Lowcountry on the Edge
Tony Bartelme’s series on climate change won an award given by the American Geophysical Union in 2017. Bartelme, a three-time finalist for the Pulitzer Prize, is a special projects reporter for The Post and Courier in Charleston, South Carolina.
The South Carolina Lowcountry is a land of many edges, some obvious, others hidden. The tides blur things.
AMERICAN GEOPHYSICAL UNION’S WALTER SULLIVAN AWARD
|The AGU’s Walter Sullivan award recognizes science feature writing that makes the Earth and space sciences accessible and interesting to the public. This story was honored in 2017.
Because of our low elevation and the moon’s pull, vast areas of land and water trade places twice a day. This makes our edges spongy instead of hard; in this soppy zone, green and gold strands of Spartina grass poke from mud so black and gooey it resembles tar; and the land’s relationship with water is so intimate, saltwater sometimes pours from the ground like sweat, as it does this warm night when Norman Levine, a geologist at the College of Charleston, steps into it all. “Very impressive.”
He says this because the moon is closer than usual to Earth tonight, and its power pushed the Atlantic deeper into our twisting tidal creeks. It’s a seasonal king tide, a foot above average, an incoming flood with so much pressure that water bursts through cracks here at the intersection of Fishburne and Hagood streets.
Levine watches it pool and shoot across the street like a rapid. He watches a nurse in blue scrubs tiptoe through the current to reach her car. His voice rises because king tides are a taste of our future, one flavored with salt; he knows that climate change is reshaping the world’s low places, and the Lowcountry is accurately named. “Sea rise is no longer a probability, yo.”
Voice of Doom
Levine has a round physique and a dark goatee framed by wire-rimmed glasses. Colleagues jokingly call him the “Voice of Doom,” but his voice is nothing like Darth Vader’s. He speaks quickly and with enthusiasm. His accent has hints of New York and the South, and he has a disarming way of tossing the word “yo” into conversations.
The doom part comes from his title as director of the Lowcountry Hazards Center at the college. The center has seismographs to measure earthquakes, weather gauges to document hurricanes and computers packed with terabytes of mapping data. He and his students have used some of these maps to make startling predictions about the Lowcountry’s edges as the climate warms.
Levine has long been fascinated by mega forces. He grew up in an area of Long Island smoothed by glaciers. He was captivated by how slabs of ice from what’s now Upstate New York could transport gneiss, schist and other glittering rocks to yards around his house. In middle school, teachers gave him the key to the school’s rock collection. In college, he stared at images of earth snapped by Apollo spacecraft, his mind transfixed by the blues, whites, browns – water, vapor, land.
And so he became a geologist, learning quickly that the field isn’t just about rocks. It’s also about water and movement and time. He would learn, for instance, that the area around Charleston is sinking. Slowly, but surely, North America’s main tectonic plate is tilting like a giant see-saw with the pivot point roughly on the Canadian border. Loosely speaking, the Canadian side is going up, and the South Carolina side down — down just a few inches a century, not such a big deal. Unless the land already is low and next to a rising sea.
Back to water instead of rocks. Imagine a big pitcher of ice cubes with the water filled to the brim. Water won’t flow over the edge as the cubes melt, even if it’s a hot day. But add more cubes, and you’ll have water pouring onto the table. That’s what’s happening in Greenland and Antarctica, thanks to another powerful force — rapidly increasing levels of carbon dioxide.
Higher CO2 levels trap more heat in our air and oceans, causing enormous amounts of ice to fall into the ocean. During the past four years alone, Greenland lost 1 trillion tons of ice, a recent study found. All told, Greenland has the equivalent of 23 feet of sea rise in its glaciers and ice. Antarctica holds even more ice — 200 feet of potential sea rise. Meanwhile, the rate of sea rise has already doubled since 1993. Cue the Voice of Doom:
“We have more ice cubes about to drop into the cup,” Levine says.
A particularly large ice sheet is perched on Antarctica’s western edge. If it slides into the Southern Ocean, we’ve just bought 11 feet of sea rise. Earlier this year, two teams of scientists reported this sheet is showing signs of shear.
“We know that sea rise is already accelerating, yo, and it’s happening more sharply than they predicted 10 years ago,” Levine says. “And we’re not talking in terms of 100 or 120 years anymore. We’re talking about 50 or 60 years.” He watches more hospital employees wade through the Hagood and Fishburne intersection. “We’re talking about big changes.”
In 2015, he and his colleagues set out to study what kinds of changes we might see on our edges. At their disposal were satellite maps capable of discerning differences in a few inches of elevation.
A look at these maps quickly revealed that the Lowcountry is indeed flat but not evenly so. It’s full of subtle rises and dips, more like an old plaster wall instead of the more uniform flatness of modern wallboard, or Florida.
They also discovered that just one foot of sea rise would flood 204,000 acres of marsh and 64,000 acres of land, about a quarter of Charleston County.
Nearly 1,000 homes, offices and other buildings would see regular flooding.
Moving up, 3 feet of sea rise inundates nearly 9,400 buildings.
Six feet? More than 34,300 structures would end up in the drink.
On another day, away from the hard edges of downtown Charleston, in a soft edge of marsh north of Georgetown, another scientist steps into a symphony.
Jim Morris, director of the Baruch Institute near Georgetown, hears it when the rumble of cars and planes fade. Then the marsh comes into itself: water lapping against oyster clusters; bubbles popping from pluff mud; shrimp crackling like oil on a hot skillet. He finds it magical, as if the marsh is one great creature, breathing.
The Lowcountry’s marshes are among its defining features, and Morris may know more than anyone about how they rise and fall. In addition to his role as director at Baruch, he’s a biology professor at the University of South Carolina who made ground-breaking discoveries in part by measuring stems of marsh grass.
“For the past 4,000 years, the sea rose, and the marshes did just fine,” he says. In fact, the marshes grew higher as the sea level rose. But no one really knew how the marsh kept up.
Morris and his colleagues had been measuring Spartina since the 1990s, tying colored bird bands around individual stems month after month. Over time, he saw patterns: the Spartina grew better some years, and yet those growth spurts had little to do with droughts or heavy rain.
Then one day he had a conversation with an oceanographer, who asked whether he’d considered changes in the sea level.
“I thought, ‘Why would I do that?’ I thought marshes were predictable places. I mean, what’s more predictable than the tide?” Turns out that the sea level rose and fell more than he thought.
It rises higher during warm-weather months because of thermal expansion — water naturally expands when it gets hotter. Certain weather patterns also make a difference: when the Bermuda High pressure system parks itself over the Sargasso Sea, the extra pressure pushes down on the water like a large man on a pool float. Such factors can add up to 7 to 10 inches of extra sea rise in any given month.
Suddenly, he understood what was happening: A bit of sea rise actually helps marsh beds grow.
During these unusual warm months, or when that pressure system sat off the coast, sediment flowed into the marshes. The marsh grass sprouted more roots and trapped even more sediment. A thin layer built up, and the marsh itself grew taller, as if alive. Morris published his finding in 2002. Some call his discovery Morris’ Rule.
But his most important discovery was that marshes had a sweet spot: When seas rose a tad, marshes grew with them, no problem. But when the sea level rose too quickly, the floods were too much for the plants; marsh edges began to fray, then disappear altogether.
Today, he’s in the creek off Baruch’s preserve, there to see how the salt marshes are keeping up. He beaches the boat and tosses an anchor into the muck. Quiet now, the marsh has that symphonic sound. The stilt homes and condominiums of DeBordieu and Pawleys Island fill the northern horizon. He steps gingerly past clusters of oysters, the mud’s suction tugging on his waders, and heads toward a pipe that other scientists planted in 1992.
“This used to be so far from the creek bed that we had a hard time finding it.”
Now it’s on the edge, a few feet from the oysters. A boat slows, and a ruddy-faced man in khaki shorts and a pink shirt asks what they’re doing.
“We’re trying to find out if marshes are keeping up with sea rise.”
“Are they?” the pink shirt guy asks.
Morris shakes his head. “No.”
A decade ago, scientists led by Chester Jackson of Georgia State University set out to map the Lowcountry’s soft and changeable edges. From the Georgia border to Edisto Island, they traced the coast’s salt creeks, marshes and beaches in roughly 3-foot increments. It was among the closest looks ever at a coastal marsh’s twists and turns. And it gave scientists an idea of just what’s at stake: All told, Jackson and his colleagues counted more than 4,200 miles of shoreline. Straighten all these estuarine edges and you could draw a line from Charleston to Norway. And that was just one-third of South Carolina. A good bit of the state’s wealth sits close to these soft edges. Statewide, more than 800 square miles of land are less than 4 feet above the high tide line. Roughly $24 billion in property, including 54,000 homes, sits in this low land. And the reality is that the Lowcountry’s edges have already moved.
Charleston averaged four days of tidal flooding 50 years ago. Last year, it was 38 days. In just 30 years, Charleston will see 180 days of tidal flooding, scientists say. The same thing is happening in the nation’s other low spots.
Washington, D.C., had an average of six days of nuisance flooding in the early 1960s; in recent years, it had 30 flooding days. Wilmington, NC, had one day of high-tide flooding in the early 1960s. Last year, it had a record 90 days. Seasonal high tides now flood the only road to Tybee Island, Ga. Another study recently found that in less than 35 years, some of the nation’s most important military bases, including the Marine Corps Recruit Depot on Parris Island, will lose one-fifth of their land during high tide.
Until recently, Charleston had no comprehensive vision of how it would react to a dramatically rising sea. Its Century V plan for the future didn’t mention sea rise once. Then last December, a team of city staffers released a more aggressive sea-rise strategy. As a guideline, the report said the city should plan for a 1.5-foot to 2.5-foot increase over the next 50 years. That’s on the conservative side of most projections; thanks to the melting icecaps, new estimates are landing in the 6-foot range and higher.
The city’s report said, “failure to act is not an option.” It said flooding events could cost the city $1.5 billion over the next 50 years. It called for a long list of actions, including hiring a new “chief resiliency officer.” But no such officer has been hired, and interviews with city officials reveal that most actions in the report are either in planning stages or have yet to be done at all.
Urgency of Tomorrow
“This isn’t even a super king tide, yo,” Norman Levine says the night of king tide. He drives from one edge of the peninsula to the other, over its slightly elevated spine, its vertebrae roughly following King Street, and into a gentrifying neighborhood on the East Side.
Water curls around a church as he parks, and floodlights from a nearby field reflect off the pooling water. Across the street, notes from a blues guitar, old John Lee Hooker, pour through a wrought-iron gate made by Charleston’s famous blacksmith, Philip Simmons.
Longtime resident Santel Powell steps onto the street. Powell tells the professor about his house: built in 1882 on a platform of cypress and pyramid-shaped brick pilings, framing made with wooden pegs. And for the Voice of Doom, this is exciting because it means the house was designed to take the brunt of both earthquakes and hurricanes. And it’s also built on one of the Lowcountry’s gentle rises, so the evening’s floods don’t reach Powell’s property.
Powell is in his 60s, and the effects of sea rise feel far away, beyond his life’s horizon. “I’ll probably have a heart attack before it gets to my house,” he jokes. “Besides, what are you going to do? Pick the city up?”
“Yeah, that’s the point,” Levine says. We’ll have to respond to sea rise in increasingly dramatic ways: with dikes and dirt, and by retreating when the oceans rise too fast. Powerful forces are reshaping the Lowcountry right now. The proof is in the floods pouring out from the storm drains 911 feet from a marsh creek, and in the marshes by North Inlet, and Miami and Norfolk and other low places. Incremental changes, though. Which can blur their seriousness.
Moments later, Levine leaves the East Side, and the king tide passes, and for the time being, so does evidence of these powerful forces — save for a salty white film marking the tide’s new edge.
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