Encroaching Tides

The report analyzes 52 tide gauges from Maine to Texas, projecting that by 2045, many U.S. East and Gulf Coast communities will face a ten-fold increase in tidal flooding. It argues that such flooding will disrupt daily life, damage infrastructure, and necessitate a coordinated national response combining local adaptation—such as elevating roads and restoring wetlands—with global carbon emission reductions.

• Tidal flooding is increasing in frequency along the U.S. East Coast, with some communities experiencing a fourfold increase in annual flooding days since 1970.
• By 2030, more than half of the 52 analyzed communities on the East and Gulf Coasts are expected to average more than 24 tidal floods per year, with two-thirds of those communities potentially seeing a tripling or more in annual flood frequency.
• By 2045, one-third of the analyzed locations are projected to average more than 180 tidal floods per year, and nine locations—including Atlantic City and Cape May, NJ—could average 240 or more.
• Sea level rise is transforming 'nuisance' flooding into 'extensive' flooding; by 2030, tides alone are expected to cause extensive flooding in locations such as Lewisetta, VA, Cambridge, MD, Charleston, SC, Duck, NC, Kiptopeke, VA, Savannah, GA, and Vaca Key, FL.
• The Gulf Coast faces particularly high rates of sea level rise, sometimes more than three times the global average, driven partly by land subsidence in regions from Mississippi to Texas.
• Tidal flooding causes significant socio-economic disruption, including the closure of primary access routes, damage to homes and businesses, and the potential for declining property values and shrinking local tax bases.
• Adaptation strategies are categorized into three main approaches: defending against the sea (e.g., seawalls, tide gates), accommodating rising water (e.g., elevating infrastructure), and retreating from the shoreline.
• The report argues that local adaptation has fundamental limits; in some areas, physical, economic, or social thresholds will make structural defenses impossible or unaffordable, necessitating a planned retreat from the shore.
• To slow the rate of sea level rise and make adaptation manageable, global carbon emissions must peak and begin to decline by the end of the decade to keep warming below 2°C.

APA

Spanger-Siegfried, E., Fitzpatrick, M., & Dahl, K. (2014). Encroaching Tides. Union of Concerned Scientists. https://www.ucs.org/sites/default/files/attach/2014/10/encroaching-tides-full-report.pdf#page=37

Chicago

Spanger-Siegfried, Erika, Melanie Fitzpatrick, and Kristina Dahl. Encroaching Tides. Union of Concerned Scientists, 2014. https://www.ucs.org/sites/default/files/attach/2014/10/encroaching-tides-full-report.pdf#page=37.

Wikipedia

{{cite report |last1=Spanger-Siegfried |first1=Erika |last2=Fitzpatrick |first2=Melanie |last3=Dahl |first3=Kristina |title=Encroaching Tides |publisher=Union of Concerned Scientists |date=October 2014 |url=https://www.ucs.org/sites/default/files/attach/2014/10/encroaching-tides-full-report.pdf#page=37 |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{spangersiegfried2014encroaching, author = {Spanger-Siegfried, Erika and Fitzpatrick, Melanie and Dahl, Kristina}, title = {{Encroaching Tides}}, institution = {Union of Concerned Scientists}, year = {2014}, month = oct, url = {https://www.ucs.org/sites/default/files/attach/2014/10/encroaching-tides-full-report.pdf#page=37}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }