COASTAL CHALLENGESRising Seas Tighten Vise on Miami Even for People Who Are Not Flooded

By Kevin Krajick

Published 19 October 2023

In coming decades, four out of five residents of Florida’s Miami-Dade County area may face disruption or displacement, whether they live in flood zones or not – and indirect pressures on many areas could outweigh direct inundation.

A new study that examines both the physical and socioeconomic effects of sea-level rise on Florida’s Miami-Dade County area finds that in coming decades, four out of five residents may face disruption or displacement, whether they live in flood zones or not. As inundation spreads, the effects will be felt predominantly by lower-income people as habitable areas shrink and housing prices rise, says the study. Only a small number of affluent residents will be able relocate from low-lying or waterfront properties, while many others without sufficient means may be trapped there, it says.

The study was just published in the journal Environmental Research Letters.

“Most studies focus on the direct effects of inundation,” said lead author Nadia Seeteram, a postdoctoral researcher at Columbia University’s Lamont-Doherty Earth Observatory. “Here, we were able to look at flooding on a very granular level, and add in other vulnerabilities.”

The study combines building-by-building projections of flooding caused by direct sea-level rise, rainfall or storm surge with fine-grained demographic data to determine how residents will be affected. Along with flood maps, the researchers used U.S. Census Bureau data to chart economic and social factors that would make people more or less vulnerable, including age, race, level of education, income and status of employment, and whether they owned or rented their homes, among other measures. They then divided the population into four categories.

With a one-meter sea-level increase—a middle-of-the-road scenario for the end of this century—56 percent of the population, primarily on higher ground, could face pressures to relocate, they say. The researchers call these people “displaced.”

The next largest group they labeled the “trapped”—some 19 percent of the population, living in chronically flooded territory, but without the means to flee to safer nearby ground. About another 19 percent would be “stable,” according to the researchers—living in areas not prone to flooding and able to remain there. Just 7 percent—basically the wealthiest, which the researchers labeled as “migrating”—would be directly exposed to flooding in waterfront or low-lying areas, but able to move to safer spots within the metro area.