What’s at stake
Sea level rise is already happening, and it’s accelerating. Manuela Andreoni of The New York Times explains it this way: Climate change “melts glaciers and ice sheets, adding water to the oceans.” Also, “higher temperatures make all that water expand, increasing its volume.”
Globally, 800 million people in 570 cities live within 10 kilometers of the coast, with an average elevation below 5 meters. This topography puts coastal residents at risk of flooding from sea level rise. About 150 million people worldwide are living on land that will be below the high-tide line by 2050.
The average global sea level has already risen about 9 inches (24 cm) since 1880. In 2021, it rose 3.8 inches (97 mm) above 1993 levels. And the rate of increase is speeding up. For most of the 20th century, the sea level rose about 0.06 inches (1.4 mm) per year, but since 2006 it has been rising twice as fast, about 0.14 (3.6 mm) per year. And high-tide flooding is now up to 900% more frequent than 50 years ago.
In the US, where 40% of the population lives along the coast, Miami and New York are most at risk from sea level rise. Indeed, they are ranked first and third in the world regarding assets exposed to coastal flooding. Research in 2012 showed that the threat of sea level rise was three to four times more than the global average along the US Atlantic coast.
But sea level isn’t the only flood risk—millions of people in the US risk river, stream, and surface flooding from heavy rainfall events. Flood risk advocates say that FEMA’s flood maps are outdated, missing the risk to about 6 million people in the US.
Not just your house
Flooding risk doesn’t just depend on whether your house is above the floodplain. Municipal drinking water, sewer systems, power plants, roads, and other infrastructure flood, making a neighborhood unlivable even if you are high and dry.
Here are a few other situations sea level rise could impact:
Weakened structures: Before salt water ever reaches street level, it could undermine skyscrapers, putting them at risk for collapse. When building foundations are repeatedly exposed to salt water, the salt can corrode reinforcing steel and chemically weaken concrete.
Groundwater and toxic waste: Sea level rise lifts groundwater. That water will likely infiltrate 326 superfund sites by 2100, releasing heavy metals, radioactive elements, pesticides, and industrial chemicals.
Jeopardized drinking water: Rising sea levels can push saltwater upstream into coastal aquifers, endangering drinking water supplies and contaminating agricultural soil.
Flood insurance soaring out of reach
Infrastructure aside, living in a flood plain is expensive, even when nothing happens. Insurance rates for flood insurance are skyrocketing. The interactive map in this article from Context shows how flood insurance rates have changed across the US over the past few years.
In 2012 and 2014, the National Flood Insurance Program (NFIP) implemented reforms to phase out government subsidies for flood insurance premiums. These reforms were partly to address wealthy second homeowners. People with expensive beach houses paid so little for NFIP insurance that they kept rebuilding after floods, largely at taxpayer expense. While this dampened sales of flood-prone properties, it also had unintended consequences. The reforms led to a 14% increase in flood insurance premiums and an 8% decrease in insurance demand. Many homeowners in flood zones are simply uninsured, an economic disaster waiting to happen.
Are buyouts the answer?
Given the many problems of living in a flood zone, it’s unsurprising that many people are already moving. A 2023 Rice University study looked at about 14,000 people in the US who moved out of their homes between 1990 and 2017 thanks to FEMA buyouts. About 75% stayed within 20 miles of their old homes, and they substantially reduced their flood risk.
FEMA and the US Army Corps of Engineers (USACES) offer significant subsidies to municipalities that want to buy people out. Buyouts benefit the people at risk of losing their homes to flooding. They also help those people’s neighbors when the land is converted into a flood mitigation project. A 2006 study found that A 2006 study found that FEMA’s buyout programs saved, over 10 years, about $5 for every $1 spent.
Garland, Texas (near Dallas), and Des Moines, Iowa, are among the cities currently offering voluntary buyouts to homeowners at risk of flooding.
Voluntary or mandatory?
Some municipalities are frustrated trying to budge holdouts who won’t sell, especially when levees and other flood mitigation projects are at stake. Some are applying eminent domain to move things along.
Knott County, Kentucky, is seeking eminent domain to condemn a surface mine so the county can use the land to build new homes for people displaced by flooding. Level land outside the flood plain is hard to come by, and the defunct mine offers an opportunity.
In a more contentious example, Cedar Rapids, Iowa, is using eminent domain to force buyouts for homeowners in a neighborhood devastated by a 2008 flood. The city needs the space to build a $750 million system of levees and gates to protect other Cedar Rapids residents from river flooding. The city is trying to move the remaining homeowners to the “dry side” and is offering them fair market compensation.
Cedar Rapids is one of the first large-scale test cases of a 2015 change to USACE’s funding rules. USACE now requires municipalities to be willing to use eminent domain if they want access to USACE buyout funds. Nashville, Brookhaven, NY, and Okaloosa County, Florida, recently agreed to those terms. In 2020, the Trump administration, faced with staggering federal costs due to flooding disasters, pushed municipalities to comply with the USACE rule.
Buyouts could be better
Unfortunately, buyouts, whether voluntary or mandatory, are complicated and time-consuming. For example, in Garland, Texas, it will take homeowners 8-10 months to find out if their application for a buyout is accepted. Still, this is speedy compared with waiting until a flood strikes. Following a disaster, it can take up to five years for disaster claims and buyouts to resolve.
The Pew Charitable Trusts’ 2022 report, Property Buyouts Can Be an Effective Solution for Flood-Prone Communities, summarized the benefits of buyouts: Effective buyouts prevent future damage, make people safer, and protect entire neighborhoods. When bought-out become natural open spaces, they absorb stormwater, reducing flooding and conserving habitats.
But the Pew report also noted numerous problems, mostly bureaucratic, that make buyouts ineffective and inefficient solutions. The report made the following recommendations to improve buyouts:
Simplify access to federal funding
Establish an interagency task force to align program requirements
Help state and local governments assess buyout options after a disaster
Reward communities for establishing effective buyout programs
Allow people to have “life estates” as part of a buyout program
Coordinate support for local disaster planning
Help communities plan and launch buyout programs
Prioritize vulnerable populations and community needs
Improve outreach to make the public aware of flood risk
Promote partnerships among agencies, nonprofits, land trusts, etc.
Bottom line
Paying to move people out of flood zones is a smart investment. It saves taxpayer dollars and lives. But it’s an emotional topic; many people don’t want to leave their homes. Not unreasonably, people want choices. But as extreme precipitation events, hurricanes, and sea level rise intensify, relocation may cease to be a choice. Planned relocation ultimately gives homeowners more control—now—over when, how, and where they move than in the chaos surrounding a disaster.