallpox, tuberculosis and typhus meant that mortality rates, especially infant mortality, were higher than fertility. As Christopher Dye notes, "by modern health standards, London in the 1700s was a slum". Because of better sanitation and access to medical care today's cities fare better, but there is a divergence between the rich and the poor even in developed countries.

The growing divide between the urban rich and the poor is a problem in all of the world's cities. It is just that in developing countries it is more visible.