Stuff You Should Know - Did Climate Cause the Collapse of the Maya?

Episode Date: December 3, 2019

After millennia of development, the Maya culture suddenly collapsed at its peak. Why is one of the biggest mysteries of history. One theory says catastrophic climate change was the cause. And it may have happened to other cultures too. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

Hey friends, when you're staying at an Airbnb, you might be like me wondering, could my place be an Airbnb? And if it could, what could it earn? So I was pretty surprised to hear about Lisa in Manitoba, who got the idea to Airbnb the backyard guest house over childhood home. Now the extra income helps pay her mortgage. So yeah, you might not realize it, but you might have an Airbnb too. Find out what your place could be earning at airbnb.ca slash host. On the podcast, Hey Dude the 90s called, David Lasher and Christine Taylor, stars of the cult classic show, Hey Dude, bring you back to the days of slip dresses and choker necklaces.

We're going to use Hey Dude as our jumping off point, but we are going to unpack and dive back into the decade of the 90s. We lived it, and now we're calling on all of our friends to come back and relive it. Listen to Hey Dude the 90s called on the iHeart radio app, Apple podcasts, or wherever you get your podcasts. Hello Seattle and hello San Francisco. We are coming out to do live shows in January for you guys like we seem to do every year now. Yeah, it's kind of a pattern that's emerging Chuck.

That's right. And the pattern is you come to see us, you laugh, we have a good time, and everyone leaves happy. That's the pattern. So if you want to leave happy, you can come see us on Thursday, January 16th at the Moore Theater in Seattle, and you can come see us Saturday, January 18th at the Castro in San Francisco. Yes, part of our annual retreat to Sketchvest. Yes, so if you want tickets and information, go to SYSKLive.com, our home on the web, powered by our friends at Squarespace, and we'll see you in January.

Welcome to Step You Should Know, a production of iHeartRadio's How Stuff Works. Hey, welcome to the podcast. I'm Josh Clark. There's Charles W. Chuck Bryant. There's Jerry over there. And this is Stuff You Should Know, the podcast. What else would it be? TV show? Not for a long time, everybody. I like that. I like that intro. Okay, that's good. I'm glad. So I'm not mistaken. Who did I say melted many years ago? Was it the Maya?

No, Neanderthals. Oh, that's right. Or Thals, if you don't want to be a douche. Can we say that? I don't know. We'll find out. Jerry didn't even hear it. Maybe she will in the edit. I bet she won't.

Yeah, it was the Neanderthals, but I'm going to go ahead and say it again. Maybe it's the Maya. Melted? Sure. Climate change. Maybe. But that's what you were talking about, right? The Neanderthals melted because of climate change.

That's right. Which I thought was hilarious. But let's talk about the Maya civilization. Oh, yeah, yeah. I meant to tell you. Let's kind of move stuff around here. Oh, great. Do you want to? Sure. I mean, what do you mean?

Well, let's talk about Charles Lindbergh first. Oh, okay. I think he's a better intro than just kind of randomly in the middle. All right. Don't you? I mean, that means we can start out in the wayback machine. Okay, good. Which we would have been in anyway, but we'll be closer.

We'll save some gas. It's way closer. That's right. We're going back to February of 1929. Yes, February 1929, when Chuck Lindbergh was flying for Pan Am, and he was flying over what is now Belize, and if you can Belize that, so sorry. But what he would do back then, and this is after, of course, his, the big flight, the big one, he would get hired to do these little exploratory routes for airlines, and in this case Pan Am, he may have done that exclusively with Pan Am.

I have no idea. I don't either. I wasn't in this contract business, but he would fly these routes to sort of blaze new trails for like, for flying routes and say, hey, this is a pretty legit flying route for delivering stuff, or even passenger routes, and maybe add it to your docket. Right. So he was doing this, and he was flying over. Is this episode on air routes?

No, it's not. Because he was flying over Mexico and Central America. Well, Belize, like you said. Yeah. And it was just very dense jungle everywhere he looked, until he went over this one part where it was described, not by Charles Lindbergh, for some reason, but by an Associated Press writer, who apparently got into the head of Charles Lindbergh, and said it looked like two emerald eyes staring up out of the jungle brush, the tangle of the jungle brush.

So he went back, flew a little lower to investigate, and what he found was what? That the emerald eyes were actually twin reflecting pools in a massive stone temple, like reflecting the sun into his face, and he was like. So is he a stone temple pilot? I guess so. Oh my gosh. Is that off the cuff? Yeah, it was.

That was pretty good. Okay. That was great, actually. And he realized that he was looking at the ruins of a lost city. That's right. A massive stone lost city. Actually, I don't think he realized that, probably, but we now know that. Well, he saw that it was covered in jungle and overgrowth and everything.

Covered in jungle. Yeah. And so the legend goes, Chuck, that Charles Lindbergh discovered the lost Mayan civilization. Right. It's just not true. No. Well, okay, it's nuanced. That particular article is probably totally made up.

Yeah, but even if he did find that part, he didn't discover, and that's probably not what you even said, he did not discover the lost Maya civilization. Right. He found a part of it. Right. It's apocryphal. It's an apocryphal story, because by that time, people were aware that the Maya had existed, but they had kind of been seen as legend for a very long time, but starting in, from

what I could tell, the 1920s, they started finding these massive, huge lost cities, just like Lindbergh supposedly found. Right. And later on, Lindbergh did actually fly over some of these lost cities and photograph them, and he got into aerial archeology, but the point is this, there are, still are, and there definitely were more lost cities that were just enormous with huge temples, some of them pyramids that were among the tallest pyramids in the world, completely overgrown by the jungle, just overtaken abandoned cities, and they started looking around, and they started

finding more of these cities, and more, and more, all over the Yucatan and northern, actually all of Guatemala, into Honduras, Belize, and El Salvador, a big chunk of Central America, that there's these lost cities that were found, and they all seem to share something in common, so much so that they now realize that they were peopled by the same cultural group, the Maya. That's right. So let's talk about the Maya. Let's go back even further.

Let's go back between 2600 and 1200, or 2600 BC, and 1200 AD, or what we now would call CE. CE. Or, I think people now just say like years ago. Do they? Do they really? Yeah. Oh well.

Yeah, they're like, get religion out of it entirely. Just say a long time ago. Yeah, this many years ago. So many, many years ago, the Maya civilization occupied this big area that we were talking about, and there's a period of time known as the classic Maya, that's what they call it. Correct. The classic period between…

They stumble on their way through the door. …between 250 and 900, where, I mean, you talk about flourishing as a culture. Yeah. And it hadn't been seen since the Roman Empire, basically. Yeah. These cities, 60 or more, 60,000, 70,000 people, they had sports arenas, they had pyramids, they had these advanced farming practices, they made calendars, they understood math, and were really, really advanced.

And I believe even at the time, some of these cities outnumbered the amount of people that were in places like London and Paris at that same time. Yeah. Yeah. In something like, say, 800 CE, if you travel over London and Paris, you find far fewer people. Like a double or triple the amount in this Maya culture. The way that I saw it put was in the area of the Yucatan and Guatemala, the southern

lowlands, I think is what they call it, where most of the great Mayan cities were. The population density is about what it is today in Los Angeles County. Wow. Imagine that. And now it's just overrun jungle, rainforest mostly, but it used to be as dense as LA County. Like people just everywhere. Yeah, that's dense. Yeah.

Super dense. So, here's the thing about the Maya empires, they were never one big group. They were never unified politically. They were just a bunch of warring city-states, but really thriving. And they also had like political alliances between city-states, but that same city-state could be at like total war 50 years later, you know? Yeah. They're shifting constantly.

That's right. But the thing we really need to hammer home is that they were doing great for themselves. Right. They were really thriving as a culture and as a people. And then in about a 150-year period between 800 and 950, they disappeared. Yeah. For all intents and purposes, the classic Maya culture just vanished into the jungle. And that is not to say that the people all died, they assimilated into other cultures.

But what you were talking about, that Maya culture and those big cities of 70,000 people just went away. Yeah. And kind of like a good analogy is if over, you know, the next 30 years, the United States just suddenly reverted to 16th century agrarian practices. That was it. We just abandoned our cities and went and farmed. And like we didn't farm with any tractors or anything like that.

We started using oxen, just completely abandoned our culture and went back to a simple farming lifestyle. That would basically be the closest analogy you could come up with. Yeah. And it happened really fast. Super fast. And as a result, that Mayan culture, like you said, was sort of looked at as a legend before we started finding these places again.

Yeah. Because locals kind of knew about, they'd be like, oh, if you go into the jungle, you're going to find a lost city. Explorers were like, we are crazy. That's not real. But then they started to actually find these lost cities. And what's really surprising to me is they're still finding lost cities. Every year, there'll be some new study coming out that says, oh, we used Lidar.

I think it's light. Lidar. Yeah. Lidar. It's basically a way of looking through vegetation to see solid structures underneath. So they're looking through the jungle. It's like a jungle x-ray. Kind of, yeah.

Yeah. Actually, it's perfect. And they're starting to find even more lost cities. And they're also finding that the lost cities that we know about, there's one called El Mirador that hasn't been kind of excavated yet, but the pyramid is so tall that it's sticking up out of the jungle canopy. So they know there's a lost city there. But using Lidar, they've seen like, oh, it's way more extensive than we thought before.

El Mirador probably had 100,000 people living in the city center at its peak. All right. So that's a good setup. We're going to take a break and discuss the merits of jungle x-ray as a band name and be back right after this. Hey, everybody, when you're staying at an Airbnb, you might be like me wondering, could my place be an Airbnb? And if it could, what could it earn?

So I was pretty surprised to hear about Lauren and Nova Scotia, who realized she could Airbnb her cozy backyard treehouse and the extra income helps cover her bills and pays for her travel. So yeah, you might not realize it, but you might have an Airbnb too. Find out what your place could be earning at airbnb.ca.host. On the podcast, Hey Dude, the 90s called David Lasher and Christine Taylor, stars of the cult classic show Hey Dude, bring you back to the days of slip dresses and choker necklaces. We're going to use Hey Dude as our jumping off point, but we are going to unpack and dive back into the decade of the 90s.

We lived it, and now we're calling on all of our friends to come back and relive it. It's a podcast packed with interviews, co-stars, friends, and non-stop references to the best decade ever. Do you remember going to Blockbuster? Do you remember Nintendo 64? Do you remember getting frosted tips? Was that a cereal? No, it was hair.

Do you remember AOL Instant Messenger and the dial-up sound like poltergeist? So leave a code on your best friend's beeper, because you'll want to be there when the nostalgia starts flowing. Each episode will rival the feeling of taking out the cartridge from your Game Boy, blowing on it and popping it back in as we take you back to the 90s. Listen to Hey Dude, the 90s called on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts. It's not bad.

What kind of band would it be? That's your specialty? Jungle X-ray sounds like a party band, right? It does. It's got a lot of funk going on. Yeah, soul and funk, I think. 70s? Sure.

But like a 70s throwback that didn't exist in the 70s. Oh, yeah. Like a Yacht Rock. Like a Yacht Rock. Oh, who's that? Wasn't that a band? Jerry Scissor Sisters? That was like a funky throwback 70s thing.

Okay, I got to listen to them. Well, they were around for a minute. I think they're not around anymore. Oh. All right. Did they leave like any kind of archive or documentation of their music? I seem to remember them being like a party band. I don't know.

But I mean, did they have a record out or what? Yeah, man, they had records. I'm going to go check them out then. I think I just made this up. All right. So the Maya disappeared. Why would Jerry know? Is she hip all of a sudden?

I don't know. I'm not going to say what she just did. So Charles Lindbergh comes around, referred to previous story. We already talked about Lindbergh. I know. Okay. Referred to previous story. That's why I said that.

Okay. And he puts this back on the map again and everyone is excited about discovering about who these people were. Right. But the whole thing, like from the outset, they're like, what happened to these people? Sure. And the more we learned about them, this is the other thing. Like the legends of the sudden civilization just vanishing.

Like the more we studied them, the more we realized that it's actually kind of accurate. The legends are true. There was this amazing culture that just vanished into the forest and one of the big things, one of the big breakthroughs in studying Maya culture was cracking their written alphabet. They used hieroglyphs and there's a really, really good documentary called Cracking the Maya Code on, I think it was a Nova episode. Oh. Dude, it is good.

Yeah. It's thrilling. And it basically is them just sitting around some house one summer trying to figure this out, but they're like going back and forth and some, like I think some like 20 year old woman figured it out. Wow. And now we understand a lot more, but what we're finding is it's like, oh, no, this really happened.

Something really weird happened here and we still aren't quite sure what caused it. That was a very odd description of how they figured that out. What? We were sitting around a house. That's what they did. Okay. I think they had like a workshop or something. They were like, we're really going to try to figure this out.

We're going to try to crack this code and they actually did at the workshop. We only had some house where we could go sit in. Well, that's what they were doing. It was a house. Someone's house, I think. I love it. Watch knowing me, it was definitely not a house by any stretch and I'll have to do a correction.

They're like, Josh, is your house Harvard University? So there are some theories that have been developed over the years that all kind of makes sense. And some of them, that's not necessarily a binary thing. Some of them could have all contributed to the collapse of the Maya. Over farming is one, which makes a lot of sense. And that's the idea that basically they were so successful. They had tons of food, tons of water.

And so they said, well, let's just make tons and tons of babies, which all of a sudden the farmers are like, geez, we're really growing. Hey, everybody. Yeah. Like, I don't know if we can grow this much corn. So let's clear some forest land and grow, grow, grow, which means they're not practicing safe and sound farming practices all of a sudden. Right.

They weren't practicing safe sex and they weren't practicing safe farming. That's right. So because of this over farming, they weren't allowed to, or they didn't have the opportunity to let their fields lay fallow because everything was in production, which is really no faster way to overstretch your agricultural resources than that. That's right. What else? We're here to tell you.

Well, warfare, we know they were a warring people for sure. So the Maya rulers were, they did a lot of disservice to their own people by kind of over inflating their resources and how tough they were, what kind of warriors they were and how powerful they were. They could make it rain. They can control the weather and thus control the crops. And this may have backfired on them as the theory goes that they warred so much that they sapped their own resources and eventually people retaliated and they were not able to

fight back. Right. And I think the guy who led that workshop at that dude's house where they cracked the code, I cannot remember his name, but he's an eminent Maya scholar. He is of the camp that's like, it was warfare. That's what it was. Plain and simple. They just fought too much and they eventually, they reached some tipping point from war.

And there's real evidence about some of these cultures at least or some of these cities going down because of warfare. Yeah. I mean, they engaged in total war or they would like target civilians. They would burn your whole city down. It wasn't like, they were a very warlike group, which is funny because for a very long time they were portrayed as one of the few Mesoamerican groups that didn't practice human sacrifice. And then once we cracked the Maya code, we're like, oh, no, actually they were prolific

at that. Wow. Yeah. It was bad news. The other is disease and this is not human disease necessarily, but like a virus from their food supply. Yeah. That's another ecological disaster.

That's right. I think Maze Mosaic virus was named in a 1979 article. So like there's a lot of good theories out there and they aren't necessary. It's not a zero-some kind of thing figuring it out. But there's over the years lately, in the last decade or two maybe, people have really started to say, you know, I think we should look a little closer at the role climate change might play in this kind of stuff. And when they look specifically at the Maya, they said, actually it looks a lot like climate

change played a big role in the decline of the classic Maya civilization. That's right. And because the Maya didn't burn fossil fuels to run cars, doesn't mean that the earth wasn't affected by climate change and that they weren't affected by climate change. Yeah. They think that probably climate change happened on its own, but they've also pinpointed some ways that the Maya may have exacerbated it too. You mean people can impact that?

Some Frooloop say so. So they've done some studies. They studied mineral deposits in caves left by dripping water, and they have been able to put together a 2000-year history of weather patterns. Based on speleothems alone. That's right. And what they found out, and this was published in an article in Science in 2012, Science Magazine. The Journal Science.

The Journal Science. Yeah, it's not called like Science Weekly or whatever. The Ohio State University. What they did find out was for the first few hundred years, and this really lends a lot of credence to the theory that they may have over-farmed and stuff like that, is they really had a lot of rain, and they flourished as a result of that. Yeah. Which you can't really blame them.

It's them saying, okay, well, let's thrive, and we can thrive in these conditions. It's not like they were like, oh, okay, this is a really wet period. Let's take advantage of it and really overstretch ourselves. They just kind of went with it, and their population grew because it could be supported. Because there was such a large amount of rain, their crops grew, their reservoirs were full. And this is a few hundred years. Right, over the course of a few hundred years. But from looking at the cave deposits, they found that there was a very wet record that

corresponds with the classical Maya period. Wet record is a Scissor Sisters album? I don't know. What was it, Jungle X-ray album? Jungle X-ray. Wet record. So... Jerry is that hip?

That's hip. Oh, Jerry doesn't like that one. She's disgusted with this at this point. Around 660 AD, this all changed. The rain. What's that funny for? I just thought of a good analogy. So Jungle X-ray, their album Wet Record, is to 70s funk soul throwbacks.

What the darkness permission to land is to 80s hair metal throwback. That's not an SAT question. I think we just did it, Chuck. Did we crack the code? Yeah. We cracked that Jungle X-ray code. Did you see where Motley Crew's going to play shows again? Again?

We supposedly saw their farewell tour that they even signed a contract saying they could legally never perform again together and they're going on a stadium tour with Poison and Def Leppard. What? I don't know. I'll see you there. Yeah. Remember, we got invited to that show by Nita Strauss, who is huge.

Yeah. Guitar player at the time, maybe still for Alice Cooper's band. Yeah. I think she does that still, I think, but she's like a guitar legend now. She's got her own jam. She's great. She's got a great sense. She's probably not.

But around 660, the weather changed. The rains did not come like they used to. They had the longest dry spell of the last 2,000 years. This is going to have a real impact when everything's flourishing and you're just planting and planting. All of a sudden, you're A, you're thirsty. That's a big one. B, you're hungry.

The first thing, it's funny because we're talking about rainforests, but this area in northern Guatemala where the Maya will live is called the Petin or the Petin, I don't know, P-E-T-E-N. It is kind of like feast or famine depending on the rain cycle. When it's dry, it's like you're in trouble because the closest groundwater is about 500 feet below the surface. It's not going to rain for a very long time. If you haven't prepared by building reservoirs, you might die of thirst.

So a drought in the Petin, which is normally dry some parts of the year, would be a real problem. If you're talking about a drought that lasts over years or possibly decades, now you have a civilization collapsing problem. That's right. Yeah. So that's a big problem in and of itself. You've got a big population that grew when it was wet.

Suddenly it's not wet and you still have that big population. There's a lot of internal problems that can develop, especially between classes too. Sure. The haves and the have-nots, which existed back then. But also the rulers who are like more human sacrifices, we need to keep this thing going to get the rain to come back. Well, and the common folk being like, jeez, I don't know about this, I hadn't rained in a while.

I know. It was my cousin before, but now he's asking for my brother. Yeah, exactly. So that created a lot of tension. The other thing that could have sped this whole thing up was the fact that they were thriving so much that they were expanding their territory and they were cutting down and deforesting the land around them for fuel and to build things. And they have found pollen, they studied pollen in these ancient layers and lake sediment

in Central America and around 800 AD, that pollen went from tree pollen to weed pollen pretty quickly. And that's about when the Maya reached their fluorescence, when they really reached their pinnacles about 800. So what that suggests is they cut down all the forests and they were using what used to be forest for crop land because they practiced slash and char where they would burn it down to introduce carbon nutrients into the ground. The problem is if there's no forest whatsoever, you've just altered your ecosystem and by

doing that you can actually alter the local climate which they think they may have. Yeah, not only that, but it's going to have just the physical effect of erosion, like a massive erosion because those tree roots are gone and that's going to screw up your farmland as well. Right. So your top soil is gone, your trees are no longer keeping things as cool as they were before. That's right.

There was a NASA model that predicted that the temperature in the area rose by about six degrees Fahrenheit, which is a lot, I mean that's noticeable for humans, but if you're talking about plants and soil, that can really exacerbate a drought when you've already got a bad drought in a normally dry area. That's not good. So the climate record is showing, okay, it was already bad, but they probably made things worse with the deforestation. Yeah, and all that stuff combined and then maybe throw in a little dash of the previous

theories could very well explain why they said, you know, we're getting out of here and we're going to go live a smaller life, a more sustainable smaller life that's not in a big city. Right. Yeah. And they think also that, you know, the other things dashed in like the warfare, like if you're in a town and you know the next town or the next city stayed over has big reservoirs and your people are dying of thirst, invading that other city might seem like a pretty

good idea. Right. So if you have times and you have a lot of war going on everywhere and that can really make your civilization decline pretty bad too. Should we take another break? Sure. All right. We'll take another break and talk about how this climate change could have affected some

other civilizations throughout history. Hey, friends, when you're staying at an Airbnb, you might be like me wondering, could my place be an Airbnb? And if it could, what could it earn? So I was pretty surprised to hear about Lisa in Manitoba, who got the idea to Airbnb the backyard guest house over childhood home. Now the extra income helps pay her mortgage. So yeah, you might not realize it, but you might have an Airbnb too.

Find out what your place could be earning at airbnb.ca slash host on the podcast. Hey, dude, the 90s called David Lasher and Christine Taylor, stars of the cult classic show Hey Dude, bring you back to the days of slip dresses and choker necklaces. We're going to use Hey Dude as our jumping off point, but we are going to unpack and dive back into the decade of the 90s. We lived it, and now we're calling on all of our friends to come back and relive it. It's a podcast packed with interviews, co-stars, friends, and non-stop references to the best decade ever.

Do you remember going to Blockbuster? Do you remember Nintendo 64? Do you remember getting frosted tips? Was that a cereal? Was that hair? Do you remember AOL instant messenger and the dial-up sound like poltergeist? So leave a code on your best friend's beeper, because you'll want to be there when the nostalgia starts flowing.

Each episode will rival the feeling of taking out the cartridge from your Game Boy, blowing on it and popping it back in as we take you back to the 90s. Listen to Hey Dude, the 90s called on the iHeart radio app, Apple podcasts, or wherever you get your podcasts. All right, Chuck. So it's not just the Maya. This is the thing. This is kind of a new way of looking at history, and especially social collapses.

The idea that climate change played some driving role in it, and they started to look around. They're like, oh, actually, this kind of explains a lot of different ones that we thought we understood before. And the understanding before would be like, well, this king died, and this created political instability. We have evidence that there was this war, and this group got invaded. What they're starting to find now is, actually, there might have been climate change that led to crop failure, that led to instability, that allowed this kingdom to be invaded because

it was weakened by a dying population. Yeah, what it is is a more nuanced look at civilization and ancient histories, because I'm sure there are a lot of people that, when you talk about the Neo-Assyrian Empire, which thrived in what is now modern day Iraq for a few hundred years, and that was one of those where the death of a king is what everyone was always said, well, that's what did it. And I'm sure there were historians who were like, you know, that there's something missing. Yeah, they had so many kings that had died leading up to why this won, and they started to look in particular at the Neo-Assyrian Empire, and they said, oh, actually, if we

go and look at the cave record again, they went to a cave called Kunaba in northern Iraq, and they said, well, actually, the record of rainfall captured by this cave, by these mineral deposits in these caves, kind of show that there was that same thing that happened with the Maya, a very wet period that corresponds with the growth of the society, and a very, very dry period that corresponds with its collapse. And that's not coincidence. They don't think so. It's starting to look like it's really not coincidence.

Another one, the Angkor Wat Temple in Asia, in Southeast Asia. That was like old timing. Who was it that said Paul or Abdul? Because I've been saying that for like 30 something years. I don't know. It was, I think, in a Spike Lee movie or something. Sounds like... It's like Tertura or maybe Paul or Abdul.

Who was the guy who ran Sal's Pizza? Danny Aiello. I could totally see him saying that. It might have been Paul or Abdul. Yeah. All I know is I've been saying it for many, many years now. So the Angkor Wat Temple, yeah, the Khmer Empire in Southeast Asia flourished for, between 802 and 1431 CE.

That's a long time. It's a very long time, but they think that drought, once again, along with like monsoon like rains, really is what brought them down as well. So again, the effects of the climate. And if you look at the Khmer Empire, particularly around Angkor Wat, that's the very famous, like lost temple in the land force that you've seen. Historians have long known that they got invaded and taken over. Now they think actually the reason that was allowed to happen is because of climate change

and it led to problems that weaken the society that allowed them to be invaded and taken over. Yeah. This idea that... It's an ingredient. Right. That a civilization is just like, doing fine, doing fine, suddenly invaded and taken over by a neighbor that's been there for hundreds of years, but have stopped asking, what was

it that did that? Right. Now they're saying, it looks like climate change may have played a role. I think that's just fascinating. Yeah. So the same with the Vikings in the 13th and 14th centuries, they left Greenland. They had been around for several hundred years. And that was because of the little ice age.

Yeah. They had farming techniques that worked before the little ice age, which was a very, very cool period around the globe, I think from like 800 to 1600 or something like that. No. This is the 19th century, I think, at any rate, their farming techniques stopped working in Greenland because it was too cold. So they had to leave. The land said, you got to leave Vikings.

And they went, oh, fine. We'll go take some shrooms and go berserk and get out of here. Yeah, berserkers. So there's a lot we can learn about looking back through history, not only on the battlefield and politically, but also if we look at it through this lens, it may be climate change was a cause of the collapse or an ingredient for the cause of collapse of some of these civilizations, that the same thing could be happening to us very slowly right in front of our eyeballs.

Yeah. I mean, one of the things is if you step back and look at these historic falls of civilizations, it's not like they were like, oh, there's a drought going on. That's it for our culture. Right. It's a underlying driver that they may or may not have pointed to as the cause of these larger things. You know, if you're engaged in like a civil war or an invasion, you're not stopping and

thinking like, gosh, it's because of this drought. Right. You're focused on the invasion. It's the immediate thing. Yeah. And in the exact same way, I mean, we're not that removed from people who lived in millennia ago as long as the way that our brains work. Yeah.

We tend to look at the trees rather than the forest too, and if that's the case, and we're in this period of climate change right now, it's really worrying to think that a little bit of climate change can lead to social collapse and not directly. Again, that's the thing that's what a lot of people argue about is climate change isn't going to cause society to collapse. Not directly. Right. But it could lay the groundwork for all the stuff that goes wrong, that we're failing

to identify is ultimately caused by climate change. That's what we need to be paying attention to if that is, in fact, the case. That's right. And like we said, there are a lot of indicators that some of these same things are going on, deforestation not being the least among them. We are cutting down a lot of trees, and we have cut down a lot of trees. 90% of the forest of Northern America. Yeah.

Just the U.S. alone. Just the U.S. have been cut down. Trees are 50% carbon, roughly, and they absorb, and this is a very big deal. They absorb between 1 and 3 million metric tons of CO2, which offsets, which we need, between 20 and 46% of what we put into the atmosphere. So you don't have to be a rocket scientist to figure out if there's fewer trees, then there's going to be more CO2 in the atmosphere. And I think it's even more significant than that.

We did a whole episode. I don't remember the ins and outs of it. We did a whole episode on cutting down trees and the effect it has on weather. And I remember it has a big effect. From single trees to huge forests, each loss of tree has an impact, for sure. And it's not like we're stopping now. In the Pacific Northwest, roughly 80% of the old growth forest is slated for logging, to go away for logging purposes, which old growth forests, I read a really cool article on the

old growth forest of Atlanta and how Atlanta is a, if anyone's ever been here from out West, maybe, they remark about how Atlanta is a city in a forest. And I was wondering what old growth meant, and it was a really cool article. The years differ depending on who you're asking, but it's basically a forest that has not been touched by humans for between 100 and 150 years. That's cool. And there's still old growth forest in Atlanta. It's great.

Oh, yeah. Wow. Like pine forests? No, just, you know. Like hardwoods? Sure. Wow, I didn't know that. Yeah.

That's pretty cool. It is. Like when you fly into town, you're like, this is just, it's like a lost city in the middle of a jungle. That's right. But it's still functioning. What about social change and what's going on with that? So I mean, one of the things that seems to be a hallmark of a collapsing civilization,

for whatever reason, as part of its collapse, it can engage in civil war, war with other neighboring countries or city-states or whatever. And if climate change is a driver of that, it seems to have happened very recently or happening right now because one of the ideas for the basis of the civil war in Syria right now is a drought brought on by climate change that started in 2006 and actually kind of cast a lot of farmers, a lot of Syrian farmers out of work from their fields into the cities. And so a lot of unemployed, restless people showed up to the cities and they think that that was one of the exacerbators that led to this civil war.

But that climate change, a drought brought on by climate change may have been the underlying driver for the Syrian civil war going on right now. Yeah. That like 400,000 people have died in so far. Human growth is another big one. We talked about both with Amaya and the Assyria empires that even if you're doing great, you still got to keep the population in check because there is a point where you can't sustain it anymore.

And we are expected to reach 10 billion people. Isn't that crazy? By 2050, 10 billion humans on earth. Yeah, just around the corner. And there's an argument that technology is our favorable climate. Like we're doing great technologically speaking. So we're just still growing and growing and growing? Yeah, we're growing because we can invent anything we need to invent to help out any

problem. But if that goes away, then we're going to be in big trouble. I have to fess up. That was me editorializing. No, I could tell. Okay. Yeah. Well, thank you for the legitimacy you added to it.

And I don't mean that goes away, but if there is a breaking point for technological advancement. Well, yeah, it's like the Green Revolution. We went from traditional agriculture to modern agriculture, but modern agriculture is on the verge of reaching its carrying capacity. And we have no idea what's coming after that. Plus, we also are well aware that our modern intensive agricultural practices are problematic. There's a lot of fertilizer runoff that can spoil water, including drinking water. There's a lot of soil depletion that comes along with it.

And in the same way that a lot of other cultures who have fallen seem to have been stubborn and not adapted, but just kept at it, kept at it, despite having warning signs that it wasn't working any longer. We seem to be doing the same thing with our farming practices. And we need to figure out a more sustainable way to farm. Yeah. I think the thing that distresses me is the lack of a, and there are a lot of people that aren't doing this, but the lack of the long-term outlook, it's like, well, it's not gonna happen

in my lifetime. Yeah, that's a bummer. So I need to keep pushing forward with whatever farming practices I'm utilizing or whatever the case may be. One of the suggestions I saw when I was researching the end of the world to get people to care about the future is to extend human lifespans, so that you're like, oh, that's like 200 years in the future. Well, if that was middle age, you would care about that.

And then just, it's weird to think, you know, it's simple if you think about it, but it's also weird to think like just how quickly that would make us start planning for the future a lot more rather than shrinking the future into human size. We would be growing human size into the future, I feel like, the human lifespan or the human awareness of what a lifespan is. Yeah, that would change the whole outlook. Yeah. You always had a good question about that too.

She's like, at what point do we stop caring about our descendants? Yeah. You know, we've got kids, grandkids, great-grandkids, great-great-grandkids. Yeah, exactly. That's my cutoff. At one point, we just stopped saying great and it's just descendants, you know? Yeah, sure. Now, I wonder, like, where do you really stop caring?

Like, do you really care about your great-grandkids? I don't know. Great-great-grandkids? I don't know, unless so. All right. Let's find it fascinating. Or maybe here's the thing. You could just not even think about it in terms of you and your family, but maybe just

planet Earth and doing the right thing. Yeah, luckily, a lot of people do think that way in increasing amount. We also have to say, Chuck, that the idea that climate change is a driver for social collapse is very new. Some people, some historians or archaeologists are like, this really smacks of a trendy thing and I'm just not on this bandwagon. Right. I mean, it's too new.

It just seems too hip, you know, like a scissors sister's record. But I guess what I'm trying to say is this isn't definitive, it's not set in stone. And there's also a lot of people who say, well, we are pretty smart. We're a lot smarter than we were a thousand years ago and we can invent our way out of any problem. That old bag. But I mean, we've done it so far. It's tough to argue with in some cases, you know?

Good point. I mean, it's not to say that the world is necessarily going to end at any point in time in the near future. Right. Or that we cannot ourselves assimilate and change and roll with it and go back to maybe a different lifestyle. Or yeah, or continue on our technological progress, but like say, adopt more sustainable farming practices.

I mean, that's the view of the future that all these dystopian films have. Is this usually, I mean, sometimes it's a barren wasteland, Mad Max style, but a lot of times it's like a return to the earth and small villages of people farming. That's exactly what happened to the Maya. They moved out into farms. The farm, the farm hinterlands where they just continued on like nothing happened. But the people in the cities were like, well, we're Mad Max now. Coastal elites.

Yeah. Right. You got anything else? No. This is the climate change leading to the fall of the Maya, the episode, and that's the end of that. And since I said that, it's time for Listener Mail. This is from Rosanna in Surrey, United Kingdom.

Hey guys, my husband and I are currently renovating an Edwardian house in very poor condition. She detailed it. It just sounds like a wreck that they're in the middle of. The loo is upside down. Not worth it in the long run. There's a lorry in the living room. There's a lift in the lorry. When everything seems to be falling apart around you, the last thing you want is to

be left with your own thoughts and your podcast is always there. So I don't have to be. For many years, I've listened to your show the way other people listen to the radio. It's the first thing I put on the morning when I get up and this continues on my drive to and from work or whenever I'm in my car and I often put it on before bed because I find your voice is so soothing. Your show really helps with my anxiety as well. Both my husband and I are doing all the work on the house ourselves now.

Electrics, plumbing, plastering, tiling, decorating. You name it. And I've left my job to work on the house full time. So for the past six months, I listened to you two talking to keep me company and learning while I'm working, which lasts at least nine hours a day. Solid Josh and Chuck. Man alive. You basically become my main source of human contact guys, for example, it's only 10, 20

in the morning. And I've already been listening to you for four hours and 20 minutes. We're 20. Are you okay? You all right? And we'll continue to do so until my husband gets home late tonight. Obviously, this means a lot of repeated shows, but it never gets boring. Much of the DIY work is unbelievably slow and tedious.

Yeah, I bet. I've been there, Rosanna. I definitely would have lost my mind long ago if it wasn't for stuff you should know. I don't want to say a huge thank you for keeping me sane, educated and chuckling along when I do would otherwise be on the floor crying about how much I have to do. That's awesome. What you guys do is brilliant and I wanted to let you know you're not just educating people and helping to expand their beliefs.

You're also genuinely helping me feel connected to others while I try to create a home for me, my husband and our two idiot cats and two house rabbits. That's awesome. I want to come see you. Yeah, that's pretty cool. I want to see your Victorian home. Edwardian. I want to see your two idiot cats and your two house rabbits.

Are you going to help? What did I say? Victorian? Yes, Edwardian. Are you going to help plaster? Help plaster the crud out of that house. Go get plastered and do some plastering. That's right.

It'll be all over the place. You'll get it all over the lorry. Well, thanks a lot, Rosanna. Best of luck in the renovation. I'm glad we can help you out. That's good to hear. If you want to get in touch with us like Rosanna did to let us know what you're doing with your time, we always want to hear about that.

You can go to StuffYshouldKnow.com and check out our social links, or you can send us an email to stuffpodcasts at iHeartRadio.com. Stuff You Should Know is a production of iHeartRadio's How Stuff Works. For more podcasts from iHeartRadio, visit the iHeartRadio app. Apple podcasts are wherever you listen to your favorite shows. From the podcast, Hey Dude, the 90s Called, David Lasher and Christine Taylor, stars of the cult classic show Hey Dude, bring you back to the days of slip dresses and choker necklaces.

We're going to use Hey Dude as our jumping off point, but we are going to unpack and dive back into the decade of the 90s. We lived it, and now we're calling on all of our friends to come back and relive it. Listen to Hey Dude, the 90s Called on the iHeartRadio app, Apple podcasts, or wherever you get your podcasts. Listen to Frosted Tips with Lance Bass on the iHeartRadio app, Apple podcasts, or wherever you listen to podcasts.