The Man Who Measured From the Surface

On March 4, 2026, a study in Nature revealed that global coastal sea levels are, on average, about a foot higher than previously assumed, meaning roughly 80 million people are already living below sea level — 50 million more than anyone realized.¹ The error traces partly to how we measure: tide gauge benchmarks in coastal Louisiana are anchored an average of 23 meters below the surface, too deep to capture the subsidence happening at ground level, missing 60 to 85 percent of it.²

We wanted to talk to someone who'd been measuring from the surface all along.

Theophile "T-Boy" Verdin is a fourth-generation oysterman out of Theriot, in Terrebonne Parish, the heart of the Barataria-Terrebonne Estuarine System, which has accounted for roughly half of Louisiana's total coastal land loss over the past fifty years.³ He is sixty-four years old. He has been on the water since he was eight. He is not a real person, though everything he knows is.

We met him at a boat launch off Bayou du Large on a Tuesday morning in March. Fog on the water, coffee from a thermos, and the particular stillness of a man who's already been awake for three hours and doesn't feel the need to talk about it.

You've seen the Nature study. Ninety percent of coastal hazard assessments were underestimating water height by about a foot.

T-Boy: Yeah, I seen it.

And?

T-Boy: And what? You want me to act surprised? I been telling people the water's higher than the maps say since the maps started being wrong. Which was a while ago.

When did you first notice?

T-Boy: That's not how it works, no. You don't notice one day. It's like asking when you noticed your kid got tall. You just look up one morning and the water's sitting different on the piling, and you think, well, that's high for October. Then the next year it's high for October again. Then it's just October.

My daddy used to mark the piling every New Year's. Pencil line, the date. He did that for thirty years, maybe more. I kept it up after he passed. Some of those marks are underwater now at regular tide. Not storm tide. Regular tide. You don't need a study for that. You need a pencil and a piling and some patience.

The study found that tide gauge benchmarks in Louisiana are anchored about 23 meters deep. Too deep to measure what's happening at the surface. The land sinks, the benchmarks sink with it, and the instruments miss most of the subsidence.

T-Boy: (laughs) Twenty-three meters. That's what, seventy-five feet? Yeah, no kidding they missed it. I'm standing in three feet of water on ground my daddy farmed shrimp ponds on. You don't need to be anchored seventy-five feet down to see that.

My piling sinks too, but I got eyes. I got my daddy's pencil marks. I got forty years of pulling up to the same dock and knowing where the water used to sit on the wood. That's not seventy-five feet of concrete and rebar. That's just being here.

Your father oystered these same waters?

T-Boy: My father, his father, his father's father. The beds moved some over the years, but the family didn't. Not till we had to. My grandfather worked beds that aren't beds anymore. They're open water. The marsh pulled back, the reef thinned out, the salt crept in, and one day there's nothing there to hold the oyster to. The reef holds the marsh and the marsh holds the reef, and when you lose one you lose the other. I watched that happen in real time on beds my family worked three generations. Didn't take seventy-five feet of instrumentation to see it. Took a boat and a Tuesday.

The study's co-author said that if sea level is higher than assumed, impacts from sea-level rise will "happen sooner than projected."¹ Does that match what you've seen?

T-Boy: "Sooner than projected." That's a real nice way to say late.

Everything they're projecting already happened. The cemetery down in Leeville, you know about that? Built around 1910 on dry land, people farmed around it, and now it sits four, five feet lower than it was.⁴ My daddy remembered when that was high ground. So when someone tells me the water's going to be a problem in 2050, I think, cher, it was a problem in 1990. You just weren't measuring it right.

The Army Corps built the Caernarvon Freshwater Diversion in '91 to fight saltwater intrusion. It ended up destroying oystermen's beds.⁵ Did anyone consult you beforehand?

T-Boy: (long pause)

Somebody came out with a clipboard once. I don't remember the year. They asked some questions. What do you harvest, where do you harvest, how's the water. I told them. I told them the fresh water was going to push the salt line and kill the beds if they opened it up like they were talking about. I wasn't the only one. Every oysterman on this bayou said that.

They did it anyway. Beds died.

And then they did a study on why the beds died. And the answer was: too much fresh water. Which is what we said. Before they built it.

The expert reaction to the study included someone saying that communities already living below sea level might carry knowledge the rest of the world needs to learn.⁶

T-Boy: (quiet for a moment) That's a nice thing to say. I don't know what they'd want to learn from me, though. I know where the water is. I know where it was. I know what the salt's doing and where the marsh is going and which beds are dead and which ones moved. But you can't put "being here for sixty years" in a report.

The state collected our data once. Participatory something. Participatory modeling.⁷ They came out, they talked to people, they mapped what we knew. And then the Coastal Master Plan came out and none of it was in there. Not one thing.

So when somebody says "the world needs to learn from these communities," okay. Fine. But learning means you actually listen. And listening means something changes after. Otherwise it's just another clipboard.

What would you want them to know?

T-Boy: (takes a long drink of coffee)

That the water doesn't care what your model says. That the land doesn't care what your benchmark says. That my daddy's pencil marks on that piling are more accurate than anything NOAA put out for this parish in the last twenty years, and I can prove it, except nobody's asking me to prove it. And I got tired of offering.

I'm not mad about it. I'm sixty-four. I've been watching this my whole life. The marsh goes, the water comes, the beds move, the family moves up the bayou a little bit. Every Tuesday, for forty years.

Do you still mark the piling?

T-Boy: Every January first. Even the ones that are underwater. I just reach down now.

Terrebonne Parish has lost more than 300 square miles of land since 1932. The Coastal Master Plan's next revision is due in 2029. T-Boy Verdin will be sixty-seven. The water will be where it is.

Footnotes

1. CNN, "Scientists find sea levels are already much higher than we thought," March 4, 2026. https://www.cnn.com/2026/03/04/climate/sea-level-higher-flooding-hazards ↩ ↩²

2. Nienhuis, J.H., et al., "A New Subsidence Map for Coastal Louisiana," GSA Today. https://www.geosociety.org/gsatoday/groundwork/G337GW/article.htm ↩

3. "Getting Into Deep Water: Coastal Land Loss and State–Corporate Crime in the Louisiana Bayou," ResearchGate. https://www.researchgate.net/publication/321747706 ↩

4. NOAA Climate.gov, "Thriving on a Sinking Landscape." https://www.climate.gov/news-features/features/thriving-sinking-landscape ↩

5. Barry Yeoman, "Louisiana Oystermen: Out of Work, Out of Options," onEarth. https://barryyeoman.com/2010/10/louisiana-oystermen-bp-spill/ ↩

6. Science Media Centre, "Expert reaction to paper saying coastal sea levels are higher than assumed," March 4, 2026. https://www.sciencemediacentre.org/expert-reaction-to-paper-saying-coastal-sea-levels-are-higher-than-assumed/ ↩

7. Louisiana Folklife Program / Bayou Culture Collaborative, Statement on CPRA Master Plan. https://www.louisianafolklife.org/lfp/BCCStatementmasterplan.pdf ↩