Dealing With Sea Level Rise (Slap Some Gills On Kevin Costner)

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Aerial view of suburban neighborhood flooded from Hurricane Katrina
Flooding like this from Hurricane Katrina could… and likely will… become more and more common

Take a look around your home right now. If you’re not at home, just picture it. Think about the furniture, the flooring, your bed. Maybe it’s an embarrassing mess, maybe it’s pristine like a magazine cover. Doesn’t matter. Now, imagine that same place, only… it’s filled with crabs.

Not… no. Not those crabs. That’s something else. I’m talking about the ocean guys with the pinchy claws. Crabs scuttling all over your place with their creepy eyes on the ends of their stalks. Crabs whose incomprehensible mouth parts are constantly a blur of motion. And they’re picking the place clean, looking for anything they can possibly eat. Getting in to everything. Your closet, your kitchen cabinets, everywhere. Why? Because it’s the year 2050 and you live in Miami. Or Mumbai. Or Bangkok. Maybe the city of Alexandria, by the mouth of the Nile. And your home is now sitting in the middle of a shallow sea. Not because some crazy storm washed it out there. No, it’s because the sea itself just moved in and covered the city. These are just a few of the major cities, not to mention a multitude of smaller towns and, in some cases, entire nations, that are projected to see serious impacts from sea level rise by 2050 and devastating damage by 2100.

“Pffffft,” you might be thinking. “Pffffffffffffffffffffffffbbbbbbbbbbbbbbbbbbbbt,” you might also think. You kind of have some issues, after all. Then you might continue to think, “That’s forever from now. I’ll be dead by then anyway. Besides, I don’t even live on the coast. I live in Des Moines.” This kind of reaction actually has a name in the environmental studies field. It’s a term that’s shared across many disciplines for similar reactions. Biologists use this term. Physicists use it. Even medical doctors use it. The word, in the scientific community, for a person who responds this way to a serious threat that might not ever affect them personally is an “asshole.” And it turns out, that 97 out of 100 science professionals recommend trying not to be an asshole. The other three guys are total dickbags. Just don’t even get me started.

Because, okay. Maybe you personally don’t have to worry about it. But a lot of other people will be financially ruined, uprooted from their homes, made into climate refugees, or even killed. People in some places are already facing these issues. Over 150 million people living in coastal areas currently, today, face regular flooding threats from large storms or even just an unusually high tide. Estimates vary, but many models show that by 2050, these areas will either be permanently underwater or only exposed during low tides, displacing everyone living there. That’s a big deal. It should matter to everyone.

I’ve gotta pay closer attention

But wait, hang on. Back up. What’s going on? Sea level rise? Why is the ocean rising? Where is this extra water coming from? Did I leave the garden hose running overnight again? Well, you ain’t gonna like the answer. Because sea level rise is climate change’s nasty kid brother. Oh, you thought ocean acidification was climate change’s little bro? Well, yeah, that too. When you go over to the climate change family’s house for dinner, it’s super crowded. There’s, like, nowhere to sit.

And it’s not too hard to see what the connection is. As the climate warms, snow and ice that used to exist year-round starts to melt. That means all these massive glaciers, and the enormous ice sheets covering the Arctic and Antarctic, have been melting for the past little while. So all this water that was being stored in ice is now going right in to the oceans. The oceans are getting bigger. But it’s even more than that. Because liquid water expands when it gets warmer. Not a lot. It’s pretty hard to notice when you’re just heating up a mug of water in the microwave. But when you’re talking about the Atlantic Ocean, a little bit of thermal expansion goes a long way. And the oceans are absorbing a lot of the excess heat from climate change.

Majestic iceberg in orange light from setting sun
We’ve gotta stop this shit from melting
Photo by NASA Goddard Space Flight Center from Greenbelt, MD, USA, Public domain, via Wikimedia Commons

So, yeah. As if climate change wasn’t horrible enough, it’s also going to literally shrink the amount of land on the planet and flood entire cities. Fun times. But it doesn’t stop there! Oh no! Because as the sea level rises, saltwater is creeping in to the freshwater aquifers. Aquifers are the underground pockets of water that provide the drinking water in many areas. It also is often the source of irrigation water for farms. As these coastal aquifers get more and more salty, the water eventually becomes undrinkable and unusable for irrigation.

In fact, in some areas there’s a phenomenon known as “ghost forests” where swaths of mature forests are dying off all at once, because sea level rise is causing the ground water to become too salty for the trees, even though they’re miles away from shore. Some trees can hold out longer against the salt levels than others, but eventually they all succumb. We’re already seeing this in some areas, including in the United States. Saltwater marshes are disappearing, being covered by the waves. Meanwhile, forests are dying and turning in to saltwater marshes, peppered with the still-standing trunks of dead trees. Ghost forests. The ocean is gaining ground.

Well, on the bright side, now we have ocean front property

For now, a lot of the direct impact on people, on homes and businesses, is sporadic. Places that used to only experience coastal flooding during major storm surges are now seeing flooding from average storms, unusually high tides, or even just strong sustained wind pushing the water inland. This is called “nuisance flooding” since it doesn’t generally destroy everything outright. But it’s still damaging, disruptive, and expensive. It’s not just getting in to homes and businesses, it’s messing with infrastructure like roads, water lines, power plants, sewage treatment plants. And if nothing else, that’s very expensive and very inconvenient. And it’s becoming a much more common problem than it used to. Depending on where you’re talking about, nuisance flooding is anywhere from three to nine times as frequent in coastal communities in the US today than it was in 1970. Cities that used to have flooding problems just a couple of days a year are now having it two or three dozen days a year.

And that’s just the small stuff. Catastrophic floods are becoming more common along the coasts, too. What we used to call “hundred year floods” in some areas are now happening every few years. Remember how Hurricane Katrina wrecked New Orleans, or how Superstorm Sandy jacked up a good chunk of the Eastern Seaboard in the US? Those were just trial runs. Events like that are going to become more common, and sometimes even more severe. Cities like New York, Houston, and San Diego, among many others, are literally spending billions more dollars on flood mitigation measures today than they did only 20 years ago. Some small coastal communities are having to choose between spending extraordinary amounts of money to protect a few hundred structures, or to just abandon the town altogether. Not a pleasant situation when you’ve lived there your whole life.

Flooded suburban street in New Orleans
Flooding like this in New Orleans will eventually force entire populations to relocate
Bart Everson, CC BY 2.0 , via Wikimedia Commons

So, if it’s already getting kind of serious, then the sea level must have already risen by quite a bit, right? Right? No, not really. The average sea level has only risen about 21 centimeters or 8 inches since 1900. Doesn’t seem like anything worth talking about, and yet it’s gotten bad enough that housing markets in some of the worst hit areas in the US are starting to tank. All of southern Florida is very vulnerable to sea level rise, including the Miami region. Both home sales and home prices in flood-prone areas there are dropping off, while the housing market in nearby areas that are just a few feet higher is staying strong. Now… that could be a temporary fluctuation. Maybe sales and prices in the low-lying areas will climb back up again. But the fact that it’s not uniform across the region suggests that at least some consumers have noticed it’s no longer a great idea to live in those flood-prone areas.

Oh and one more note about the nature of sea level rise: it’s not uniform across the globe. The physics of the ocean, across the globe, from the surface down to the deepest depths, is pretty complicated. All sorts of things happen to make the local sea level a little off from the global average. Ocean currents and prevailing winds can pile water up in some areas. Tides are stronger in some areas than others. Local weather patterns can heat or cool the local waters, which in turn affects the local thermal expansion.

Even the land itself isn’t sitting still. In some areas, the land is actually slowly rising, because it’s still recovering from the weight of the glaciers in the last ice age that were pushing it down. In other areas, the land is sinking, or subsiding. This can be from natural geological causes, but it can also be the result of pumping groundwater or even oil from the ground. Sometimes that water or oil is actually helping to support the layer of rock or sediment it’s in, and when it gets removed, that layer can collapse or become compacted. Put it all together, and there’s a lot of complicated forces that interact to make some coastal areas have only a few inches of sea level rise, while others have seen over a foot.

Maybe just get a really big sponge?

Okay, so, we get it. Sea level rise is a problem. The question is, how bad is it going to get, and what can we do about it?

Well, how bad it’ll get is a moving target. We have a pretty good handle on how much warmer things could get at this point. We’re still improving our climate models, and there’s bound to be some surprises left to discover, but the predictions aren’t likely to change wildly at this point. But sea level is a whole ‘nother thing, and it’s a little less well understood than its big brother, climate change. Sometimes a new model will say things are going to get even worse than we thought. A recent study out of the Netherlands using supercomputers to include small local current variations in the model came up with a scenario that was actually a little more optimistic, predicting that oceans in the Arctic will actually get colder and slow the ice sheet melt for a while. So, the jury is still out on exactly how bad things will get. But… nobody is saying they’re not going to get worse. It’s just a matter of, will sea level rise be enough to swallow the world’s seaports and displace a huge percentage of the total population by the year 2100, or will it take until 2200?

In fact, more sea level rise is probably impossible to prevent at this point, no matter what we do. The processes involved with both climate change and sea level rise don’t happen instantaneously. There’s a delay between when carbon dioxide is emitted and when you see the impact on the climate. It takes a few years for changes to work their way through the system, from burning coal to melting Greenland’s ice sheet and every step in between. Which means, even if we stopped all greenhouse emissions today, we would still see the global average temperature rise for a number of years, and that means some sea level rise is baked in, too.

fire and explosions during a show at the Waterworld attraction at Universal Studios Hollywood
For better or worse, the future probably won’t look like Waterworld, seen here at Universal Studios Hollywood
Photo by Jks93, CC BY-SA 3.0 , via Wikimedia Commons

Okay, but how bad will it get though? Just keep in mind, these figures are subject to change in the future, but this is where the current consensus is sitting. The very best case scenario, if superhuman efforts were taken to curb climate change, if Greta Thunberg were able to scowl everyone into submission, is still about another foot of sea level rise, or 30 centimeters, by the year 2100. This is the fantasy scenario, better than anything that’s at all likely to actually happen. That will still be enough to rob Southern states like South Carolina, Florida and Louisiana of a pretty significant amount of land mass, displacing tons of people and having all kinds of other local effects. But… that’s not going to happen. Or, rather, that is most definitely going to happen, just a lot sooner than 2100.

Instead, the current estimates are that we’ll see around three feet or one meter of sea level rise by 2100. At that point, hundreds of millions of people around the world will be displaced, either by losing their homes entirely to the ocean, or because frequent floods and contaminated drinking water will make the areas unlivable. The city of Miami Beach will be mostly underwater at high tide, as will a large chunk of Charleston, South Carolina. Huge sections of major seaports like Shanghai or Mumbai will be lost. Globally, over $14 trillion dollars worth of property and infrastructure will be lost, and that’s probably low-balling it.

But those estimates are based on a moderately strong attempt to curb climate change. If we do nothing, if we keep going on like we are right now, things get much, much worse. By 2100, the ocean could rise by well over 2.5 meters or 8 feet, maybe much more. At that point, Miami and Charleston will be a series of islands at high tide. Whole neighborhoods in New York City will be lost. The Atlantic and Gulf Coast will be unrecognizable. And worldwide, many coastal cities will be washed out entirely. Shanghai, Mumbai, Bangkok, basically gone. Shanghai by itself has a population of 26 million human beings. Any city on the coast, worldwide, that remains habitable will be at risk of severe flooding from every storm, and we expect those storms to be more frequent and stronger. A huge percentage of the global population will be displaced. And take everything I just said about a sea level rise of 3 feet, and figure that all that stuff happens around 2050. We will literally have to redraw the maps.

Meh we’ll all be dead anyway LOL

And those are just projections for the year 2100. That’s an arbitrarily chosen date. Climate change and sea level rise won’t suddenly stop when the calendar flips over that year. It will keep going. How long and how bad all depends on us. If we get the dream scenario, the Greta Staredown scenario, then it might not get much worse after that point. But, on the other hand, if we do nothing, we could be looking at a sea level rise of 30 feet or 9 meters by 2200. Maybe worse.

Now, again, I really want to be clear that these models and predictions are fluid, a work in progress. They can, and almost certainly will, get better and worse over time as we get better data and our models become more accurate. So don’t get all pissy with me if you’re reading this five years from now in 2026 and the science is saying something different. That’s to be expected. But, again, the overarching theme here is, sea level rise is bad, it’s already begun, and it will get worse. The only question is, how much worse and how long will it take. A rise of 9 meters in a thousand years, we can cope with that. Plenty of time to adjust. But a more rapid rise is going to be hard to deal with. Moving entire populations is no easy feat. In all likelihood, people will die before it’s all said and done. Maybe a lot of people.

Protester holding sign reading "Like the sea level we rise"

So, what can we do about it? Well, the most obvious thing, of course, is to stop climate change. Stop carbon dioxide and methane emissions. Reduce energy consumption. Aggressively adopt strategies to remove carbon dioxide from the atmosphere. And there’s a thousand conversations to be had about how to do all of that, and we’ve got to have all of them. Not, like, right now, you and me. That would be… well look, no offense, but I’m just not sure I’m ready to spend that much time with you, we barely know each other. But as a society, as a species, it’s got to be all hands on deck for climate change.

Gonna need some bigger beavers

Beyond that, there are things we can do to try to deal with sea level rise specifically. Some of them are common sense, others are pretty extreme. Some cities, such as Amsterdam or New Orleans, have actually been dealing with these problems for a while, as large portions of those areas are already below sea level. They use systems of levees, seawalls, and other flood control measures to keep the sea out and to help drain areas when they do flood. These cities will have to put a lot of work in to strengthening these measures. Other cities that don’t currently use these kinds of artificial barriers have begun to build them. In fact, Dutch engineers are in high demand around the world right now to help cities do just that. This is something we’re probably going to be seeing a lot of cities doing… building new infrastructure to keep the ocean out.

A simpler, but still very expensive, measure is to just artificially build up the beaches in cities. Many smaller towns on the eastern coast of the US have been doing this for a few years now, especially after Superstorm Sandy completely washed away the beaches in some area. Beaches aren’t just nice for bringing in tourists who want a good sunburn. They also serve as a physical barrier to stop storm surges that would otherwise wash right in to town. You can just pile up more sand and build a bigger beach. But, this isn’t cheap. Generally you get the material by dredging the ocean bottom nearby, dragging it to shore, and dumping it. It’s a very labor-intensive process. Some cities like San Francisco already dredge their bays out on a regular basis to keep them deep enough for ships, and this sediment could also be used to build up the local shoreline, killing two birds with one stone. Of course, this is only a temporary measure. Each storm that comes along degrades these barriers, and so they have to constantly be built back up if they’re to be effective.

Other solutions are more drastic, sometimes by sheer necessity. The Republic of Maldives is probably in more danger from sea level rise than any other country on Earth. That’s because it’s comprised of a string of islands in the Indian Ocean, and the highest natural point in the entire country is only 2.4 meters or a little under 8 feet above sea level. I say natural highest point, because apparently there’s a golf course on one of the islands where they built a mound that rises 17 feet above sea level. They call it “Mount Villingili”. I’m not making this up. I refuse to find a picture of it because I want to believe that it’s topped by a plastic windmill that you have to putt your ball through.

Malé, the capital city of the Maldives, showing a densely populated and very low lying island
I really just don’t see why they’re worried about sea level rise in the Maldives
Photo by Shahee Ilyas, CC BY-SA 3.0 , via Wikimedia Commons

Anyway. Around 80% of the nation will be underwater at 1 meter of sea level rise, the sort of median estimate for how bad things get by 2100. For a while there, the Maldives was actually considering just buying land somewhere and relocating their entire population. While it’s one of the smaller countries in the world, it still has a population of a half million people, so relocating them is no small task. They’ve shelved that plan for now, and have instead been focusing on just building a taller island. Literally. They’ve created an artificial island that’s 2 meters above sea level.

They actually started the project back in the ’90s, but now they’ve focused on continuing it as their main hope for survival as a nation. In fact, the settlement there is called the City of Hope. About 50,000 people live there now, and they plan to eventually house half the entire population there. So, that’s one solution. Build a bigger island. I guess. But while it’s feasible… extremely difficult but doable… if you want to put 250,000 people there, for most places, that’s not going to be a viable option. The Maldives just doesn’t have much choice. It’s pretty much this or move the entire nation somewhere else, because it’s almost certain that the majority of the nation, along with its handful of freshwater sources, will be swallowed up before too long.

They’re gonna WHAT?

In an even more extreme proposal, some scientists have proposed damming the North Sea in an effort to protect Europe from the rising water levels. There would be two massive dams in this project. One spanning from Scotland to Norway, and another blocking off the English Channel. It’s… not exactly a serious proposal. It’s more like an attempt to shake policy makers awake. Because… it would probably work, it would probably protect a lot of shoreline in Northern Europe. It would also totally screw the ocean up behind the dam. The fisheries would probably collapse, there would be a ton of other consequences, it would be a mess. But it could work. They did the math and decided it was technically and even financially feasible, although extraordinary. And that’s kind of the point of the proposal. Not that this is a great idea to protect Europe from sea level rise, but to point out these are the choices we’re faced with: stop carbon emissions, or build a dam across the ocean. If you think the one is crazy, then you’d better your shit together and take care of the other one.

So, that’s the general idea. Some sea level rise is inevitable at this point. The process is already in motion. And we’re going to need all kinds of solutions to deal with it, from engineering protective walls and building up shoreline, to creating new land from nothing or even building the largest structure ever created by man. But the best solution is going to be to just stop climate change altogether.

So, you know, just clone Greta Thunberg a million times and see if you can weaponize that angry glare so we can force politicians to act. In the meantime, I’ll be starting a new business, crab-proofing homes in Miami. It may seem like a dumb idea for now, but in a few years I think business will pick up.


Future Sea Level Viewer (USA)

We Can Do Something About It
Global Vulnerability to Rising Sea Level
Current models overestimate future Sea Levels
NOAA Sea Level Rise Information

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