Historically Grounded Spatial Population Scenarios for the Continental United States

Bryan Jones, National Center for Atmospheric Research (NCAR)
Brian C. O'Neill, National Center for Atmospheric Research (NCAR)

Large-scale spatial population projections are of growing importance to the global-change community. Settlement patterns are a key determinant of vulnerability to climate-related hazards, land-use change, energy use, and emissions. Currently few large-scale spatial projections exist, and while recent efforts improve on earlier scaling/trend extrapolation approaches, models generally have not been calibrated to nor validated against historical trends. Here we present spatially explicit 100-year projections for the United States consistent with different socio-economic development scenarios. The projections are based on a new model that is calibrated to observed spatial changes in regional populations, corrects for border effects, and employs a spatial mask for designating protected/uninhabitable land. Using new metrics for comparing spatial outcomes, we find that our projections anticipate more moderate trends in urban sprawl and coastal settlement than widely used existing projections, and that differences in outcomes across models are much larger than differences across scenarios for a given model.