From the Vault: The Sunken Lands, Part 4

mythical sunken civilizations. And sorry to be a bummer to the many Atlantis hunters out there, but yes, it does seem like the experts on the original sources that this story comes from, namely a couple of dialogues of Plato, think that it probably is a fictional invention and not a reference to a real place that existed but that doesn't mean that there are not lands that have been within the history of the human species submerged by water.

In fact, we know of some examples of places that were both inhabited by humans and sunk under the water, not really anything like was described in the Atlantis story, but there are examples of the sunken land masses of Beringia and dogger Land, which during and briefly after the Last Ice Age formed land bridges between North America and Asia, and Great Britain and continental Europe perspectively. We also talked

about vanished islands in the Pacific. Some of these supposedly vanished islands are probably a result of errors in their original reporting, but others are places that probably actually did vanish or sink beneath the water due to cataclysmic seismic activity. We also talked about atolls, how they're formed, and where their central islands went. There was a hypothesis that Darwin had about this going all the way back to his

voyage on the Beagle. There are new ideas related to karcification and the dissolution of carbonate rock or limestone when it's exposed over the surface of the sea. Dissolution by rain water. And then also finally, in the last episode, we talked about places that have been flooded by damming, the damming of freshwater resources, damming rivers and streams to end up submerging areas that used to be exposed land now under lakes.

And in any case, we're talking about situations that may entail both rising and lowering sea levels, as well as land that is pushed up and or created by volcanic, organic, or seismic forces, and land that lowers sometimes beneath water level due to erosion, seismic forces, etc. So just in all cases, just keep in mind that, yeah, sunk in sinking maybe doesn't fully capture the picture of what's going on.

But one thing that's different now is how much of the physical infrastructure and culture of modern human civilization was designed on the assumption of current sea levels staying where they are. Whole cities, whole countries even are threatened by rising waters because they have been built without those rising waters in mind.

had put together a series of estimates. First of all, they look at the question of what is happening to global mean sea level right now, what has already happened in the traceable recent past, whatever happens in the future. One thing we know for certain is that the sea level is already rising and has already risen, and the rate at which it rises will very likely accelerate in

the future. Based on our best measurements averaged over different time periods, we can see that sea levels have risen over the past century, and basically the more recent the chunk of time you look at is the faster they're rising.

So the IPCC report points out that sea levels rose about one point four millimeters per year if you look at the time period nineteen oh one to nineteen ninety If you shift more recently and look at nineteen seventy to twenty five fifteen, it's two point one millimeters per year. If you just look at nineteen ninety three, to twenty fifteen, it's three point two millimeters per year. If you just look at two thousand and six to twenty fifteen, it's

three point six millimeters per year. So the later the period of the last century you look at, the more it is rising per year. Now you might reasonably wonder, how do you actually measure sea level down to the millimeter? Like the top of the water is always moving, So that's a reasonable question. What methods do you have to know that the average level of the sea is rising. There are a couple of major metrics here cited, and I didn't fully know how these worked beforehand, so I

thought this was interesting. One method used is tide gauges. These systems have been used in some form to record sea levels for hundreds of years, or at least going back I think to the early eighteen hundreds, though now they've changed form to incorporate different types of sensors and computers other modern components, but they still have some things

in common. So the old method here was that they would use a device called a stilling well, and this was basically a pipe about a foot wide that would be plunged down into the water from a place called a tide station essentially a house built out on a dock, and this pipe would still the water around a floating device.

The float would be suspended down into the well by a wire, and then that wire would be attached at the other end to a recording device, which might be something like a pin that would mark the water level automatically on a paper strip. So the float floats on the top of the water. As the water rises, the pin moves and marks that level on the paper strip.

As the water goes down, the pin moves again, and then these marks were analyzed and averaged together to form a picture of the tidal variance and the average sea level over time. This method changed so that the data could be fed directly into computers, and these tide stations also they had measuring staffs as well. You've probably seen things like this somewhere around the coast before, where it's

just like a stick poking out of the water. Is basically a ruler, you know, it's got height markings on them, and then the operators could visually observe the staff and compare that to the mechanical readings from the float device. Now, tide gauges still exist, and they still make readings, but they've got new systems, new types of sensors today to get their readings from. Modern tide gauges tend to use acoustic sounding tubes instead of a float and distilling well.

So the acoustic sounding tube will admit, will emit a sound wave from a fixed height and then wait for it to bounce off of the water's surface and come back. And the time to return of the signal allows you to calculate the height of the water across the tidal variants. So you can put in place these tide gauges in coastal environments all around the world and average them out to try to get some information about what the global

sea levels are doing all around the world. And if you look at that information, it shows yes, indeed the sea levels have been rising. They've been rising over the last century along the lines of the measurements I mentioned a minute ago. But if you're able, you'd also want to compare that data to other sources of information to make sure you're getting the most accurate possible average. So there is another method that is used, and that is altimetry.

This is the use of satellite based tools called radar altimeters to measure the height of the sea. Basically, you can know the altitude of a satellite with a high degree of precision. You can track that with instruments like laser range rangefinders, like you bounce a laser off the satellite, so you can tell pretty much exactly how high it is. And then with that information in mind, you can use a satellite to send out a microwave pulse toward the Earth.

That pulse bounces off of the surface of the ocean and then ounces back to the satellite and hits a return sensor, and then the satellite measures the time of the round trip between the emitter and the surface of the ocean to get a very precise measurement of the distance between the satellite and the water, which, again in combination with the precisely known altitude of the satellite, can

be used to measure the level of the sea. And of course radar altimetry can be used to measure average sea level changes over time and get global averages and stuff. But it can be also used. I thought this was interesting to measure variations in the height of the water around the world at the same time, so a kind of crazy thing about the ocean is that it is not at the same height everywhere on Earth all the time.

That seems counterintuitive because you think of water in a container like a bowl or something eventually finding you know, finding its own level. It kind of levels out. But across the world's oceans, there are peaks and valleys that arise in certain places at certain times, and so one

example we're all familiar with is the tide. You know, the tide is caused mainly by gravity, by the gravitational influence of the Moon, but also the Sun, but there are other factors that can cause local and sometimes temporary high and low altitudes of seawater as well. I was reading a report from NASA Earth Observatory about this and it mentioned friction caused by wind on the surface of the water. So like wind sort of dragging the water

around and piling it up in certain places. I guess that's a crude way of describing it, but that is sort of what happens. There are also Coriolis effects and ocean currents, and there are also effects of variations in atmospheric pressure, so you know, the atmosphere pushing the surface of the water down in regions where the pressure is high and so forth, and we can measure these altitude variations across the ocean with the help of satellite based

radar altimetry. As just one example of the variance in the high of the oceans around the world. According to NASA, the sea level in the Pacific Ocean is generally higher than the Atlantic Ocean, roughly twenty centimeters or about eight inches higher. How is that possible, Well, the volume of seawater is not static. Changes in the temperature and salinity of seawater affect its density, so warmer water generally is less dense it takes up more space per unit of mass.

The Pacific is on average warmer, so its volume is greater, and thus Pacific sea levels are higher and other factors contribute like this as well. This kind of variation is actually acknowledged in the IPCC report where they say quote sea level rise is not globally uniform and varies regionally.

Thermal expansion, ocean dynamics, and land ice loss contributions will generate regional departures of about plus or minus thirty percent around the global means sea level rise, and those regional variations in changes in sea level I want to come back to that in a minute. Now, of course, we all know the main cause of the current warming that is driving sea level rise is of course what the

IPCC report calls anthropogenic forcing. This means results of human activity, primarily the changing of the composition of the atmosphere causing it to trap more heat. This is the famous greenhouse effect. Putting more things like carbon methane into the atmosphere increases the heat trapping potency of the atmosphere. It traps more heat the earth worms. So we know sea levels have been rising and they will continue to rise, but how much and how fast they rise is highly variable from

our current point of view. So there are some estimates based on current data. According to the IPCC predictions relative to the mean sea level in the period from nineteen eighty six to two thousand and five, they predict that the global mean sea level will rise probably somewhere between zero point four to three meters or about one point four feet to zero point eight four meters, which is about two point eight feet, by the year twenty one hundred, and then due to a cascade of factors, sea levels

will continue to rise for centuries after that, and will probably stay higher for thousands of years. Now. I wouldn't hang on those exact numbers too much because those are estimates. They are also averages of estimates, and I've seen other reports with different estimates, especially at the high end of like how bad could it possibly get if we just

keep increasing more and more greenhouse gas emissions? But the important thing to note is that the high and low end projections here are dependent on the variable of human activity. If we continue increasing the concentration of greenhouse gases in the atmosphere, we're somewhat closer to the top end of that range, and the low end is feasible if we drastically reduce greenhouse gas output and factor in some kind of negative emissions as well, such as massive natural or

artificial carbon sequestration. And natural carbon sequestration would be I think, you know, trapping carbon in things like plants and forests.

The question is how much worse will it get, and that outcome is clearly dependent to a large extent on what we do, But in most plausible scenarios we can expect somewhere between something like one and three feet of global sea level rise by the end of this century. Now I mentioned there are other estimates I've come across. Some of these are specifically focused on like certain countries or regions, or might be drawing on some emphasizing different

data sources or something. But another estimate I came across was a twenty twenty two joint report by NASA, the NOAA, and several other federal agencies of the US government called Global and Regional Sea Level Rise Scenarios for the United States. This was an update to a previous report from twenty seventeen, and this report quote concludes that sea level along US coast lines will rise ten to twelve inches or twenty five to thirty centimeters on average above today's levels by

twenty fifty. So that's predicting, you know, roughly a foot of increase by the middle of the century. Also on the more dire end, this one was predicting much higher levels of sea level rise at the you know, basically at the letter rip scenario. It's just like do nothing scenario by the end of this century. If you want to experiment with the findings of this report, it actually has an online mapping tool you can look up you and mess around with yourself, called the Interagency Sea Level

Rise Scenario Tool. You can google that and mess with it yourself if you want. Now, there are a couple of major contributors to the actual physical causes of sea level rise due to a warming climate. One of them is melting ice melting glaciers and ice sheets. Already talked about the roll of melting ice in the sea level increases at the end of the Pleistocene, which were responsible for inundating Doggerland and Boringia. But there's still a lot

of ice on Earth left to melt. Another important cause of sea level rise is the thermal expansion of water. Remember what I was talking about a minute ago with the difference in the height of the Pacific Ocean versus the Atlantic Ocean. One factor there being that the Pacific Ocean waters on average are warmer. This stacks on top of the melting, but as water heats up, it becomes less dense and takes up more space. Warmer water takes up more space pre unit of mass, so warmer oceans

will be taller. And the thermal expansion of water plays a role already in a number of different phenomena that happened within the ocean, for example in the in the creation of ocean currents and in stratification of water levels within the ocean. Like warmer water floats on top of colder water, but anyway, as the earth worms, the water thermally expands also, so that contributes to the sea level

being higher. Now, what does this actually mean for the everyday life of people living in low lying coastal areas of planet Earth. I think one thing people sometimes like, if you haven't read much about this, you might have trouble imagining the form exactly this will take. Like you're just imagining the sea rising in a kind of static way, Like you know, it's either dry land or it's underwater, what's in between. There actually is something in between, which

is frequent flooding. The way many people will probably experience sea level rise at first is an increase in the frequency and destructiveness of extreme weather events that are dependent on sea level for the amount of damage they cause. So a person who lives in a low lying coastal city will start dealing with storm related floods on a more and more frequent basis. What used to be a once in a century flood will become a regular occurrence, until at some point the flooding becomes so common that

people may start to simply consider a place uninhabitable. And this happens before that place is more or less permanently underwater, But that eventually happens too. Of course, this kind of flooding and water encroachment, it comes with all kinds of consequences of massive economic damage, destruction of property, destruction, of livelihoods, displacement of people, and all of the downstream effects of that.

But another factor people might not think about are the effects of the ingress of salt water into places with freshwater resources, like into river deltas and so forth. Of course, this kind have negative effects on habitats and wildlife, but also on agriculture and groundwater and all that. You don't

want to salt your earth. But to come back to an issue I raised earlier, an interesting factor contributing to the coming inundation of coastal areas and especially coastal cities is that not only are sea levels definitely rising around the globe and differently in different places, in some places the ground is literally sinking. The lands are not just metaphorically sunken because the water covers them, they are quite

literally directly sunken. The land is going down. So you might have a coastal city that is experiencing more and more frequent flooding during storm surges as the sea grows taller, but also the ground level of the city is several millimeters lower every year, which makes the relative sea level

rise even worse. Now, how is that possible? Well, there are multiple causes but I was reading about this in a major One of the causes seems to be the extraction of ground water from underlying aquifers, especially you're extracting it faster than those aquifers are replenished, and as the

water is extracted, it creates these voids underground. These voids grow, the soil gets compressed, especially if you're putting a bunch of heavy stuff on the soil, such as a city like building on top of it, and then that compressing of the ground and the compressing into the voids below essentially means the city literally starts to sink. And this is happening to cities all around the world. I was

reading a really interesting article that addresses this issue. It's in Wired by Matt Simon called sea level rise will be catastrophic and unequal. So this article is emphasizing again that the global means sea level rise estimates are averages. In specific places, the problem could be not as bad or much much worse. Simon writes, quote, Galveston, Texas, where the land is slumping, could see almost two feet of

rise by the year twenty fifty. Meanwhile, Anchorage, Alaska could see eight inches of sea level drop thanks to the fact that its land is actually rising following the departure of long gone glaciers. So why is Galveston, Texas sinking relative to the sea level? He says, mainly there are two causes here, and they're both related to the extraction of liquids from underground reservoirs. One is the extraction of

water and the other is oil extraction of oil. And this is true in many places as a result of the combination of global sea level rise and land subsidence. Some of the areas of the world that are going to be the hardest hit by the greatest relative local sea level rise are on the Gulf Coast of the United States, the Gulf Coast, because they're suffering both of these at the same time. The land is going down

and the sea is coming up. Simon in this article quotes a guy named Bob Stokes who is president of the conservation nonprofit called the Galveston Bay Foundation, and he tells a story that I thought was wild. So this is Stokes talking in the article. He says, quote, the numbers I'm going to give you are are going to

be hard to believe. But there is an area in Baytown where there is a big ex On mobile industrial plant that sank about eleven feet in a period of fifty or sixty years because they were unsustainably pulling water out of there. There was a nice and upper middle class subdivision where all the Exxon executives lived that ultimately had to be condemned because water was lapping up the foundations of these houses. So there water and oil being extracted from below. The land is sinking and the sea

is coming up. Meanwhile, with the example of Anchorage, Alaska, this is typical of many areas on the southern coast of Alaska where the ground is rising due to glacial retreat. This is called glacial isostatic adjustment, and Simon uses the analogy of when you get up off of a memory foam mattress and that mattress gradually fills in the dent he left with your body. That's kind of what the land does when a glacier retreats. When a glacier melts away,

it sort of bounces back up. So areas where the land is rising relative to the sea are going to be on average hit less by global mean sea level increases, and areas where the land is literally sinking such as in many cities on the Gulf Coast they're going to be hit harder than average, and there are a lot of sinking cities, not just on the Gulf Coast, but

according to the map included all along the US East coast. Now, this article goes on to talk about other factors contributing to the regional variation in the effects of sea level rise as well, such as local characteristics of water. You know, warmer waters, as we said earlier, usually mean higher sea levels, but also more storm surge and things like that. But important thing to remember at the end of this projections

are variable. At this point, some amount of sea level rise is locked in, but humanity has power over how much worse the problem gets, and the recipe for minimizing damage to world civilization is reducing greenhouse gases in the atmosphere as much as possible, stop adding them, and to the extent possible, take them out.

in the past, in which case my apologies. But the Ramayana, which chronicles the life of King Rama or Ram, an incarnation of Vishnu. If you're not familiar with the story, there are lots of ins and outs. It's essentially the story of of this mythical king, this divine king's life. But there's perhaps the most famous plot line in there is that his wife Sita is kidnapped by the ten headed demon king of Ravana, who takes her away to the land of Lanka, provoking a great war to reclaim her. So,

of course Rama has to assemble the troops. He has to gather his forces, and this includes various figures and factions, including a people known as the Vanara. In short, the Vanara are the monkeys. If you've seen illustrations of the Ramayana before, you know some of the related traditions. You you've probably seen images of these various monkey troops aiding Rama. And of course you may be familiar with Haniman, the

most famous of the Vannara. This is, you know, the tireless friend to Rama and his you know, his key champion and a very powerful entity that is I believe the son of a wind deity in some traditions. So but I was looking into the Venera a bit more.

And according to the author Nanditha Krishna in the book Sacred Animals of India, which I've referred to in the past, the Sanskrit word for primate is actually copy but the word used in the Ramayana Vanara essentially translates to people of the forest, with Vana being forest and Nara being men. Interesting yeah, the author writes that this term probably never

actually meant monkey. In fact, in Jainism, the Vanara are described as a forest dwelling tribe of people, and elsewhere in the Hindu epic the Mahabarata, they are also discussed as such, contributing to this kind of mythic transformation from perhaps, you know, some sort of forest dwelling people, too intelligent humanoid primates. It might have been that these people, to

whatever extent you know, they were real. They may have been worshippers of a primate themed deity, or they might have used a some sort of primate themed totem of some sort, or some sort of totem system. But the author's stresses that it could also be neither of these. We just don't know, And so the Bnara include several important individuals that pop up in the epic. There's Mighty Hanaman, as we already noted, most famous of them all. There's King Sogriva, and there's also a pair of twins known

as Nala and Nila. And the twins ate is especially important because Rama must deliver his army across the waters to the island fortress of Lanka in order to reclaim his bride, and so, as the epic describes, they have to create a bridge. And this is where Nala and sometimes Nila depending on the version, becomes essential. This is a quote from the Ramayana in translation of course, quote a bridge was thrown by Nala or the narrow sea

from shore to shore. They crossed to Lanka's golden town, where Rama's hands smote Ravana down.

Other times it's described more as I mean, it's still something that's constructed, but with a lot more magic involved. Like there are stories about the Varna using floating stones to build this bridge, throwing the stones in the water, and in some cases these are stones that kind of

float on their own already. But then there are other accounts where like there's a certain amount of monkey trickiness that's involved, like they do something like I think the account that I was reading, one of the accounts is that they were like throwing holy items into the water, and the gods said, okay, that's that nothing. The monkey's throwing the water can sink. Everything has to float. We

can't have the stuff sinking to the bottom. And then they starts throwing the stones in and they kind of find a loophole to build the bridge.

This is Rama's bridge or the Rama sit to now, especially since this has already come up in this series we're doing, I know some of you are thinking about those floating pumice rocks and wondering if observations of this phenomenon might have influenced the myth making or if this has anything to do with it, And apparently this has been discussed those the number of criticisms emerge concerning like the lack of such stones in areas that are discussed

as possibly linking up with the area where this great bridge could have been or its supposed to have been. More on that in a second, And then of course you get into some other situations too, Like it's one thing for you could I guess you could say, like the idea could be passed on and then could spill over into some myth making. But could you actually build a bridge using pummice stones? I think there's significantly less evidence for that.

different objectives in mind. Very broadly speaking, some researchers seek to prove religious accounts correct by finding corroborating evidence in archaeology, history, and geology, while others seek to employ religious text to

it to better understand human and geologic history. Again very broadly speaking, because you can wind up with a little bit of column A and column b and vice versa, and human motivations are ultimately complicated, But it also means that these sorts of discussions can generate strong emotions as well. So I would suppose we should stress something that we often touch on, that mythology is not fiction, even if

it is not objective of reality. Not to say that it is necessarily completely removed from objective reality, but it's kind of this third category between the two that can still empower us on multiple levels and give life meaning without being like one to one with the objective world.

of time. There's a lot of room for various influence is to shape the final form of the thing. So, anyway, coming to this idea of a bridge, where would you possibly look for evidence of this? So a lot of it comes down to the possible location of the island of Lanka. And there's a great deal of scholarship on this question alone, with the prime candidate seeming to be the island of Sri Lanka. The Maldives, Sumatra, and even Madagascar have also been discussed, and of course, conspiracy minded

folks are not above suggesting Atlantis. It was Atlantis, but it was Yeah, it was not Atlantis. So for our purposes here, we're going to focus mostly on Sri Lanka as that's where there's some really interesting evidence to discuss, and that seems where to be where a lot of the energy seems to be going. Sri Lanka is easily spotted on any map, separated from the Indian Peninsula by

the Gulf of Manar and the palk Straight. It is been inhabited by humans since prehistoric times, and so it's you know, it's been presented, and there's additional evidence to support this idea as well that we don't have time to get into. But a lot of people make the case that Sri Lanka was Lanka. And so, yeah, how would you get an army, an ancient army, supernatural otherwise from point A to point B. Well, this is of

course where the bridge comes in. And of course, in the context of a mythic story, you know, the bridge doesn't have to be anything that corresponds with actual geology or time specific technology. I mean, people can imagine bridges spanning impossible distances, that sort of thing. I think all

that goes without saying. And there's plenty of things that happen in the Hindu epics that are inherently supernatural, but attempts to nail down a possible actual bridge to Sri Lanka would constitute either a manufactured bridge and or a naturally occurring bridge. It's the idea of at least some

level of naturally occurring bridge. This is where it gets really interesting, because there is a chain of limestone shoals between Minar Island off the northwest coast of Sri Lanka and Ramaswaram Island off the southeast coast of India, interconnected with sandbanks. It all forms a thirty mile or forty eight kilometer long quote unquote bridge and it is shallow enough to pose a navigational hazard to ships.

the mountain in question here is also sacred in Hinduism. Anyway, there's a lot of evidence to suggest that these shoals and sandbars constitute a former land bridge, though estimated dates vary.

Cartographical records suggests that it may have been whole and even traversible until the year fourteen eighty, and the beginning in fourteen eighty you might have had a series of storms that ended up washing sections of it away, storm breaches that end up making taking away this portion of it, then another portion, until you're left with something that is no longer traversible. Ah.

to what extent can we trust those We've already talked about whole islands that have been cataloged due to various errors or sort of deciding to err on the side of caution when identifying things that could be a navigational hazard to ships and so forth. But at any right, there is evidence of something here, and there are various theories about its natural formation. They ranged from tectonic forces to coral sand trapping, water, current movements of sand, and

so forth. So there is this idea that it could have been certainly a naturally occurring opportunity that could have been augmented then by human beings to some degree, which I don't think is all that outrageous, at least if you consider like small scale efforts to shore up or repair individual segments in a chain like this, and then on top of that, I mean, ancient peoples were certainly capable of larger scale engineering projects as well, though based

on the sources I was looking at, I don't think there's any strong scientific evidence for the idea that it was largely constructed or that it was constructed entirely. But again this is an area of controversy. So setting aside how it came to be, we can be reasonably sure that remnants that the remnants we see here do constitute a one time land bridge that in its current form is no longer traversible, likely due to changes in sea

level and storm activity some combination of the two. And there have been proposals to dredge more of it out in order to improve navigation by boat. But this is controversial, both due to environmental reasons but also to religious objections. And you also see proposals to rebuild the bridge quote unquote, and this would be a project that would have tremendous religious significance as well as of course just being like

a major avenue of transportation between nations. By the way, we won't really have we don't have time to go into this one. But I also wanted to acknowledge that there is a mythical continent named Kumari condom linked in some traditions to ideas like Limuria, that it have been

that would have been situated in the Indian Ocean. It would have allegedly hosted an ancient Tamil civilization, and I think it's generally described as a Tamilized take on the concept of Limuria, So, you know, a fairly recent idea in the grand scheme of things, But then in the twentieth century the idea ends up being taken up by Tamil revivalist so it has remained since that point a culturally charged idea as well, which kind of takes us back to a lot of what we were talking about

just in general, about the idea of sunken lands, whether real or mythological, even fictional, and how the classifications may shift over time, and how they can become important, they can become vitally important, they can be things that are sought after not only as a way to sort of understand mysteries about the natural world, such as how similar species can be found on two sides of a vast ocean, but also in trying to make connections that aid in

the conceptualization of one's worldview that sort of thing.

Just a reminder that Stuff to Blow your Mind is primarily a science podcast, with core episodes on Tuesdays and Thursdays. On Mondays we do listener mail. On Wednesdays there tends to be a short form artifact or monster fact episode, and on Fridays we set aside most serious concerns to just talk about a weird film on Weird House Cinema. I should point out I do not think we've done an Atlantis movie on Weird House. I know we've had some flooding occur in some of the shows we've watched,

but I don't recall Atlantis popping up. I could be wrong. There's a submerged city or two. I think a few submerged lands.