Making Room for a Planet of Cities

The authors document the results of a five-year study of global urban expansion, initiated in 2005 with a grant from the World Bank that resulted in the report, The Dynamics of Global Urban Expansion (Angel et al. 2005). That initial phase of the study focused on analyzing and comparing satellite images and urban populations in a global sample of 120 cities circa 1990 and 2000. A second phase of the study, with support from the National Science Foundation, involved a survey of housing conditions and the regulatory regimes governing urban expansion in the same sample of 120 cities. The survey was conducted by local consultants in 2006–2007.

The third and fourth phases, with support from NASA (National Aeronautics and Space Administration), Cities Alliance, and the Lincoln Institute of Land Policy, involved several additional steps and resulted in three Institute-sponsored working papers. They present historical research on urban expansion in 20 U.S. cities from 1910 to 2000; historical analysis of a representative global sample of 30 cities from 1800 to 2000; and the analysis of a new global urban land cover map of all 3,646 named large cities with 100,000 people or more in the year 2000 (Angel et al. 2010a; 2010d; 2010e). The complete data sets, with their associated maps and spreadsheets, are available in The Atlas of Urban Expansion on the Lincoln Institute Web site at www.lincolninst.edu/subcenters/atlas-urban-expansion.

This report provides both the conceptual framework and, for the first time, the basic empirical data and quantitative dimensions of past, present, and future urban expansion in cities around the world that are necessary for making minimal preparations for future growth. At the very least, the report lays the foundation for fruitful discussion of the fate of our cities and our planet as we seek to identify and employ appropriate strategies for managing urban expansion at sustainable densities.