Amid a Worsening Climate Crisis, How Can Coastal Cities Protect Affordable Housing?

In coastal towns and cities, affordable housing is often located in low-elevation areas vulnerable to the effects of climate change, like flooding and rising sea levels. This housing tends to be not up to modern housing codes, of poorer quality than other housing, and subject to deferred maintenance and structural problems. Flooding, even at low levels, can devastate households by damaging belongings, disrupting utilities, contaminating water, and generating mold.

Many residents of these units are socioeconomically vulnerable: they have low incomes and are more likely to be people of color, disabled, or seniors. And they are particularly vulnerable to the adverse effects of climate change because they have fewer financial assets, less political power, and are less connected to information about disaster recovery aid.

The combination of the physical vulnerability of affordable housing, socioeconomic vulnerability, and increasingly frequent flooding presents a serious threat to residents of already scarce affordable housing stock. To quantify the extent of these challenges and understand the equity implications of coastal climate change, the authors conducted the first nationwide assessment of present and future risks of coastal flooding to affordable housing in the United States.

The study focused on Alabama, California, Connecticut, Delaware, District of Columbia, Florida, Georgia, Hawaii. Louisiana, Maine, Maryland, Massachusetts, Mississippi, New Hampshire, New Jersey, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, South Carolina, Texas, Virginia, and Washington. Using projected sea level rise, annual flood probabilities, and data on general and affordable housing stock in coastal cities, the researchers assessed the threat of sea level rise and subsequent flooding to individual affordable housing units nationwide at national, state, and city levels. The researchers defined affordable housing as housing subsidized or supported by a federal program, housing directly subsidized by known state-funded subsidies, and unsubsidized affordable housing, or that which is rented below market rates, or 30 percent of median income levels, without rental assistance. The analysis identified locations where affordable housing units are at greatest risk and where the exposure of affordable housing units may be disproportionately high. Projections looked at risks posed by the year 2050. Researchers used a 30-year outlook to reflect current threats and those that could affect private developers and government investments in the future, as this time period spans the typical loan duration.

Key findings

• 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. Nearly half of New Jersey’s stock of exposed affordable housing units could flood at least four times per year.
• The 20 cities with the most at-risk affordable housing units face exposure to flooding at least four times per year, posing maintenance and public safety challenges.
• These 20 cities, which are highly concentrated along the northeastern corridor and in California, account for three-quarters of the United States’ aggregated expected flood exposure. Cities like Crisfield, Maryland, and Revere, Massachusetts, have relatively less affordable housing and more than 90 percent of that stock is exposed.
• The 20 most vulnerable cities are also some of the poorest in the country, with an average median household income ($28,618) that is half the national median, and have a correspondingly high need for affordable housing. In addition, the cities’ shares of people of color (81.2 percent) is double the national average.

Policy implications

• Flood resilience measures are essential to help residents and city managers cope with increasingly frequent flooding, which may be particularly challenging in legacy cities and other poorly resourced cities, such as Camden, New Jersey.
• Coastal flood risks to affordable housing units tend to be geographically clustered, so coordinated flood protection and climate resilience measures in the most vulnerable cities and neighborhoods could help many affordable housing residents.
• As cities implement climate resilience and other sustainability strategies, complementary policies will be needed to protect against resident displacement. This is especially important given the high proportion of people of color and low median household incomes in the most vulnerable cities. Infrastructure improvements and climate-resilient sustainability measures can result in new amenities that can attract wealthier households and drive up property values and rents, a process known as green gentrification. Cities must navigate improving the resilience of affordable housing stock, a key environmental justice concern, without compromising vulnerability or promoting displacement.
• Public-private partnership programs like Energy Efficiency for All, which upgrades energy efficiency in multifamily affordable housing complexes, and the Urban Land Institute’s Urban Resilience program, which shares resilience information and strategies, could help scale resilience in coastal cities.
• The overall supply of resilient affordable housing must be substantially increased to help ensure communities can absorb the effects of increased flooding among other climate-related hazards.