Urbanization on the US landscape: looking ahead in the 21st century

Conversion of rural lands to urban and other built-up uses affects the mix of commodities and services produced from the global land base. In the United States, there was a 34% increase in the amount of land devoted to urban and built-up uses between 1982 and 1997. This increase came predominantly from the conversion of croplands and forestland, with the largest increases in developed area happening in the southern region of the country. In an analysis of drivers influencing developed land uses in the US, we found results that were consistent with hypothesized relationships, including significant increases in development as a result of increases in population density and personal income. From these results, we projected changes in potential future urbanization and development by 2025 given estimated increases in population and real personal income. The projections suggest continued urban expansion over the next 25 years, with the magnitude of increase varying by region. US developed area is projected to increase by 79%, raising the proportion of the total land base that is developed from 5.2 to 9.2%. Because much of the growth is expected in areas relatively stressed with respect to human–environment interactions, such as some coastal counties, implications for landscape and urban planning include potential impacts on sensitive watersheds, riparian areas, wildlife habitat, and water supplies.