Virginia stands to lose most of its tidal wetlands to sea level rise this century according to an analysis by a nonprofit organization urging Gov. Tim Kaine to take actions that could help curb future losses.
The Norfolk-based group, Wetland Watch, said in a letter to the governor that the state could lose between 50 percent and 80 percent of the tidal marshes that surround the Bay and portions of its tributaries as water levels rise, drowning surrounding areas and threatening homeowners.
“Every day of inaction limits the options available to coastal communities and the ecosystems on which they depend,” said Skip Stiles, who heads the group. “We stand ready to help but the state government must first take the lead.”
Specifically, the group would like the state to undertake an extensive coastal mapping program, as has been done in Maryland and North Carolina, to better estimate the potential extent and location of future losses. The group’s analyses was based on existing low-resolution photos and maps that made more precise estimates impossible, Stiles said.
“Until and unless the state of Virginia does some decent high-resolution mapping in coastal areas which then allows people to do more sophisticated modeling and ecosystem impact work, it is going to be impossible to tell whether the loss will be closer 50, 80, 30 percent or whatever,” Stiles said.
The group also wants the state to lead a process that involves local governments, landowners, land trusts and other non-profit organizations to identify a “tool kit” of land use actions that might help mitigate future potential losses.
For instance, Stiles said, maps could identify low-lying areas adjacent to existing wetlands where marshes may migrate in the future. The maps could help land use planners protect those areas from development. Because such “future” wetlands have no legal protection, local governments may need to work with land trusts or other organizations to purchase or secure conservation easements on those properties.
“You are basically telling a local government you have to forgo the property taxes on that piece of property, and the landowner that you have to forgo the development of your property because at some time in the future we need that land to naturally erode and become a new wetland,” Stiles said. “There’s the problem.”
The group noted that the state promised, when signing the Bay Program’s Chesapeake 2000 agreement seven years ago, to evaluate the impacts of sea level rise on wetlands. Further, the group said, the state has done little to meet another commitment in the agreement that called for helping local governments institute local wetlands preservation plans.
State Natural Resources Secretary Preston Bryant responded in a letter that Virginia and other states were in the “early stages” of developing tools that could address issues related to sea level rise, but warned that the mapping Stiles called for was expensive and would likely require federal assistance. In the meantime, he noted the state was developing new shoreline management techniques—especially alternatives to traditional bulkheads—that would make it easier for tidal wetlands to migrate inland.
Maryland conducted an extensive mapping program several years ago that identified areas at risk of inundation in the future to aid planning. It also estimated the state was losing 580 acres a year—both uplands and wetlands—to sea level rise and related shoreline erosion.
Carl Hershner, a wetlands scientist at the Virginia Institute of Marine Science and chair of the Bay Program’s Scientific and Technical Advisory Committee, agreed the 50–80 percent loss projection for Virginia was “a reasonable estimate.”
Virginia’s tidal wetlands are “changing very obviously and in ways you can’t ignore…We certainly don’t know where we’re gaining any.”
He said that an improved mapping program could aid in pro-active management to stem future losses.
Stiles said failure to act has both ecological and economic consequences. Insurance companies have already begun to balk at selling new homeowners policies in coastal areas, citing concerns about sea level rise and the increased potential for storm-related damage.
The tidal wetlands that fringe the Bay sometimes form vast expanses of marshes, help to reduce runoff, filter pollution and provide habitat for fish, shellfish, waterfowl and other organisms. In addition to wetlands, the group said other key coastal ecosystems, such as dunes, shoreline buffers, mud flats, oyster reefs and underwater grass beds will be threatened by sea level rise and would benefit from mapping and planning actions.
“Unmitigated losses of wetlands, buffers and coastal dunes at the upper predicted ranges would trigger an ecosystem collapse throughout the Chesapeake Bay,” Stiles wrote in the letter to Kaine
The Chesapeake Bay has risen about 1 foot since the 1930s, and scientists predict at least another 1.5–2 feet of sea level rise in the Bay within the next century. Some scientists believe the rate of sea level rise could be even greater.
Most of that increase is considered to be “locked in” as efforts to reduce greenhouse gas emissions would likely not have an impact until later. If climate change is not addressed, the group warned, the problem would only become more severe in the next century.
Sea level rise is taking place in part because of global warming, but is especially severe in the mid-Atlantic because land along the coasts is also subsiding.