New method reveals potential losses at four U.S. locations
What will happen as the ocean continues to rise? That’s a key question NOAA researchers and collaborators asked regarding sea level rise in four U.S. coastal metro areas. Using several sources of global and local information, a team examined how rising sea levels would impact four U.S. housing markets, finding that coastal properties are expected to become more prone to flooding in the coming decades with risk dependent on location.
In the study published in the journal Environmental Systems and Decisions, researchers looked at Atlantic City, NJ; Miami, FL; Galveston, TX; and Newport–San Pedro, CA, to delve into the potential impacts of sea level rise on thousands of homes in areas of concern.
A Novel Methodology
Given that approximately 40% of the U.S. population lives in coastal communities, the study team set out to create an easy-to-replicate way to discern the impact of sea level rise. Earth’s warming is expected to exacerbate rising coastal waters in the short and long term. Sea level has risen 8–9 inches (21–24 centimeters) since 1880. In 2020, global sea level set a new record high—3.6 inches (91.3 millimeters) above 1993 levels, according to NOAA. The researchers used readily available data about housing characteristics, local topography, tidal conditions, elevation, and sea-level-rise (SLR) projections as the basis for a methodology to serve the public’s need for climate change information.
The methodology uses freely available datasets to show 1) refined measurement of property inundation elevation; 2) estimated timing of SLR inundation; and 3) SLR risk that accounts for variations in climate conditions.
“Our results provide an important perspective on the timing of future losses, the associated uncertainty, and highlight positive (high-skewed) asymmetry of risk from sea-level rise inundation,” according to the authors, who included representatives of the Federal Reserve Bank of Kansas City, MO, and the Cooperative Institute for Research in Environmental Sciences (CIRES), a NOAA partner.
Risk to Local Real Estate Markets
Social, economic, and financial costs due to SLR could differ depending on many issues, including the extent of global greenhouse gas (GHG) emissions. The team offered a range of possible outcomes at the local level regarding the timing, number of homes likely to be impacted, and estimated value of those losses. The metro areas selected for in-depth analysis were chosen due to their geographic diversity.
Examining only single-family residences, townhomes, and 2–4 unit residences, the researchers looked at the current elevation above sea level for about 590,000 homes in the four metro areas. Using digital elevation models (DEMs) in the NOAA Sea-Level Rise Viewer and the nearest local sea-level projections for Permanent Service for Mean Sea-Level tidal stations, they determined which residences might be prone to inundation.
The team based its calculations on a scenario of medium GHG emissions, known in the scientific community as RCP4.5 (Representative Concentration Pathway 4.5). The researchers also filtered for low- and high-risk factors to take into account the potential for accelerated ice sheet loss, which could change outcomes in coastal communities. The primary analysis is structured in terms of the counts of impaired residential units rather than the relatively less stable market (financial) values.
In the study, the team also produced figures to track changes over shorter periods, between now and 2100. In addition, costs due to SLR property losses were estimated and ran into the billions of dollars in many instances.
“Our risk-matching methods could be used by other researchers and practitioners to refine previous loss estimates for at-risk properties, assess SLR risk in other coastal markets (e.g., mortgages, commercial real estate, etc.), or be used to assess SLR risk for various housing strata and populations (e.g., owner-occupied vs. renters, income level, etc.),” the authors conclude.
The abstract for this scientific paper is currently available online. To read the paper in its entirety and see the full suite of charts and maps, please contact your local public library or university to place an interlibrary loan request.
Reference: Rodziewicz, D., C. J. Amante, J. Dice, and E. Wahl. Housing market impairment from future sea-level rise inundation. Environment Systems and Decisions (2022). https://doi.org/10.1007/s10669-022-09842-6.