The Vulnerability of U.S. Cities To Coastal Flooding and Sea Level Rise (Graphic and Report: Climate Central)
On the five year anniversary of Hurricane Sandy, an October 2017 research report written by Climate Central highlights some of the major U.S. cities that are most vulnerable to major coastal flooding and sea rise using a variety of metrics, including the total population within the FEMA 100-year floodplain, that population as augmented by sea level rise projections for the year 2050, and the total social vulnerability populations that are most at risk.
Each analysis in the report examined coastal cities with overall populations greater than 20,000; the first metric (cities most vulnerable to coastal flooding today) were tabulated by overlaying 2010 Census block population counts against FEMA's 100-year coastal floodplains, a comprehensive evaluation which factors in storm surge, tides, and waves.
Based on locations meeting the criterion that there is at least a 1% annual chance of flooding, New York City ranked first for cities most vulnerable to coastal flooding today, with over 245,000 people at risk, followed by Miami with 126,000 people at risk, Pembroke Pines, Coral Springs, and Miramar. Of the 25 most vulnerable cities, 22 of them were located in Florida, with just New York City, Charleston, South Carolina, and Atlantic City, New Jersey making the list.
In a second analysis, one that re-ranked the cities based on which have the largest populations that could be threatened by the year 2050 due to sea level rise driven by climate change, as well as local land subsidence, New York City again fared to be the most vulnerable city. This was determined using media local sea level rise projections for midcentury by (Kopp et al 2014) to additively elevate the FEMA 100-year floodplain, extending it as topography allowed. Much like in the previous analysis, 36 cities in Florida placed in the top 50.
Lastly, coastal cities were ranked by their high social vulnerability population, a metric that was determined using the a Social Vulnerability Index developed by the Hazards and Vulnerability Research Institute, an index that incorporates nearly 30 different socioeconomic variables to help evaluate a community's preparedness and responsiveness to environmental hazards such as floods.
New York City, Philadelphia, Baltimore, Houston, and Miami were ranked as the top five cities with the largest social vulnerability within the future FEMA 100-year floodplain, and once again, as was in the case with the other metrics, cities in the state of Florida overwhelmingly made the top of the list.
It is clear that the report suggests that the state of Florida, as well as other urban, under-prepared areas such as Atlantic City and New York City, could be the most widely affected by major coastal flooding and sea level rise due to climate chance in the next few decades.
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© 2018 Meteorologist Chris Stubenrauch