When Rising Seas Hit Home

The Union of Concerned Scientists (UCS) defines 'chronic inundation' as tidal flooding affecting 10% or more of a community's usable land at least 26 times per year. Under a moderate (intermediate) scenario, nearly 170 communities will reach this threshold by 2035, increasing to over 270 by 2060 and nearly 490 by 2100. A high scenario projects up to 670 communities affected by 2100, including over 50 populous cities such as New York City (four boroughs), Boston, and Oakland. The report highlights that socioeconomically vulnerable neighborhoods are disproportionately affected and argues that aggressive emissions reductions aligned with the Paris Agreement could spare hundreds of communities from this fate. Adaptation options include defending (seawalls, levees), accommodating (elevating homes, pumps), and managed retreat.

• UCS defines 'chronic inundation' as tidal flooding that occurs an average of 26 times per year (roughly twice monthly) and affects 10 percent or more of a community's usable, nonwetland area.
• A high sea level rise scenario projects that nearly 670 communities will face chronic inundation by 2100, including nearly 60 percent of all East and Gulf Coast oceanfront communities.
• By 2100, under the high scenario, more than 50 populous cities with populations over 100,000 will experience chronic inundation, including Oakland, San Mateo, Newark, and four of the five boroughs of New York City.
• Socioeconomic vulnerability overlaps significantly with flood risk; more than half of the communities facing chronic inundation by 2035 are home to one or more socioeconomically vulnerable neighborhoods.
• Adhering to the Paris Agreement's goal of limiting warming to 2°C or less (represented by the 'low scenario') could spare hundreds of communities from chronic inundation, including 49 populous cities that would otherwise be affected under the high scenario.
• Chronic inundation threatens critical infrastructure and economic assets, such as schools in San Mateo, energy facilities in Port Arthur, and tourism-dependent waterfronts in Ocean City and Key West.
• Adaptation strategies are categorized into three types: defending (e.g., seawalls, levees), accommodating (e.g., elevating homes, pump systems), and retreating (abandoning risky areas for open space).

APA

Spanger-Siegfried, E., Dahl, K., Caldas, A., Udvardy, S., Cleetus, R., Worth, P., & Hammer, N. H. (2017). When Rising Seas Hit Home. Union of Concerned Scientists. https://www.ucs.org/sites/default/files/attach/2017/07/when-rising-seas-hit-home-full-report.pdf

Chicago

Spanger-Siegfried, Erika, Kristina Dahl, Astrid Caldas, Shana Udvardy, Rachel Cleetus, Pamela Worth, and Nicole Hernandez Hammer. When Rising Seas Hit Home. Union of Concerned Scientists, 2017. https://www.ucs.org/sites/default/files/attach/2017/07/when-rising-seas-hit-home-full-report.pdf.

Wikipedia

{{cite report |last1=Spanger-Siegfried |first1=Erika |last2=Dahl |first2=Kristina |last3=Caldas |first3=Astrid |last4=Udvardy |first4=Shana |last5=Cleetus |first5=Rachel |last6=Worth |first6=Pamela |last7=Hammer |first7=Nicole Hernandez |title=When Rising Seas Hit Home |publisher=Union of Concerned Scientists |date=July 2017 |url=https://www.ucs.org/sites/default/files/attach/2017/07/when-rising-seas-hit-home-full-report.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{spangersiegfried2017when, author = {Spanger-Siegfried, Erika and Dahl, Kristina and Caldas, Astrid and Udvardy, Shana and Cleetus, Rachel and Worth, Pamela and Hammer, Nicole Hernandez}, title = {{When Rising Seas Hit Home}}, institution = {Union of Concerned Scientists}, year = {2017}, month = jul, url = {https://www.ucs.org/sites/default/files/attach/2017/07/when-rising-seas-hit-home-full-report.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }