2025 Reports

Enhancing Adaptation to Sea Level Rise and Coastal Flooding in New York City

Gornitz, Vivien

New York City, a major seaport and international financial center, has significant economic assets and populations potentially exposed to coastal flooding along its 837-kilometer-long shoreline. The New York Panel on Climate Change (NPCC, 2015, 2019; 2024), initially convened by Mayor Michael Bloomberg in 2008, provides advice to the city in strengthening its resiliency to future coastal storms in the face of globally rising sea level (over 4 mm/yr within the past decade vs a 3 mm/yr global average rise since the 1990s (IPCC, 2021).

Previously, the NPCC found a sea level rise (SLR) of 0.28–0.53 meters by the 2050s, 0.56 m–1.27 meters (25-75 percentile) and up to 1.9 meter (90th percentile), at the Battery, Manhattan by 2100, relative to 2000–2004. SLR could reach nearly 3 m by 2100, in the very low likelihood (<3%), extreme high ARIM (Antarctic Rapid Ice Melt) scenario, which assumes partial destabilization of West Antarctica by 2100 (NPCC, 2019, 2015). Updated sea level projections for New York City now show a mid-range sea level rise of 0.36-0.48 m by the 2050s, 0.64-0.99 m by the 2080s, and up to 1.5 m by 2100, relative to the revised baseline period, 1995-2014 (NPCC, 2024).

Monthly tidal flooding in low-elevation neighborhoods ringing Jamaica Bay and Queens and elsewhere in the city starting in the 2050s would become more widespread by 2100. By late 21st century, areas that previously experienced monthly tidal flooding in the 90th percentile NPCC (2019) SLR scenario could suffer daily, even permanent high tide flooding under a more extreme SLR scenario, such as ARIM. Future extreme high coastal flooding events upper end SLR scenarios could potentially compromise habitability. Similar flood hazards could affect other low-elevation waterfront communities elsewhere (Fig. 1).

Ongoing and proposed city initiatives tailored to neighborhood needs include engineering solutions such as strengthening raising bulkheads and seawalls, constructing local levees and storm surge barriers, enforcement of stricter building codes to reduce flood risk, and restoring wetlands and beach dunes. Additional recommendations include updating FEMA (Federal Emergency Management Agency) coastal flood zone mapping, continued collaboration with the NPCC to update and refine local climate change projections, and strengthen coastal defenses, while tailoring approaches to specific neighborhood needs. Adaptations include new City resiliency projects designed to augment both hard and soft coastal defenses, increase protection of critical infrastructure, enable more public access to the waterfront, and provide recreational opportunities.