December 7, 2023 • 45 mins
In this 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.
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Speaker 1 (00:03):
Welcome to Stuff to Blow Your Mind, the production of iHeartRadio.
Speaker 2 (00:13):
Hey you welcome to Stuff to Blow your Mind. My
name is Robert Lamb.
Speaker 3 (00:16):
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.
Speaker 2 (00:30):
Now.
Speaker 3 (00:30):
In previous parts of the series we talked about, of course,
legendary lands of this sort Atlantis and other fictional or
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
(00:52):
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,
(01:12):
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
(01:34):
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
(01:57):
related to karsification 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
(02:17):
streams to end up submerging areas that used to be
exposed land now under lakes.
Speaker 2 (02:24):
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.
(02:45):
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
(03:07):
sinking maybe doesn't fully capture the picture of what's going on.
Speaker 3 (03:12):
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
(03:35):
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
(03:57):
they are. Whole cities, whole countries even are threatened by
rising waters because they have been built without those rising
waters in mind.
Speaker 2 (04:06):
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 3 (04:15):
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
(04:37):
or so. That depends on a number of variables, but
I was looking at the most recent ipc SA 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.
(04:57):
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 over the past century, and the basically the more
(05:18):
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 fifteen, it's two point one
millimeters per year. If you just look at nineteen ninety
(05:40):
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
(06:02):
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
(06:24):
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 and 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,
(06:45):
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,
(07:08):
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
(07:29):
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.
It's basically a ruler, you know, It's got height markings
on them, and then the operators could visually observe the
(07:51):
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 system 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
(08:14):
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
(08:35):
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
(08:56):
most accurate possible average. So there is another method 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
(09:19):
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 bounces
back to the satellite and hits a return sensor, and
(09:39):
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
(10:02):
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
(10:22):
seems counterintuitive because you think of water and 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
(10:44):
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
(11:07):
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
(11:28):
the ocean with the help of satellite based radar altimetry.
As just one example of the variance in the height
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
(11:51):
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
(12:12):
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
(12:33):
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.
Speaker 2 (12:42):
Now.
Speaker 3 (12:42):
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 it to trap more heat This is
the famous greenhouse effect. Putting more things like carbon methane
(13:06):
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,
(13:28):
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
(13:51):
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 continued to rise for centuries after that,
and we'll probably stay higher for thousands of hyears. Now,
I wouldn't hang on those exact numbers too much because
(14:14):
those are estimates. There 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. So if we continue increasing the concentration
(14:37):
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 trapping carbon in things like plants, forests.
Speaker 2 (15:01):
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
(15:22):
just we'll roll the dice and see, like that's not
how it's going to work out.
Speaker 3 (15:26):
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
(15:48):
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.
(16:11):
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 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
(16:34):
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 roughly
a foot of increase by the middle of the century.
(16:56):
Also on the more dire end, this one was predicting
much higher levels of sea level rise at the 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
(17:18):
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. We've already
talked about the role of melting ice in the sea
level increases at the end of the Pleistocene, which were
(17:41):
responsible for inundating Doggerland and Beringia, 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
(18:04):
of the melting, but as water heats up, it becomes
less dense and takes up more space. Warmer water takes
up more space per 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
(18:25):
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 warms, 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
(18:47):
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
(19:13):
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
(19:33):
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
(19:55):
consequences of massive economic damage, destruction of property, destruction of life, 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,
(20:17):
this can 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
(20:38):
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,
(20:59):
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
(21:23):
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
(21:44):
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
be catastrophic and unequal. So this article is emphasizing again
(22:05):
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
(22:28):
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
(22:48):
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
(23:10):
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
(23:31):
be hard to believe. But there is an area in
Baytown where there is a big Exxon 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
(23:54):
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
(24:16):
analogy of when you get up off of a memory
foam mattress and that mattress gradually fills in the dent
you 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,
(24:40):
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
(25:01):
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
(25:23):
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.
Speaker 2 (25:36):
Yeah, basically, the natural environment is maguable, as we've discussed,
and humanity has tremendous power and tremendous will. We see
that 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 we are interacting with
(25:58):
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 3 (26:09):
Correct.
Speaker 2 (26:19):
All right, So this is the fourth part of our series,
and we could honestly easily keep going, but we can't
because they've got some Christmas 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 the
(26:40):
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 if you're not familiar with the story,
there are lots of ins and outs. It's essentially the
story of this of this mythical king, this divine king's life.
(27:03):
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,
(27:24):
including a people known as the Vanara. In short, the
Vanara are the monkeys if you've seen illustrations of the
Ramayana before, you've you know, some of the related traditions.
You've you've probably seen images of these various monkey troops
aiding Rama. And of course you may be familiar with Hahneman,
(27:44):
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 in the into the venera a
bit more. And according to the author Nanditha Krishna in
(28:05):
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 Venara essentially
translates to people of the forest, with Vana being forest
and Nara being men. Interesting, yeah, the author writes that
(28:26):
this term probably never actually meant monkey. In fact, in Jainism,
the Venara 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,
(28:48):
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 some sort of primate themed totem of
some sort, or some sort of totem system, But the
author stresses that it could also be neither of these.
(29:09):
We just don't know, And so the Venar include several
important individuals that pop up in the epic. There's Mighty Haneman,
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
(29:32):
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
(29:54):
from shore to shore. They crossed to Lanka's Golden town,
where Rama's hands smote Ravi down.
Speaker 3 (30:01):
A bridge was thrown. Wow, how do you throw a bridge?
Speaker 2 (30:05):
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,
(30:29):
it is like a huge megalwork 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,
(30:53):
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.
It'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
(31:13):
they starts throwing the stones in and they kind of
find a loophole to build the bridge.
Speaker 3 (31:19):
Brilliant leve a loophole.
Speaker 2 (31:21):
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, and I know some of you are thinking
about those floating pumice rocks and wondering if observations of
(31:44):
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 it's supposed to have been.
(32:07):
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 pumice stones? I think there's significantly less
evidence for that.
Speaker 3 (32:24):
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 2 (32:30):
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
(32:51):
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
(33:15):
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 reality. Not to say that it
(33:38):
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 3 (33:53):
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 2 (34:08):
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 spread out
(34:29):
across different communities and cultures over long stretches of time,
there's a lot of room for various influences 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.
(34:52):
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. But and of course conspiracy minded folks are
not above suggesting Atlantis. That it was Atlantis, but it was, Yeah,
(35:12):
it was not Atlantis. So for 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 to 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 Strait. It has been
(35:35):
inhabited by humans since prehistoric times, and so it's you know,
it's been it's been presented and There's 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, uh,
supernatural otherwise from point A to point B. Well, this
(35:57):
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.
(36:21):
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
(36:43):
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 ship.
Speaker 3 (37:00):
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 2 (37:10):
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,
(37:32):
that holds that Adam's Peak on Sri Lanka is where Adam,
the first human and Abrahamic traditions fell to earth, and
the mountain in question here is also sacred in Hinduism.
But anyway, there's a lot of evidence to suggest that
these shoals and sandbars constitute a former land bridge, Though
(37:54):
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
(38:16):
this portion of it in another portion, until you're left
with something that is no longer traversible.
Speaker 3 (38:20):
Ah. 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 Boringia,
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 2 (38:42):
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 you know believe, is it
evidence of something that is described in the Hindu epics.
(39:03):
So it's 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 sing deciding to err on
the side of caution when identifying things that could be
(39:25):
a navigational hazard to ships and so forth. But at
any rate, 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
(39:47):
have been augmented them 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
(40:08):
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
(40:31):
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
(40:55):
bridge quote unquote, and this would be a project that
would have tremendous religion just 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
(41:19):
have been It 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
(41:40):
by Tamil revivalists, and 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
(42:00):
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.
Speaker 3 (42:24):
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, Rob.
Speaker 2 (42:32):
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 in the categories we've
discussed in these episodes. If you have some firsthand 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. Just a reminder that
(42:54):
Stuff to Blow your Mind is primarily a science podcast,
with core episodes on Tuesdays and Thursdays. On Mondays we
do mail. On Wednesdays there tends to be a short
form artifactor 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.
(43:14):
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.
Speaker 3 (43:25):
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.
Speaker 2 (43:34):
I forget what it was called. It was pretty funny,
like they're coming up the stairs, that sort of thing
swimming up the stairs, you know.
Speaker 3 (43:41):
Oh, I'm trying to look it up. It's not Gator
from nineteen seventy six, so that has Burt Reynolds in it,
and now I kind of kind of need to see it.
Oh it might it might not be about alligators, might
be about a guy called Gator.
Speaker 1 (43:54):
I don't know.
Speaker 2 (43:56):
All right, Well, this is this is also a fair
game as well for anyone who wants to and 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.
Speaker 3 (44:09):
Oh, 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 2 (44:15):
That's what it is, all right, that sounds great.
Speaker 3 (44:19):
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 at stuff to Blow your Mind dot com.
Speaker 1 (44:43):
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
Speaker 2 (45:00):
Passed with the pattor
Welcome to Stuff to Blow Your Mind, the production of iHeartRadio.
Speaker 2 (00:13):
Hey you welcome to Stuff to Blow your Mind. My
name is Robert Lamb.
Speaker 3 (00:16):
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.
Speaker 2 (00:30):
Now.
Speaker 3 (00:30):
In previous parts of the series we talked about, of course,
legendary lands of this sort Atlantis and other fictional or
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
(00:52):
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,
(01:12):
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
(01:34):
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
(01:57):
related to karsification 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
(02:17):
streams to end up submerging areas that used to be
exposed land now under lakes.
Speaker 2 (02:24):
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.
(02:45):
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
(03:07):
sinking maybe doesn't fully capture the picture of what's going on.
Speaker 3 (03:12):
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
(03:35):
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
(03:57):
they are. Whole cities, whole countries even are threatened by
rising waters because they have been built without those rising
waters in mind.
Speaker 2 (04:06):
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 3 (04:15):
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
(04:37):
or so. That depends on a number of variables, but
I was looking at the most recent ipc SA 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.
(04:57):
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 over the past century, and the basically the more
(05:18):
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 fifteen, it's two point one
millimeters per year. If you just look at nineteen ninety
(05:40):
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
(06:02):
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
(06:24):
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 and 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,
(06:45):
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,
(07:08):
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
(07:29):
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.
It's basically a ruler, you know, It's got height markings
on them, and then the operators could visually observe the
(07:51):
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 system 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
(08:14):
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
(08:35):
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
(08:56):
most accurate possible average. So there is another method 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
(09:19):
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 bounces
back to the satellite and hits a return sensor, and
(09:39):
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
(10:02):
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
(10:22):
seems counterintuitive because you think of water and 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
(10:44):
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
(11:07):
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
(11:28):
the ocean with the help of satellite based radar altimetry.
As just one example of the variance in the height
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
(11:51):
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
(12:12):
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
(12:33):
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.
Speaker 2 (12:42):
Now.
Speaker 3 (12:42):
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 it to trap more heat This is
the famous greenhouse effect. Putting more things like carbon methane
(13:06):
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,
(13:28):
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
(13:51):
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 continued to rise for centuries after that,
and we'll probably stay higher for thousands of hyears. Now,
I wouldn't hang on those exact numbers too much because
(14:14):
those are estimates. There 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. So if we continue increasing the concentration
(14:37):
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 trapping carbon in things like plants, forests.
Speaker 2 (15:01):
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
(15:22):
just we'll roll the dice and see, like that's not
how it's going to work out.
Speaker 3 (15:26):
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
(15:48):
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.
(16:11):
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 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
(16:34):
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 roughly
a foot of increase by the middle of the century.
(16:56):
Also on the more dire end, this one was predicting
much higher levels of sea level rise at the 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
(17:18):
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. We've already
talked about the role of melting ice in the sea
level increases at the end of the Pleistocene, which were
(17:41):
responsible for inundating Doggerland and Beringia, 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
(18:04):
of the melting, but as water heats up, it becomes
less dense and takes up more space. Warmer water takes
up more space per 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
(18:25):
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 warms, 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
(18:47):
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
(19:13):
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
(19:33):
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
(19:55):
consequences of massive economic damage, destruction of property, destruction of life, 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,
(20:17):
this can 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
(20:38):
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,
(20:59):
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
(21:23):
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
(21:44):
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
be catastrophic and unequal. So this article is emphasizing again
(22:05):
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
(22:28):
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
(22:48):
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
(23:10):
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
(23:31):
be hard to believe. But there is an area in
Baytown where there is a big Exxon 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
(23:54):
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
(24:16):
analogy of when you get up off of a memory
foam mattress and that mattress gradually fills in the dent
you 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,
(24:40):
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
(25:01):
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
(25:23):
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.
Speaker 2 (25:36):
Yeah, basically, the natural environment is maguable, as we've discussed,
and humanity has tremendous power and tremendous will. We see
that 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 we are interacting with
(25:58):
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 3 (26:09):
Correct.
Speaker 2 (26:19):
All right, So this is the fourth part of our series,
and we could honestly easily keep going, but we can't
because they've got some Christmas 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 the
(26:40):
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 if you're not familiar with the story,
there are lots of ins and outs. It's essentially the
story of this of this mythical king, this divine king's life.
(27:03):
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,
(27:24):
including a people known as the Vanara. In short, the
Vanara are the monkeys if you've seen illustrations of the
Ramayana before, you've you know, some of the related traditions.
You've you've probably seen images of these various monkey troops
aiding Rama. And of course you may be familiar with Hahneman,
(27:44):
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 in the into the venera a
bit more. And according to the author Nanditha Krishna in
(28:05):
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 Venara essentially
translates to people of the forest, with Vana being forest
and Nara being men. Interesting, yeah, the author writes that
(28:26):
this term probably never actually meant monkey. In fact, in Jainism,
the Venara 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,
(28:48):
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 some sort of primate themed totem of
some sort, or some sort of totem system, But the
author stresses that it could also be neither of these.
(29:09):
We just don't know, And so the Venar include several
important individuals that pop up in the epic. There's Mighty Haneman,
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
(29:32):
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
(29:54):
from shore to shore. They crossed to Lanka's Golden town,
where Rama's hands smote Ravi down.
Speaker 3 (30:01):
A bridge was thrown. Wow, how do you throw a bridge?
Speaker 2 (30:05):
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,
(30:29):
it is like a huge megalwork 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,
(30:53):
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.
It'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
(31:13):
they starts throwing the stones in and they kind of
find a loophole to build the bridge.
Speaker 3 (31:19):
Brilliant leve a loophole.
Speaker 2 (31:21):
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, and I know some of you are thinking
about those floating pumice rocks and wondering if observations of
(31:44):
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 it's supposed to have been.
(32:07):
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 pumice stones? I think there's significantly less
evidence for that.
Speaker 3 (32:24):
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 2 (32:30):
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
(32:51):
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
(33:15):
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 reality. Not to say that it
(33:38):
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 3 (33:53):
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 2 (34:08):
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 spread out
(34:29):
across different communities and cultures over long stretches of time,
there's a lot of room for various influences 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.
(34:52):
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. But and of course conspiracy minded folks are
not above suggesting Atlantis. That it was Atlantis, but it was, Yeah,
(35:12):
it was not Atlantis. So for 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 to 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 Strait. It has been
(35:35):
inhabited by humans since prehistoric times, and so it's you know,
it's been it's been presented and There's 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, uh,
supernatural otherwise from point A to point B. Well, this
(35:57):
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.
(36:21):
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
(36:43):
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 ship.
Speaker 3 (37:00):
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 2 (37:10):
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,
(37:32):
that holds that Adam's Peak on Sri Lanka is where Adam,
the first human and Abrahamic traditions fell to earth, and
the mountain in question here is also sacred in Hinduism.
But anyway, there's a lot of evidence to suggest that
these shoals and sandbars constitute a former land bridge, Though
(37:54):
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
(38:16):
this portion of it in another portion, until you're left
with something that is no longer traversible.
Speaker 3 (38:20):
Ah. 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 Boringia,
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 2 (38:42):
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 you know believe, is it
evidence of something that is described in the Hindu epics.
(39:03):
So it's 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 sing deciding to err on
the side of caution when identifying things that could be
(39:25):
a navigational hazard to ships and so forth. But at
any rate, 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
(39:47):
have been augmented them 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
(40:08):
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
(40:31):
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
(40:55):
bridge quote unquote, and this would be a project that
would have tremendous religion just 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
(41:19):
have been It 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
(41:40):
by Tamil revivalists, and 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
(42:00):
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.
Speaker 3 (42:24):
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, Rob.
Speaker 2 (42:32):
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 in the categories we've
discussed in these episodes. If you have some firsthand 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. Just a reminder that
(42:54):
Stuff to Blow your Mind is primarily a science podcast,
with core episodes on Tuesdays and Thursdays. On Mondays we
do mail. On Wednesdays there tends to be a short
form artifactor 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.
(43:14):
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.
Speaker 3 (43:25):
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.
Speaker 2 (43:34):
I forget what it was called. It was pretty funny,
like they're coming up the stairs, that sort of thing
swimming up the stairs, you know.
Speaker 3 (43:41):
Oh, I'm trying to look it up. It's not Gator
from nineteen seventy six, so that has Burt Reynolds in it,
and now I kind of kind of need to see it.
Oh it might it might not be about alligators, might
be about a guy called Gator.
Speaker 1 (43:54):
I don't know.
Speaker 2 (43:56):
All right, Well, this is this is also a fair
game as well for anyone who wants to and 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.
Speaker 3 (44:09):
Oh, 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 2 (44:15):
That's what it is, all right, that sounds great.
Speaker 3 (44:19):
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 at stuff to Blow your Mind dot com.
Speaker 1 (44:43):
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
Speaker 2 (45:00):
Passed with the pattor
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