Study projects major local tax losses due to sea level rise

A new analysis by Climate Central finds that as sea level rise shifts tidal lines along the nation’s coast, local governments face potentially steep drops in tax revenue as a sizable amount of once-taxable land is subject to flooding. 

“Coastal flooding caused by sea level rise is shifting the tide lines that many coastal states use to delineate boundaries between public and private property,” the study found. “Changes in property boundaries can have significant implications for both property owners and local property tax revenues — a primary source of funding for schools and services provided by local governments.” 

Virginia law generally allows private property on bays, rivers, creeks and shores to extend “to the mean low-water mark but no farther.”

But as sea level rise alters coasts, the mean low-water mark is increasingly creeping upward, erasing land once held by the property owner, as well as the taxes the local government might have assessed on it. 

In Virginia, tens of thousands of parcels of land and hundreds of millions in property value could be affected. 

In Accomack County on the Eastern Shore of Virginia, for example, the study found that almost 14,000 acres of property that currently lie above the elevation of the mean low-water line are projected to be at or below it by 2050. The affected acreage has an assessed land value of $58.1 million.

In Middlesex County on the Middle Peninsula, over 35,000 acres with an assessed land value of $45.7 million could be similarly affected. 

The city of Norfolk’s projected impacted acreage is lower — 178 acres — but with a greater value of $48.81 million. 

Overall, Climate Central found that Virginia could have more than 44,000 properties that are partly below the tidal boundary line and an additional 2,300 that are fully below it by 2050. Over 1,100 buildings could also be affected by the shifting tidal boundaries, although the analysis cautions that researchers lacked data on improvements made to properties for roughly a dozen counties in the state, leaving “only a partial financial picture of the overall threat.” 

What changing tidal lines could mean for property rights remains murky. In Virginia, tensions have already emerged over how rising seas affect the state’s delineation of mandatory 100-foot-wide buffers that abut shorelines, tidal wetlands and other water bodies within the Chesapeake Bay watershed.

“How, when, and whether legal boundaries will be adjusted in response to physical changes in the behavior of tides is very much an open question,” the Climate Central study notes.