As seas rise, U.S. coastal landowners urged to let the water in
A salt marsh near Ocean City, Maryland, in 2019. Matt Kane at The Nature Conservancy/Handout via Thomson Reuters Foundation
What’s the context?
As climate change drives rising sea levels, local governments and conservation groups are offering landowners incentives to let threatened saltwater marshes 'migrate' inland.
- The U.S. loses 80,000 acres of coastal marsh per year
- Projects aim to let saltwater marshes move inland as seas rise
- Key wildlife habitats, marshes also capture and store carbon
By Carey L. Biron
DORCHESTER COUNTY, Maryland - Rising seas were never an issue for Donald Webster for the first 45 years he lived and farmed alongside the Chesapeake Bay. But since the mid-1990s, he has been forced to give up parts of his fields to the saltwater creeping its way inland.
This year alone, he lost three acres (1.2 hectares) of sorghum-growing land to encroaching seawater, probably resulting in an annual loss of about $300, he told the Thomson Reuters Foundation, as he stood in a patch of white, parched soil.
But the bigger question for Webster, 67, who manages about 300 acres for a landowner in Dorchester County, was what to do with that salt-affected property
Hoping to slow the damage, Webster tried an experiment two decades ago, building three-foot-high (1-meter-high) berms of soil around eight acres of farmland that had become too salty, helping trap rainwater and create freshwater marsh.
Today, the verdant area attracts mallards, teals, wigeons and other water birds, while keeping adjacent fields farmable.
"It was at least of some value as far as wildlife goes. At that time I felt that was the best thing to do," said Webster, who is also a waterfowl habitat manager for the state.
"Like a lot of landowners, we wanted to keep this land somewhat productive if we weren't able to farm it."
The contamination of groundwater and freshwater sources by saltwater - known as saltwater intrusion - is a leading-edge effect of climate change, scientists say, as communities around the world fight a losing battle against rising seas.
Maryland is likely to see sea-level rise of upwards of four feet by the end of this century, according to a state expert group.
In search of a solution, the state and other parts of the country are taking Webster's strategy further: trying to convince coastal landowners not to keep out rising waters but let them in to help create saltwater marshes, a key habitat threatened by climate change.
"They provide a lot of public-good benefits, in terms of carbon sequestration, nutrient retention … wildlife habitat and storm damage prevention," said Keryn Gedan, an associate professor of biology at George Washington University.
As a whole, the U.S. Mid-Atlantic region sees about three times more sea-level rise than the global average, posing an "existential threat" to the area's coastal wetlands, Gedan said.
The United States has about 40 million acres of coastal wetlands - including saltwater marshes - and loses about 80,000 acres per year, most of it destroyed by human activity or swallowed by storms and rising seas, according to the latest federal data available.
In Maryland, which has more than 7,700 miles (12,390 km) of coastline, officials are analyzing where saltwater marshes are likely to "migrate", or shift inland, as waters rise, allowing for efforts to safeguard and even prepare these areas.
A "coastal resilience easement" pilot program is giving landowners a one-time payment to allow parts of their property to permanently convert to salt marsh.
Participants can use the land until the water takes over, but they can't use pesticides or fertilizers, nor can they construct roads or buildings, said Christine Conn, acting unit director with the Maryland Department of Natural Resources, which is implementing the effort.
The program has completed two such easements so far, with about 10 more in the pipeline, she said, noting there is high interest from landowners.
The Nature Conservancy, a global charity, is building on the program to standardize such easements and figure out funding sources, to help introduce the strategy in other states.
Jackie Specht, who directs the group's Resilient Coasts program, says the project is nothing short of an attempt at a paradigm shift.
"We're trying to be proactive, to get practices on the ground now that will allow for a more natural reaction to the impacts that landowners might face, instead of just reacting to storms," she said.
Urban 'escape routes'
South of Maryland, some cities and wetlands experts in the state of Virginia are thinking about how such strategies might work in urban areas.
A state report last year found that Virginia, where nearly three-quarters of the population lives along the coast, could lose nearly 90% of its tidal wetlands to sea level rise by 2080, though that does not take into account marsh migration.
The nonprofit Wetlands Watch is working with the cities of Chesapeake and Norfolk to try to influence planning decisions to make sure shoreline development doesn't encroach on wetland zones.
The idea is to safeguard marsh "escape routes", ensuring the marshes have somewhere to move when their original locations are engulfed by seawater, explained the group's executive director Skip Stiles.
At issue is when and how communities should retreat from rising seas, with an added consideration for wetlands, said Mary-Carson Stiff, the group's policy director.
Proposals include property buyouts based on where rising water is likely to go and removing structures already threatened by rising sea levels, both to allow wetlands to migrate.
Wetlands Watch has so far focused on establishing the legal framework for such projects, with community outreach to begin in the coming months.
"It's working in advance of a tipping point," Stiff said. "It's daunting to think about how we're going to handle marsh migration in such a densely developed area."
Executive director Stiles said that so far the initiatives have seen no public pushback, though he noted the projects are still in early stages and the reality of wetlands taking over people's land on a large scale is still some years away.
Places on the move
Some groups are casting a wider net, including a project that got underway last year to safeguard a million acres of saltwater marsh stretching continuously from North Carolina to Florida.
But work to conserve "one of the world's most amazing habitats" is complex, said Joseph Gordon, director of campaigns to protect marine life along the U.S. Atlantic coast for the Pew Charitable Trusts.
The project is working with more than 200 partners - state and federal agencies, the military, tribal nations, private landowners and more - to conserve and restore the marsh, which includes identifying lands that can be used to allow these wetlands to move inland.
Mapping and outreach is now underway, and a draft regional conservation plan is to be readied by early next year.
"We like to think about parks and (wildlife) refuges and towns or properties as fixed places, as lines on the map," Gordon said. "But along the coast, those places are on the move, and those lines are changing."
- Extreme weather