AUTHORS: John Vogler*, Ross Meentemeyer, Jelena Vukomanovic – North Carolina State University
ABSTRACT: Population growth and accelerating urbanization profoundly transform urban and rural landscapes worldwide and represent a major global sustainability challenge of the 21st century. Understanding the co-evolution of people and the built environment is essential for assessing impacts to natural resources, ecosystems, and land availability and for monitoring and identifying places in need of more sustainable patterns of development. This research tracks human footprint across the urban-rural landscape of the conterminous U.S. by quantifying and mapping trends in settlement density, land consumption and use efficiency at the turn of the century (1990-2010). We coupled percent impervious surface cover (developed land) data from the National Land Cover Database with standardized block group population and housing data from Decennial Censuses (1990, 2000, 2010). We analyzed changes in patterns of urban, suburban, exurban, and rural housing densities, and uniquely assessed spatial and temporal variation in total and per capita developed land consumption and use efficiency along this urban-rural gradient. By 2010, proportions of total land area (~7.66M km2) in urban, suburban, exurban, and rural densities were 0.2%, 1.9%, 19.9%, and 80%. Lands under urban, suburban, and exurban densities saw 17.6, 41.3, and 28.5 percent increases. Conversely, rural density areas decreased 6.1% with rural-exurban transitions occurring over 5.1% of the U.S. Despite rural impervious developed land totaling ~25% of the 22 million combined developed acres found in urbanizing areas, less people result in a disproportionate share of higher footprints (averaging 1.8 ac/person) with diminished use efficiencies in rural landscapes, where the environmental impacts of development are perhaps even more significant. Not surprisingly, consumption rates dropped precipitously toward denser urban cores, averaging 0.03 acres/person nationally, where greater city efficiencies can, but do not always, yield more sustainable futures. We conclude by applying these fine scale metrics to case studies comparing and highlighting U.S. megaregions.