And knew not until the flood came, and took them all away

February 17, 2015 3:59 AM

What the collapse of ancient capitals can teach us about the cities of today — Warnings from history: Angkor was a thriving metropolis of 750,000 before a series of mega-monsoons made it unliveable. Can modern flood-threatened cities learn from its downfall?
posted by cenoxo (29 comments total)

For those in the UK, there was a BBC mini-series on this topic recently I enjoyed. It's not on the iPlayer currently, but might be rebroadcast at some point, and there's some clips on that site.
posted by Happy Dave at 4:11 AM on February 17, 2015

Look on my works, ye mighty and despair?
posted by Segundus at 4:26 AM on February 17, 2015 [4 favorites]

Can modern flood-threatened cities learn from its downfall?

From the looks of it, Betteridge's Law of Headlines wins again.
posted by eclectist at 4:45 AM on February 17, 2015 [4 favorites]

Facinating, and creepy.

I'm no geographer, but what impact would planting more trees in our low density cities have? From the article, it was floods followed by droughts. Tree roots help stop flooding, preventing the damage that made the drought so destructive. On the other hand, trees need water.

What I'm asking is what should be done?
posted by Braeburn at 4:50 AM on February 17, 2015 [1 favorite]

The answer is, "no, not really." Things are, of course, different now. And in ways that make the response and fallout much harder to evaluate.

But a rising sea floods all basements.
posted by clvrmnky at 5:27 AM on February 17, 2015 [1 favorite]

Their comparison with modern cities makes no sense at all. The ancient megalopolises were "low density" because they had no transportation infrastructure and had to grow their own food. The modern situation is completelyl different; our cities are low density not because they need to supply their own agriculture, but because transportation makes it possible to commute from suburbs to work centers. Transportation makes it possible to grow our food a thousand miles from where it is eaten, where the weather is completely different. It's true that we have also driven the resilience out of our agricultural lands, but we can draw food for anybody from anywhere so if there is a drought in California we can still eat what is grown in Kansas.

This also gives our civilization a resilience of its own which has never existed before. As a native of New Orleans I can scarcely believe how well the city has recovered (and this despite what most people, including myself, would consider some horrible botches of the job). This is possible because food and other resources can be brought in from great distances and at great intensity to be applied to restoration after a catastrophe.

This is not to say we don't face threats, but nothing in modern times has caused the permanent abandonment of a city of half a million people, and that includes disasters like the Chicago fire, the San Francisco earthquake, firebombing of Dresden, the atomic bombings of Hiroshima and Nagasaki, and of course the flooding of New Orleans. All of those cities were rebuilt after nearly total destruction, and I've probably left some out.

(There is one notable exception, which is notable precisely because it's an exception. Hint: It's in Russia, and the disaster that emptied it wasn't natural.)

If drought was enough to make a city uninhabitable nobody would ever have lived in Los Angeles in the first place. Transportation of food, water, and people all make our cities large for totally different reasons than Angkor and Tikal.
posted by localroger at 5:52 AM on February 17, 2015 [8 favorites]

After the top of the Prudential Center is chipped out of the massive glacier covering what was once Boston, future scientists will wonder what motivated the ancient inhabitants to build in such a cold and desolate location.
posted by backseatpilot at 5:53 AM on February 17, 2015 [12 favorites]

This is not to say we don't face threats, but nothing in modern times has caused the permanent abandonment of a city of half a million people, and that includes disasters like the Chicago fire, the San Francisco earthquake, firebombing of Dresden, the atomic bombings of Hiroshima and Nagasaki, and of course the flooding of New Orleans. All of those cities were rebuilt after nearly total destruction, and I've probably left some out.

Miami may be the first city we can't rebuild because the flood waters will rise up from the ground through the limestone.
posted by hydropsyche at 6:11 AM on February 17, 2015 [6 favorites]

future scientists will wonder what motivated the ancient inhabitants to build in such a cold and desolate location

I'm pretty sure current residents are wondering this right now. Take that, future scientists!
posted by GenjiandProust at 6:30 AM on February 17, 2015 [1 favorite]

localroger: "nothing in modern times has caused the permanent abandonment of a city of half a million people, "

Didn't have a globalised disaster where dozens (or hundeds) of megalopolises were becoming unlivable all around the same time. It's great that we have excess capacity and transport, so we can ship in all kinds of crap. But what happens when it's time to triage?
posted by meehawl at 6:44 AM on February 17, 2015

I was just looking at FloodMap. Which seems relevant.
A fairly simple lok at which bits start flooding if the sea rises by x.
posted by Just this guy, y'know at 6:52 AM on February 17, 2015 [1 favorite]

But what happens when it's time to triage?

Oh, I'm not saying we're immune from problems. The very power that makes us immune to the kind of collapses that emptied Angkor and Tikal may destroy us in other more interesting ways. We destroyed Dresden, Hiroshima, Nagasaki, and Chernobyl ourselves. Nuclear war is no longer at the top of that list (at least for now) but climate change is knocking on the door.

My complaint is that the article is off its rocker suggesting that there is some parallel to be drawn between what happened to those ancient cities "because they were large and low density," and our modern cities because they are large. There is really no similarity there at all.

Miami may be the first city we can't rebuild

Miami is also due for a major hurricane. The year that Katrina struck New Orleans, NOLA was #3 on that list of most at-risk cities for a hurricane. #2 was New York City, which has since gotten kindasortahurricane Sandy. #1 was Miami.

Miami's tract suburbs are going to be washed away but I would expect technology to keep it habitable for a major population even when the water is six feet deep; a lot of existing buildings are taller than that and we know how to build on pilings. The bigger problem will be transportation. It's going to get very expensive to keep high capacity roads open to that part of Florida and it won't be easy to get sufficient fresh water there, either.
posted by localroger at 6:56 AM on February 17, 2015 [1 favorite]

Not to mention that there are signifiant problems with utilities once the "base" of the city is underwater -- water pressure makes sewage systems more complex when the water table is essentially "above ground." Seattle had issues with this early in its history.
posted by GenjiandProust at 7:39 AM on February 17, 2015

Hint: It's in Russia, and the disaster that emptied it wasn't natural.)
Chernobyl is in Ukraine which is what I think you were hinting at but if not can you elaborate?
posted by Mitheral at 7:49 AM on February 17, 2015

Miami's tract suburbs are going to be washed away but I would expect technology to keep it habitable for a major population even when the water is six feet deep; a lot of existing buildings are taller than that and we know how to build on pilings.

That is not the Miami I am familiar with. The CBD and Miami Beach contain a lot of high rises, but the vast majority of Miami-proper is "tract suburbs". It is a huge, sprawling low-density area, hardly any of which is more than a couple feet taller than 6 feet. I don't know where your 'major population' could possibly live when all their one story ranch houses are underwater.

My spousal dude is from Miami, with a lot of his family still there, and I have a ton of affection for the place, its people, its food, its culture, and its scenery. I will be incredibly sorry to see it go. But it is going (along with many other similar coastal cities throughout the world, all the island countries, and likely the entire nation of Bangladesh).
posted by hydropsyche at 8:32 AM on February 17, 2015 [1 favorite]

When its branch of Nile dried up, the ancient Egyptians just packed up their capital city of Pi-Ramesses and moved it 100km. Of course, they didn't have to deal with cable companies.

(I must re-read The Drowned World...)
posted by Devonian at 8:51 AM on February 17, 2015 [2 favorites]

I don't know where your 'major population' could possibly live when all their one story ranch houses are underwater.

Same place all the residents of Lakeview in New Orleans live -- in new structures which will replace them if there's enough reason for people to still live there. In some parts of NOLA hardly any original structures exist, and the new ones are either elevated or have sacrificial first "floors" devoted to garages and storage. I can see Miami shrinking considerably but still existing even as a sort of Venice on the Gulf.

The bigger problem will be whether there is still a reason for a city where Miami is, since its port is only valuable because of inland transportation which will be inundated, the surrounding agriculture will be drowned, and so on.
posted by localroger at 8:56 AM on February 17, 2015

But in Lakeview, New Orleans East, the 9th Ward, etc., the water receded. Rebuilding took time, but for the most part things were rebuilt the same way they were--with the obvious exceptions of some houses on stilts in some places, but those were built on solid ground, just low ground. And with the changes to MRGO, they will likely never face the same form of (anthropogenic) flooding again.

You're talking about somehow rebuilding an entire city on permanently inundated limestone. I just don't see how that is possible. Let alone rebuilding the entire country of Bangladesh on stilts on inundated alluvial soils.
posted by hydropsyche at 9:38 AM on February 17, 2015 [1 favorite]

The ancient megalopolises were "low density" because they had no transportation infrastructure and had to grow their own food.

To what extent that's true of Tikal and Angkor I have no idea, but ancient Rome, for one, did ship quite a lot of its food in from thousands of miles away. Grain from Egypt and so on. They had the "food and other resources can be brought in from great distances" thing figured out for their smaller empire at least as well as the world as a whole does today.
posted by sfenders at 11:55 AM on February 17, 2015

Cities/towns abandoned in the twentieth century:

Beichuan
Prypiat
Humberstone and Santa Laura
Hashima
Centralia
Ağdam

And a special addition, Detroit - Sort of.
posted by Joey Michaels at 12:09 PM on February 17, 2015 [2 favorites]

Interesting list, Joey. Of those towns the only one emptied by a natural disaster was Beichuan, and the decision not to rebuild it may reflect a difference in Chinese and Western philosophies on such things. Pripyat was a not so natural disaster, Agdam was war, and it wasn't rebuilt and the rest were emptied because their single natural resource or trade advantage became exhausted or irrelevant.

Rome is a much better example to compare with us, and it was never reduced to a ghost town; the empire was lost, but the city itself has been continuously occupied since the time of the Caesars. They had their own transportation advantages in the form of road-building, wheels, and shipping across the Mediterannean basin, and those things outlasted the empire that had thrived on them.

In any case the pattern identified in the OP has not been the reason for abandoning a large city for a long time. You could say the means to support the population disappeared in the case of a mining town like Centralia, but everyone should know going in that's a finite resource and when it's gone so will be everything it supports. Farming is kind of expected to be viable indefinitely.
posted by localroger at 12:26 PM on February 17, 2015

You're talking about somehow rebuilding an entire city on permanently inundated limestone. I just don't see how that is possible. Let alone rebuilding the entire country of Bangladesh on stilts on inundated alluvial soils.

I don't recall saying anything about Bangladesh, but it's not all that hard to build on pilings. In limestone you have to encase them. Similar techiques are used to build things like tall bridges and skyscrapers in southern Louisiana because there is no bedrock.
posted by localroger at 12:34 PM on February 17, 2015

For what its worth, I wasn't making a point, just my curiosity got the best of me and I was surprised to find that there's quite a few abandoned towns and cities from the past century.
posted by Joey Michaels at 12:40 PM on February 17, 2015 [1 favorite]

Read ya, Joey. I did find it an interesting list. But it's stark how different the reasons for modern city abandonment were from what unfolded at Angkor and Tikal.
posted by localroger at 12:49 PM on February 17, 2015 [1 favorite]

Changes in flood plain handling and regulation have led to a long-term abandonment of many low-lying areas in North America. In Wisconsin one entire (more or less) town was moved uphill 30 years ago. In a lot of river communities this has also happened on a smaller scale, with riverbank properties gradually converted to parkland or otherwise more resilient uses. And of course the cycle of industrialization and deindustrialization has ravaged cities across the Western world, particularly in the US Rust Belt.

If drought was enough to make a city uninhabitable nobody would ever have lived in Los Angeles in the first place. Transportation of food, water, and people all make our cities large for totally different reasons than Angkor and Tikal.

I hear what you're saying, but I think the argument is really that exactly what you think make things different this time is what probably doesn't make them different in the long run. (In the long run, we're all dead, &c.) Right now the global economy is especially dependent on certain balances of energy and labor costs. There are already victims of this equation right here in the US -- look at any inner city and you'll find an ethnic population that moved there when jobs existed and got left behind when the jobs went elsewhere.

And of course that balance itself depends on certain costs being externalized -- i.e. the carbon effects which result in climate change. So this relationship is much more complex and self-compromising than "Hey, we're smart, we've got internal combustion engines. Solved it."

And since a great deal of current geopolitics is apparently, if you follow the chain of causation back far enough, about resource competition, I don't think it's right at all to paint our current scenario as rosy by comparison.
posted by dhartung at 1:57 PM on February 17, 2015

dhartung, I wasn't trying to paint our situation as rosy. I fucking live in New Orleans. What I'm saying is that it's very different. If we had communities like those at Angkor and Tikal in California, the exodus would have started five years ago. If New Orleans was a community like Angkor or Tikal, nobody would live here now. There are risks -- big ones. But they are different risks, and drawing conclusions from what happened at Angkor and Tikal is not very informative.

I suppose what chafes me about the OP is an old thing about the way grants are written, which is that everything somehow curls around to curing cancer. It's not enough to say we learned this cool thing about what happened to these ancient cities, we have to draw some Useful Conclusion from it. Except that it's not really a useful conclusion for us. Most of our cities would never have existed if they were built like Angkor and Tikal because they were never meant in the first place to sustain themselves by local agriculture. Even the oldest US cities separated urban and agrarian spaces in ways the people who built Angkor and Tikal couldn't. For that matter, so did the builders of Rome, which is a reason it has been continuously inhabited for over 2,500 years.
posted by localroger at 3:14 PM on February 17, 2015

Rome is an interesting case. From a peak of 1 million in the 1st centuries BC and AD, it managed to maintain much of its population during the slow decline of the Western Empire, entering the 5th Century with about 3/4 million people, but by the end of that century it was down to about 100,000 people. Gee, I wonder what happened between 400 and 500 AD?

(Answer: without the Empire it lost that massive food-importing infrastructure, invaders cut the aqueducts, and war and famine gutted the population.)

For hundreds of years during the middle ages, Rome's population was stuck at about 20,000, just 2% the size of its glory days. Not abandoned, but a shadow of its former self. Nobody took a census of Angkor after the fall, but I'd argue that its 1000 square kilometres would still have contained a lot more than 20,000 people (that's 5 hectares per peasant farmer).

Today's developed countries have huge reserves, but also huge vulnerabilities. As long as disasters are localised and economies are robust, we can cope, but I'm not sanguine about our prospects should that change. And the weight will fall heavily on the poor before the super-rich who control most of our wealth will care.
posted by Autumn Leaf at 6:00 PM on February 17, 2015

The evidence they present are tree rings from Vietnam and topography snap shots of water system failure?

The system had been neglected for a long time. 1431 is the date most scholars give to Angkors fall. Here are the causes thumbnailed.

1 building frenzy
2 loss of revenue
3 conversion to Hinayana Buddhism
4 loss of labor supply
5 sack of the capital.

When the capital was moved from Angkor to Ayuthia, the Move to the lower Menam does suggests closer access to consistent water source.
But the emigration was to sudden and there other chronicles that do not report any such constant flood and erosion other then by neglect.
posted by clavdivs at 8:03 PM on February 17, 2015

From the FA:

For centuries, the Maya at Tikal had been erecting stelae – upright stone slabs with hieroglyphs and depictions of gods and rulers. The last one is dated 869. Soon after, there are signs of what might today be called urban decay, with palaces being occupied by squatters. Charred, gnawed human bones from this late period suggest desperate times.

Yes, I should say so.
posted by Joe in Australia at 10:09 PM on February 17, 2015