Maryland and the Surging Sea
Description: A vulnerability assessment with projections for sea level rise and coastal flood risk.
Date: September 2014
An intermediate high sea level rise scenario leads to better than even chances of record-breaking coastal floods within the next 60 years in the Baltimore and Annapolis areas, and as soon as 20 years in other parts of the state. Under a slower scenario, floods are still likely this century to reach dangerously more than 5 feet above the high tide line throughout the state. Under a high sea level rise scenario, floods are likely to top 9 feet statewide.
265,000 acres of land lie less than 5 feet above the high tide line in Maryland, after taking into account potential protection from levees or ridges. More than $19.6 billion in property value (more than 40% in Worcester County, and a third in Ocean City), plus 41,000 homes with 55,000 residents, sit on this area. These figures jump to $42.3 billion, 94,000 homes and 132,000 residents on more than 440,000 acres of land under 9 feet.
The state has 1,488 miles of road below 5 feet, plus 6 museums; 98 houses of worship; 3 power plants; and 154 EPA-listed sites such as hazardous waste dumps and sewage plants. At 9 feet, these numbers grow to more than 3,009 miles of road, 18 museums, 188 houses of worship, 7 power plants, and 335 EPA-listed sites.
Somerset and Worcester have the highest percentages of their homes and assets exposed out of all counties – between 30 and 50 percent at 5 feet.
Delmarva as a whole includes some 183,000 people, 116,000 homes, $42 billion in property value, 3,400 miles of roads, and 401 EPA-listed sites on 582,000 acres of unprotected land below 5 feet. Among its neighbors, Maryland faces the greatest threats to land, property value, road miles and EPA-listed sites at this level, but Virginia faces greater threats at 9 feet.
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/maryland.
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.