How is sea level rise measured?
Measurement of sea level at any particular location is "relative." “Relative” sea level rise is the sum of global sea level rise plus the amount of vertical land movement for a given location. In order to calculate "relative" sea level rise in the Mid-Atlantic region, scientists examine both changes in historic tide gauge levels along with measurements of regional land subsidence.
These records document that sea level is rising in Mid-Atlantic waters and the Chesapeake Bay at an average rate of 3 to 4 millimeters (mm) per year – for a total of approximately one foot of sea level rise in the Bay over the past century. This rate is nearly twice that of the global historic average.
Maryland is experiencing more of a rise in sea level than other parts of the world because of naturally occurring regional land subsidence. Due to our geography and geology, the Chesapeake Bay region is ranked the third most vulnerable, behind Louisiana and Southern Florida. In fact, sea level rise impacts are already being detected all along Maryland’s coast. The primary impacts of sea level rise include intensified coastal flood events, increased shore erosion, inundation of wetlands and low-lying lands, and salt-water intrusion into groundwater. Maryland’s varied coastline is highly susceptible to all such impacts, and land is currently subsiding in the Chesapeake Bay region at a rate of approximately 1.3 mm/year.
- Zoe Johnson
Maps of Lands
Vulnerable to Sea Level Rise - Chesapeake Bay
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