Mississippi and the Surging Sea
Description: A vulnerability assessment with projections for sea level rise and coastal flood risk.
Date: August 2015
Low-range sea level projections lead to an even chance of floods exceeding 6 feet above the high tide line by mid-century, at sites across Mississippi’s coastline, exposing nearly $1.5 billion in today’s property. Under midrange projections, floods exceeding today’s historic records are likely to take place within the next 55 to 65 years. Under high-range projections, there is a roughly 2 in 3 chance of floods above 10 feet by end of century, exposing more than $3.7 billion. Higher floods are possible, with lower probability.
More than 99% of people, property and infrastructure in harm’s way in Mississippi are in Jackson, Hancock, and Harrison counties. We find that in Mississippi, some $1.5 billion in property value plus more than 14,500 people living in more than 8,000 homes sit on 131 square miles of land less than 6 feet above the local high tide line. The exposure of populations with high social vulnerability is disproportionately high, 50% greater than would be expected by chance alone. Of the exposed high vulnerability population, more than 60% live in just one zip code, in Bay St. Louis. Compared to 6 feet, more than double the total property, population and housing sit on land below 10 feet: $3.7 billion and nearly 44,000 people living in more than 22,000 homes, across 227 square miles.
Nonresidential buildings and infrastructure are widely at risk as well. All told, 386 miles of road lie on land below 6 feet in the state; 2 museums; 2 schools; 9 houses of worship; 2 power plants; and 57 EPA-listed sites, screened to include mostly hazardous waste sites, facilities with significant hazardous materials, and wastewater generators. At 10 feet, these numbers amount to 898 miles of road, 4 museums, 6 schools, 60 houses of worship, 2 power plants, and 112 EPA-listed sites.
Nonresidential buildings and infrastructure are widely at risk as well. All told, and still accounting for levees, 4,390 miles of road lie on land below 6 feet in the state; 5 hospitals; 21 libraries; 76 schools; 202 houses of worship; and 2,084 EPA-listed sites, screened to include mostly hazardous waste sites, facilities with significant hazardous materials, and wastewater generators. At 10 feet, these numbers amount to 7,809 miles of road, 15 hospitals, 31 libraries, 185 schools, 415 houses of worship, and 3,562 EPA-listed sites.
Sea levels are rising at an accelerating rate, and the scientific community is confident that global warming is the most important cause. Higher sea levels translate to more and higher coastal floods. To forecast future risk, this analysis integrates historic local sea level trends and flood statistics with global sea level rise scenarios, developed by a multi-agency federal task force led by NOAA in support of the recent U.S. National Climate Assessment.
This report is being released as a high-level summary of findings and methods, coincident with the online launch of a Surging Seas Risk Finder tool for the state, providing much more detailed and localized findings, and accessible via https://sealevel.climatecentral.org/ssrf/mississippi.
The tool includes:
Interactive local projections of sea level rise and increasing coastal flood risk from 1-10 feet by decade;
A zooming, zip-searchable map of low-lying areas threatened, plus layers showing social vulnerability, population density and property value;
Detailed assessments of populations, property, infrastructure and contamination sources exposed, for each implicated county, city, town, zip code, planning district, legislative district and more;
State- and county-wide heat maps facilitating high-level vulnerability comparisons; and
- Brief customized “fast look” reports that integrate key findings from across all analyses for each locality, and provide interpretation and context.
Detailed knowledge of vulnerability is a critical tool for communities seeking to build resiliency to the climate challenges of today and the future.