Study Shows 300,000 US Homes at Risk, $1 Trillion Price Tag as Rising Seas Trigger Chronic Flooding

Driven by the climate crisis and rising seas, coastal flooding could become a common occurrence for the owners of more than 300,000 American homes in the coming decades, according to a new study--and could have a domino effect on surrounding communities, schools, and infrastructure.

The Union of Concerned Scientists (UCS) released a report (pdf) on Monday showing that as many as 311,000 homes in coastal areas could flood more than 26 times per year over next 30 years--even without major storms taking place.

"Even homes along the Gulf coast that are elevated would be affected, as they'd have to drive through salt water to get to work or face their kids' school being cut off," Kristina Dahl, a senior climate scientist at UCS, told the Guardian. "You can imagine people walking away from mortgages, away from their homes."

Potential chronic flooding is expected to affect homes collectively valued at $117.5 billion and businesses costing more than $18 billion. By the end of the century, more than 2 million homes and commercial properties costing about $1 trillion could be at risk.

As houses become unlivable due to repeated damage, a declining property tax base could mean falling quality in schools, roads, infrastructure, and hospitals for many towns and cities, UCS found.

"For some communities, the potential hit to the local tax base could be staggering," said Dahl. "Some smaller, more rural communities may see 30, 50, or even 70 percent of their property tax revenue at risk due to the number of chronically inundated homes."

Meanwhile, communities with high poverty levels could be all but wiped out by repeated flooding events.

"While wealthier homeowners may risk losing more of their net wealth cumulatively, less-wealthy ones are in jeopardy of losing a greater percentage of what they own," said Rachel Cleetus, a co-author of the report.

"Homes often represent a larger share of total assets for elderly or low-income residents. Renters too might find themselves in a tight market or having to put up with decaying buildings and increased nuisance flooding. Hits to the property tax base in low-income communities, which already experience significant underinvestment in critical services and infrastructure, could prove especially challenging."

The report comes about a year after President Donald Trump's withdrawal from the Paris climate agreement, and as the Trump administration has rolled back regulations aimed at curbing fossil fuel emissions--and gone to great lengths to erase scientifically-backed information about the climate crisis from government documents.

"Actions today, especially the amount of global warming emissions we release, will help determine what our coasts will look like at the end of the century," said Astrid Caldas, a co-author of the report.