When Cities Sink: Sea Level Rise and the Cost of Staying Home

Jakarta is sinking. The Maldives are vanishing. And cities like Miami and New York are racing to hold back the sea. This week, we dig into what’s really driving sea level rise, how it’s affecting real people right now, and what it means when staying home becomes a risk.

Transcript

[Opening]

Good morning, good afternoon or good evening, whatever is is wherever you happen to find yourself today, I’m Dave and thank you so much for joining me on Running My Mouth Off. 

Earlier this week I was in Indonesia riding the riding the fastest bullet train outside of China. And this thing is in Indonesia, of all places. It runs from Jakarta to a city called Bandung, which is about 100 miles away, or 160 kilometers, and it makes the trip in about 35 minutes. By the way, it took me an hour and a half to go the 5 miles in a taxi from the hotel to the train station, but anyway, that’s neither here nor there. This train tops out at 350 kilometers an hour—and as we were finishing the journey,  pulling into Jakarta, I found myself staring out the window at a city that’s literally sinking.

The weird thing is though, Jakarta’s skyline is still growing. It’s not like there are cranes as far as the eye can see, but there’s still a lot of investment dollars going into building some pretty substantial buildings there. It’s kind of a strange collision, if you will, of speed and collapse. Culture and business are busy racing forward while the ground underneath underneath the city is literally disappearing.

And it’s not a metaphor. The city is literally sinking. Some neighborhoods are sinking by as much as 10 centimeters a year. And, for those of us who are metrically challenged, that 10 cm equals a little bit less than 4 inches per year. And the oceans that border Jakarta? Not showing a whole lot of mercy.

We talk a lot about climate change in terms of heatwaves and wildfires. But sometimes the biggest threat doesn’t come roaring in like a storm. Sometimes, it’s just… water. Quietly and slowly rising. Every so slowly taking over the places that a lot of us call home. 

And it kinda begs the question:

What happens when the places we live just… stop working?

[Context + Key Facts]

Again, Jakarta, it’s sinking. Again, not just metaphorically. Not just slowly. But actually, physically sinking.

And it’s happening for a few reasons.

The first? Groundwater. A lot of Jakarta’s water use—bathing, brushing teeth, doing laundry, things that we do with water, no called drinking—comes from underground aquifers, as it does in most places. But when too many wells tap into that supply, the land above starts to collapse. Especially on a city built on soft sediment, this place has literally been built an a marsh. If you pull the water out, the ground sinks down.

Again, in some parts of the city,  we’re seeing as much as 10 centimeter drop every year. At current rates, the government estimates that a quarter of Jakarta will be submerged by 2050.

I mentioned drinking water? Most people don’t even trust the tap. It’s plastic bottles all day long. Industry, both in Jakarta and Bandung, which is where a lot of this water originates. This industry has completely destroyed any idea of drinking this water. 

But the second reason is Sea level rise. As the planet heats up, two things happen: glacier melt, and ocean water expands, and we’ll dig into this more in a minute. But the combination of these two, means higher seas worldwide, and again, Jakarta’s sitting right on the coast.

And third, and kind of outside of our topic today, but it’s one the reasons for Jakartas mess so I’ll mention it anyways. Urban planning that didn’t account for any of this. A lot of Jakarta’s infrastructure—like drainage, like seawalls, and sewage—wasn’t built for the 11 million people that live in Jakarta proper. So when it floods? It floods, it’s not just a little water, it kinda floods badly.

Now, Indonesia’s trying something, I’ll just say, some, would say  bold: they’re moving the capital because of this sinking. They’re building a new city that’s called Nusantara, which is about 800 miles away on what they call Kalimantan and the rest of the world calls Borneo, not that they’re a just a little bit defensive about this, but they are. This city though it’s basically built on higher, better ground. And it’s supposed to be smart, green, and sustainable — so they’re bulldozing a jungle and displacing things like orangoutangs, to build a green city. Alright, makes sense, but whatever. Whether this thing actually pans out, and there’s a lot of discussion about whether it’s going to work or not, completely different story.

But the point is: Jakarta’s not alone.

Take Venice, for example. It floods so often that they’ve built giant underwater gates to hold back the sea.

New York City. It’s planning a $119 billion sea wall system.

Miami is seeing insurance costs absolutely skyrocket, with some companies refusing to cover homes.

The Maldives? They’re barely above sea level to begin with, and we’ll talk about them a little bit more in the closing. For them, this isn’t future planning, it’s existential, it’s their existence.

And, switching gears a little bit, we hear all of this talk about keeping temperatures below this 1.5c threshold. If we blow past that 1.5 degrees Celsius of warmth? The best estimates say we’re looking at 10 to 21 inches of sea level rise by 2100. And these are the best case estimates, not worst-case scenarios. That’s just kinda what happens if things go… okay-ish.

And in the U.S., we’re seeing it too.
Dozens of coastal cities now experience five, ten, sometimes twenty times more flooding days than they did just 50 years ago. It’s not always dramatic though, sometimes it’s just water bubbling up through storm drains on a sunny day, but it adds up.

In some places, like New Orleans, a previous disaster has brought investment and improvement the city. After Hurricane Katrina back in 2005, the city rebuilt its levees and flood walls. Fourteen billion dollars later, those walls seem to be holding, for now. So it looks like it’s buying them a little bit of time.But not every city gets that wake-up call like a Katrina. And even fewer get the funding to do something about it.

[The Real Cost]

And, sea level rise. We typically talk about that in terms of property values and Real estate loss. Infrastructure damage. Economic displacement. And yeah, all of that stuff  matters.

But at the core of it, this isn’t just about square footage or flooded roads. It’s about home.

I work with a factory in North Jakarta, and every now and then I’ll get a text: “Don’t come out today, it’s flooded.” There’s no drama, no panic. Just a heads-up. I’ll then look at photos online and see people wading through water that’s waist-deep, sometimes neck deep. And cars and scooters submerged. Kids still playing in the shallows or swimming in the water, like it’s just another Tuesday.

And the thing is, it is just another Tuesday.
 

This isn’t a freak event. It’s life, it’s normal life.
People plan around it. Businesses work around it. It’s something that’s expected a couple times a year. You eventually get used to knowing that the place you live might suddenly turn into a lake.

And it kinda makes me wonder, it kinda makes me think: what if normal, where we live; what if, in a major city, owning a boat wasn’t just a luxurious hobby, but it’s just… practical? There are now quite a few boats in North Jakarta that are used solely for flooding, it’s weird

There’s this phrase that gets tossed around a lot: climate resilience, and that’s what the purpose these boats are serving. And sure, it all sounds good. But sometimes “resilience” is just a polite way of saying you’re basically on your own.

Because if you live in a place like New York or Tokyo, resilience is a billion-dollar infrastructure project. If you live in Jakarta? It means moving the capital. And if you live in a low-lying villages with no resources and no voice on the world stage. It means standing by, as you watch your history wash away, and being told, “Well, you’re just gonna have to adapt.”

Sea level rise, it doesn’t just redraw coastlines. It redraws the boundaries of who gets help… and who gets forgotten.

[How Sea Level Rise Actually Works]

Let’s zoom out for a second though. What’s actually driving sea level rise?

Two main things.

First: melting ice, this one seems kind of obvious.

Glaciers, ice sheets, especially in Greenland and Antarctica; they’re melting into the ocean and that adds more water to the system. Pretty straightforward, right? And we’ve all heard about this stuff.

Second is thermal expansion, this one is less obvious.

As water heats up, it expands. And the ocean? They’ve been doing us a huge favor, for quite a while now. They’re the biggest heat sink we’ve got, they absorb over 90% of the excess heat from global warming. And, without that, the planet’s surface would be a heck of lot hotter than it already is.

Honestly I wish I had some actual numbers for you, but that’s really hard math. We’re talking about energy budgets though, atmospheric modeling, long timelines. But here’s the thing—none of that absorption is free.

Heat doesn’t just disappear, it doesn’t just disperse into nothing. And sea water doesn’t get a “get out of physics jail free” card. It follows the same rules as everything else: it warms up, it expands, it takes up more space, and it rises.

Thermal expansion alone is responsible for roughly half of the sea level rise we’ve seen over the past century. So even if glaciers froze solid tomorrow, the oceans would still keep creeping up, just from the heat they’re holding.

So yeah, sea level rise isn’t just some far off threat tied to a single glacier breaking off a continent. It’s baked into the physics of warming water.

And then there’s groundwater extraction, especially in places like Jakarta. When people pump too much water from underground aquifers, the land above sinks. It’s called land subsidence, if you’re interested at all, and it can dramatically worsen flooding and sea level impacts. Basically, the ocean doesn’t even have to rise—the land just sinks to meet it.

So when we talk about cities going under, it’s not just one thing. It’s an entire system that’s kind of moving things up and moving things down and, they’re kinda meeting at the same place.

[Closing]

At this point, we’re not talking about if the seas will rise, because they are rising; this is reality, this is a fact. And, regardless of how effectively we’re able to control global temperatures, we’re still talking  about how much the seas will rise and, ultimately, who’s gonna pay the price.

In places like Venice or New York, we throw billions at the problem. In Jakarta, the solution is to move the capital.

And in the Maldives, we touched on that earlier, there realistically isn’t a Plan B.

Back in 2021, the president of the Maldives, and I could say his name but it’s kinda hard to pronounce and I don’t want to butcher it, stood in front of a bunch of world leaders and said this:

“If we do not reverse this trend”, and he’s talking about global temperature rise, “the Maldives will cease to exist by the end of this century.”

This was just a few years ago back in 2021. Since then, the oceans has risen another 1.5 to 2 centimeters. And while that might not sound like a lot, when you’re a country made up of coral islands that are barely above sea level to begin with, every single millimeter counts, and every single millimeter of sea level rise eats away at your future.

More than 90% of the islands are already dealing with some pretty severe erosion issues. Almost all of them have lost access to fresh groundwater. Flooding that used to happen two or three times a year? It’s now showing up twice a month in places.

And their environment minister asked a question that kinda cuts through everything:

“Are you willing to take the Maldives as climate refugees?”

We talked about climate refugees a few weeks ago, kind of an interesting issue. But ya, what’s going to happen to these people?

So, I live in Silicon Valley, and our valley floor kinda goes up and down all of the time. Mexico City, same thing. And literally, the ground beneath us is shifting.
 As we’re attempting to figure out what to build next, the real question is: who do we bring with us when we do? Because climate change isn’t just a science problem. Or a tech problem.It’s a values problem.
 It’s a question of who we think deserves to be safe. And whose losses we’re willing to accept.

And with that, I think I”m calling this one a wrap. So what is up next week? 

There’s quite a bit that I’ve been exposed to here in Jakarta, but one issue? And, one issue, it doesn’t seem that flashy, but it’s a thing we can’t live without, it’s not something that we can afford to scale up globally without some pretty serious consequences. And that’s the very simple, yet highly, highly complex topic of air conditioning. 

Again, might not seem like the most engaging of topics, but it is one that’s pretty sobering, and it’s also an issue that a lot of really smart people, they’re pretty much trying to solve. 

Anyway, again, thank you so much for joining me today on Running my mouth off, I’m Dave and I hope you have an amazing week.