The tide is high, and so is the cost to U.S. property values

In the United States, one of the more difficult challenges in facing climate change is what to do about coastal communities already seeing sea level rise that’s disrupting their lives. It’s true in low-lying Louisiana, where 98 percent of the town of Isle de Jean Charles is gone. Its inhabitants are known as America’s first “climate refugees,” with at least USD$48 million in federal funding to relocate them.

The Gulf of Mexico state – home to New Orleans and its Mardi Gras tradition – was about 25 percent bigger in the 1930s than it is now, according to one comprehensive ProPublica report. Because of climate change, engineering projects and the oil and gas industry, it loses land about the size of a football pitch every 48 minutes and that’s just getting worse. Miami, Charleston and New York City face rising seas, as do places like Norfolk and its U.S. Navy base, small fishing communities on the Chesapeake and tony ocean resorts.

New data from Columbia University and the First Street Foundation released in February completes an analysis of 17 states, all but two on the Eastern Seaboard, to evaluate the impact to property values. So far, the peer-reviewed studies of residential housing markets have found USD$15.8 billion in home value appreciation loss tied to higher and more frequent normal tides as well as extreme storms. In one case, a single home near the Atlantic Ocean in the state of Delaware lost $481,258 across 12 years..

“From Maine to Florida and through the Gulf Coast, we have seen the same phenomenon,” said Dr. Jeremy Porter of Columbia. “Increased tidal flooding has led to a loss in home value appreciation. We expect this trend to not only continue in the coming years, but to accelerate along with the accelerating rate of sea level rise.”

“This is critical information for people in coastal areas because it contextualizes the cost-benefits of personal and municipal adaptation measures,” added Steven McAlpine, the head of data science for First Street. “It also empowers people to make informed decisions when buying or selling a home.”

The group works with SeaLevelRise.org to help visualize the data and future projections, and make it publicly available, but even that hard work is easier than deciding what to do about the risks. What’s more, while the coastal risks are obvious in places like Charleston or Cape May, there are climate-related flooding issues nowhere near the oceans. Ellicott City, in inland Maryland, is installing a flood alarm warning system, much like tornado or tsunami sirens, after fatal floods in 2016 and 2018 wiped out its downtown. Charlotte, nearly 400 kilometers from the North Carolina coast, launched a home buyout program in its flood-prone areas. So did coastal New Jersey after Superstorm Sandy in 2012.

In Annapolis, on the Chesapeake Bay, there were 63 flooding high-tides in 2017 and just four in the 1960s. What to do about these communities is complicated by factors that include private property rights and compensation – some people refuse to leave – and how the insurance and related industries are evolving. Cities don’t want to lose land and residents valuable to their tax bases, and managed retreat isn’t always working. Yet the costs are ever more clear, even as the time window for making good decisions narrows.

“The only way we can reduce the damage that will be caused by future storms and the rising sea is to stop urban renewal at the coast,” writes emeritus Duke University professor Orrin Pilkey, who studied the problem for decades. “We can do this by not replacing buildings that have been demolished or damaged by storms or shoreline erosion. We can move some buildings back or even off the (barrier) islands to the mainland, although today’s high-rises and multi-story homes will be difficult to move.” Forward thinking is what’s needed, because more climate refugees are coming and the seas will continue to rise.