Stuff You Should Know - [Insert Your Own Catchy Title About Younger Dryas Here]

Episode Date: October 21, 2025

Quick, name your favorite geological mystery. You can’t do it! Well, don’t worry. In this episode we’re going to tell you all about what will surely be your favorite (albeit only) one when we get into one weird millennium that happened not that long ago.See omnystudio.com/listener for privacy information.

This is an I-Heart podcast. Samihante, it's Anna Ortiz. And I'm Mark and Delicado. Might know us as Hilda and Justin. From Ugly Betty. Welcome to our new podcast. Viva Betty! Yay!

We're re-watching the series from start to finish. And talking to iconic guests like Betty herself, America Ferreira. There was this moment when the glasses went on and it was like, this is our Betty. Listen to Viva Betty on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. What's up, everybody? It's snacks from the trap nerds and all October long. We're bringing you the horror. We're kicking off this month with some of my best horror games to keep you terrified. Then we'll be talking about our favorite horror in Halloween movies and figuring out why black people always die further. And it's the return of Tony's horror show, SideQuest written and narrated by yours truly.

We'll also be doing a full episode. reading with commentary and we'll cap it off with a horror movie battle royale open your free iHeart radio app and search trap nurse podcast and listen now welcome to stuff you should know a production of iHeart radio hey and welcome to the podcast i'm josh and there's chuck and jerry's here too and this is stuff you should know and what we've got on our hands today chuck is a high A Hot Potato of a Real Deal Geological Mystery. Hot potato? Mm-hmm.

That's how Emily's family says potato. I think I would only say it when it's preceded by hot. I would only say it like, I wouldn't say it, I'm going to have a baked potato. Like, you'd be out of your mind to say it like that. Nor would you say a hot potato. Like, what a square. Yeah, that is pretty square, isn't it? Get the stick out of your butt, fella, loosen up.

Right. Loosen up. Get the cardigan. out from around your shoulders. Yeah, geez. So that was obscure, but still. So, like I said, this is a mystery today. And just to give a brief brush stroke overview with the widest brush,

real lot of space in between bristles, just barely any paint on it, that kind of overview. Oh, wow. What we're talking about is something called the Younger Dryas, which is a pretty, it's a pretty terrible name for this if you want to be catchy, right? I mean, I think a lot of people will probably say WTF. Right. Well, let's just call it the YD

if we're going to put initials on things. How about that? Or abbreviate things. So the YD, the younger dryness, is this surprising, shocking period in Earth's history, fairly recent history, where we came out of the last Ice Age,

everything was going smoothly, and then bam, we got hit by another Ice Age out of nowhere. That lasts for over a thousand years, and then, bam, it goes away just as fast as it came along. And paleo-geologists, paleo-climatologists, all the paleos are perplexed as to what caused it, and then why it stopped so suddenly, too. That's why I said it is a real deal geological mystery. Yeah, and a time, as we'll see, where the earth and its inhabitants and animals and, um, nature was all going like, all right, thank God, we can finally get down to business and start

being an earth, like a legit earth. And then, you know, the YDs come along and say, not so fast. Right. And you call it a legit earth because when it finally ended, and actually that period in between the last Ice Age and the YD, those are like really habitable for human beings. Like, we love those kind of conditions, so much so that after the YD ended, it became the age of humans. Yeah. Like, this is the age where we began our civilizations. We started farming. We began to flourish as a species and basically take over the planet.

And what's interesting is, this is the most recent ice age. There have been seven in Earth's history. And just as an aside, this was the Wisconsinian Ice Age that we're talking about. The last one was 250 million years before, right? So it was pretty significant that we just, geologically speaking, came out of an ice age because there's not that many. And then not coincidentally, when the second to last ice age ended, that opened the door for the dinosaurs to come along and take over the earth.

So big things happen when an ice age changes. So for it to switch back to an ice age all of a sudden and then switch back to nice and temperate for us humans, it is just very weird. It was actually, I've seen it described as an extreme weather millennial event. Yeah, and you know, it kind of made me wonder, had this not happened, because we were sort of headed toward, you know, legit Earth, like I said, before, you know, I mean, it would obviously wouldn't change the year, but let's say as far longness goes, we would be like the year 3,000 something. Right. Like, would we be just, that much further along as a planet? Or would we be nowhere because in a thousand years we will

have already destroyed ourselves? The second one. Okay. All right. So it's a good thing this happened or we wouldn't be talking about it right now. Exactly. That's exactly right. So, yeah, that's a really anthropic way of looking at it. Well, speaking of, I bought a copy of if anyone builds it, everyone dies, the Eliezer-Yukowski-Nate Sora's book that just came out. Okay. It did not know about it. You say that as if it was just on the tip of my tongue, which I appreciate. No, you do. Remember, I basically mischaracterized it in the Zizian's episode and had to leave that book, right, about building AI. And if anyone builds it, then we're all going to die. Like, just the existential threat of AI. It is really good. You could read it in, if you had a day

that you could dedicate to reading it, you could read it in a day. It's really popularly written. Lots of really cool anecdotes. It's just very good. So I strong. recommend that book. Great. Okay, so let's kind of just back it up a little bit and go to the previous Ice Age, the Wisconsinian Ice Age, and talk about what Earth looked like, like that. Yeah, so it was very icy. There were huge ice sheets covering a lot of Earth, like most of North America, Northern Europe and Asia, and as we'll see, a lot of the YD has affected the northern hemisphere, much more than the southern, but also weird things happen in the southern hemisphere that don't quite jive. That's why it's such a kind of a strange mystery. But lots of ice

everywhere. We had barren plains, very harsh conditions. We had things like, you know, woolly mammoths, like ice-loving creatures dwelling the earth and, you know, human populations that were sparse and scattered and constantly kind of moving around trying to survive. Right. And so that the last ice age, started about 100,000 years ago and it took about 80,000 years to reach its peak point. So 20,000 years ago, it hit what's called the last glacial maximum, right?

So it took 80,000 years to get there and then 10,000 years to basically melt. It melted a lot faster than it developed. And just, like, right after it peaked, it just started warming up. And it took about

9,000 years and all the ice sheets, all the glaciers, all the stuff that was covering Earth and keeping it in an ice age just basically went away and Earth just blossomed into a version that we like. Yeah, and it became, you know, not terribly unlike what we're looking at now. There was a jump in temperatures that was, you know, kind of close-ish to today. And this was called the, and I never know how to pronounce. It's an umla. Is it really? Yeah, I'm, that's all it is. Yes. So all of our Nordic friends, the circle with the forward slash through or the O with the forward slash through?

That's an umlaught, right? Okay, I mean, I guess we call it the null set because it looks like a zero with a slash through it. So call it that? I mean, we don't really call it that, but that's what it looks like. Pronounce it like that. All right, what, with the umlao? No, the null set.

No. I would know how to do that. With the umlaut, I guess my best stab would be the Burling Alarud interstadial. I think you nailed it. All right. A lot more rain. We achieved a sea level that's not what we have today, but about half of what we have today.

With that rain, obviously, you're going to get a lot of plants. The woodlands are thriving. Animals are now, you know, forest dwelling and walking alongside things like cave bears and woolly mammoths. And things are going pretty good. We have homo sapiens at this point or are the only humans that are around at this point. And they're like, they're loving life, man. They're saying, all right. we can travel a little bit more, and as we'll see, you know, kind of dabble, stick their toe in settling here and there.

Yeah, this was actually right before this was the point when people from Eurasia migrated into North America. So this was the point where they were cut off. They couldn't go back. There was no going back. They were in North and South America now because the Bering Land Bridge was covered up by those rising sea levels, which turned it into the Bering Sea. And this time, so remember we're talking about this little period. after the end of the Ice Age, before the YD comes along, where everything seems to be going smoothly for humans,

this is where we started taking our first stabs at agriculture. We're just like, let's try something new. We just came out of an Ice Age. Let's just get as funky as we can with it. And we're going to basically take some of that energy in that time that we dedicate to hunting and gathering and put it into farming. I just made that word up, but let's call it that.

from now on. They're like, what is farming? They're like, you're doing it right now, buddy. I see over there picking weeds. Exactly. And tending to those wild plants. And that's basically the, you know, kind of, I guess the argument for the beginning of agriculture, at least, right?

Yeah, where we basically said, that's a good looking plant. Let's just try to make that one grow as well as we can. That's right. So things are going along swimmingly. People are not moving around as much. They enjoy sitting for the first time. and things like that. And then all of a sudden, the YD comes along

and the glacial conditions return in the broad sense in a very quick way. I mean, how long did it take? I mean, the whole thing was like a thousand years, but we reached kind of close to that last glacial maximum in about 500 years. Yeah, I think by 100 years, it was really like in full swing.

And then, yeah, 500 years is basically like the ice age is back. I wonder if they were like, hey, does anyone think it's getting colder? Right. No, just keep farming and be quiet. Right, yeah, yeah, just keep planting those plants. We should also say Kyle helped us with this, and he said that the younger dryest came along and spoiled the party. That's truer than you would think, because right before this, in that Booling Olerod interstadial was when we started making beer, too. So that got disrupted as well.

Oh, we'd be so much drunker today. So another reason we would have wiped ourselves out in just one global bar fight, basically. Yeah. So this kicks off 1,300 years of really, really cold weather. And then all of a sudden it just stops. And it comes along, it like happened starting about 100 years, 500 years into it. It was really basically back to ice age conditions in a lot of places. But when it stopped, it swung back to nice and humid, even faster.

And there's actual ice cores from Greenland that show that Greenland, in 10 years, the average temperature increased by 18 degrees Fahrenheit, 10 degrees Celsius. That is insane. And for comparison, so the global warming that's going on today that scientists are quite concerned about and thinking people as well, that's a rise. of 2 degrees Fahrenheit, not 18 degrees Fahrenheit, 2 degrees Fahrenheit in about 20 decades. We're talking about 18 degree rise in one decade. That's how fast this thing warmed up. Yeah, that's super quick.

And again, you know, whenever you talk about this kind of stuff, you've got to zoom out and look at it from a sort of macro point of view. But yeah, that's super fast and got super hot. And also super cold previously during the YDs, which was named, by the way, after flower. the driest octopatala yeah nailed it uh and the odd thing about this flower and why they named the y ds after it is that it it thrives in cold arctic regions is one of these uh flowers that that loves the ice kind of the mountains of scandinavia and in the late 1800s like the 1870s

Swedish scientists were studying clay deposits that they discover and they discovered this flower and they were like, this flower shouldn't be here between these layers of clay. It was deposited by melting glaciers, but none of that makes any sense. No, because you've got clay from melting glaciers above it and clay for melting glaciers below this flower, and this flower thrives in temperatures

where the glaciers are not melting at all. So it was a huge mystery. And then what made it even more mysterious is that it was confirmed by other clay deposits elsewhere in Scandinavia. So there was definitely something weird going on, And they named it younger dryus because there actually had been an older dryus before. Yeah. That was not nearly as much of a bizarre freak as the younger dryus was.

That's right. So we got the O.D. We got the YD. Mm-hmm. Should we take a break? Yeah, that sounds like a pretty good time for a break, yay? Yeah. Yeah.

All right. We'll be right back. Chuck and Josh. Stuff You should know. Okay, friends, real talk. You are worth the wait. We've all been there,

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Start your love story on Bumble. Samihante, it's Anna Ortiz. And I'm Mark and Delicado. You might know us as Hilda. And Justin. Ugly Betty. We played mother and son on the show, but in real life, we're best friends. And I'm all grown up now.

Welcome to our new podcast. Viva Betty! Yay! Woo-hoo! Can you believe it has been almost 20 years? That's not even possible. Well, you're the only one that looks that much different. I look exactly the same.

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Drive safe, everybody. Don't drive distracted. A message brought to you by the National Highway Traffic Safety Administration, Project Yellow Light, and the Ad Council. So, Chuck, we've been talking, like, pretty big shots, pretty confident here, right? A couple of tough guys. Exactly. And the reason why we're doing that is because of ice core samples, a lot from Greenland, also from Antarctica.

and sedimentation from high altitude European lakes. That's why we're talking so tough right now. Yeah, and those are big deals. You can find out a lot from an ice core. You can find out, like, basically what it accumulated there, like stuff that the wind blew in there from other places. You know, they've got these little bubbles in that ice, and you can trace gases even that were present back then

and compare to, like, other parts of the world at that time. and like, oh, well, they have these gases here. We have this sediment here. We have a distinct lack of pollen for this period here, which means like probably a lot of plant life was killed off and stuff like that. And then the lake stuff is super valuable too, right? Yeah, because constantly sediment is accumulating at the bottom of a lake and very similar stuff's getting trapped down there,

like air bubbles, soot, pollen, all that stuff. And it just gets deposited year after year, and you can actually date that stuff. You can take a sample of the lake bottom and date that and then see what was going on around the lake at that time, too. And lakes are advantageous because they're all over the world. Ice shelves and glaciers are not all over the world. So you're limited from where you can take ice cores. And then also lakes can last like thousands of years, whereas if you're reading tree rings, you're reading maybe decades, maybe a century or two worth.

A lake, it's going to give you way more than that. So it's pretty clever the way that they can take this stuff. figure out when this sediment deposit or this ice deposit was put down, but also what like a lack of pollen or what type of pollen means for like the world at large at the time. I just think that's pretty cool that humans are able to do that. And they don't seem to just be making this up. You know, a very niche nerdy stuff you should know T-shirt could just be lake bottom greater than symbol tree ring. That's a super nerdy.

I think that would actually offset the be dumb and happy one that you got generated. I think so. But just, you know, you walk around like Comic-Con and somebody will say, I know exactly what you're doing, buddy. And they'll just silently walk past you and give you the high-five and the low-five without stopping. Right. But it'll be sort of a nerdy. They'll miss the high-five. It won't be quite right.

They'll try and fist-bump you when you put up your hand or something. Or they lock fingers with you on the lo-fi, and you guys keep trying to go in different direction. That's got to be the worst. I thought the fist pump and the hand together was the worst. But when you high five and someone holds on and locks fingers, it's not what you're after. It's so weird. Oh, goodness.

I don't know why I think of Oprah Winfrey when, does she, has she ever done that? I think she likes to raise people's hands like they just won a boxing match or something. All right. So we're settling into the YD. I mentioned earlier that the Northern Hemisphere was the one that was really, affected the most, especially around the North Atlantic. The southern hemisphere, we'll talk about some weird abnormalities there as well, but these ice sheets advanced across the Arctic Sea just like they did during the old

LGM, the last glacial maximum. Is it glacial or glacial? Oh, I don't know. Depends on whether you say potato or patata. Yeah, I guess so. The Rockies here would later be the United States expanded. the Alps expanded. They found very weird things

like penguin-like creatures in southern Italy. Like things were getting really out of whack again and everyone back then was like WTF. Yeah, and the, like even if you weren't living in an iced over area, you know, basically due south of that was tundra.

Like so Western Europe, which is nice and verdant and lush right now, was tundra at the time you got grasses, maybe a fox or to if you're lucky and you're bored just looking around because it's not the most pleasant landscape to look at. Yeah. I remember humans are running around at this time. I think we shrunk tremendously as a population down to maybe the highest estimate I saw was

around 10 million people across the entire planet at this time. That sounds nice, actually. We kind of talk about elbow room. But all the plants and animals that had started to thrive in the middle, between the Ice Age and the YD, they died back, and all the animals and plants that had died back during that interstodial period, they came roaring back, and they were like,

we love the YD, we're happy again. Yeah, for sure. I mentioned the pollen retreating, being evidence of, like, you know, the tree cover going away, and they found evidence of that, an ice core, once again. This is in the Hulu cave in China,

and it showed, you know, a drastic reduction in China, tree pollen, which, you know, basically you can infer that, like, yeah, a lot of a lot of trees died out during this icy period. Right. And from that, you can also infer that there was probably less rain because trees help generate clouds, and they also help keep the planet warm. So it was obviously a lot colder and a lot drier. That was the two characteristics of the YED. And then, like you said, the Southern Hemisphere experienced something radically different, right? So remember, Northern Europe is covered in ice again

It's tundra right below that And then if you go down to Antarctica They basically hand you like a lay and a Hawaiian shirt And like a Mai Tai Yeah, it's so crazy When I was going through this stuff That to me was like the big reveal I mean I'm a big dummy when it comes to this stuff

So I just figured that would have been even colder And even worse But temperatures actually rose In the southern hemisphere and a lot of the southern hemisphere became warmer and wetter. And the sea surface temperatures increased in the Caribbean and the tropical Pacific and the mountains of New Zealand saw a warmer condition.

So it was like everything was kind of upside down all of a sudden. Yeah, but you also mentioned earlier that it didn't happen. There were weird pockets here there, which also goes to underscore how bizarre the younger driest was. Like there's a basin around Venezuela, and it actually had temperatures drop. So this is the Southern Hemisphere, right? It saw a temperature drop of 3 degrees Celsius, 5.5 degrees Fahrenheit.

And every time I see something like that, I'm like, so? Like, that's not that big of a deal. Right. It turns out it is a really big deal. Even though to you, an average winter temperature of 55 going down to 50 doesn't sound all that bad. But climatologically speaking, any change in temperature, even by half degrees, has really huge weather consequences over, say, the course of a year. So in this case, dropping by three degrees Celsius or five and a half degrees Fahrenheit,

it might not have seen that much temperature-wise over an average winter, but it also opened up the door for way more freak weather. So they might have gone from like no blizzards whatsoever, maybe one blizzard a year, to three blizzards a year. And that definitely impacts local conditions in the life there. So it makes a really big difference, even when you see little changes to average temperatures. Yeah, for sure. There were likely some animal extinctions happening.

You mentioned the amount of humans, which was probably at an all-time high at this point, started going back lower and lower. Their available food was getting slimmer and slimmer. We mentioned they were dabbing their toe in the pond of kind of settling down a little bit and not hunting and gathering and traveling everywhere, and all of a sudden they had to pack it up and start moving around again to try and find food again. Yeah, and there's the evidence that people,

the human population contracted, meaning there was a lot of die-off, shows up in archaeological sites like the Herensburg culture in present-day Germany, Austria, and Belgium. During the YD, the archaeological sites dropped by half compared to what they had been just before the YD, which suggests that there are a lot fewer people making a lot fewer camps or villages.

And then also significantly, in North America, this is when the very famous Clovis culture just disappears from the record too. The Clovis. We did a whole episode on the Clovis. Yeah, they used to pop up a bunch. Remember the whole Clovis first police and all that stuff? Yeah. Yeah. Man, it feels like a thousand years ago. It really does. So this is when they disappeared. And they don't think that the Clovis all just died off. But they think that these weather conditions and hardships for living basically disperse them. And they started forming the prototypes to the bands of Native Americans that we see today. Yeah, for sure.

Another interesting thing is, you know, sometimes in the times of trouble, there can be human advancement because you're struggling and need to think of better ideas on how to do what you're doing. And it seems like that might have happened with the hunting because the animals are more skis. Cairs. Hunting is harder. The game is just not around. So this is where we saw at least one thing that we think might have been an advancement was the Heriff Point, H-A-R-I-F, which is basically a new and improved arrowhead came about. And they think it's probably because they were struggling and they needed to kill better. Yes. And it was quite an innovation because the arrowheads they were using before were made of dandelion heads. I know. And those, you know what? The animals loved them. They were like, shoot me again. Yeah, shoot one of those my way. I could use a laugh.

Right. And then also, Chuck, it really helps that there were people dabbling in agriculture before the YD came along because it seems to have given the people related to them a bit of a leg up. Like they didn't have to figure out agriculture from scratch under these conditions. So in pockets where there was vegetation and a decent amount of game, people did settle down again in those areas. There's a place called the Zagros region, which is in modern Iran, which shows settlements that were basically probably not just hunting camps. They were probably permanent or semi-permanent settlement. So people did, like, sit down where they could and set up shop. And as a matter

of fact, some people say, okay, people were kind of dabbling in agriculture before, but it was just dabbling. And in fact, that culture might not have been passed along. It is possible. that the younger dryus did force humans to basically adopt agriculture. Because, again, remember, conditions are so terrible that whatever leg up you, a human, can give to this plant that you're going to eat later is invaluable. So that's basically what agriculture is, is helping plants along to make them grow better. Yeah. And, you know, that became a challenge in a lot of ways, not just because the ice,

but they found, once again, in those ice deposits or the ice cores, They found air bubbles with a noted decrease in concentration of CO2 in the atmosphere. Yeah. And so all of a sudden these wild cereals that are growing, their yields are going to be way down. And, you know, they had some, you know, for the time, some fairly advanced agriculture burgeoning there. They were like pest control and like watering things, weeding things, transplanting things. The basics. Yeah, the very basics.

But that's, you know, the very beginnings. and, yeah, this put a big sort of stop sign in front of all of that. Yeah, like, imagine being the guy who is watching the other guy pour water out of his gazelle flask under like a little, yeah, like some wheat. Be like, what are you doing? And they'd say, just watch, just give me a couple thousand years and you're going to be blown away. Yeah, you want this water to be beer one day, fella? Exactly.

Let me pour it on this grain. And then it magically turns out. than the beer. Oh, man. Shall we take another break? I think we shall, Chuck. Chuck and Josh. Stuff you should know.

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Samihante, it's Anna Ortiz. And I'm Mark and Delicado. You might know us as Hilda and Justin from Ugly Betty. We played mother and son on the show, but in real life, we're best friends. And I'm all grown up now. Welcome to our new podcast, Viva Betty! Yay! Woo-hoo! Can you believe it has been almost 20 years? That's not even possible. Well, you're the only one that looks dead. much different. I look exactly the same. We're re-watching the series from start to finish and getting into

all the fashions, the drama, and the behind-the-scenes moments that you've never heard before. You're going to hear from guests like America Ferreira, Vanessa Williams, Michael Yuri, Becky Newton, Tony Plana, and so many more. icons, each and every one.

All of a sudden, like, someone, like, comes running up to me and it's Selma Hayek. And she's like, you are my ugly bitchy. And I was like, what? Is she even talking about? Listen to Viva Betty as part of the MyCultura podcast network. Available on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. In sitcoms, when someone has a problem, they just blurt it out and move on.

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Not insulation, insulation, with a no. And this is how much solar warmth reaches the Earth's upper atmosphere. And the basic pattern of, you know, warming the globe is driven by this. And the younger dryness is definitely like this weird, exceptional pocket that stands out. And because of this, everyone, you know, that nerds out on this kind of stuff was like, well, we've got to figure this out. I mean, why did this happen? And they have emerged with four main hypotheses. The one that has the most traction we're going to start with is the melt water interrupting thermohaline circulation.

And that sounds very sort of like sciencey and nerdy and like guys, I hope you explain this. But it's really very simple. It is. It's that a bunch of water disturbed the cycle of the warming cycle of the ocean very, very quickly. Yeah, specifically in the North Atlantic, which has this thing, you mentioned, the thermohaline circulation, which is where warm water, warm by surface air on top of the ocean, falls down into the deep water. And as it does it, it displaces the cold water, which comes up to the top and gets warmed itself. Then it sinks and the cycle just keeps going on and on, right? This is how warmth is delivered to the north, the northern hemisphere. right, those, it moves northward, so the warmer sea water is always moving toward the north, so it's delivering warmth. And at the same time, that cold water upwells in the southern hemisphere, so it delivers cold

to the southern hemisphere, which is why, under normal conditions with the thermohaline circulation, the Antarctica is cold, and comparatively speaking, the northern hemisphere is warmer. That's right. All right, so park that in your brain. and then understand that North America at the time had this huge 700-mile by 200-mile lake called Lake Agassiz, I guess. Sure.

Agassiz, if you're an Andre Agassi fan. It developed as the Laurentide Ice Sheet and extended down to the Great Plains and blocked the great lakes. And all the rivers that were flowing there backed up and it formed this big natural reservoir that was 700 by 200 miles big. And this theory holds, the meltwater theory holds,

that as that last glacial maximum warm things up, that ice sheet retreated, the block passage to those Great Lakes opened up, and all of a sudden billions and billions of gallons of freshwater make its way down to the North Atlantic. They think a similar sort of thing happened in the Nordic region. But you're like, all right, so that makes sense, but was this water like super cold or something?

It was cold, but the main thing it did was, desalionate that upper ocean water, right? Yeah, and so fresh water is less dense than seawater, and so a bunch of freshwater mixed in with seawater makes it less dense than it normally would be, and it needs to be dense to fall down to the deep ocean, which makes the other deeper water come back up, right? Yeah.

So that means that the thermohaline circulation is interrupted, and if you have an interruption in the thermohaline circulation, it just stops moving like that. you would expect to see the northern hemisphere get cold because there's warmth is not being delivered there any longer. You'd also expect to see Antarctica warm up because that cold deep ocean water is not welling up around the very southern, southern hemisphere.

And that's exactly what you see with the younger dryest. It's a really beautiful, elegant explanation that I think was hypothesized in 1982. And up until very, very recently, you are a fringy nut, if you believed anything besides that as the explanation for where the younger dryest came from. Yeah, I mean, it makes sense to me, but that's why I love science,

is people keep poking around, and the fringe nut maybe one day is proven somewhat right. And that, well, I still think that the meltwater is probably the reason why, but one of the other hypotheses is the impact hypothesis, and that is, like you said, It was pretty controversial until more recently. It has gained a little bit of traction because some things do kind of add up.

But the idea here is that a meteorite or a comet or something impacted the Earth, maybe an airburst even. And that released a thermal pulse that kind of set the world on fire almost. Like all these massive wildfires across all the continents, the air is filled with soot, it's blocking sunlight. And in fact, there's so much soot. There's atmospheric dust such that you reduce solar radiation and all of a sudden you have what's called an impact winter or, you know, kind of like a new, the idea of a nuclear winter. Yeah, basically the same exact result, but just it was different things that got us there, right? So there's evidence for this that most people point to is like, this is pretty good evidence. There's something called a black mat, which is a layer of carbon matter that seems to be a soot deposit that you find all over.

over North America and in parts of Europe. And all that suggests that there were wildfires going on on different continents at the same time, which would suggest like some sort of massive comet or meteorite bursting and setting off this thermal pulse. So the fact that those things coincide on two different continents with the onset of the younger dryus has definitely made the impact hypothesis much more popular than it was before. one thing detracting from it that probably makes some legitimate scientists wary of embracing it publicly right now is the writer in science contrarian Graham Hancock latched onto the impact hypothesis because he has this theory, I guess you could call it that,

that there was an ancient apocalypse around the time that the younger dryest happened that wiped out massively advanced civilizations that we don't even know it really existed and reset humanity, and then we had to rebuild from there. And there's not a lot of evidence, if any, for this stuff. It's really, really fascinating, but the evidence we do have,

the scientific evidence we do have, doesn't set that up. But anyway, he basically said, see this impact hypothesis supports my idea that there was an ancient apocalypse, and scientists tend not to agree with Graham Hancock much. Yeah, and the other thing, there's a couple of more sort of smaller points that might support this. One is there was a platinum spike in South Africa that preceded the YD and in some other places.

And platinum is, you know, a lot of time within meteorites, so maybe some support there. And also sometimes people kind of combined the first one and say maybe there was an impact combined with this meltwater thing. So there was a low atmospheric explosion over North America. and that's what released all this meltwater all over the place. Yeah, which makes sense. It's basically like handing an olive branch from one hypothesizer to another, you know? Let's work together. Yeah, let's go get a drink and just settle it.

Also, as an aside, remember our goblecky-tepe episode? Oh, yeah. It's been a while. I don't remember exactly how to pronounce it. We talked about how there was this guy who also kind of fringly concluded that some astronomical engravings that the site recorded the comet or the meteorite burst that happened at this time, which is kind of cool, but, again, there's not a lot of evidence to support it. Moving on, there's a couple of other explanations that don't have nearly as much traction,

but they do make sense. One is a supernova explosion. Supposedly a star went supernova in the Vela constellation at the right time that could have affected Earth by burning away its ozone, layer, which would cool the upper stratosphere, which is the second most layer above Earth, which would prevent it from holding much water vapor. Water vapor is a greenhouse gas, and without a very strong greenhouse gas in the atmosphere, heat would just go out into space much more easily from Earth, and it would get cooler as a result. The problem with this one that I have is wouldn't that happen all over the planet if the ozone

layer was burned away by a supernova? I think so. So I'm going to toss that one, okay? Yeah, nailed it. The last one is another sort of example where the sun is blotted out, so there's a massive drop in temperature very quickly. But this time it is because a volcano erupted, a massive volcano. This is the Locker Sea volcano, not C-E-A, or I'm sorry, S-E-A, but S-E-E-E, because we all know that Germany doesn't have any water, right? Well, it's landlocked, yes.

Yeah, but this is a German volcano. Of course, we're kidding. That's a reference to an older episode. We know all about the Black Sea. So hold your emails. But this volcano, it was definitely a mega eruption. It spewed 6.3. I mean, what is that even?

Trillion? What is that? That's a cubic kilometers. So 3 million cubic kilometers? No, 6.3 cubic kilometers. To the third power, though. No, so that's what makes it cubic. So if you took a kilometer of land, right?

Oh, yeah, yeah, yeah. And you made it square, and you did six, that's six point three times. And then you also made it a kilometer tall, a cube that's six point three kilometers on each side. Yeah. Just of magma got released from that volcano. It was a massive eruption. Yeah, I just outed myself in a mathematical way. Well, finally, you did.

I'm the one who does it all the time. Well, comparatively speaking, Mount St. Helens released one cubic kilometer. Vesuvius was three, and this was 6.3. So the other interesting thing about this one is volcanoes can produce platinum. Yeah. Or at least, you know, part of, like, groups of platinum metals. And that could account for that spike we talked about in South Africa. Yes.

And so the volcanic eruption hypothesizers frequently say, hey, how about this? A volcano erupted and attracted a comet that blew up over North America, which kicked off the melting of the ice caps, which caused the thermohaline circulation problem. Yeah, and then the supernova person's like, what about me? And they're like, sorry, you're not invited. Josh said you were dismissed. Exactly. All right. So that was the YDs.

I guess we could talk a little bit about what happened afterward. afterward is where we are, the Holocene period. And that was when the climate finally worked itself out. That pendulum stopped swinging, and things started warming up and stabilizing. And, you know, people started thriving again. The animals came out. The birds started chirping. The bees started pollinating.

And it led to, you know, not the modern, modern era, but just, you know, what we know now is planet Earth. Yeah, the beginnings of our era all find its roots in this time. Like, this is where agriculture developed. This is where civilization first developed. The writing came along a few thousand years later. I mean, all of this happened in a really short period of time. Like, essentially, everything that has to do with, like, human civilization began in the 10,000 years immediately following the younger dryus. Yeah.

I mean, the current shape of our planet happened after the younger dry. dryest, like the way the coastlines were shaped. I mentioned the Rockies and the Alps, you know, those mountain ranges all over the world even. I was about to say took their final shape, but of course, that's not true, but took the shape that we know and love today. Yeah, and that's actually one reason why it's difficult to track what humans were doing during the younger dryest because the settlements that they had that were closer to the coastline then are now under hundreds of feet of ocean water and are probably just totally just totally destroyed. So we lost a lot of archaeological sites because of that sea level rise. But it was a

tradeoff because, again, we have writing. Yeah, that's right. And those wild serials that we talked about that we're having such a hard time, you know, became Captain Crunch. Yeah. And really, is there anything more you need to prove that humans have reached peak civilization than that? I don't think so. Okay. Well, I guess that's it for the YD, right, Chuck? Uh, that's it for now. I mean, who knows what's ahead. Well, but, and because Chuck said who knows what's ahead, truly, it's time for listener mail. Uh, this is called birthmark episode, because we, I think that might have been a selector. Maybe Patrick just listened to it again, I think so. That's what happened.

Hey, guys, listen to that episode again recently because I have a birth mark that makes me, perpetually look like I have a black eye. On a regular basis, someone will ask me some variation of like who punched you, what happened to your face. I used to enjoy giving a clever story as a way to mess with them, like getting kicked out of a nightclub or squaring off with a bear, but I started to feel bad for lying even to my friends, even if only for a minute. So now I usually just take the boring route and explain that it's a birth mark. It's just subtle enough that friends can go years without noticing it even. But once it's brought to their attention, they can't unsee it. Many don't believe me when I tell them it's just a birth mark, and they think I'm trying to cover something up.

My mom even told me that she was interrogated when I was a child by doctors. Oh, wow. And we'd get dirty looks from other parents when they notice a mark on my face, and I feel bad that her experience of my birth mark has never been as fun as mine. Anyway, ever since my wife, Christine, introduced me to your show about nine years ago. Stuff you should know has been a staple for us during house chores and road trips. Your chemistry together is very comforting, and we especially like hearing Josh make Chuck laugh. Do it right now. Hot patata.

That actually worked. I was like, I'm going to have to take a laugh here, but you got me. Awesome. Keep up the great work, guys. Thanks for making the two of us smile again and again and again. We've made them smile three times. All the best from Troutdale, Oregon. That is Patrick Burton.

Awesome, Patrick. Thank you for that. Patrick and his wife, Christine, right? Yep. So thanks to you both. And Patrick, I have to say, if you're going to have to be, a birthmark that's not in the shape of Abraham Lincoln, the place that you have it is about as cool as it can be.

Agreed. If you want to be like Patrick and Christine and let us know how long you've been listening to us and what you think, hopefully it's generally positive. You can send us an email too. Send it off to StuffPodcast at iHeartRadio.com. Stuff you should know is a production of IHeartRadio. For more podcasts, My Heart Radio, visit the IheartRadio app. Apple Podcasts, or wherever you listen to your favorite shows.

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Listen to Viva Betty on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. I'm I'm Ida Gama Jujan, and this week on our podcast, Hungry for History, we talk oysters, plus the Mianbe Chief stops by. If you're not an oyster lover, don't even talk to me. Ancient Athenians used to scratch names onto oyster shells to vote. politicians into exile. So our word ostracize is related to the word oyster. No way. Bring back the OsterCon. Listen to Hungry for History on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Welcome to Decoding Women's Health. I'm Dr. Elizabeth Pointer, chair of women's health and gynecology at the Atria Health Institute in New York City. I'll be talking to top researchers and

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