Research Note: Demographic Change on the United States Coast, 2020–2100

Abstract

Prospective demographic information of the United States is limited to national-level analyses and subnational analyses of the total population. With nearly 40% of the U.S. population being residents of coastal areas, understanding the anticipated demographic changes in coastal counties is important for long-range planning purposes. In this research note, we use long-range, county-level population projections based on a simplified cohort-component method to discuss demographic changes by age, sex, and race and ethnicity for coastal counties between 2020 and the end of the century, and we compare these changes to inland counties. Presently, coastal counties are statistically significantly different from inland counties by race and ethnicity (more diverse) and sex (more women) but not by age, yet by 2025, we expect coastal counties to become significantly older than inland counties. We note several important trajectories of predicted demographic outcomes in coastal counties across the remainder of the century: (1) the non-Hispanic White population is expected to decrease, both numerically and as a percentage of the population; (2) the population older than 65 is projected to increase, both numerically and as a percentage of the population; and (3) the ratio of women to men remains constant over the century at 1.03. These trends combine to suggest that the future U.S. coastline will likely be both increasingly diverse racially and ethnically and significantly older than it is today.

Future Population Exposure to Flood Risk: A Decomposition Approach across Shared-Socioeconomic Pathways (SSPs)

“…Across all five SSPs, we find that there will be significant increases in expected annual exposure for populations 80 years and older, with the second most increases occurring in the 70 to 79 year age group. This population aging in risky areas supports other research finding that populations living in risky areas will increase in their average and median ages (Hauer et al, 2022). This may be due to increased family ties to existing areas of residence, and decreased opportunities in other locations, so that the economic benefit of moving away from those risky areas is decreased, and the cost is increased.…”

“…Recent work by Hauer (2019) has made publicly available countylevel population and demographic projections across the Contiguous United States (CONUS) at five year increments along all five SSP trajectories out to 2100. In addition to work on general population forecasting, follow up work by Hauer et al (2022) investigated these demographic changes at the county level for coastal versus inland areas as an indicator of increasing flood risk.…”

Urbanization and the Paradox of Rural Population Decline: Racial and Regional Variation

“…The rural Midwest has experienced White net out-migration for decades but now faces chronic population decline as a result of population aging and natural decrease from high mortality and low fertility (Johnson 2020). Not surprisingly, America’s mostly White rural and agricultural heartland lags bicoastal and urban population centers on most indicators of economic and social well-being (Hauer, Saunders, and Shtob 2022).…”

The changing demography of hurricane at‐risk areas in the United States (1970–2018)

“…These changing demographics have altered the demographic composition of places across the United States, including hurricane at-risk areas. Just as it is important to predict future demographic trends in the coastal areas (Hauer et al, 2022), it is also crucial to look back at the past demographic changes. To confront the challenge of climate change and increasing risk from natural hazards, it is important to understand which populations have been historically affected and who has experienced the greatest exposure.…”