Researchers this month have published what they say is the first nationwide look at the risks that sea level rise pose to affordable housing in the United States, and it’s not a pretty picture.
The report, published by Environmental Research Letters, is based on high-resolution building footprints and probability distribution for local flood heights and expected sea level rise and says it expects the number of affordable housing units at imminent risk of flooding to triple in coastal states and cities by 2050.
That’s 30 years from now, the length of a standard fixed-rate mortgage, to put it in investor’s terms, and the detailed report lays out the costs and risk to the nation’s already scarce stock of both subsidized and market-priced affordable housing.
As sea levels rise and 'climate gentrification' begins
"If communities aim to preserve affordable housing stock in coastal areas, significant resiliency planning and investment is likely to be needed," the researchers write.
That’s because by 2050, most coastal states are estimated to have at least some affordable housing units exposed to flood risk events at least four times per year, including nearly half of such housing in New Jersey.
And that’s changing fast. For instance, Delaware, Washington, and South Carolina had zero affording housing units exposed to flooding at least four times per year in the year 2000 but will have approximately 100 exposed to such frequent flooding by 2050, the report says.
That’s not a surprise to observant residents in the lower-lying peninsular areas of Charleston, South Carolina, where tidal and routine rainfall flooding used to be rare events but are now becoming commonplace.
One result of that already is the beginnings of "climate gentrification," where homebuyers move to nearby higher elevations, the local newspaper, The Post & Courier, reported in its Dec. 4 article on the Environmental Research Letter report.
A concentrated risk that varies by location
The report shows that the top 20 cities in its rankings account for 75% of the aggregated expected annual exposure of affordable housing to repeated flood risk. They’re highly concentrated along the Northeastern corridor and in California.
At the top of the list in absolute numbers, of course, is the nation’s largest city. New York City is predicted to have more than 4,000 affordable housing units in vulnerable areas by 2050.
But, as the report says, "that’s less than 2% of the city's affordable housing stock and rich cities like New York generally have more resources to bolster protection than poorer ones. For example, New York City not only plans to increase its supply of affordable housing by 50% in 10 years but has also revised its building design guidelines to address the projected impacts of climate change."
Meanwhile, the report says, in some cities with smaller affordable housing stocks, more than 90% of the stock is exposed, including Crisfield, Maryland, and Revere, Massachusetts.
The Millionacres bottom line
Real estate investors with a long-term view of their holdings and their markets may want to read this report in its entirety. It’s not that long, and it provides a mix of ground-level building detail and community exposure to flooding -- and the response that’s needed to protect these investments -- that can help inform some serious thought for what to do now and in the years ahead.
The impact is going to vary by market and by neighborhood, and it’s now time to watch for action and inaction in the neighborhoods where you might be considering investing, either on your own or through government-subsidized or tax-incentive programs, including the new Opportunity Zone Program.