Population Projections and Risk of Inundation from Mean Sea Level Rise for the United States in 2100

Mathew E. Hauer, University of Georgia

The demographic impacts of climate change are some of the most pressing questions of our time, yet precise projections of the populations at risk of sea level rise for the United States are unknown. By combining small area population projections with spatially-explicit modeling of flood risk from sea level rise, we estimate the magnitude and locations of potential displacement from sea level rise. We find that up to 11.7 million people are at risk of displacement in 292 coastal U.S. counties by 2100. Geographic topography and population growth rates determine how many and when populations could be displaced. Accounting for population dynamics leads to projected displaced populations three times larger than current populations in coastal floodplains. Future mitigation and adaptation strategies should account for population dynamics. Variability in both magnitude and locations suggest a one-size-fits-all national approach could prove problematic.