Speaker 1: Welcome to Stuff you Should Know, a production of iHeartRadio.
Speaker 2: Hey, and welcome to the podcast. I'm Josh, and there's
Speaker 2: Chuck and Jerry's here too, and this is stuff you
Speaker 2: should know and what we've got on our hands today.
Speaker 2: Chuck is a hot potato of a real deal geological mystery.
Speaker 3: Hot potato. That's how Emily's family says potato.
Speaker 2: I think I would only say it when it's preceded
Speaker 2: by hot. I would only say it like like I
Speaker 2: wouldn't say I'm going to have a baked potato, like
Speaker 2: you'd be out of your mind.
Speaker 3: To say it like that. Nor would you say a
Speaker 3: hot potato like what a square?
Speaker 1: Yeah?
Speaker 2: That is pretty square, isn't it.
Speaker 3: Get the stick out of your butt, fella, and loosen up.
Speaker 2: Right, loosen up, get the card again out from around
Speaker 2: your shoulders.
Speaker 3: Yeah, jeez, So that was obscure.
Speaker 2: But still so, like I said, this is a mystery today.
Speaker 2: And just to give a brief brushstroke overview with the
Speaker 2: widest brush, real lot of space in between bristles, just
Speaker 2: barely any paint on it. That kind of overview.
Speaker 3: Oh wow.
Speaker 2: What we're talking about is something called the younger dryis,
Speaker 2: which is a pretty it's a pretty terrible name for this,
Speaker 2: if you want to be catchy, right.
Speaker 3: Yeah, I mean I think a lot of people will
Speaker 3: probably say WTF.
Speaker 2: Right, well, let's just call it the YD. If we're gonna,
Speaker 2: if we're gonna put initials on things, how about that
Speaker 2: or a breath other things? So the YD, the Younger
Speaker 2: Dryas is this this surprising, shocking period in Earth's history,
Speaker 2: fairly recent history, where we came out of the last
Speaker 2: ice Age, everything was going smoothly, and then bam, we
Speaker 2: got hit by another ice age out of nowhere that
Speaker 2: lasts for over a thousand years, and then bam, it
Speaker 2: goes away just as fast as it came along. And
Speaker 2: paleo geologist, paleo climatologist, all the paleos are perplexed as
Speaker 2: to what caused it and then why it stopped so
Speaker 2: suddenly too. That's why I said it is a real
Speaker 2: deal geological mystery.
Speaker 3: Yeah. And a time, as we'll see, where the Earth
Speaker 3: and its inhabitants and animals and nature was all going
Speaker 3: like all right, thank god, we can we can finally
Speaker 3: get down to business and start being an earth, like
Speaker 3: a legit Earth. And then you know, the YDS come
Speaker 3: along and say not so fast.
Speaker 2: Right, and you call it a legit Earth because when
Speaker 2: it finally ended, and actually that period in between the
Speaker 2: last Ice Age and the yd those are like really
Speaker 2: habitable for human beings, Like we love those kind of
Speaker 2: conditions so much so that after the y D ended,
Speaker 2: it became the age of humans. Yeah, like this is
Speaker 2: the this is the age where we began our civilizations,
Speaker 2: we started farming, we began to flourish as a species
Speaker 2: and basically take over the planet. And what's interesting is
Speaker 2: this is the most recent ice age. There had been
Speaker 2: seven in Earth's history and just as and aside, this
Speaker 2: was the Wisconsinian ice Age that we're talking about. The
Speaker 2: last one was two hundred and fifty million years before, right,
Speaker 2: So it's pretty significant that we, just geologically speaking, came
Speaker 2: out of an ice age because there's not that many.
Speaker 2: And then not coincidentally, when the second to last ice
Speaker 2: age ended, that opened the door for the dinosaurs to
Speaker 2: come along and take over the Earth. So things, big
Speaker 2: things happen when an ice age changes. So for it
Speaker 2: to switch back to an ice age all of a
Speaker 2: sudden and then switch back to nice and temperate for
Speaker 2: us humans it is just very weird. It was actually
Speaker 2: I've seen it described as an extreme weather millennial event.
Speaker 3: Yeah, and you know, it kind of made me wonder
Speaker 3: had this not happened, because we were sort of headed
Speaker 3: toward you know, legit Earth, like I said before, you know,
Speaker 3: I mean, it would obviously wouldn't change the year. But
Speaker 3: let's say, as far as longness goes, we would be
Speaker 3: like the year three thousand something, right like, would we
Speaker 3: be just that much further along as a planet or
Speaker 3: would we be nowhere? Because in a thousand years we
Speaker 3: will have already destroyed ourselves the second one. Okay, all right,
Speaker 3: So it's a good thing this happened, or we wouldn't
Speaker 3: be talking about it right now exactly.
Speaker 2: That's exactly right. So yeah, that's a really anthropic way
Speaker 2: of looking at it. Well, speaking of I bought a
Speaker 2: copy of If Anyone Builds It, Everyone Dies, the Ellie
Speaker 2: is or Yukowski Nate Sores book that just came out.
Speaker 3: Okay, and did not know about it. You say that
Speaker 3: as if it was just on the tip of my tongue,
Speaker 3: which I appreciate. No, you do.
Speaker 2: We remember I basically mischaracterized it in the Zizians episode
Speaker 2: and had that Oh yeah, okay, that book right about
Speaker 2: building AI and if anyone builds it, then we're all
Speaker 2: going to die, like just the existential threat of AI.
Speaker 2: It is really good. You could read it and if
Speaker 2: you had a a day that you could dedicate to
Speaker 2: reading it, you could read it in a day. It's
Speaker 2: really popularly written, lots of really cool anecdotes. It's just
Speaker 2: very good. So I strongly recommend that book. Great, Okay,
Speaker 2: so let's kind of just back it up a little
Speaker 2: bit and go to the previous ice ages of Wisconsinian
Speaker 2: ice Age and talk about what Earth looked like like that.
Speaker 3: Yeah, so it was. It was very icy. There were
Speaker 3: huge ice sheets covering a lot of Earth, like most
Speaker 3: of North America, northern Europe, and Asia. And as we'll see,
Speaker 3: a lot of the YDS affected the northern hemisphere much
Speaker 3: more than the southern. But also weird things happen in
Speaker 3: the southern hemisphere that don't quite jibe. That's why it's
Speaker 3: such a kind of a strange mystery. But lots of
Speaker 3: ice everywhere. We had barren planes, very harsh conditions. We
Speaker 3: had things like you know, wooly mammos like ice ice
Speaker 3: loving creatures dwelling the earth, and you know human populations
Speaker 3: that were sparse and scattered and constantly kind of moving
Speaker 3: around trying to survive.
Speaker 2: Right, And so that the Last ice Age started about
Speaker 2: one hundred thousand years ago, and it took about eighty
Speaker 2: thousand years to reach its peak point. So twenty thousand
Speaker 2: years ago it hit what's called the last glacial maximum, right,
Speaker 2: So it took eighty thousand years to get there and
Speaker 2: then ten thousand years to basically melt. It melted a
Speaker 2: lot faster than it developed. And just like right after
Speaker 2: it peaked, it just started warming up. And it took
Speaker 2: about nine thousand years and all the ice sheets, all
Speaker 2: the glaciers, all this stuff that was covering Earth and
Speaker 2: keeping it and ice age just basically went away. And
Speaker 2: Earth just blossomed into a version that we.
Speaker 3: Like, yeah, and it became, you know, not terribly unlike
Speaker 3: what we're looking at now. There was a jump in
Speaker 3: temperatures that was you know, kind of close ish to today.
Speaker 3: And this was called the and I never know how
Speaker 3: to pronounce it's a umla, is it really?
Speaker 2: Yeah?
Speaker 3: I'm that's all it is.
Speaker 2: Yes, So all of our Nordic friends, the circle with
Speaker 2: the the forward slash through or the O with the
Speaker 2: forward slash through. Yeah, that's an um lot right.
Speaker 3: Okay, I mean I guess we call it the null
Speaker 3: set because it looks like a zero with a slash
Speaker 3: through it, So call it that. I mean, we don't
Speaker 3: really call it that, but that's what it looks like.
Speaker 2: Pronounce it like that, all right?
Speaker 3: What with the oomlount, No, the null set, I would
Speaker 3: know how to do that with the umlaut. I guess
Speaker 3: my best stab would be the berling alarud interstadio.
Speaker 2: I think you nailed it, all right.
Speaker 3: A lot more rain we got to, you know, we
Speaker 3: achieved a sea level that's not what we have today,
Speaker 3: but about half of what we have today. With that rain,
Speaker 3: obviously you're going to get a lot of plants. The
Speaker 3: woodlands are thriving. Animals are now are you know, forest
Speaker 3: dwelling and walking alongside things like cave bears and wooly
Speaker 3: mammoths and things are going pretty good. We have Homo
Speaker 3: sapiens at this point, or are the only humans that
Speaker 3: are around this point, and they're like their love and
Speaker 3: life man. They're saying, all right, we can travel a
Speaker 3: little bit more and as we'll see, you know, kind
Speaker 3: of dabble stick their toe in, settling here and there.
Speaker 2: Yeah, this was actually right before. This was the point
Speaker 2: when people from Eurasia migrated into North America. So this
Speaker 2: is the point where they were cut off. They couldn't
Speaker 2: go back. There's no going back. They were in North
Speaker 2: and South America now because the Bearing Land Bridge was
Speaker 2: covered up by those rising sea levels which turn it
Speaker 2: into the Bearing Sea. And this time, so remember we're
Speaker 2: talking about this little period after the end of the
Speaker 2: ice Age, before the yd comes along, where everything seems
Speaker 2: to be going smoothly for humans. This is where we
Speaker 2: started taking our first stabs at agriculture. We're just like,
Speaker 2: let's try something new. We just came out of an
Speaker 2: ice age. Let's just get as funky as we can
Speaker 2: with it, and we're going to basically take some of
Speaker 2: that energy in that time that we dedicate to hunting
Speaker 2: and gathering and put it in to farming. I just
Speaker 2: made that word up, but let's call it that from
Speaker 2: now on.
Speaker 3: Like, what is farming? They're like, you're doing it right now, buddy.
Speaker 3: I see over there picking weeds exactly and tending to
Speaker 3: those wild plants. And that's basically the you know, kind
Speaker 3: of I guess the argument for the beginning of agriculture
Speaker 3: at least, right, Yeah, well.
Speaker 2: We basically said, that's a good looking plant. Let's just
Speaker 2: try to make that one grow as well as we can.
Speaker 3: That's right. So things are going along swimmingly, people are
Speaker 3: not moving around as much, they enjoy sitting for the
Speaker 3: first time and things like that, and then all of
Speaker 3: a sudden, the yd comes along and the glacial conditions
Speaker 3: return in the broad sense in a very quick way.
Speaker 3: I mean, how long did it take, Like, I mean,
Speaker 3: the whole thing was like a thousand years, but we
Speaker 3: reached kind of close to that last glacial maximum in
Speaker 3: about five hundred years.
Speaker 2: Yeah, I think by one hundred years it was really
Speaker 2: like in full swing. And then yeah, five hundred years
Speaker 2: is basically like the ice age is back.
Speaker 3: I wonder if they were like, hey, does anyone think
Speaker 3: it's getting colder? Right?
Speaker 2: No, just keep farming and be quiet.
Speaker 3: Right, yeah, yeah, just keep planting those plants.
Speaker 2: We should also say Kyle helped us with this, and
Speaker 2: he said that the younger driest came along and spoiled
Speaker 2: the party. That's truer than you would think, because right,
Speaker 2: before this, and that booing all a rod inner stadial
Speaker 2: was when we started making beer too, so that got
Speaker 2: disrupted as well.
Speaker 3: We'd be so much drunker today.
Speaker 2: So another reason we would have wiped ourselves out in
Speaker 2: just one global bar fight. Basically, Yeah, so this is
Speaker 2: this kicks off thirteen hundred years of really really cold
Speaker 2: weather and then all of a sudden it just stops
Speaker 2: and it comes along it like happened starting about one
Speaker 2: hundred years, five hundred years into it. It was really
Speaker 2: basically back to ice age conditions in a lot of places.
Speaker 2: But when it stopped, it swung back to nice and
Speaker 2: humid even faster. And there's actual ice cores from Greenland
Speaker 2: that show that Greenland in ten years the average temperature
Speaker 2: increased by eighteen degrees farent height ten degrees celsius. That
Speaker 2: is insane and for comparison so the global warming that's
Speaker 2: going on today that scientists are quite concerned about and
Speaker 2: thinking people as well, that's a rise of two degrees
Speaker 2: farent height, not eighteen degrees farent height. Two degrees farentheight
Speaker 2: in about twenty decades. We're talking about eighteen degrees rise
Speaker 2: in one decade. That's how fast this thing warmed up.
Speaker 3: Yeah, that's super quick. And again, you know, whenever you
Speaker 3: talk about this kind of stuff, you gotta zoom out
Speaker 3: and look at it from a sort of macro point
Speaker 3: of view. But yeah, that's super fast and got super
Speaker 3: hot and also super cold. Previously during the YDS, which
Speaker 3: was named, by the way, after flower the driest octopus octapitala. Yeah,
Speaker 3: nailed it. And the odd thing about this flower and
Speaker 3: why they named the YDS after it is that it
Speaker 3: thrives in cold Arctic regions. Is one of these flowers
Speaker 3: that loves the ice kind of the mountains of Scandinavia.
Speaker 3: In the late eighteen hundreds, like the eighteen seventies, Swedish
Speaker 3: scientists were studying clay deposits that they discovered, and they
Speaker 3: discovered this flower and they were like, this flower shouldn't
Speaker 3: be here between these layers of clay. It was deposited
Speaker 3: by melting glaciers. But like, none of that makes any sense, no.
Speaker 2: Because you've got clay from melting glaciers above it and
Speaker 2: clay from melting glaciers below this flower, and this flower
Speaker 2: thrives in temperatures where the glaciers are not melting at all,
Speaker 2: So it was a huge mystery. And then what made
Speaker 2: it even more mys serious is that was confirmed by
Speaker 2: other clay deposits elsewhere in Scandinavia. So there was definitely
Speaker 2: something weird going on. And they named it younger Dryis
Speaker 2: because there actually have been older dryis before. Yeah, that
Speaker 2: was not nearly as much of a bizarre freak as
Speaker 2: the Younger Dryas was.
Speaker 3: That's right. So we got the O D, we got
Speaker 3: the Y D. Should we take a break? Yeah, that
Speaker 3: sounds like a pretty good time for a break. Yeah, yeah, yeah,
Speaker 3: all right, we'll be right back.
Speaker 4: Jok, Mad, Josh, stop, you should.
Speaker 2: Know, so, Chuck, we've been talking like pretty big shots,
Speaker 2: pretty confident here right.
Speaker 3: Now, a couple of tough guys exactly.
Speaker 2: And the reason why we're doing that is because of
Speaker 2: ice core samples a lot from Greenland, also from Antarctica,
Speaker 2: and sedimentation from high altitude European lakes. That's why we're
Speaker 2: talking so tough right now.
Speaker 3: Yeah, And those are big deals. You can find out
Speaker 3: a lot from an ice core. You can find out
Speaker 3: like basically what it accumulated there, like stuff that the
Speaker 3: wind blew in there from other places. You know, they've
Speaker 3: got these little little bubbles in that ice, and you
Speaker 3: can trace gases even that were present back then and
Speaker 3: compare to like other parts of the world at that time,
Speaker 3: and like, oh, well they have these gases here, we
Speaker 3: have this sediment here, We have a distinct lack of
Speaker 3: pollen for this period here, which means like probably a
Speaker 3: lot of plant life was killed off and stuff like that.
Speaker 3: And then the lake stuff is super valuable too, right.
Speaker 2: Yeah, because constantly sediment is accumulating at the bottom of
Speaker 2: a lake, and very similar stuff's getting trapped down there,
Speaker 2: like air bubbles, soot, pollen, all that stuff, and it
Speaker 2: just gets deposit a year after year, and you can
Speaker 2: actually date that stuff. You can take a sample of
Speaker 2: a lake bottom and date that and then see what
Speaker 2: was going on around the lake at that time too.
Speaker 2: And lakes are advantageous because they're all over the world.
Speaker 2: Ice shelts and glaciers are not all over the world,
Speaker 2: so you're limited from where you can take ice cores.
Speaker 2: And then also lakes can last like thousands of years,
Speaker 2: whereas if you're reading tree rings, you're reading maybe decades,
Speaker 2: maybe a century or two worth. A lake it's going
Speaker 2: to give you way more than that. So it's pretty
Speaker 2: clever the way that they can take this stuff not
Speaker 2: only figure out when this sediment deposit or this ice
Speaker 2: deposit was put down, but also like a lack of
Speaker 2: pollen or what type of pollen means for like the
Speaker 2: world at large at the time. I just think that's
Speaker 2: pretty cool that humans are able to do that, and
Speaker 2: they don't seem to just be making this.
Speaker 3: Up, you know, a very niche nerdy stuff. You should know.
Speaker 3: A T shirt could just be uh lake bottom greater
Speaker 3: than simple tree ring.
Speaker 2: That's a super nerdy. I think that would actually offset
Speaker 2: the be dumb and happy one that you got generated.
Speaker 3: I think so. But just you know, you walk around
Speaker 3: like Comic Con and somebody will say, I know exactly
Speaker 3: what you're doing, buddy.
Speaker 2: And they'll they'll just silently walk past you and give
Speaker 2: you the high five and the low five without stopping.
Speaker 3: Right, but it'll be a sort of a nerdy. They'll
Speaker 3: miss the high five won't be quite right. They'll try
Speaker 3: and fist bump you when you put up your hand or.
Speaker 2: Right, or they lock fingers with you on the lof
Speaker 2: and you guys keep trying to.
Speaker 3: God, that's gotta be the worst. I thought the fist
Speaker 3: bump in the hand together was the worst. But when
Speaker 3: you high five and someone holds on and locks fingers.
Speaker 2: Yeah, so weird.
Speaker 3: Oh goodness, I don't know why I think of Oprah
Speaker 3: Winfrey when does she? Has she ever done that?
Speaker 2: I think she likes to raise people's hands, like they
Speaker 2: just want a boxing match or something.
Speaker 3: All right, so we're settling into the YD. I mentioned
Speaker 3: earlier that the northern hemisphere was one that was really
Speaker 3: affected the most, especially around the North Atlantic. The southern hemisphere.
Speaker 3: We'll talk about some weird abnormalities there as well. But
Speaker 3: these ice sheets advanced across the Arctic seed just like
Speaker 3: they did during the Old LGM, the last Glacial maximum?
Speaker 3: Is it glacial or glacial?
Speaker 2: Oh? I don't know. It depends on whether you say
Speaker 2: potato or patata.
Speaker 3: Yeah, I guess. So the Rockies here and what would
Speaker 3: later be the United States expanded, the Alps expanded. They
Speaker 3: found very weird things like penguin like creatures in southern Italy.
Speaker 3: Like things were getting really out of whack again, and
Speaker 3: everyone back then was like WTF.
Speaker 2: Yeah, and the like, even if you weren't living in
Speaker 2: an iced over area, you know, basically due south of
Speaker 2: that was tundra, like so western Europe, which is nice
Speaker 2: and verdant in lush right now, So it was tundra
Speaker 2: at the time. You got grasses, maybe a fox or
Speaker 2: two if you're lucky and you're bored just looking around,
Speaker 2: because it's not the most pleasant landscape to look at.
Speaker 2: I remember humans are running around at this time. I
Speaker 2: think we shrunk tremendously as a population, down to maybe
Speaker 2: the highest estimate I saw was around ten million people
Speaker 2: across the entire planet at this time.
Speaker 3: That sounds nice.
Speaker 2: Actually we kind of talk about Elba room. But all
Speaker 2: the plants and animals that had started to thrive in
Speaker 2: the middle in between the ice age and the YD
Speaker 2: they died back. And all the animals and plants that
Speaker 2: had died back during that innerstodial period they came roaring
Speaker 2: back and they were like, we loved we love the YD.
Speaker 2: We're happy again.
Speaker 3: Yeah, for sure. I mentioned the pollen retreating being evidence
Speaker 3: of like you know, the tree cover going away, and
Speaker 3: they found evidence of that an ice core once again.
Speaker 3: This is in the Hulu Cave and chin and it showed,
Speaker 3: you know, a drastic reduction in tree pollen, which you know,
Speaker 3: basically you can infer that like, yeah, a lot of
Speaker 3: trees died out during this icy period.
Speaker 2: Right, And from that you can also infer that there
Speaker 2: was probably less rain because trees helped generate clouds and
Speaker 2: they also helped keep the planet warm. So it was
Speaker 2: obviously a lot colder and a lot drier. That was
Speaker 2: the two characteristics of the YD And then, like you said,
Speaker 2: the southern hemisphere experienced something radically different, right, So remember
Speaker 2: northern Europe is covered in ice again, it's tundra right
Speaker 2: below that. And then if you go down to Antarctica,
Speaker 2: they basically hand you like a lay and a Hawaiian
Speaker 2: shirt and like my tie.
Speaker 3: Yeah, it's so crazy. When I was going through this stuff,
Speaker 3: that to me was like the big reveal. I mean,
Speaker 3: I would I'm a big dummy when it comes to
Speaker 3: this stuff. So I just figured that would have been
Speaker 3: even colder and even worse. But tmperatures actually rose in
Speaker 3: the Southern Hemisphere, and a lot of the Southern Hemisphere
Speaker 3: became warmer and wetter, and the sea surface temperatures increased
Speaker 3: in the Caribbean and the tropical Pacific. In the mountains
Speaker 3: of New Zealand that saw warmer conditions, so it was
Speaker 3: like everything was kind of upside down all of a sudden.
Speaker 2: Yeah, but you also mentioned earlier that it didn't happen
Speaker 2: there were weird pockets here there, which also goes to
Speaker 2: underscore how bizarre the younger dryest was like, there's a
Speaker 2: basin around Venezuela and it actually had temperatures drop. So
Speaker 2: this is the southern hemisphere, right, It saw a temperature
Speaker 2: drop of three degrees celsius five and a half degrees farentheight.
Speaker 2: And every time I see something like that, I'm like, so, like,
Speaker 2: that's not that big of a deal. Right, It turns
Speaker 2: out it is a really big deal. Even though to
Speaker 2: you an average winter temperature of fifty five going down
Speaker 2: to fifty doesn't sound all that bad, but climatologically speaking,
Speaker 2: any change in temperature, even by half degrees has really
Speaker 2: huge weather consequences oversay the course of a year. So
Speaker 2: in this case, dropping by three degrees celsius for five
Speaker 2: and a half degrees farentheight, it might not have seen
Speaker 2: that much temperature wise over an average winter, but it
Speaker 2: also opened up the door for way more freak weather,
Speaker 2: so they might have gone from like no blizzards whatsoever.
Speaker 2: Maybe one blizzard a year, two three blizzards a year,
Speaker 2: and that definitely impacts local conditions in the life there.
Speaker 2: So it makes a really big difference, even when you
Speaker 2: see little changes to average temperatures.
Speaker 3: Yeah, for sure, there were likely some animal extinctions happening.
Speaker 3: You mentioned the amount of humans, which was at a
Speaker 3: you know, probably at an all time high at this point,
Speaker 3: started going back lower and lower. Their available food was
Speaker 3: getting slimmer and slimmer. We mentioned they were dabbing their
Speaker 3: toe in the pond of kind of settling down a
Speaker 3: little bit and not hunting and gathering and traveling everywhere,
Speaker 3: and all of a sudden they had to pack it
Speaker 3: up and start moving around again to try and find
Speaker 3: food again.
Speaker 2: Yeah, and the evidence that people, the human population contracted,
Speaker 2: meaning there was a lot of die off. It shows
Speaker 2: up in archaeological sites like the Herrinsburg culture in present
Speaker 2: day Germany, Austria and Belgium. During the YD the archaeological
Speaker 2: sites dropped by half compared to what they had been
Speaker 2: just before the YD, which suggests that there are a
Speaker 2: lot fewer people, making a lot fewer camps or villages.
Speaker 2: And then also significantly in North America. This is when
Speaker 2: the very famous Clovis culture just disappears from the record too.
Speaker 3: CLOBs, we did a whole episode on the Clovis.
Speaker 2: Yeah, they used to pop up a bunch, Remember the
Speaker 2: whole Clovis first Police and all that stuff.
Speaker 3: Yeah, yeah, man, it speels like a thousand years ago.
Speaker 2: It really does. But so this is when they disappeared.
Speaker 2: And they don't think that the Clovis all just died off,
Speaker 2: but they think that these weather conditions and hardships for
Speaker 2: living basically just burst them and they started forming the
Speaker 2: prototypes to the bands of Native Americans that we see today.
Speaker 3: Yeah, for sure. Another interesting thing is in you know,
Speaker 3: sometimes in the times of trouble, there can be human
Speaker 3: advancement because you're struggling and need to think of better
Speaker 3: ideas on how to do what you're doing. And it
Speaker 3: seems like that might have happened with the hunting because
Speaker 3: the animals are more scarce, hunting is harder, the game
Speaker 3: is just not around. So this is where we saw
Speaker 3: at least one thing that we think might have been
Speaker 3: in advancement was the Harriff Point h A r I F,
Speaker 3: which is basically a new and improved arrowhead came about,
Speaker 3: and they think it's probably because they were struggling and
Speaker 3: they needed to kill better.
Speaker 2: Yes, and it was quite an innovation because the raw
Speaker 2: heads they were using before were made of dandelion heads.
Speaker 3: I know, and those you know what, the animals loved them.
Speaker 2: They did. They was like shoot me again.
Speaker 3: Yeah, shoot one of those, my way.
Speaker 2: I could use a laugh, right and then also chuck.
Speaker 2: It helps that there were people dabbling in agriculture before
Speaker 2: the yd came along, because it seems to have given
Speaker 2: the people related to them a bit of a leg up,
Speaker 2: like they didn't have to figure out agriculture from scratch
Speaker 2: under these conditions. So in pockets where there was vegetation
Speaker 2: and a decent amount of game, people did settle down again.
Speaker 2: In those areas. There's a place called the Zagros region,
Speaker 2: which is in modern Iran, which shows settlements that were
Speaker 2: basically probably not just hunting camps. They were probably permanent
Speaker 2: or semi permanent settlements. So people did like sit down
Speaker 2: where they could and set up shop. And as a
Speaker 2: matter of fact, some people say, okay, people were kind
Speaker 2: of dabbling in agriculture before, but it was just dabbling,
Speaker 2: and in fact that culture might not have been passed along.
Speaker 2: It is possible that the younger dryas did force humans
Speaker 2: to basically adopt agriculture, because again, remember, conditions are so
Speaker 2: terrible that whatever leg up you a human can give
Speaker 2: to this plant that you're going to eat later is invaluable.
Speaker 2: So that's basically what agriculture is is helping plants along
Speaker 2: to make them grow better.
Speaker 3: Yeah, and you know that became a challenge in a
Speaker 3: lot of ways, not just because the ice, but they
Speaker 3: found once again in those ice deposits or the ice cores,
Speaker 3: they found air bubbles with a noted decrease in concentration
Speaker 3: of CO two in the atmosphere. Yeah, and so all
Speaker 3: of a sudden, these wild cereals that are growing their
Speaker 3: yields are going to be way down. And you know,
Speaker 3: they had some, you know, for the time, some fairly
Speaker 3: advanced agriculture burgeoning there. They like pest control and like
Speaker 3: watering things, weeding things, transplanting things.
Speaker 2: The basics.
Speaker 3: Yeah, they're very basics, but that's you know, the very beginnings.
Speaker 3: And yeah, this put a big sort of stop sign
Speaker 3: in front of all of that.
Speaker 2: Yeah, Like imagine being the guy who is watching the
Speaker 2: other guy pour water out of his gazelle flask. Yeah,
Speaker 2: unto like a like a yeah, like some wheat, Like
Speaker 2: what are you doing? And they'd say, just just watch,
Speaker 2: just give me a couple of thousand years and you're
Speaker 2: to be blown away.
Speaker 3: Yeah, you want this water to be beer one day,
Speaker 3: fella exactly. Let me pour it on this this grain.
Speaker 2: And then it magically turns into beer.
Speaker 3: Oh man, shall we take another break?
Speaker 2: I think we shall chuck.
Speaker 4: Chalk had Josh stop.
Speaker 1: You should know, all.
Speaker 3: Right, we should talk a second about something called solar insulation,
Speaker 3: not insolation, insolation with an O. And this is how
Speaker 3: much solar warmth reaches the Earth's upper atmosphere, and the
Speaker 3: basic pattern of you know, warming the globe is driven
Speaker 3: by this, and the younger dryest is definitely like this
Speaker 3: weird exceptional pocket that stands out. And because of this,
Speaker 3: everyone you know that nerds out on this kind of
Speaker 3: stuff was like, well, we got to figure this out,
Speaker 3: I mean, why did this happen? And they have emerged
Speaker 3: with four main hypotheses. The one that has the most
Speaker 3: traction we're going to start with is the melt water
Speaker 3: interrupting thermohaline circulation, and that sounds very sort of like
Speaker 3: sciencey and nerdy and like guys. I hope you explained this,
Speaker 3: but it's really very simple. It's that a bunch of
Speaker 3: water disturbed the cycle of the warming cycle of the
Speaker 3: ocean very very quickly.
Speaker 2: Yeah, specifically in the North Atlantic, which has this thing
Speaker 2: that you mentioned, the thermohaline circulation, which is where warm water
Speaker 2: warm by surface air on top of the ocean falls
Speaker 2: down into the deep water and as it does it
Speaker 2: it displaces the cold water which comes up to the
Speaker 2: top and gets warmed itself. Then it sinks and the
Speaker 2: cycle just keeps going on and on. Right, This is
Speaker 2: how warmth is delivered to the north, the northern hemisphere,
Speaker 2: right those It moves northward, so the warmer sea water
Speaker 2: is always moving toward the north, so it's delivering warmth.
Speaker 2: And at the same time that cold water upwells in
Speaker 2: the southern hemisphere, so it delivers cold to the southern hemisphere,
Speaker 2: which is why under normal conditions with the thermohaline circulation,
Speaker 2: the Antarctica is cold, and comparatively speaking, the northern hemisphere
Speaker 2: is warmer.
Speaker 3: That's right, all right, So park that in your brain
Speaker 3: and then understand that North America at the time had
Speaker 3: this huge seven hundred mile by two hundred mile lake
Speaker 3: called Lake Aga Seas. I guess sure a gasses if
Speaker 3: you're an Andreagacy fan. It developed as the Laurentide ice
Speaker 3: sheet and extended down to the Great Plains and blocked
Speaker 3: the Great Lakes and all the rivers that were flowing
Speaker 3: there backed up, and it formed this big natural reservoir
Speaker 3: that was seven hundred by two hundred miles big. And
Speaker 3: this theory holds. The meltwater theory holds that as that
Speaker 3: last glacial maximum warmed things up, that ice sheet retreated,
Speaker 3: the block passage to those Great Lakes opened up, and
Speaker 3: all of a sudden, billions and billions of gallons of
Speaker 3: freshwater make its way down to the North Atlantic. They
Speaker 3: think a similar sort of thing happened in the Nordic region.
Speaker 3: But you're like, all right, so that makes sense, But
Speaker 3: was this water like super cold or something. It was cold,
Speaker 3: but the main thing it did was desaliinate that upper
Speaker 3: ocean water, right.
Speaker 2: Yeah, And so fresh water is less dense than seawater,
Speaker 2: and so a bunch of fresh water mixed in with
Speaker 2: seawater makes it less dense than it normally would be.
Speaker 2: And it needs to be dense to fall down to
Speaker 2: the deep ocean, which makes the other deeper water come
Speaker 2: back up, right. Yeah, So that means that the thermohaline
Speaker 2: circulation is interrupted. And if you have an interruption in
Speaker 2: the thermohaline circulation, it just stops moving. Like that, you
Speaker 2: would expect to see the Northern hemisphere get cold because
Speaker 2: there's warmth is not being delivered there any longer. You'd
Speaker 2: also expect to see Antarctica warm up because that cold
Speaker 2: deep ocean water is not welling up around the very
Speaker 2: southern southern hemisphere. And that's exactly what you see with
Speaker 2: the younger dryas. It's a really beautiful, elegant explanation that
Speaker 2: I think was hypothesized in nineteen eighty two and up
Speaker 2: until very very recently, you were a fringy nut if
Speaker 2: you believed anything besides that as the explanation for where
Speaker 2: the younger Dryest came from.
Speaker 3: Yeah, I mean, it makes sense to me. But that's
Speaker 3: why I love science, is people keep poking around and
Speaker 3: the fringe nut maybe one day is proven somewhat right,
Speaker 3: and that well, I still think that the meltwater is
Speaker 3: probably the reason why, but one of the other hypotheses
Speaker 3: is the impact hypothesis, and that is, like you said,
Speaker 3: it was pretty controversial until more recently it has gained
Speaker 3: a little bit of traction because some things do kind
Speaker 3: of add up. But the idea here is that a
Speaker 3: meteorite or a comet or something impacted the Earth, maybe
Speaker 3: an air burst even, and that released the thermal pulse
Speaker 3: that kind of set the world on fire. Almost like
Speaker 3: all these massive wildfires across all the continents. The air
Speaker 3: spieled with soot. It's blocking sunlight, and in fact there's
Speaker 3: so much soot there's atmospheric dusts such that you reduce
Speaker 3: solar radiation, and all of a sudden you have what's
Speaker 3: called an impact winter or you know, kind of like
Speaker 3: the idea of a nuclear winter.
Speaker 2: Yeah, basically the same exact result, but just it was
Speaker 2: different things that got us there. Right, So there's evidence
Speaker 2: for this that most people point to is like, this
Speaker 2: is pretty good evidence. There's something called a black mat,
Speaker 2: which is a layer of carbon matter that seems to
Speaker 2: be a soot deposit that you find all over North
Speaker 2: America and in parts of Europe, and all that suggests
Speaker 2: that there were wildfires going on on different continents at
Speaker 2: the same time, which would suggest like some sort of
Speaker 2: massive common or meteorite bursting and setting off this thermal pulse.
Speaker 2: So the fact that those things coincide on two different
Speaker 2: continents with the onset of the Younger Dryest has definitely
Speaker 2: made the impact hypothesis much more popular than it was before.
Speaker 2: One thing detracting from it that probably makes some legitimate
Speaker 2: scientists weary of embracing it publicly right now is the
Speaker 2: writer in Science, contrarian Graham Hancock latched onto the impact
Speaker 2: hypothesis because he has this theory, I guess you could
Speaker 2: call it that that there was an ancient apocalypse around
Speaker 2: the time that the Younger Dryest happened, that wiped out
Speaker 2: massively advanced civilizations that we don't even know it really existed,
Speaker 2: and reset humanity and then we had to rebuild from there.
Speaker 2: And there's not a lot of evidence, if any, for
Speaker 2: this stuff. It's really really fascinating, but the evidence we
Speaker 2: do have, the scientific evidence we do have, doesn't set
Speaker 2: that up. But anyway, he basically said, see this impact
Speaker 2: hypothesis supports my idea that there was an ancient apocalypse,
Speaker 2: and scientists tend not to agree with Graham Hancock munch. Yeah.
Speaker 3: And the other thing. There's a couple of more smaller
Speaker 3: points that might support this one, as there was a
Speaker 3: platinum spike in South Africa that preceded the YD and
Speaker 3: in some other places, and platinum is you know, a
Speaker 3: lot of time within meteorites, so maybe some support there.
Speaker 3: And also sometimes people kind of combined the first one
Speaker 3: and say maybe there was an impact combined with this
Speaker 3: meltwater thing. So there was a low atmospheric explosion over
Speaker 3: North America and that's what released all this meltwater all
Speaker 3: over the place.
Speaker 2: Yeah, which makes sense. It's basically like handing in all
Speaker 2: of branch from one hypothesizer to another. You know, let's
Speaker 2: put it together.
Speaker 3: Yeah, let's go get a drink and just settle it.
Speaker 2: Also, as an aside for remember our Gooblacky Teppee episode.
Speaker 2: Oh yeah, it's been a while, I don't remember exactly
Speaker 2: how to pronounce it, we talked about how there was
Speaker 2: this guy who also kind of fringely concluded that some
Speaker 2: astronomical engravings at the site recorded the comet or the
Speaker 2: meteorite burst that happened at this time, which is kind
Speaker 2: of cool. But again, there's not a lot of evidence
Speaker 2: to moving on. There's a couple of other explanations that
Speaker 2: don't have nearly as much traction, but they do make sense.
Speaker 2: One is a supernova explosion. Supposedly a star went supernova
Speaker 2: in the Vela constellation at the right time that could
Speaker 2: have affected Earth by burning away its ozone layer, which
Speaker 2: would cool the upper stratosphere, which is the second most
Speaker 2: layer above Earth, which would prevent it from holding much
Speaker 2: water vapor. Water vapor is a greenhouse gas, and without
Speaker 2: a very strong greenhouse gas in the atmosphere, heat would
Speaker 2: just go out into space much more easily from Earth
Speaker 2: and it would get cooler as a result. The problem
Speaker 2: with this one that I have is wouldn't that happen
Speaker 2: all over the planet if the ozone layer was burned
Speaker 2: away by a supernova? I think so, So I'm gonna
Speaker 2: I'm gonna toss that one.
Speaker 3: Okay, Yeah, nailed it. The last one is another sort
Speaker 3: of example where the Sun is blotted out, so there's
Speaker 3: a massive drop in temperature very quickly, But this time
Speaker 3: it is because a volcano erupted. A massive volcano. This
Speaker 3: is the Locker C volcano, not ce A. I'm sorry,
Speaker 3: se A, but see, because we all know that Germany
Speaker 3: doesn't have any water, right.
Speaker 2: Well, it's it's laying locked.
Speaker 3: Yes, yeah, but this is a German volcano. Of course
Speaker 3: we're kidding. That's a reference to an older episode. We
Speaker 3: know all about the Black Sea to hold your emails.
Speaker 3: But this volcano, it was definitely a mega eruption. It
Speaker 3: spewed six point three I mean, what is that? Even trillion?
Speaker 3: What is that?
Speaker 2: That's a cubic kilometers.
Speaker 3: So three million cubic kilometers, No.
Speaker 2: Six point three cubic kilometers.
Speaker 3: It's to the third power though.
Speaker 2: No, so that that's what makes a cubic So if
Speaker 2: you took a kilometer of way.
Speaker 3: Oh yeah, yeah, yeah.
Speaker 2: And you made it square, and you did six point
Speaker 2: three times, and then you also made it a kilometer tall,
Speaker 2: a cube that's six point three kilometers on each side.
Speaker 2: Just of magma got released from that volcano. It was
Speaker 2: a massive eruption.
Speaker 3: Yeah, I just added myself in a mathematical way.
Speaker 2: Well, finally you did. I'm the one who does it
Speaker 2: all the time.
Speaker 3: Well, comparatively speaking, Mount Saint Helens released one cubic kilometer.
Speaker 3: Vesuvius was three and this was six point three. So
Speaker 3: the other interesting thing about this one is volcanoes can
Speaker 3: produce platinum, Yeah, or at least you know, part of
Speaker 3: like groups of platinum metals, and that could account for
Speaker 3: that spike we talked about in South Africa.
Speaker 2: Yes, and so the volcanic eruption hypothesizers frequently say, hey,
Speaker 2: how about this. A volcano erupted and attracted a comet
Speaker 2: that blew up over North America, which kicked off the
Speaker 2: melting of the ice caps, which caused circulation problem. Yeah,
Speaker 2: and then the supernova. Person like, what about me, and
Speaker 2: they're like, sorry, you're not.
Speaker 3: They were dismissing exactly, all right. So that was the YDS.
Speaker 3: I guess we could talk a little bit about what
Speaker 3: happened afterward. Afterward is where we are, the Holycene period,
Speaker 3: and that was when the climate finally worked itself out,
Speaker 3: that pendulum stopped swinging and things started warming up and stabilizing,
Speaker 3: and you know, people started thriving again. The animals came out,
Speaker 3: the birds started chirping, the bees started pollinating, and we
Speaker 3: and it led to you know, the not the modern
Speaker 3: modern era, but just you know, what we know now
Speaker 3: is planet Earth.
Speaker 2: Yeah, the beginnings of our era all find its roots
Speaker 2: in this this time, like, this is where agriculture developed,
Speaker 2: this is where civilization first developed. Writing came along a
Speaker 2: few thousand years later. I mean, all of this happened
Speaker 2: in a really short period of time, Like essentially everything
Speaker 2: that has to do with like human civilization began in
Speaker 2: the ten thousand years immediately following the Younger Dryas.
Speaker 3: Yeah, I mean the current shape of our planet happened
Speaker 3: after the Younger Dryas, Like the way the coastlines were shaped.
Speaker 3: I mentioned the Rockies and the Alps, you know, those
Speaker 3: mountain ranges all over the world. Even they I was
Speaker 3: about to say, took their final shape that of course
Speaker 3: that's not true, but took the shape that we know
Speaker 3: and love today.
Speaker 2: Yeah, And that's actually one reason why it's difficult to
Speaker 2: track what humans were doing during the Younger dryat because
Speaker 2: the settlements that they had that were closer to the
Speaker 2: coastline than are now under hundreds of feet of ocean
Speaker 2: water and are probably just totally destroyed. So we lost
Speaker 2: a lot of archaeological sites because of that sea level arise.
Speaker 2: But it was a trade off because again we have writing.
Speaker 3: Yeah, that's right, and those wild cereals that we talked
Speaker 3: about that we're having such a hard time, you know,
Speaker 3: became Captain Crunch.
Speaker 2: Yeah, and really, hey, is there anything more you need
Speaker 2: to prove that humans have reached peak civilization than that?
Speaker 3: I don't think.
Speaker 1: So.
Speaker 2: Okay, well, I guess that's it for the YD, right, Chuck.
Speaker 3: That's it for now. I mean, who knows what's ahead?
Speaker 2: Well? Put? And because Chuck said who knows what's ahead,
Speaker 2: truly it's time for listener mail.
Speaker 3: This is called birthmark episode because I think that might
Speaker 3: have been a selector. Maybe Patrick just listened to it again.
Speaker 3: I think, so that's what happened. Hey, guys, listen to
Speaker 3: that episode again recently? Because I have a birthmark that
Speaker 3: makes me perpetually look like I have a black eye.
Speaker 3: On a regular basis, someone will ask me some variation
Speaker 3: of like who punched you? What happened in your face?
Speaker 3: I used to enjoy giving a clever story as a
Speaker 3: way to mess with them, like getting kicked out of
Speaker 3: a nightclub or squaring off with a bear, But I
Speaker 3: started to feel bad for lying, even to my friends,
Speaker 3: even if only for a minute. So now I usually
Speaker 3: just take the boring route and explain that it's a birthmark.
Speaker 3: It's just subtle enough that friends can go years without
Speaker 3: noticing it even but once it's brought to their attention,
Speaker 3: they can't unsee it. Many don't believe me when I
Speaker 3: tell them it's just a birthmark, and they think I'm
Speaker 3: trying to cover something up. My mom even told me
Speaker 3: that she was interrogated when I was a child by
Speaker 3: doctors wow, and would get dirty looks from other parents
Speaker 3: when they notice a mark on my face, And I
Speaker 3: feel bad that her experience of my birthmark has never
Speaker 3: been as fun as mine. Anyway. Ever since my wife
Speaker 3: Christine introduced me to your show about nine years ago,
Speaker 3: stuff you should know has been a staple for us
Speaker 3: during house chores and road trips. Your chemistry together is
Speaker 3: very comforting, and we especially like hearing Josh make Chuck laugh.
Speaker 3: Do it right now, Hot Patata. That actually worked. I
Speaker 3: was like, I'm gonna have to fake a laugh here,
Speaker 3: but you got me.
Speaker 2: Awesome.
Speaker 3: Keep up the great work, guys. Thanks for making the
Speaker 3: two of us smile again and again and again. We've
Speaker 3: made them smile three times. All the best from Troutdale, Oregon.
Speaker 3: That is Patrick Burton.
Speaker 2: Awesome, Patrick, Thank you for that. Patrick and his wife Christine, right, yep.
Speaker 2: So thanks to you both, and Patrick, I have to say,
Speaker 2: if you're going to have a birthmark that's not in
Speaker 2: the shape of Abraham Lincoln, now the place that you
Speaker 2: have it is about as cool as it can be.
Speaker 1: I agreed.
Speaker 2: If you want to be like Patrick and Christine and
Speaker 2: let us know how long you've been listening to us
Speaker 2: and what you think, hopefully it's generally positive, you can
Speaker 2: send us an email to send it off to stuff
Speaker 2: podcast at iHeartRadio dot com.
Speaker 3: Stuff you Should Know is a production of iHeartRadio. For
Speaker 3: more podcasts my heart Radio, visit the iHeartRadio app, Apple Podcasts,
Speaker 3: or wherever you listen to your favorite shows.