November 30, 2024 • 45 mins
In this classic episode of Stuff to Blow Your Mind, Robert and Joe explore the world of lost islands and forgotten continents, in both actual geologic history and the mists of the human imagination. (Part 4 of 4, originally published 12/07/2023)
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Speaker 1 (00:06):
Hello, and welcome to Stuff to Blow your Mind. My
name is Joe McCormick. Today we're going to finish out
the Vault series that we've been running this week. This
is part four of our series called The Sunken Lands.
This originally published on December seventh, twenty twenty three. Hope
you enjoy.
Speaker 2 (00:27):
Welcome to Stuff to Blow your Mind, the production of iHeartRadio.
Speaker 3 (00:37):
Hey you welcome to Stuff to Blow your Mind. My
name is Robert Lamb.
Speaker 1 (00:40):
And I am Joe McCormick. And we are back with
the fourth and final part in our series called the
Sunken Lands, about places on Earth that relatively recently used
to be dry land but are now covered by water now.
In previous parts of the series we talked about, of course,
legendary lands of this sort Atlantis and other fictional or
(01:01):
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
(01:23):
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
(01:44):
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.
(02:09):
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
(02:30):
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.
Speaker 3 (02:49):
Now. A quick note on just the idea of sunken
islands and sunken lands. We had a listener ask about
this and discord, so I want to just briefly point
out that, especially in our discussion of atolls in the
last episode, the terms sunk in or to sink may
ultimately be too simplistic for these discussions because they're all
very based on the human perspective of what's going on.
(03:10):
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
(03:31):
sinking maybe doesn't fully capture the picture of what's going on.
Speaker 1 (03:36):
Well. Actually, as luck would have it, I do want
to get to one example of actual sinking of lands
in just a bit here. So in the background of
discussing these historical cases of landscapes covered by rising seas,
there is the knowledge that most of us have now
that relatively rapid increases in sea level are happening right
(03:59):
now and will continue in the coming decades due to
climate change, due to the warming of the seas, the
melting of glaciers. Sea level changes have happened on Earth before.
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
(04:21):
they are. Whole cities, whole countries even are threatened by
rising waters because they have been built without those rising
waters in mind.
Speaker 3 (04:31):
Yeah, some of the very places we've discussed, at least
in passing in these episodes, like the Maldives, are greatly
threatened by these rising sea waters.
Speaker 1 (04:39):
Yes, absolutely, But of course this applies to coastal settlements
all over the world, on every continent on Earth, though
though in different ways. Not every coastal settlement will be
affected the same, And I want to get to some
of that variance in just a bit here. But as
a baseline, I thought we should look at how much
are sea levels expected to rise in the next century
(05:01):
or so. That depends on a number of variables, but
I was looking at the most recent IPCC report, which
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.
(05:21):
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
(05:43):
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,
(06:06):
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
(06:28):
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
(06:50):
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
(07:13):
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
(07:36):
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
(07:58):
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,
(08:20):
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
(08:42):
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
(09:05):
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.
(09:27):
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.
(09:48):
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
(10:10):
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
(10:31):
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,
(10:52):
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
(11:15):
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
(11:37):
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
(11:59):
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
(12:25):
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.
(12:49):
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
(13:11):
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
(13:32):
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
(13:54):
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
(14:16):
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.
(14:39):
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.
(15:00):
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,
(15:22):
you know, trapping carbon in things like plants and forests.
Speaker 3 (15:26):
Yeah, so as is I've heard a lot of experts
say it's not that there isn't room for optimism in
all of this, but the optimism does not come without action, right,
there are definite steps that need to be taken. We
can't just be like, ah, it might be, it might
be okay, maybe it's just gonna be the lower We'll
(15:47):
just we'll roll the dice and see, like, that's not
how it's going to work out.
Speaker 1 (15:50):
Yeah, that's exactly right. The lower end of the prediction
range there is based on an assumption of action if
humanity does something to massively reduce the contribution to global
warming through greenhouse gases. So in that case, yes, we
could limit it to the lower levels of sea level rise.
But to be clear, some amount of sea level rise
(16:12):
at this point has already happened and is basically locked in.
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.
(16:36):
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
(16:56):
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
(17:18):
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
(17:39):
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
(18:00):
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
(18:21):
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
(18:43):
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
(19:04):
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,
(19:25):
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.
(19:48):
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
(20:09):
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.
(20:29):
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
(20:50):
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
(21:11):
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
(21:31):
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,
(21:57):
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
(22:21):
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
(22:42):
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
(23:05):
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
(23:29):
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
(23:50):
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
(24:11):
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
(24:32):
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,
(24:54):
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
(25:15):
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
(25:37):
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
(25:58):
the extent possible, take them out.
Speaker 3 (26:01):
Yeah, basically, the natural environment is maluable, as we've discussed,
and humanity has tremendous power and tremendous will. We see
that in the in the in the degree to which
we have and are changing things. But that power and
will can also be applied to changing the ways that
(26:21):
we're interacting with the natural world for the better. But again,
it does require action. It doesn't require just setting back
and hoping that it will be better or pretending that
the problem does not exist.
Speaker 1 (26:33):
Correct.
Speaker 3 (26:44):
All right, So this is the fourth part of our series,
and we could, we could honestly easily keep going, but
we can't because I've got some Christma stuff to do
next week. So in this last section, I'd like to
refer to the ancient Hindu Hindu epic the Ramayana, which
I do want to add a note. I've brought this up
in the show, but I've brought the topic up on
(27:04):
the show before, but I don't know that I've been
using the proper pronunciation. I may have said it wrong
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.
(27:27):
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,
(27:48):
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
(28:09):
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
(28:30):
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
(28:52):
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
(29:14):
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
(29:37):
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
(29:59):
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,
(30:22):
where Rama's hands smote Ravana down.
Speaker 1 (30:25):
A bridge was thrown. Wow, how do you throw a bridge?
Speaker 3 (30:30):
Well, this is where this sort of things get get interesting,
dissecting all of this because the accounts apparently vary. In
some cases, the resulting bridge that gets thrown or constructed
is in fact a great bridge that it's you know,
something built. It's constructed. It's perhaps made. It would at
the base and then become stone further up. You know,
(30:54):
it is like a huge megawork that connects one land
to the next so that the army can march over it.
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,
(31:17):
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
(31:38):
they starts throwing the stones in and they kind of
find a loophole to build the bridge.
Speaker 1 (31:43):
Brilliant leve a loophole.
Speaker 3 (31:45):
Yeah, but at any rate, there's no like one way.
Apparently there are different accounts, different stories, but we end
up with the idea of a bridge one way or another.
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
(32:09):
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.
(32:31):
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.
Speaker 1 (32:48):
Yeah, would they support your weight? I mean I would
think it'd be more like the you know, the ball pit,
you kind of fall in between them.
Speaker 3 (32:54):
Yeah. And I think they're also just more convincing ideas
regarding all of this. So, of course, the big questions
here would be, Okay, first of all, did something even
remotely like the events of this Hindu epic ever take place?
And if so, where did it take place? Where would
this bridge have been, and what land masses would it
(33:16):
have been linking So versions of question one, to be clear,
turn up in all religions, and they're often asked with
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
(33:40):
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
(34:02):
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.
Speaker 1 (34:18):
Well, yeah, I've often spoken this opinion with reference to
things like the creation story told in Genesis or something
that are you sure that the people who first wrote
this story even necessarily meant it to be taken as
a literal, factual account.
Speaker 3 (34:33):
Yeah, And you know, it kind of comes back to
some of the things we're discussing just concerning some of
these ideas of different lost islands and so forth. It's
like we always want to find that one reason, that
one explanation, and you know, oftentimes, especially when we're dealing
with things like this, that are concepts that exist not
only in one human imagination, but in multiple human imaginations
(34:53):
spread out across different communities and cultures over long stretches
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
(35:15):
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
(35:36):
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
(35:56):
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
(36:19):
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
(36:41):
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
(37:05):
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.
Speaker 1 (37:25):
Oh okay, So it's almost like, if you know, if
the water levels were a little bit lower or something
were piled up here, you can imagine something like a
bridge emerging.
Speaker 3 (37:34):
Yeah. Yeah, And so this and this is something that
has captivated the human imagination for a while and cause
people to, you know, logically, wonder could this be what
the epics are talking about? So this is also commonly
known as Adams Bridge. The name linked to an Islamic
tradition and I think sometimes a Christian tradition as well
(37:56):
that holds that Adam's Peak on Sri Lanka is where
the first human in Abrahamic traditions fell to earth, and
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.
(38:21):
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
(38:43):
no longer traversible. Ah.
Speaker 1 (38:45):
Well, so that is much more recent than any of
the than the land bridges we've been talking about in
the other episodes of like the or the so called
land bridges, the former areas of dogger Land and Beringia,
which are that are now underwater and have been for
many thousands of years. This is just a question of
a few centuries comparatively very recent, if true.
Speaker 3 (39:06):
Yeah, yeah, though of course there are all sorts of
questions that arise in this, like is it too recent,
is it something that would be something that might have
emerged and then resemble something from pre existing mythology, or
as indeed, as many people believe, is it evidence of
something that is described in the Hindu epics, So it's
(39:28):
fascinating to think about those things, and also thinking about
like reports of it being traversible from centuries past, like
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
(39:50):
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
(40:11):
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
(40:33):
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
(40:56):
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.
(41:17):
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
(41:39):
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
(41:59):
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
(42:25):
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.
Speaker 1 (42:49):
Well, I think maybe that spells the end of our
exploration of sunken lands, but this has been a really
interesting journey to go on with you.
Speaker 3 (42:56):
Rob, Yeah, this has been This has been a lot
of fun. I learned a lot, and I would love
to learn some more from listeners out there. If you
have some additional examples of anything we've discussed any of
the categories we've discussed in these episodes, If you have
some first hand knowledge or observations you'd like to share
about the various places we've discussed, all of that is
fair game and we would love to hear from you.
(43:17):
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
(43:39):
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.
Speaker 1 (43:49):
I watched a movie a few years back. That's about
just like there's like a hurricane and a flood, and
it's just about a bunch of gators getting in somebody's house.
I forget what it's called.
Speaker 3 (44:00):
It was pretty funny, like they're coming up the stairs,
that sort of thing.
Speaker 1 (44:04):
Swimming up the stairs, you know.
Speaker 3 (44:05):
Oh nice.
Speaker 1 (44:06):
I'm trying to look it up. It's not Gator from
nineteen seventy six, so that has Burt Reynolds in it.
Now I kind of kind of need to see it.
Oh it might. It might not be about alligators. It
might be about a guy called Gator.
Speaker 2 (44:18):
I don't know.
Speaker 3 (44:20):
All right, Well, this is this is also fair game
as well for anyone who wants to write in. If
you have suggestions for Atlantis based movies, sunken world movies
that we can discuss in Weird House Cinema, well we'd
love to get those as well. Oh.
Speaker 1 (44:33):
I found what it was. It's called crawl. It starts
in a crawl space and then the house is full
of gators as it floods.
Speaker 3 (44:40):
That's what it is, all right, that sounds great.
Speaker 1 (44:44):
It's great, Okay, anyway, huge thanks as always to our
excellent audio producer JJ Posway. If you would like to
get in touch with us with feedback on this episode
or any other, to suggest a topic for the future,
or just to say hello, you can email us at
contact that Stuff to Blow Your Mind dot com.
Speaker 2 (45:08):
Stuff to Blow Your Mind is production of iHeartRadio. For
more podcasts from my heart Radio, visit the iHeartRadio app,
Apple Podcasts, or wherever you listen to your favorite shows.
Hello, and welcome to Stuff to Blow your Mind. My
name is Joe McCormick. Today we're going to finish out
the Vault series that we've been running this week. This
is part four of our series called The Sunken Lands.
This originally published on December seventh, twenty twenty three. Hope
you enjoy.
Speaker 2 (00:27):
Welcome to Stuff to Blow your Mind, the production of iHeartRadio.
Speaker 3 (00:37):
Hey you welcome to Stuff to Blow your Mind. My
name is Robert Lamb.
Speaker 1 (00:40):
And I am Joe McCormick. And we are back with
the fourth and final part in our series called the
Sunken Lands, about places on Earth that relatively recently used
to be dry land but are now covered by water now.
In previous parts of the series we talked about, of course,
legendary lands of this sort Atlantis and other fictional or
(01:01):
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
(01:23):
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
(01:44):
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.
(02:09):
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
(02:30):
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.
Speaker 3 (02:49):
Now. A quick note on just the idea of sunken
islands and sunken lands. We had a listener ask about
this and discord, so I want to just briefly point
out that, especially in our discussion of atolls in the
last episode, the terms sunk in or to sink may
ultimately be too simplistic for these discussions because they're all
very based on the human perspective of what's going on.
(03:10):
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
(03:31):
sinking maybe doesn't fully capture the picture of what's going on.
Speaker 1 (03:36):
Well. Actually, as luck would have it, I do want
to get to one example of actual sinking of lands
in just a bit here. So in the background of
discussing these historical cases of landscapes covered by rising seas,
there is the knowledge that most of us have now
that relatively rapid increases in sea level are happening right
(03:59):
now and will continue in the coming decades due to
climate change, due to the warming of the seas, the
melting of glaciers. Sea level changes have happened on Earth before.
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
(04:21):
they are. Whole cities, whole countries even are threatened by
rising waters because they have been built without those rising
waters in mind.
Speaker 3 (04:31):
Yeah, some of the very places we've discussed, at least
in passing in these episodes, like the Maldives, are greatly
threatened by these rising sea waters.
Speaker 1 (04:39):
Yes, absolutely, But of course this applies to coastal settlements
all over the world, on every continent on Earth, though
though in different ways. Not every coastal settlement will be
affected the same, And I want to get to some
of that variance in just a bit here. But as
a baseline, I thought we should look at how much
are sea levels expected to rise in the next century
(05:01):
or so. That depends on a number of variables, but
I was looking at the most recent IPCC report, which
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.
(05:21):
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
(05:43):
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,
(06:06):
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
(06:28):
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
(06:50):
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
(07:13):
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
(07:36):
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
(07:58):
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,
(08:20):
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
(08:42):
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
(09:05):
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.
(09:27):
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.
(09:48):
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
(10:10):
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
(10:31):
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,
(10:52):
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
(11:15):
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
(11:37):
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
(11:59):
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
(12:25):
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.
(12:49):
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
(13:11):
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
(13:32):
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
(13:54):
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
(14:16):
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.
(14:39):
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.
(15:00):
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,
(15:22):
you know, trapping carbon in things like plants and forests.
Speaker 3 (15:26):
Yeah, so as is I've heard a lot of experts
say it's not that there isn't room for optimism in
all of this, but the optimism does not come without action, right,
there are definite steps that need to be taken. We
can't just be like, ah, it might be, it might
be okay, maybe it's just gonna be the lower We'll
(15:47):
just we'll roll the dice and see, like, that's not
how it's going to work out.
Speaker 1 (15:50):
Yeah, that's exactly right. The lower end of the prediction
range there is based on an assumption of action if
humanity does something to massively reduce the contribution to global
warming through greenhouse gases. So in that case, yes, we
could limit it to the lower levels of sea level rise.
But to be clear, some amount of sea level rise
(16:12):
at this point has already happened and is basically locked in.
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.
(16:36):
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
(16:56):
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
(17:18):
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
(17:39):
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
(18:00):
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
(18:21):
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
(18:43):
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
(19:04):
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,
(19:25):
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.
(19:48):
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
(20:09):
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.
(20:29):
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
(20:50):
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
(21:11):
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
(21:31):
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,
(21:57):
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
(22:21):
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
(22:42):
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
(23:05):
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
(23:29):
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
(23:50):
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
(24:11):
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
(24:32):
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,
(24:54):
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
(25:15):
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
(25:37):
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
(25:58):
the extent possible, take them out.
Speaker 3 (26:01):
Yeah, basically, the natural environment is maluable, as we've discussed,
and humanity has tremendous power and tremendous will. We see
that in the in the in the degree to which
we have and are changing things. But that power and
will can also be applied to changing the ways that
(26:21):
we're interacting with the natural world for the better. But again,
it does require action. It doesn't require just setting back
and hoping that it will be better or pretending that
the problem does not exist.
Speaker 1 (26:33):
Correct.
Speaker 3 (26:44):
All right, So this is the fourth part of our series,
and we could, we could honestly easily keep going, but
we can't because I've got some Christma stuff to do
next week. So in this last section, I'd like to
refer to the ancient Hindu Hindu epic the Ramayana, which
I do want to add a note. I've brought this up
in the show, but I've brought the topic up on
(27:04):
the show before, but I don't know that I've been
using the proper pronunciation. I may have said it wrong
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.
(27:27):
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,
(27:48):
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
(28:09):
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
(28:30):
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
(28:52):
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
(29:14):
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
(29:37):
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
(29:59):
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,
(30:22):
where Rama's hands smote Ravana down.
Speaker 1 (30:25):
A bridge was thrown. Wow, how do you throw a bridge?
Speaker 3 (30:30):
Well, this is where this sort of things get get interesting,
dissecting all of this because the accounts apparently vary. In
some cases, the resulting bridge that gets thrown or constructed
is in fact a great bridge that it's you know,
something built. It's constructed. It's perhaps made. It would at
the base and then become stone further up. You know,
(30:54):
it is like a huge megawork that connects one land
to the next so that the army can march over it.
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,
(31:17):
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
(31:38):
they starts throwing the stones in and they kind of
find a loophole to build the bridge.
Speaker 1 (31:43):
Brilliant leve a loophole.
Speaker 3 (31:45):
Yeah, but at any rate, there's no like one way.
Apparently there are different accounts, different stories, but we end
up with the idea of a bridge one way or another.
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
(32:09):
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.
(32:31):
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.
Speaker 1 (32:48):
Yeah, would they support your weight? I mean I would
think it'd be more like the you know, the ball pit,
you kind of fall in between them.
Speaker 3 (32:54):
Yeah. And I think they're also just more convincing ideas
regarding all of this. So, of course, the big questions
here would be, Okay, first of all, did something even
remotely like the events of this Hindu epic ever take place?
And if so, where did it take place? Where would
this bridge have been, and what land masses would it
(33:16):
have been linking So versions of question one, to be clear,
turn up in all religions, and they're often asked with
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
(33:40):
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
(34:02):
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.
Speaker 1 (34:18):
Well, yeah, I've often spoken this opinion with reference to
things like the creation story told in Genesis or something
that are you sure that the people who first wrote
this story even necessarily meant it to be taken as
a literal, factual account.
Speaker 3 (34:33):
Yeah, And you know, it kind of comes back to
some of the things we're discussing just concerning some of
these ideas of different lost islands and so forth. It's
like we always want to find that one reason, that
one explanation, and you know, oftentimes, especially when we're dealing
with things like this, that are concepts that exist not
only in one human imagination, but in multiple human imaginations
(34:53):
spread out across different communities and cultures over long stretches
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
(35:15):
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
(35:36):
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
(35:56):
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
(36:19):
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
(36:41):
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
(37:05):
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.
Speaker 1 (37:25):
Oh okay, So it's almost like, if you know, if
the water levels were a little bit lower or something
were piled up here, you can imagine something like a
bridge emerging.
Speaker 3 (37:34):
Yeah. Yeah, And so this and this is something that
has captivated the human imagination for a while and cause
people to, you know, logically, wonder could this be what
the epics are talking about? So this is also commonly
known as Adams Bridge. The name linked to an Islamic
tradition and I think sometimes a Christian tradition as well
(37:56):
that holds that Adam's Peak on Sri Lanka is where
the first human in Abrahamic traditions fell to earth, and
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.
(38:21):
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
(38:43):
no longer traversible. Ah.
Speaker 1 (38:45):
Well, so that is much more recent than any of
the than the land bridges we've been talking about in
the other episodes of like the or the so called
land bridges, the former areas of dogger Land and Beringia,
which are that are now underwater and have been for
many thousands of years. This is just a question of
a few centuries comparatively very recent, if true.
Speaker 3 (39:06):
Yeah, yeah, though of course there are all sorts of
questions that arise in this, like is it too recent,
is it something that would be something that might have
emerged and then resemble something from pre existing mythology, or
as indeed, as many people believe, is it evidence of
something that is described in the Hindu epics, So it's
(39:28):
fascinating to think about those things, and also thinking about
like reports of it being traversible from centuries past, like
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
(39:50):
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
(40:11):
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
(40:33):
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
(40:56):
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.
(41:17):
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
(41:39):
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
(41:59):
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
(42:25):
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.
Speaker 1 (42:49):
Well, I think maybe that spells the end of our
exploration of sunken lands, but this has been a really
interesting journey to go on with you.
Speaker 3 (42:56):
Rob, Yeah, this has been This has been a lot
of fun. I learned a lot, and I would love
to learn some more from listeners out there. If you
have some additional examples of anything we've discussed any of
the categories we've discussed in these episodes, If you have
some first hand knowledge or observations you'd like to share
about the various places we've discussed, all of that is
fair game and we would love to hear from you.
(43:17):
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
(43:39):
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.
Speaker 1 (43:49):
I watched a movie a few years back. That's about
just like there's like a hurricane and a flood, and
it's just about a bunch of gators getting in somebody's house.
I forget what it's called.
Speaker 3 (44:00):
It was pretty funny, like they're coming up the stairs,
that sort of thing.
Speaker 1 (44:04):
Swimming up the stairs, you know.
Speaker 3 (44:05):
Oh nice.
Speaker 1 (44:06):
I'm trying to look it up. It's not Gator from
nineteen seventy six, so that has Burt Reynolds in it.
Now I kind of kind of need to see it.
Oh it might. It might not be about alligators. It
might be about a guy called Gator.
Speaker 2 (44:18):
I don't know.
Speaker 3 (44:20):
All right, Well, this is this is also fair game
as well for anyone who wants to write in. If
you have suggestions for Atlantis based movies, sunken world movies
that we can discuss in Weird House Cinema, well we'd
love to get those as well. Oh.
Speaker 1 (44:33):
I found what it was. It's called crawl. It starts
in a crawl space and then the house is full
of gators as it floods.
Speaker 3 (44:40):
That's what it is, all right, that sounds great.
Speaker 1 (44:44):
It's great, Okay, anyway, huge thanks as always to our
excellent audio producer JJ Posway. If you would like to
get in touch with us with feedback on this episode
or any other, to suggest a topic for the future,
or just to say hello, you can email us at
contact that Stuff to Blow Your Mind dot com.
Speaker 2 (45:08):
Stuff to Blow Your Mind is production of iHeartRadio. For
more podcasts from my heart Radio, visit the iHeartRadio app,
Apple Podcasts, or wherever you listen to your favorite shows.
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