[Insert Your Own Catchy Title About Younger Dryas Here] | STUFF YOU SHOULD KNOW

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 hot potato of a real deal. geological mystery. >> Hot potato. >> Mhm. 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 like I wouldn't say 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. Um, 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 drius, which is a. pretty it's a pretty terrible name for. this if you want to be catchy, right? >> Yeah. >> I mean, I think a lot of people will. probably say WTF, >> right? Well, let's just call it the YD. if we're gonna if we're going to put. initials on things. How about that? Or. abbreviate things.

>> So, um the the YD, the younger dus, is. this 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. G paleogeeologists, paleocclimatologists, all the paleos are.

perplexed as to what caused it and then. why it stopped so suddenly too. That's. why I said is a real deal geological. mystery. >> Yeah. in a in a time as we'll see where. uh the earth and its inhabitants and uh. animals and um nature was all going like. all right thank God we can we can. finally get down to business and start. being an earth uh 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. Um, 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 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. Um, 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's 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, things 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. 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 cuz we were. sort of headed toward, you know, legit. Earth, like I said, >> uh, before, you know, I mean, it would.

obviously wouldn't change the year, but. let's say as far alongness goes, we. would be like the year 3000 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, >> um, speaking of, I bought a copy of If.

Anyone Builds It, Everyone Dies, the. >> Eleazar Yukowski Nate Soros book that. just came out. >> Okay. Did not know about it that you say. that as if it was just on the tip of my. tongue, which I appreciate. >> No, you do. Um, we remember I basically. mischaracterized it in the Zizians. episode and had to okay 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 a 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 strongly 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 uh it was very icy. Uh. there were huge ice sheets covering a a. lot of Earth like most of North America,

uh Northern Europe and Asia. And as as. we'll see, a lot of the um the YD is. 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. >> Mhm. >> But uh lots of ice everywhere. We had. barren plains, very harsh conditions. Uh. we had things like, you know, woolly. mammoths, like iceloving creatures. dwelling the earth. and uh you know. human populations that were sparse and.

scattered and and constantly kind of. moving around trying to survive, >> right? And so that the last ice age um. started about a 100,000 years ago and it. took about 80,000 years to reach its. peak point. Um so 20,000 years ago it. hit what's called the last glacial. maximum, right? Um 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. Um, and just like right after. it peaked, it just started warming up.

And it took about 9,000 years and all of. 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. Uh, there was a jump in. temperatures that was, you know, kind of. closeish to today. And this was called. the And I never know how to pronounce. >> It's a umla. >> Is it really? >> Yeah. I'm I. >> That's all it is.

>> Yes. So all of our Nordic friends, the. circle with the the forward slash. through or the O with the forward slash. through it, that's an um lot, right? >> Okay. I mean, I guess we call it the. null set because it looks like a zero. with a 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? What? With the uh. >> No, the null set. No. I wouldn't know how to do that with the. umloud. I guess my best stab would be. the uh Burling Allerude uh interstial.

>> I think you nailed it. >> All right. Uh a lot more rain. Um we. got, you know, we achieved a sea level. that's um not what we have today, but. about half of what we have today. >> Um with that rain, obviously, you're. going to get a lot of plants. The. woodlands are thriving. Uh animals are. now are, you know, forest dwelling and. and walking alongside things like cave. bears and woolly mammoths. >> and things are going pretty good. We. have homo sapiens at this point are are. the only humans that are around at this.

point. Uh and they're like they're. loving life, man. They're saying, "All. right, um 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 uh actually. right before this was the point when um. 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 Bearing Landbridge was covered up by. those rising sea levels which turn it.

into the Bearing 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, uh where. everything seems to be going smoothly. for humans. Uh this is where we started. taking our first stabs at agriculture. >> Um 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 um we're going to basically take. some of that energy and that time that. we dedicate to hunting and gathering and. put it into farming. I I just made that.

word up, but let's call it that from now. on. >> They're like, "What is farming?" And. they're like, "You're doing it right. now, buddy. I see you over there picking. weeds. >> Exactly. >> And uh tending to those 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 uh things like that. And. then all of a sudden the YD comes along. and the glacial conditions return in a. in in the broad sense in a very quick. way. Uh I mean how how long did it take? Like 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 a hundred years it was. really like in full swing and then yeah. 500 years is basically like the 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, um, Kyle helped us. with this and he he um he said that the. the younger Dryus came along and spoiled. the party. Um, that's truer than you. would think because right before this. and that, um, Booling Allar Rod. Interstadial was when we started making. beer, too. So, that got disrupted as. well.

>> We'd be so much drunker today. So, another reason we would have wiped. ourselves out in in just one global bar. fight, basically. >> Yeah. >> So, um this is this kicks off 1300 years. of really really cold weather. Um and. then all of a sudden it just stops and. it it it comes along. It like happened. starting about a hundred years, 500. years into it. It was really basically. back to ice age conditions in a lot of. places. But um when it stopped, it swung.

back to nice and humid even faster. And. there's actual um ice cores from. Greenland that show that Greenland in 10. years, the average temperature increased. by 18 degrees Fahrenheit, 10° C. >> That is insane. And for comparison, so. the global warming that's going on today. that um scientists are quite concerned. about and thinking people as well, um. that's a a rise of 2 degrees Fahrenheit,

not 18 degrees Fahrenheit, two 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. Uh and again, you know, whenever you talk about this. kind of stuff, you got to zoom out and. look at it some from a sort of macro. point of view. >> But yeah, that's super fast and got. super hot. Uh and also super cold. previously during the YDS uh which was. named by the way after a flower uh the. driest octap octa patala. Yeah, nailed.

it. Uh and the odd thing about this. flower and why they named the YDS 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 uh 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. Uh it was.

deposited by melting glaciers." But like. none of that makes any sense. >> No, because you've got clay from melting. glaciers above it and clay from melting. glaciers below this flower. And this. flower thrives in in uh temperatures. where the glaciers are not melting at. all. So it's a huge mystery. And then um. 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 um much of a bizarre freak as. the younger Dryus was. >> That's right. So we got the OD uh we got. the YD. Mhm. >> Should we take a break? Yeah, that. sounds like a pretty good time for a. break. Yeah. >> Yeah. Yay. >> All right, we'll be right back. >> Chuck and Josh. stuff. you. should know.

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 uh samples.

>> a lot from Greenland, also from. Antarctica and um 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. Uh you. can find out like basically what's what. it accumulated there like stuff that the. wind blew in there from other places. uh you know they've got these little. little uh 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 we have these gases here we have. this sediment here. >> um we have a a distinct lack of pollen. for this period here which means like. probably a lot of uh plant life was. killed off and stuff like that. >> and then the lake stuff is super. valuable too right. >> yeah because um constantly uh sediment. is accumulating at the bottom of a lake. And very similar stuff's getting trapped. down there like air bubbles, um, 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 and um. 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, not only figure out when this. sediment deposit or this ice deposit was. was put down, but also what like a a. lack of pollen or what type of pollen. means for like the world at large at the. time. I 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 re very niche nerdy stuff. you should know t-shirt could just be uh.

lakebottom greater than symbol tree. ring. >> That's a super nerdy. I think that would. actually offset the um 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 they'll just silently walk. past you and give you the high five and. the low five without stopping. >> Right. But it'll be a 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 the. low five and you guys keep trying to go. in different directions. It's. >> That's got to be the worst. I thought. the fist bump and the hand together was. the worst. But when you high five and. someone holds on and locks fingers, >> not what you're after. >> It's so weird. >> Oh goodness. Uh 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 one that was. really affected the most uh especially. around the North Atlantic. um the southern hemisphere. We'll we'll. talk about some weird abnormalities. there as well, but uh 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. Uh the Rockies here in.

would later be the United States uh. expanded. Uh the Alps expanded. Um they. found very weird things like uh. penguin-like creatures in southern. Italy. Uh like things were getting. really out of whack again and everyone. back then was like WTF. >> Yeah. And um the the like even if you. weren't living in a 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 two if you're lucky, and. you're bored just looking around because. it's not the most pleasant landscape to. look at. >> Remember, humans are running around at. this time. I think um we are 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. >> Kind of. Talk about elbow room. But the. the all the plants and animals that had.

started to thrive in the the middle in. between the ice age and the YD, they. died back. And all the animals and. plants that had died back uh during that. interstial period, they came roaring. back and they were like, "We loved the. we love the YD. We're happy again.". >> Yeah, for sure. Uh I mentioned the the. pollen retreating um being evidence of. like you know the tree cover going away. and they found evidence of that an ice. core once again. Uh this is in the Hulu. cave in China and it showed you know a a.

drastic reduction in tree pollen which. you know basically you can infer that. like yeah a lot of uh 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. Um. so it was obviously a lot colder and a. lot drier. That was the two. characteristics of the YD. And then um. 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 lei and a Hawaiian shirt. and like a my tie. >> Yeah. It's so crazy. When I was going. through this stuff, that to me was like. the big reveal. Uh I I I mean I would. 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 temp uh temperatures actually rose.

uh in the southern hemisphere and a lot. of the southern hemisphere became warmer. and wetter and the the sea surface. temperatures increased in the Caribbean. and the tropical Pacific and uh the. mountains of New Zealand warmer. conditions. 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 drius. was like there's a basin around. Venezuela and it actually had um.

temperatures drop. So this is the. southern hemisphere right? Uh it saw a. temperature drop of 3° C 5 12 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. Uh. even though to you an average winter. temperature of 55 going down to 50. doesn't sound all that bad but climate. 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 3 degrees. Celsius or 5 and a half degrees. Fahrenheit. It might not have seen that. much temperature- wise over an average. winter, but it also opened up the 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. Um, there were likely. some animal extinctions happening. Uh. you mentioned the amount of humans which. was at an you know probably at an. all-time high at this point. Um started. going back lower and lower. Uh their. available food was uh getting slimmer. and slimmer. >> Uh 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 the evidence that the. that people the human population. contracted meaning a there was a lot of. die off um it shows up in archaeological. sites like the Harrensburg 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 were a lot fewer.

people making a lot fewer camps or. villages. And then also significantly in. um North America, this is when the very. famous Clovis culture just disappears. from the record, too. >> 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, man. This feels like a thousand. years ago. >> It really does. But 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 dispersed.

them and and they started forming the. prototypes to the bands of uh of Native. Americans that we see today. >> Yeah, for sure. Uh another interesting. thing is in in you know sometimes in the. the times of trouble there can be uh. 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 uh. animals are more scarce, hunting is. harder, the game is just not around. So, uh this is where we saw at least one.

thing that we think might have been an. advancement was the hariff point. H A R. I F, >> which is a basically a new and improved. arrow head 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 did. They were like, "Dude, shoot. me again.". >> Yeah. Shoot, shoot one of those my way. I could use a laugh. >> Right. Um, 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, um which shows settlements. that were basically probably not um just.

hunting camps. They were probably. permanent or semi-permanent settlements. So people did like sit down where they. could and and set up shop. Um 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 that culture. might not have been passed along. It is. possible that the younger dus 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 is invaluable. Um. so that's basically what agriculture is. is helping plants along to make them. grow better. >> Yeah. And you know it be that became a. challenge uh 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 uh air bubbles with um. a noted uh 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 uh you. know they they had some you know for the. time some fairly advanced uh 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 uh yeah. that this put a 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. >> Yeah. onto like a like a little Yeah. like some wheat. >> Be like, "What are you doing?" And they. they'd say, "Just 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 uh this grain. >> Right. And then it magically turns into. beer. >> Oh man. Shall we take another break? >> I think we shall, Chuck. Chuck and Josh.

stuff. you. should know.

All right, we should talk a second about. uh something called solar insulation. Not insolation. uh insolation with an O. And this is how. much solar warmth reaches the Earth's. upper atmosphere. And the basic pattern. uh of you know warming the globe uh is. driven by this. And the younger dus 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.

got to figure this out. I mean, why did. this happen? And they have emerged with. four main hypotheses. Uh the the one. that has the most traction we're going. to start with is the meltwater. interrupting thermmoaline circulation. And that sounds very sort of like uh. sciency 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. the the cycle of the warming cycle of. the ocean very very quickly.

>> Yeah. specifically in the North Atlantic. which has this thing that you mentioned. the thermmoaline circulation which is. where um warm water warmed 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 uh warmed itself. then it sinks and the cycle just keeps. going on and on right and this is how. warmth is delivered to the north the. northern hemisphere right those it moves.

northward. So the 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. thermmoaline circulation the Antarctica. is cold and comparatively speaking the. northern hemisphere is warmer. >> That's right. All right. So park that in. your in your brain and then understand.

that North America at the time had this. huge 700 mile by 200 mile lake called. Lake uh Agasses I guess. >> Sure. >> A gases if you're an Andre Agassi fan. uh 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 m big. And. this theory holds, the meltwater theory.

holds that as that last glacial maximum. warmed 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 fresh water make its way down to the. North Atlantic. Uh they think a similar. sort of thing happened in the in the. Nordic region. Um but you're like, "All. right, so that makes sense, but was this. water like super cold or something?" Um. it was cold but the main thing it did. was uh desalinate that that upper ocean.

water. Right. >> Yeah. And so s fresh water is less dense. than seawater. And so a bunch of fresh. water 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 uh which makes the other. deeper water come back up. Right. Yeah. >> So that means that the thermmoaline. circulation is interrupted. And if you. have an interruption in the thermmoaline. circulation, it just stops moving like. that. Um, 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 uh. southern southern hemisphere. And that's. exactly what you see with the younger. dest. It's a really beautiful, elegant. explan explanation that I think was. hypothesized in 1982. And up until very, very recently, you were a fringy nut if. you believed anything besides that as.

the explanation for where the younger. dus came from. >> Yeah, I mean, it makes sense to me. Uh, but that's why I love science is people. keep poking around and the fringe nut. maybe one day is proven somewhat right. uh and that well I I still think that. the meltwater is probably the the the. reason why but um one of the other. hypotheses is the impact hypothesis. and that is like you said was pretty. controversial until more recently. um 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 air burst even. >> and that released a a thermal pulse that. kind of set the the world on fire almost. like all these massive wildfires across. all the continents. Uh the air is filled. with soot. It's blocking sunlight and in. fact it's there's so much s 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 like a n the. idea of a nuclear winter. >> Yeah. Basically the same exact result. but just it was different things that. got us there. Right. >> So um 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 North. America and in parts of Europe. And all. that suggests that there were wildfires.

going on on different continents at the. same time. >> Yeah. >> Which would suggest like some sort of. massive comet or meteorite bursting and. setting off this thermal pulse. Um, so. the fact that those things coincide on. two different continents with the onset. of the younger dus has definitely made. the the impact hypothesis much more. popular than it was before. Um, one. thing detracting from it that probably. makes some legitimate scientists um, wary of of embracing it publicly right.

now is um, the writer in science. contrarian Graham Hancock latched on to. the impact hypothesis because he has. this um, theory, I guess you could call. it that, that there was a ancient. apocalypse around the time that the. younger dus happened that wiped out. massively advanced civilizations. that we don't even know 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. Uh it's really really fascinating, but. the 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 um agree with Graham Hancock. much. >> Yeah. Yeah. And the other thing there's. a couple of more um sort of smaller. points that might support this. Uh one. is there was a platinum spike uh in. South Africa that preceded the YD uh and. in some other places and platinum is um.

you know a lot of time within. meteorites. So maybe some support there. Uh and also sometimes people kind of. combine the first one and say maybe uh. there was an impact uh combined uh with. this um meltwater thing. So there was a. low atmospheric explosion over North. America and that's what released all. this melt water 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. >> Um also as an aside for remember our. goleepy. episode. >> Oh yeah. >> It's been a while. I don't remember. exactly how to pronounce it. He talked. about how there was this guy who who. also kind of fringily concluded that. some astronomical engravings at the the. site recorded the the comet or the. meteorite um 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. Uh. supposedly a star went supernova in the. Veila 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. Uh which. would prevent it from holding much water. vapor. Water vapor is a greenhouse gas. and um 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 I'm going to toss that. one. Okay. >> Yeah, nailed it. Uh the last one is um. another sort of example where uh 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. Uh this is. the Locker Sea volcano. Uh not CEA or. I'm sorry EA but E because all we all. know that Germany doesn't have any. water, right? >> Yeah. Well, it's it's landlocked. Yes. >> Yeah. But this was a German volcano. Of. course we're kidding. That's a reference. to an older episode. We know all about. the Black Sea to hold your emails. But. this volcano, it was a definitely a mega. eruption. It spewed 6.3.

um I mean what is that even trillion? What what is that? >> That's a a cubic kilometers. >> So 3 million cubic kilm. >> No, 6.3 cubic kilometers. >> to the third power though. >> No. So that was that's what makes it. cubic. So if you took a a kilometer of. land. >> Oh yeah yeah yeah. >> and you made it square and you did six. that 6.3 times and then you also made it. a kilometer tall a cube that's 6.3.

kilometers on each side yeah. >> just of magma got released from from. that volcano. It was a massive eruption. >> Yeah. I I I just outed myself uh in a. mathematical way. >> Well finally you did. I'm the one who. does it all the time. >> Well, com comparatively speaking, Mount. St. Helens released one cubic kilometer. >> Vuvius was three and this was 6.3. So, uh the other interesting thing about.

this one is u volcanoes can produce. platinum. >> Yeah. >> Or at least you know part of uh 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. circulation problem. Yeah. And then the. supernova person's like, "What about.

me?" And they're like, "Sorry, >> you're not dismissed.". >> Exactly. >> Uh all right. So that was the YDS. I. guess we could talk a little bit about. what happened afterward. um afterward is. is where we are the the holysine period. and that was when uh the the climate. finally worked itself out. Um that. pendulum stopped swinging and things. started warming up and stabilizing and. uh you know people started thriving.

again. The animals came out, the birds. started chirping, the the bees started. pollinating and and we and it led to you. know the the not the modern modern era. but just you know what we know now as. planet earth. Yeah, the beginnings of. the our our era all find its roots in. this this time. Like this is where um. agriculture developed. This is where. civilization first developed. Writing. came along a few thousand years later. Um 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 Dus. >> Yeah. I mean the current the current. shape of our planet uh happened after. the younger dryest like the the the way. the coastlines were shaped I mentioned. the Rockies and the Alps you know those. those mountain ranges all over the world. even they they I was about to say took. their final shape that of course that's. not true um 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 dus because the 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 destroyed. So we we lost a lot of archaeological. sites because of that sea level rise. But it was a trade-off because again we. have writing. >> Yeah, that's right. And those wild. cereals that we talked about that were. having such a hard time, you know, became uh 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. >> Uh, 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. uh episode cuz 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. uh recently because I have a birthmark. that makes me perpetually look like I. have a black eye. On a regular 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. birthmark. It's just subtle enough that. friends can go years without noticing it. even. >> Wow. >> But once it's brought to their. attention, they can't unsee it. Uh 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. Uh, my mom. even told me that she was interrogated. uh when I was a child by doctors. >> Oh, wow. >> And would get dirty looks from other. parents when they noticed a mark on my. face. And I feel bad that her experience. of my birthmark has never been as fun as. mine. Uh, anyway, ever since my wife. Christine introduced me to your show.

about 9 years ago, uh, 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. >> Uh, uh, hot pata. That actually worked. I was like, I'm. going to have to fake a laugh here, but. you got me. >> Awesome. >> Uh, keep up the great work, guys. Thanks. for making the two of us smile again and. again and again. Uh, we've made them. smile three times. Uh, 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. Um, and Patrick, I have to say, if you're going to have 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. >> Uh, if you want to be like Patrick A 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 stuff at. iiheartradio.com.

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