Catalyst Fall 2014



coastal flooding

During an extreme high tide along the coast of Jamaica Bay, NY, a high school student wades through shin-deep water on her way to the subway station. Photo: Peter Mahon/West 12th Road Block Association

Coastal Communities Must Cope with Flooding

by Melanie Fitzpatrick

Scores of coastal communities in the United States are learning to cope with an ominous development—more frequent and severe tidal flooding. According to new analysis by UCS, places such as Annapolis, MD, and Washington, DC, are likely to endure more than 150 tidal floods every year by 2030; by 2045 (within the lifetime of today’s typical home mortgage) many more communities will experience tidal flooding as a matter of course, with serious implications for local economies and environments.

Sea levels are rising due to a variety of factors: climate change is causing ocean water to expand as it warms, and land ice in Greenland and Antarctica to melt; in some places, the land is also subsiding. A recent report from the National Oceanic and Atmospheric Administration (NOAA) showed that in many coastal communities, flooding at high tide has already increased significantly. In Annapolis, for example, this problem has grown nine-fold since 1960.

Our analysis used data from 52 NOAA tide gauges along the Atlantic and Gulf Coasts to project what kinds of flooding cities and towns will experience when high tides occur on top of higher seas. As our results for many locations suggest, the mid-Atlantic region could experience some of the worst increases in flood frequency (see chart below).

Smart Planning at the Local Level

To learn more about how tidal flooding is already affecting communities, and what they are doing to protect themselves, UCS analyst Erika Spanger-Siegfried and I spoke to business owners, emergency responders, city councilors, town planners, and activists in communities up and down the East Coast. We found that many cities are already taking action.

Philadelphia, for example, has adopted a master plan for its riverfront that includes the creation of wetlands to provide the city with a buffer zone against flooding. In Boston, the city is collaborating with property managers and developers on strong new building codes that require boilers, generators, and other critical utilities to be situated above the first floor. In frequently flooded Norfolk, VA, some local officials are using Twitter to disseminate information about flood conditions and road closures.

Given the scale of the problem, however, cities can’t bear the burden of coping with rising seas and higher tides alone. That’s why UCS continues to push for climate resilience funding as a national priority, and for steep reductions in the heat-trapping emissions that drive climate change.

Melanie Fitzpatrick isa climate scientist in the UCS Climate and Energy Program. Read more from Melanie on our blog, The Equation.

The Growing Threat of Coastal Flooding