MS. REBECCA SHEIR
So we've all heard talk about the balance of nature, right? The theory that ecological systems are usually stable, they're an equilibrium. So if a small change comes along, the system will correct it to achieve that original point of balance. But then there are those who believe the natural world is unstable. It's constantly flowing, it's constantly changing. So expecting everything to balance out in the end, to get even, if you will, isn't exactly the most realistic thing to do.
MS. REBECCA SHEIR
In any case, in this next story, WAMU environmental reporter, Sabri Ben-Achour sheds light on a situation in nature where things definitely are not evening out. More specifically, the land and the sea.
MR. SABRI BEN-ACHOUR
The beach in Ocean City is a major tourist draw. It stretches hundreds of feet from the boardwalk with giant dunes studded with grasses a little farther south. This beach probably would not be here right now. It'd be open water if it weren't for the fact that tons of sand are brought in every few years to replenish it, especially after major storms.
MR. TERRY MCGEAN
Beach replenishment serves as a storm protection for the town of Ocean City. It's the equivalent of the levies in New Orleans for us.
Terry McGean is the City Engineer for Ocean City.
They dredge sand from a couple miles off shore and we pump that material onto the beach and basically bring the beach back.
You know, storms and erosion aren't new, but there's something else going on here. Something that's making every storm a little more serious each time one hits. Tidal gauges here have measured an increase in sea level. It's gone up seven inches over 30 years. That's 5 ½ millimeters per year and a foot and a half per century. Dr. John Boone is a professor emeritus with the Virginia Institute of Marine Science. He recently co-authored a paper on sea level rise in the Chesapeake Bay itself, but he says the sea level is rising throughout this region.
DR. JOHN BOONE
So we have relative sea level rise rates that are highest on the U.S. east coast.
Now, you may wonder why or how our sea level might be rising more than anywhere else is. I mean, the sea is the sea, right? Well, no.
The ocean circulation moves water masses to different parts of the globe and gravity changes as ice masses at the polar regions melt. There's differential heating in the oceans.
And in our region, there's an extra factor that's actually more important than the rising sea. The ground is sinking. It's called subsidence. And Boone says it's been going on for a while now.
Some 90,000 years ago, we had a very large ice mass to the north of us, an ice sheet of almost a mile thick. This placed a great load on the earth's surface up there. And an adjustment to that, we had what is called a glacial forebulge.
Picture yourself, say, stepping into a mud puddle.
You notice that around your foot where it sinks in, there's a little bit of a bulge that rises. The land is the same way.
So when the glacier is melted, the weight to the north lifted and our area started sinking back down like a seesaw. And as if that weren't enough, towns in the southern bay are paying the price for an asteroid that hit 35 million years ago.
That crater has created some regions in the southern bay that seem to have higher subsidence rates than elsewhere.
And then, on top of all that, we have human cause sea level rise, which Boone says in our region contributes about two millimeters a year. He says he hasn't been able to show yet whether that factor is accelerating, but many researchers and the National Oceanic and Atmospheric Administration say it is very likely that it will. They say sea level may rise by as much as three feet by 2100.
Regardless, the combination of factors means the water is already rising everywhere in this region, but certain areas are seeing it more than others.
MR. JOHN CARLOCK
People have noticed it with their piers and we've certainly observed it with storms over the last decade.
John Carlock is a city planner for Hampton Roads, Va. where sea level rises has been measured at about 4 ½ millimeters per year. That's a foot and a half over a century, if things stay the same, let alone what's predicted with climate change.
If we see a one meter rise in sea level, considerable areas will flood and then you add a storm on top of that and it's pretty ugly.
Carlock says they're starting to plan for it. Detailed studies are underway to figure out how to address flooding, either with better drainage or pumping or barriers. And back in Ocean City, city engineer Terry McGean says building codes have been tightened to keep new construction and redevelop higher up or further in from the water. But flooding has already become a problem around the bay separating Ocean City from the mainland.
And that's a tough one for us because, you know, the houses are where the house are.
And if water levels keep rising the way scientists expect them to, it might not be too long before those houses aren't anywhere at all. I'm Sabri Ben-Achour.
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