Sea Level Rise Will Affect 4 Out of 5 Miami Residents, Even Those Living Outside of Flood Zones, Study Says

Sea-level rise due to climate change is becoming an increasing concern for island nations and low-lying areas, such as Miami-Dade County, Florida.

The primary focus of research on sea-level rise has been the direct effects of flooding, but a new study also considers socioeconomic vulnerabilities.

The study found that, in the coming decades, four out of five Miami-Dade County residents could face displacement or disruption due to sea-level rise, whether or not they live in a flood zone, a press release from the Lamont-Doherty Earth Observatory at Columbia Climate School said.

The researchers concluded that, as inundation increases, lower-income residents will bear the brunt of a lack of habitable areas and skyrocketing housing prices. A small percentage of affluent residents will have the means to move from waterfront or low-lying properties, but others may have no choice but to stay, according to the study.

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

The study, “Modes of climate mobility under sea-level rise,” was published in the journal Environmental Research Letters.

The researchers looked at a combination of rainfall, storm surge and projections of flooding caused directly by sea-level rise that went from building to building, as well as demographic data, in determining the effects on residents, the press release said.

The team used data from the U.S. Census Bureau along with flood maps to chart the social and economic factors that would lead to residents being more or less vulnerable. These included age, income, employment status, race, education level, whether they were homeowners or renters and other factors.

The population was then divided into four categories. The first and most common were those residents facing sea-level rise of one meter, considered a “middle-of-the-road” possibility by the year 2100. This scenario would affect 56 percent of residents who live mostly on higher ground. The researchers called this portion of the population “displaced,” saying they could be faced with pressure to relocate.

The next most common group — 19 percent — were those living in perpetually flooded areas without the means to move to higher ground. The research team called this portion of the population “trapped.”

Another 19 percent of residents were those considered “stable” because they lived in areas that weren’t prone to flooding and were able to stay.

The wealthiest percentage of the population, the seven percent the team called “migrating,” would be subjected to flooding in low-lying or waterfront areas, but would be able to relocate to safer metro area locations.

“However, social and economic risks may extend to communities substantially beyond flooded areas as the spatiotemporal dynamics of flood risks are realized through housing markets, insurance and risk-transfer mechanisms, and adaptation investments,” the study said. “Notably ‘climate gentrification’ and affordable housing shortages can result from increasing demand for housing in safer areas. Furthermore, disaster-related displacement and declining property values and household wealth from [sea-level rise] and extreme flooding have the potential to exacerbate existing social inequity.”

The research team said that beyond a meter of sea-level rise would mean direct flooding, rather than economic pressures, would become the main factor affecting the population.

Two meters — a “fairly high” estimate — would cause inundation for more than half the population from more rainfall and sea-level rise. This would lead to 49 percent of residents becoming trapped and a quarter displaced. Just eight percent would be classed as stable.

“This is where it gets to be more drastic, more existential,” Seeteram said in the press release.

Seeteram said both scenarios would mean the potential for depopulation and devaluation of flooded properties. This could make it harder for tax collection by authorities to fund infrastructure adaptation to hold back flood waters.

Flooding is already a routine occurrence in the area, as rain collects in the streets and high tides come up through sewers. Seeteram said during the wet season from May to October, flash flooding is common.

Signs of climate gentrification have already begun, with property values and development in a neighborhood 10 lofty feet above sea level called Little Haiti soaring. The predominantly Black residents of the neighborhood fear they may be forced to move.

“I suspect it is already happening,” said co-author of the study Katharine Mach, who is University of Miami’s chair of the Department of Environmental Science and Policy, in the press release.

Mach said other factors may be more responsible for changing real-estate values at the moment, such as already established pro-development policies.

“The question is, what fraction [of rising prices] can you put on climate?” Mach said.

Mach added that waterfront and low-lying areas are seeing increased real-estate prices, while locations less prone to flooding aren’t going up as quickly, which may indicate that buyers’ decisions are being affected by predicted rises in sea levels.

Seteeram said the study’s projections might not happen, but it depends on how the city deals with these issues in the future. The effects of sea-level rise could be tempered with measures like infrastructure modification.

“We could see different kinds of housing development, to make the population denser in some areas, or more climate resilient. But then you would have to see what the intersection would be with affordability for a lot of people,” Seteeram said in the press release.