I'm about to step onto brand new land. And admittedly, yes, it is a
little bit underwater right now because, well, that
river there is in flood. But 50 years ago, this
would've been open water and I would've been jumping
off this boat up to my neck. And yes, I was extremely nervous about that little jump [laughs] 'cause that's the first
time I came off here. But yeah, this is the Wax Lake Delta. 50 years ago: no trees, no plants,
nowhere to put your feet, I would've been swimming,
on a coastline that's famous not for building up but for eroding. And to explain why, we have to
go just a little bit inland. The Mississippi River
is so murky and brown because it's filled
with silt and sediment. Throughout history, roughly
every thousand years or so, deposits of that sediment build up enough that the river basically blocks itself and then takes a different and
steeper route to the ocean, at least until silt builds up
on that new route and the river moves again. That massive and relatively sudden change is called an avulsion. And avulsions were fine
until modern times, when the industry that you can hear and the livelihoods of
untold numbers of people rely on the river being
exactly where it is. But in the past, every time that humans have tried to fix the rivers around here, there have been unintended consequences. We built levees like this one to protect towns like Baton Rouge here, but they make the river
flow faster and higher because all the water is now
concentrated into one channel. And because they restrict water flow,
they move the flooding upstream, which means the next neighbourhood over has to build their levee
higher to deal with it. There are regulations
to prevent 'levee wars', when communities have to keep
building their levees higher because their neighbours
are doing the same. Those regulations aren't always followed. And downstream, levees mean that
instead of a wider river during floods, you get a faster river, eroding away those
silt and sediment deposits, literally washing away the
land that it once created. And now, the river doesn't flood as much, so the ground next to it
dries out and settles and sinks. Louisiana's coastline is disappearing. In 2011, government cartographers
retired 35 placenames, taking them off the maps because those islands and bays
just don't exist anymore. They're just open water. But there is one place on the coastline,
a couple of hours south of Baton Rouge, where land is appearing again, and that is also an
unintended consequence, which brings us back
to where I was standing at the Wax Lake Delta. - The Wax Lake Outlet is a
channel off the Atchafalaya River. The Atchafalaya River is a
channel off the Mississippi. So, a channel off a channel off
the Mississippi River. [thunder booms] Excuse me, I heard a little thunder. - Okay, no, we--
- Let's get out of here. - The Wax Lake Outlet was
built in the early 1940s and it was designed to pull water
off the Atchafalaya River and reduce flood stress on Morgan City. One of the unintended consequences was the development of a delta
at the mouth of the Wax Lake Outlet. And so, the Wax Lake Outlet
and the Atchafalaya River carries a lot of sediment, and then when it gets to the coast,
the river flow slows down and all of the sediment
in the river settles out. We're talking tens of millions
of metric tonnes of sediment every year. This is solid enough land
that you can walk on it and you can stand on it. Louisiana has lost nearly 2,000 square miles'
worth of land over the last century, and there's a large effort
to rebuild the coast. A big part of that effort is
to try to partially divert the flow of the Mississippi River to create new deltas that
are like the Wax Lake Delta. And so, people like myself want
to study the Wax Lake Delta so we understand how deltas build so we can better design
coastal restoration projects. It's important to restore the coast, one, to push back the sea to
enhance flood protection in Louisiana, and it's also a place where you could
potentially bury carbon. We have too much CO2 in the atmosphere, and highly productive
deltas like the Wax Lake may be one of those places
where we can do that. I often feel like the numerical models that we have to understand the
coast are pretty darn good. The much more difficult thing to model
is to understand people and how people are going to behave
with this changing coast. And I feel like, that, we barely
even know the equations. We don't necessarily know
even what the rules are to govern how do people deal with
a stressful changing environment. - So, yes, it's still wet
underfoot here right now because this whole area's still in flood. But that just means there's more mud,
more sediment being deposited. This land is going to be a
couple of centimetres higher and this coastline is going
to be just a little bit safer. I've sunk about an inch into the mud and it's gone in my shoes.
It's in my shoes. Right, I should totally
have gone with the sandals. [laughing] [grunts] All right.
Tom Scott is one of the best youtuber