When will the Earth become uninhabitable?

the things we hold dear will simply fade away. And at the same time we can be so very resistant to change and the idea of change, we wind up taking certain things for granted, even the very planet that we live on. To invoke the Goldilocks principle, our planet is just right for life. We've got the right ingredients, the right crusts, the right temperature, the right moon, the right star, the right core, the just the right celestial neighbors. We've largely lucked out when it comes to near Earth

objects in five major distinction events. Later here we are thriving within and in some cases beyond the portion of the Earth's atmosphere and climate that we evolve to thrive in. But when will it all end? When will this place become uninhabitable to us? Some of the threats are so distant that they're almost impossible to really weigh. Will we even be us when our species encounters them? Others, however, are far more pressing. Yeah, So I'm going to try

to give you all an example. I'm gonna take this from the personal to the macro. Okay, yesterday I had to go to a retirement planner. I didn't have to. I chose to um a human or a website. It was a huge I did the website first, and then they said, you might want to talk to a human about this, and so I went, I had a meeting. I sat down, we like looked at forms and stuff

like that. But you know, it's not I'm forty. It's not the kind of thing that I've really spent a lot of time thinking about other than just having jobs that have, for one case, building up right. Uh, And I just just really, you know, haven't thought in a

future oriented way like that before. And then immediately after that, I came home and I started to research for this episode, which is essentially about planning for global annihilation, right for for getting ready for the world, for Earth specifically to be uninhabitable for us as human beings. Well and hopefully. I mean the optimistic spin on that is preventing these the events and preventing the kind of cascading effects that

could leave the earth uninhabitable. Yeah, but as we get as we will get into some of them are inevitable and there's literally nothing we can do about them. But those are luckily billions of years away. Yeah, some of these things are just so far off it's pointless to worry about them. But some of them are worth worrying about, and we're going to spend some time with those as well.

You know what's kind of interesting is in your intro that you presented just now, you touched on the very first topic that you and I ever worked on together, which is the Goldilocks prince bole. Do you remember I wrote a script for a brain Stuff episode like four years ago that you performed, and it was you and Kristen con and it was about the gold lux principle. And then uh, then the stuff about mass extinction. My first official episode as a co host of Stuff to

Blow Your Mind was about mass extinction. So this this is interesting. Yeah, that that one was interesting because I remember that the topic was great. Uh and yet even though you know, I had plenty of interactions with with Congre previously. That was when I got to realize, oh,

we have no on air chemistry to get at all. Well, that was actually that That was sort of like along the lines of what we were trying to do was we were trying to test out all the various people who did on screen stuff to see who did have chemistry yea yeah. And while we were filming that, I was like, I can I can tell we don't really have we don't have a lot of it. I don't know. People can go watch it and judge for themselves. It's out there and the content is still good. It is yeah.

Uh so let's yeah, and this episode we're going to discuss some long term concerns, some short term concerns regarding the habitability of the planet Earth, as well as some sort of random concerns thrown in there. Uh. I guess you can sort of think about it in terms of a really complex board game, right where you have you have sort of the early game uh opponents or early

game threats you have to deal with. You have the in game stuff, you know, the real doom counter type scenarios, and then you just have random events that may pop up and just in the game. Yeah, you're using a lot of Arkham asylum phraseology here. I like it. I

like it. Uh yeah. And and also, to be clear, the reason why I was really interested in covering this, uh, even though we somehow ended up pairing this together with zoophilia on the same day as topics that we're going to discuss, it's actually because I'm working on this sci fi horror story and I want it to be about trans humans returning to an uninhabitab Earth. As I started thinking to myself, like when will Earth be uninhabitable and

what will it look like? Yeah? Yeah, I mean this is a This is a common trope in in science fiction, the idea of of the world becoming poisoned of humans of course moving beyond the Earth and then coming back to it. Yeah, and in some cases the Earth is gone. Um, if I remember correctly, in the in the Dune books, it's reference that the original terror, the original Earth no longer exists. Is that right? I didn't even know that

they acknowledged any connection to actual like humanity. Okay, yeah, well, the like the Tradees are supposed to be um descendants of the Greeks, is that right, But but I believe it's it's what God Emperor of Dune. In one of the many lectures that the title character gives, he refers to the original Earth and how it no longer exists. It may be a reference elsewhere in the in the saga as well. But yeah, this episode is kind of like, how do we to what extent can is that unavoidable?

The eventuality of Earth being gone or Earth being just there but but nothing that we could live upon, And what can we do about especially some of these random and short term threats to the habitability of Earth. Now one of the long term effects this is not something we need to worry about tomorrow or technically in the next hundred years, but it is going to be a concern.

It's probably one of the first things most people think of, right, is the death of the Sun. That's right, like the Sun just eventually turning into a red giant and swallowing the planet Earth. Yeah. Again, I would say, don't don't lose any sleep over this, but it does exists as the like the late game game ending Doom counter situation totally, this is the point at which the game has to end, or may have to end. Well, we'll get into some of that presently. So I like to think of the

Sun is kind of a dot com erab business. It's running on a huge influx of funding, but destined to eventually burn out. Eventually the money is gonna gonna go away, Eventually the energy is going to go away. So our son has been going strong though as a business, as a star, as the center of our solar system for four point five billion years, and by most estimates it has it has another five billion years left in the tank.

So it's got a lot of pivoting left to do. Yeah. Well, no, well the pivots are key, because the pivots are or what what we're gonna have to worry about. So when the core runs out of hydrogen fuel, it's going to contract under the weight of gravity. Uh So again, think of like a bloated business that's suddenly the money is

not there to support it and it has to downsize. Um, this is where the metaphor kind of becomes more difficult to engage here, because, uh, some hydrogen infusion is still gonna occur in the upper layers at this point, and is the depleted core contracts, it heats up and this it's up the upper layers of the Sun, causing them to expand. As the outer layers expand, the radius of

the Sun will increase and it will become a red giant. Now, the radius of the red giant Sun would be a hundred times what it is now, lying just beyond the Earth's orbit. Some scientists have estimated that this would vaporize our planet, but there's also a good chance that it would push Earth in its moon outward after consuming mercury and venus. Now, obviously there's there's again nothing to lose

sleep over here. Um, you know, five billion years, that's longer than the Earth has existed, and the span of the human species is virtually nothing in that well of time. And of course there's a lot that can and will happen before the Sun turns into a red giant. Long before this happens, say in a mirror one point two billion years, the Earth will grow hot enough to boil

the way our oceans. And then, after all this takes place after the red giant phase, in nine point five billion years, the Sun will collapse into a white dwarf and the remaining dead world will continue to orbit around it. Eventually, the white dwarf will go dark, and there'll be this inevitable collision between it and another black dwarf, and this

will blast apart the remnants of our solar system. This according to an excellent article in Forbes, of all places, even Ethan seagulls how our solar system will end in the far future. I actually read the same piece, and Uh, Siegell says, when our son was newborn, this is this is good to get some perspective on it. It only

had of the power that it has right now. But the properties of planet Earth, the flora, the fauna, the ocean, the atmosphere, all of that stuff has allowed us to adapt right Also, the astrophysicist Robert Smith, not to be confused with the frontman of cure Uh, says even just the aging of the Sun will accelerate global warming to a point where Earth's water just simply evaporates, as you mentioned earlier, so there's not a whole lot we can

do about that. The atmosphere will be laden with water vapor at that point, Uh, And it's going to turn out like the water vapor will act like a greenhouse gas, which we're obviously going to come back to later. In this episode, the oceans will boil dry. But all right, let's think really cosmic here for a second. Okay, let's like zoom out. Let's pretend like we're Galactus from from

Fantastic four Comics or something here. Okay, what if we could harness comets and asteroids so they gravitationally slingshot past Earth, but move us into a wider orbit away from the Sun. That might be possible in the future. Um, and I believe on the Kardaship scale, that's like one of the sort of ladder parts of the scale. Rights, if you can harbor harness cosmic entities, well, I mean, first of all, if you can harness all the power of the planet, and then if you can harness all the power of

the Solar System. So yeah, just at that level, he would consivably have the ability to to move the planet around to find a new orbit for it in some of the the more extreme cases. You know, I've seen it argue that, you know, you could take the planet

and move it beyond the Solar System. Certainly, when you get into those upper levels of K three and K four, Uh, you're talking about godlike power, where on one level it becomes easy to say, well, of course we could do this because of the amount of power that we would have.

And then on the other you have you have to say, what would we be if we had that much power, if we had the power to harness uh all the power of a solar system or or or you know, scales beyond that, then what would what would our values be? What would we need? Would we care about moving the Earth? We'd just be like, well, let it burn. We've got these crazy spaceships now. Well, another theoretical way to move

the Earth is to build a planetary sunshade. That would have a similar effect, and it would move it out into a further orbit. But hey, guess what, even if we can do that, the red giant phase of the sun is it's gonna get earth like. Even if we can move it far enough out that we can somehow use it to mitigate climate change, for instance, it's it's not gonna matter that red giant is eventually going to swallow us. Well, I'm not not by all. It depends

on how far out I guess you move it. Yeah, but even if we escape, what's the world look like afterward? As we're slouching towards extinction. Okay, so astrobiologist Jack O'Malley James of Cornell University actually sketched out a sequence of extinctions over the course of four billion years. So here we go, all right, at five hundred million years from now, from right now, that's when the sun is going to start getting hotter and c O two will be sucked

out of the Earth's atmosphere. That's gonna make all of the plants die off because they can't photosynthesize. Following that, large vertebrates will go, then the small ones because there's no plants for them to eat. Then the only remaining animals will be marine invertebrates along with microbes. Maybe some insects that can eat dead plants will still be around, but mostly the only creature, uh, the only creatures that don't need to eat plants are gonna be able to

survive this. The last non microscopic remaining animals will probably be those tube worms around the deep sea hydrothermal vents. Then at one billion years out from now, that's when the oceans start to boil. Uh. And then if that doesn't kill the microbes, the actual boiling of the oceans, the CEO two levels eventually will fall so low that even microbial photosynthesis will end. Okay, then at seven point five billion years out, that's when we're talking about the

Red Giant engulfing Earth and the Moon. But what if Jupiter's moon tighten suddenly became warm enough for life to evolve. So maybe that's the next place where there's going to be a habitable society. Well, it comes back around to the the frequent argument you see from from various astrophysicists and futurists, and that's just the the long long term survival of the human race depends on us UH expanding beyond Earth absolutely. Now, some additional concerns for the future

in any case of the far future. One is magnetosphere loss. So Earth's magnetosphere is essentially a magnetic bubble that protects the Earth from charge particles and plasma Earth's solid intercore and liquid outer core. This generates the field. Okay, it generates the magnetosphere, and according to the dynamo theory, differences in temperature and composition in the two core regions drive

this powerful dynamo UH, emitting Earth's protective electromagnetic field. Now, some scientists theorized in about two to three billion years, the dynamo MD half, leading to the decay of the magnetosphere. And remember again how essential this field is. It's absence on planets such as Mars make colonization a challenge. Like it's hard to imagine life being being able to to really take a firm um hold of a planet that

does not have a magnetosphere in place to shield life. Yeah, protects us from so many of the hazards of space. It's one of the key aspects of the Goldilocks principle, you know, one of the things that makes this planet just right. And it's uh, it can be kind of frightening or sobering to think about the fact that this is not something that will last forever. But what about

the Moon. I've seen a lot of people talk about the moon is being like, well, if we could go anywhere if climate change gets too bad, let's just go to the Moon. Well, um, yeah, that well, the Moon is probably not a great option for for living on either. Uh. But but it does play into another long term concern, and that has to do with the perturbation effects. So our large moon ensures climate stability by minimizing changes in planetary tilt. If our planet didn't have a tilt, it

wouldn't have seasons. Likewise, a severe tilt would result in extreme seasons. As we've discussed on the show before, the Moon is drifting away from Earth. Eventually, given you know, enough time, it will be just far enough away to make a total solar eclipse impossible. Yeah, I've actually got some stats on that the Moon is moving away from us at three point seven eight centimeters a year. Between one point five and four point five billion years from

now is when it's going to stop stabilizing our tilt. Yeah. The so the Moon pulls on the Earth, and the Earth orbits the Sun, resulting in a torque that causes the Moon to move a little bit farther away from the Earth and slow the planet's rotation. Rotation slows by

one point four milliseconds per century. But in fifty billion years time, the Moon will orbit in forties, you know, at a rate of forty seven days as opposed to the twenty seven point three days we know today, and the twenty four hour Earth day will be forty seven days long, and the Moon and Earth will then become tidally locked as well. Luckily, we've already established that well before that fifty billion year mark, the Sun is gonna

eat both of them, so it doesn't really matter. Yeah, and so the idea here is that, uh, once the stabilizing of the Earth's tilt stops, the poles are gonna tip to a point where like the North and South poles are going to be where the equator would have been. And this is going to cause obviously extraordinary climactic effects. But it goes back to what we were talking about earlier. I mean, we have just the right moon for life to be able to thrive here on Earth. So how

does this explain Transformers five? Then? Because in that movie, the planet Cybertron just parks itself right next to Earth and I think destroys the Moon. So I mean, clearly they thought through the science on them. I assume they brought um just being silly here. Obviously those don't make a like a sense. But when this whole thing happens with the tilt, some regions of the planet and it will still be protected by the Sun, So it would be possible to still live on the planet after this

perturbation effect. So h What would be bad though, is that some parts would dip to below a hundred degrees celsius for part of the year. The only thing that would be able to survive would be microbes inside these cold trap caves. And then even two point two billion years after that, those caves then will suddenly become too hot. So yeah, it's no win scenario. You have to This is when humans have to start living in the big pyramids. The last re doubt of William Hope Hodgens The Night Lands.

Maybe that's what that hidden vault inside the pyramid was that they just found recently. It's it's specifically designed for when the moon's moon stops affecting her tilt. I do recommend any anyone who is interested in sort of uninhabitable

earth sci fi. William Hope Hodgins The Night Lands is fabulous of kind of challenging to read because it depicts uh an age in which humans will have to live in these artificial structures UH on a dark earth like everything else is just cold and dark, but they're I believe they're using thermo thermal energy to to maintain themselves. In the book, Hodge and stuff is just fascinating, especially when you consider the era that he lived and how far ahead. He was thinking, why don't we take a

break and then we come back. We can talk about some just random concerns, things that we can't particularly track for how they might end life on Earth. Thank, alright, we're back. So this first one is is a major threat. Uh and it is a proven major threat to life on Earth. We're talking about near Earth objects or ane os, So impact events are possible factors in three out of

five major extinction events here on Earth. Space collisions occur all the time, and most of them don't make too much noise, or at least those that have occurred during human history haven't. That's because in space no one can hear you scream. Well, of course, the thing is Earth is in space too, so we're counting the Earth colliding with things, we're accounting the moon called lighting with things, etcetera. But even when they do make noise, we've been very lucky.

For instance, consider Night to Munguska event, which hit a sparsely populated corner of Siberia rather than a major population center, and it's it's been pointed out that a mere four hours of planetary rotation would have placed the bull's eye on densely populated St. Petersburg instead, So instead of having this just this devastating crater in this blast you know, heard over vast distances, instead of it occurring in the middle of nowhere, what if it had occurred in in St. Petersburg?

What have it occurred in a major center of human population. And you like to think, like in these big budget blockbuster disaster movies that like we'll be able to chart the course of these things, will know that when they're coming, and we'll evacuate cities. Right, But well, I mean this is this is this is where he gets into something I've talked about before, Like this is one of those one of the few areas where where you can conceivably

save the world. Um, because the odds are that a large INEO will come into play in the future and humans will hopefully be in the technological and cultural position to identify it, to track it and mitigate the situation. There are a number of different um methods that have been proposed for deflecting an incoming INEO, and they range from you know, blowing it up to just sort of nudging it out of the way, to you know, harvesting it,

et cetera. You send Bruce Willis and Steve BUSHEMI up there, Uh, Peter, storm are and problem solved. Well, hopefully, I think we're getting to the stage we realize we only need to send UM. But yeah, this is one of those few areas where the work of NASA and other space agencies their work to track ineos and and and eventually mitigate them. This is one of the few areas where concentrated human

efforts can actually save the world. And of particular interest here are asteroids that are six point two miles or ten kilometers in diameter or larger. The These are extinction class ineos. So here's some stats that I found on this. A third of those thousand mile wide asteroids that are hurtling across Earth's orbital path will eventually strike us. But luckily, the rate of which that they will strike us is

one in every three hundred thousand years. Now. For instance, similar to the Tunguska event in nine, a small one way smaller than that crossed our orbit just six hours after Earth had passed through. Uh. This thing had the kinetic impact force equivalent to a thousand nuclear bombs. So we've talked before, UH, specifically in our rods from God episode about dropping basically like metal telephone polls from outer

space as weapons. Uh, the impact, just the basic kinetic impact of something from outer space hitting the planet is considerable. So something that small would be the equivalent of a thousand US. Yeah. I remember in our Inner Interplanetary War episode we talked about that a bit like having having orbital superiority over a planet. It gives you just tremendous power without even having any explosives or nuclear devices, just the ability to drop things if you have those things

with you. I think we we concluded in that episode, if you have a ship that is capable of interplanetary travel, that alone is enough of a weapon to destroy an entire planet. Yeah, just by crashing it into it. Yeah, it's not like Star Trek where the Enterprise like just like you know, like a like lands in the lake or whatever. Now, another area to concern getting away from d e O s um it comes. It gets downd

to the issue of Near Earth supernova. So this is another concern that's even more insidious in some ways because there's not much of a way to stop them. Other other cosmic threats include gamma ray bursts caused by the birth of a black hole or the collusion of two neutron stars. It's been estimated did a ten second burst originating within six thousand light years could deplete up to half the planets ozone layer, and such an event might

have played in the Ordovician mass extinction. Okay, Well, another figure that I read in the various articles that we looked up for this Supposedly the Andromeda Galaxy is on a multi billion year collision course with the Milky Way as well. So not only are we worrying about the planet, but our entire galaxy is in trouble too. Yeah. Yeah, things, things fall apart, and things have a way of colliding

together as well. But all of this stuff is either random or a long way out, right, Like we've established, like the asteroids, there's a pretty low percentage chance or hopefully we'll be able to track it. And and that's not random, but but it's it's it's not something that like we know for sure is going to happen the Sun we know for sure, that's super far away. Yeah, Like the long term issues are long term issues that made be unavoidable, and we can't lose much sleep as

far as the random issues go. I do believe there is a real need to focus on ineos, and I think that like basic planetary protection is essential there. But still it's the kind of thing where, yes, someone could make an argument for well, we'll just let the next generation figure that out. You know, you remember when we were kids in the eighties and the Reggae administration developed the Star Wars system. My first reaction was I confused

it with the movie Star Wars. My second was that I assumed that it was about asteroids, that it was the whole defense system was designed to protect us from asteroids. Turns out, no, not at all, to perfect us from us. Yes, it turns out, and we'll get to that threat. So what about shorter term concerns, Like, let's narrow this down right, like when are we going to have to get off Earth? Basically?

So here's some good news. Uh, Mammal species tend to only last about a million years on average anyway, So we as human beings have already had two hundred thousand years, So we've got eight hundred thousand years left. That's pretty good, right, That's more than we've already had. So yeah, well that of course is not counting in counting on the various ways that we are working at our own destruction exactly. Uh. Stephen Hawking, though recently he actually gave an interview in

the last couple of years talking about this stuff. He is a proponent of us freeing ourselves from other Earth, as he calls it. And he says, quote, it will be difficult enough to avoid disaster on planet Earth in the next hundred years, let alone the next thousand or million. All right, So we all of a sudden went from like billions of years to the next hundred years as being like potential problem. And he says, this is either nuclear weapons or the aging sun acceleration and and this

isn't the Sun swallowing the Earth. We're talking about global warming here. And as we've already discussed, Hawking says, if man doesn't make the planet uninhabitable or the sun, then we're going to encounter a supernova or an asteroid or even a black hole. We didn't even touch on black holes. So all right, let's talk about it. Climate change. Some starter facts here. I didn't know this. Eighteen eight is when scientists first started keeping track of global temperature logs.

Last year two thousand sixteen. We're recording this in two thousand seventeen. Last year was the hottest year the world has seen since scientists started recording global temperature logs. Now. Overall, the planet has warmed two point three degrees fahrenheit or one point to six degrees celsius in that time. Let's try to keep those numbers in mind as like a point of perspective as we're looking towards the future. And I want to talk briefly to as we get into

this about climate change. As I guess I would define it as like a rhetorical communication problem. Is this article in the Atlantic where Robinson Meyer argues there's three shifts that are going on right now, primarily here in the USA, but globally as well with climate change that make it hard to communicate. The first is that the consequences of climate change are severe and devastating. We've got a lot of examples that we've given so many examples on this

show before. Uh we're talking about mega droughts, We're talking about sweltering summers, or the destruction of the Great Barrier reef, among others. Secondly, some people are trying to address climate change with things like solar and wind as energy or say electric cars as a way to attempt to stabilize

the amount of carbon that's released in the atmosphere. But we have to acknowledge that, as of this recording, the country that Robert and I live in, the United States of America is undermining climate policy because we've abandoned the Paris Agreement. Yeah, there's a there's an episode that Joe and I recorded few months back back titled Science Communication Breakdown.

And now we get into into this topic a fair amount, like getting into the idea of like, Okay, we have we we have the science of climate change, and yet we have a large portion of the population that that denies it or or is an opposition to it. Why does that occur? Why has this topic become politicized when it is a matter of scientific consensus. So I would I would refer listeners back to that episode if if you want a more like in depth tackling of that

of that issue. Yeah, I think so, what we're facing here are two opposed visions of the future, right, and neither are really scientific in nature. One is economic, one is political in there in opposition to one another. So all of this leads us to this article that actually, you know, we talked at the beginning about the impetus for doing this episode. I was unaware of this, but it just came out this July in New York magazine.

It was written by David Wallace Wells, and the articles type was the Uninhabitable Earth, and in this he argued that parts of Earth will become uninhabitable by the end of this century. Many climate scientists and science communicators strongly disagreed with him on this, and they said that this was a doomsday scenario, it wasn't realistic, and that it wasn't supported by evidence. They also said that his article doesn't identify his sources either. Now I want to step

back for a second. I read through his whole article and a number of rebuttals to his article. Okay, I'll provide my thoughts later, but he definitely cites sources, and he provides links to a lot of statistics that he uses throughout the piece. Now, either he added those after the criticism, or his detractors are exaggerating their complaints. Uh. I didn't fact check every one of his sources, but it looks like he at least attempted to provide some

kind of logical evidence for his claims. Well basic Based on what I was looking at, it seems like a lot of the complaints were basically making the charge that you were you're presenting this a is U is a scare piece that you're and that that is not how one needs to communicate the topic. Uh. And and based on previous research for the Communicy Science Communication Breakdown episode, I mean, I I can agree with that, like that does not seem to necessarily be the way to reach

new minds about the topic. Uh, it's just I mean, it could be useful, I guess as a rallying cry for people who are already convinced. And and maybe that's the prime purpose of the peace I mean, one has to take the readership into mind here, like where where was the article published? And who are the the intended

readers of the piece? Yeah, so the article itself is problematic for climate scientists, and and you know, because of the reasons we outlined above, obviously, but also because they're trying to be very very careful about how they communicate climate change with the public. They want to make sure that the facts that are resented are absolutely indisputable. And they also have research that shows that we respond better

to hopeful messages instead of fatalistic messages. So that's along the lines of I think what you and Joe covered in Communication Breakdown. This is my take on it. Okay, I would argue that climate change communicators they're facing a branding problem. And this is just from my experience working on this show and doing science communication. There's so much evidence for climate change that we've encountered just while we've been researching other topics on this show, not even intending

to talk about climate show. Yeah, when we did our small Barred episode, it was all over the place. And there when we've talked tomorrow Heart about coral reef biology, it was all over there. It's it just it keeps coming up every time I'm presented with that evidence. It's even more convincing. Some people that just have a knee jerk response the minute they heard they hear this terminology climate change, right, they just assume that it's automatically disinformation

for some reason. Now, if you just present the evidence of the impact, they seem to believe that, but you don't attach those terms to it. It's like, for some reason it has a branding problem in rhetoric. This is what might be called an ethos problem. There seems to be a negative connection between the terminology and the quality

of its character. And that might be because of doomsayers like Wallace Wells, right, because of scare pieces like this, which which again I can see where a scare piece would be would be beneficial to people who are you know who who don't deny the scientific consensus, that that just needs something that maybe to is a rallying cry, you know, as a reminder of what's at stake. Um.

You know, I don't think we should sugarcoat topics. But again, the argument is there that if you're looking to reach new minds, if you're looking to to connect with people who are in a state of denial or doubt, then this is not the best tactic. Well, let's go through his piece. Uh and well, I'm I've outlined his claims here along with the counter arguments against them. I do want to cite him specifically here. This is a quote

from the article. He says. This article is the result of dozens of interviews in exchanges with climatologists and researchers in related fields, and reflects hundreds of scientific papers on the subject of climate change. Later on, he says, it is a portrait of our best understanding of where the planet is heading absent aggressive action. Again, my personal take

on this, I read through the whole piece. I'll say that outside of the problems that we're going to outline with his evidence, the pros itself reads like a rant. So along the lines of like just saying like, oh, this seems like a scare piece, it sort of reads like that, it's it's difficult to understand it, and he bombards you with information in this way that just isn't persuasive, And I think that in and of itself is problematic

if the goal is to change reader's minds. So he says, the likely warming expectation from a scenario is presented by the United Nations inter Governmental Panel on Climate Change, and this was in now. They say we're looking at somewhere between a two point six and a four point eight degrees celsiust shift by the time we reach one somewhere between that period of time. Now, I think it's worth noting that Wallace Wells argues the upper end of the

probability curve actually runs as high as eight degrees. So he goes way higher than this. This study that he cites, they say highest is four point eight. He goes all the way up to eight degrees. That's way higher than their prediction the Paris Climate Accords. Just to give you, like again, like some perspective here. All they're trying to do is get us to the point where we only go up by two degrees in that period of time.

So you see just how much of a difference there is in these seem like relatively small numbers, right, two for eight, But there's a lot. There's a lot there now. Wallace Wells also starts by saying that the sea level rise isn't the worst of our concerns with global warming. This is because there there's a lot of attention paid to sea level rise earlier in this year in scientific articles. He says, yes, cities will drown, but other parts of

the world will become uninhabitable by the end of the century. Quote, most of the scientists I spoke with assume we're gonna lose Miami and Bangladesh within the century, even if we stop burning fossil fuels within the next decade. He also says that cities like Karachi and Kolkata would be so hot that they would be close to inhabitable, and he wonders if this is why we have this obsession with apocalyptic fiction, right all the zombie movies or Mad Max

movies and the world scenarios. He says, maybe this is a collective result of displaced climate anxiety. Okay, I know we're hitting you with a lot of heavy stuff. So here's a fun aside. I'm doing the research on this yesterday, and I've been listening to a lot of led Zeppelin in the last week because I saw that Thor Ragnarok movie and they play immigrant song and yeah, yeah, yeah, it's it's it's prime. So I'm listening to led Zeppelin and while I'm prepping these notes here when the levy

breaks comes on. That was that was pretty eerie, like worrying about flooding and all that. Uh, and then like the soundtrack just kicked in there. All right. Back to the study, he also says the world's perma frost is going to send its methane into our atmosphere as it melts, and that is going to accelerate the planet's warming in the in just the next couple of decades to come. He uses the thawing of the ground around this fall barred vault as an example. We talked about this in

our small part example. Now he also says that perma frost contains one point eight trillion tons of carbon. That is more than twice as much as what is currently suspended in Earth's atmosphere. Okay, so that's his argument about the perma frost. His detractors say, alright, yes, perma frost will emit methane, and yes, methane is a potent greenhouse gas, but scientists don't actually think that that much is going

to escape in this century. There was a study that was published in twenty that found that perma frost melt would only release about five to fift pent of its carbon, and that that would be in the form of carbon dioxide and not methane. So that's substantial. It's still something we need to worry about. It's not as dire. Wallace Wells says, Actually, methane is thirty four times as powerful as c O two, so we should keep that in mind.

Another example that he brings up in his piece. Do you remember earlier this year when the um there was that crack in the ice shelf. I think it started in May and then it broke off and calved off into this like massive iceberg. He used that as an example as well, along the lines of the perma frost um. He also said that satellite data shows that the planet has warmed twice as fast as we thought it would.

He adds a qualifier though afterwards he says that quote the underlying story was considerably less alarming than the headlines. This was one of the things that he had to update in his article afterwards after so many people complained. There's a footnote at the end of the article that lets you know all the things that were changed afterwards. So while he warns us about the satellite data, he also kind of backs up and he says, I know,

like that was kind of scaremongering. Uh. In actuality, it seems like those satellite models have tracked closer to what we predicted. He also says carbon dioxide levels, so remember earlier they said, oh, it's gonna be carbon dioxide instead of methane. Well, he said, carbon dioxide levels, if they go up, they're actually going to depress our brain functions on a global level. Other scientists argue back and they say, this seems like it will only be an indoor problem,

not an outdoor problem. I don't know. I'm not a climatologist. Now, in his own defense, Wallace Wells argues he didn't want to be misleading in his portrayal of the research, but he ran his peace by climate experts, and he wanted the piece to survey worst case scenarios because he believes quote, the public does not appreciate the unlikely but still possible dangers of climate change. So that seems like he's he's making his sort of rhetorical purpose clear here, right, Like

he he acknowledges that he was, uh somewhat being extremist. Right. His main concerns in the conclusion of the piece are that climate change is going to lead to a threat to our food supplies in the next hundred years. There's going to be a risk of increased violence as temperature goes up, and that fears of long dormant viruses awakening from the Arctic permafrost will come true. This is a plot of Fortitude, the TV show that I keep talking about on here, that that's one of the things that

happens there. Because they're on small bard. Uh He also mentions unbreathable air and the danger of extreme heat combined with high humidity. Now, this is something I've never heard of before, but it's related to climate change, something called the wet bulb temperature concept. Have you heard of this? What it relates to the human body's ability to cool itself? Right, Yeah, exactly so. Uh. The idea here is that we cool our skin by sweating, right, which is how we stay

alive in the worst heat. I can tell you, Uh. Here in Atlanta it was like almost eighty agrees yesterday in November, and I walked home two miles. I swept quite a bit. Okay, that was me staying alive in that heat. When you get above thirty three degrees celsius or nine degrees fahrenheit, our threshold for heat stroke comes up, and that can be fatal. Based on that I p c c worst case scenario that he's citing, a third of the US population would be facing a day or

more of such dangerous conditions. The typical summer day would exceed this heat stroke threshold. So that's concerning, Yeah, I mean, especially when you take into account the limited ability of of various people, great portions of the population to stay cool. Yeah, exactly. Now, the terms weird, right, wet bulb temperature will it turns out that it comes from wrapping a thermometer in a

damp sock. The idea there is that that will actually reflect both heat and humidity simultaneously, and Wallace Wells argues in his peace that the resulting dehydration that comes as an effect of all of this is going to cause chronic kidney disease across our entire culture. So we're just in cascading effects here as Yeah, okay, a little bit

more about this. His detractors say that the post climate change world is actually gonna look a lot like the world currently looks like, except it's going to be more unequal and more impoverished. So essentially they're saying, we're not you know, a hundred years from now, the world isn't going to be uninhabitable, it's just gonna be less equitable. Uh. They argue that he glosses over reasons why climate advocates

actually have some hope. They also make one important point his articles citation of those I P c C numbers. Not only are they like way higher, but he also doesn't necessarily clarify between celsius and fahrenheit in his story, and there's huge discrepancies there. More likely, though, because of trends like the Paris Climate Agreement, human society will bend emissions downward without hitting these worst case scenarios that he's outlined.

Even in an email with The Washington Post, Wallace Wells conceded the most likely scenario is about a two point five to three degree celsius change by the end of the century. Since eighteen eighty we've only seen a one point to six degree celsius changed, so that's still pretty significant if you think about it. So even if we're able to drop carbon emissions to zero tomorrow, like if we made waived a magic wand right and all of a sudden, all cars, all all of our technologies stopped

emitting carbon, that's obviously not going to happen. We would still be dealing with climate change for centuries afterward. So our only option at this point is to adapt to it as painlessly as possible. And how do we address this well. One proposal is to develop technology that takes CEO two out of our atmosphere to dampen the greenhouse

effect that seems interesting but also problematic to me. Right, It's like the technology got us in this problem in the first place, right, and it will build more of it and we'll use that to sap out the bad stuff. But then what will be the repercussions of that, Well, it's one of those scenarios where you imagine that a little more hot water because the bath is too cold, a little more cold water because the bath is too hot,

and then eventually the bath is overflown. So let's try to ground this in some more recent studies that are maybe a little more closer how things are going to shake out in the next hundred years. A study published in the June issue of Science by the Climate Impact Lab. They argued that actually, climate change is going to have an economic impact. First, the poor are going to get

poorer and the rich are going to get richer. Great, uh, this will impoverish the poorest communities in the United States first, and the outline that the south, the Southwest, and communities along the Gulf coasts are going to be the ones that are hit the hardest. Cities and coastal suburbs, however, are going to just get richer. Contributing to this is that ocean rise that he addressed at the beginning. We're looking at an ocean rise of two to three feet

by the year twenty one. That could displace up to four million people around the world. So essentially, sell your beachfront property right because it's gonna be underwater soon. Another study out of Columbia University's Program on Climate Science, Awareness and Solutions finds that summers in general are becoming hotter than the average recorded between nineteen fifty one in nineteen eighty.

This will lead to increased heat in the subtropics, it's going to cause more droughts, increased floods, and it's going to start impacting our human health. You know, like when you you look up the weather and you see like those those warnings it's like extreme air quality or something

like that, those orange air quality warnings a lot here. Yeah, I think we're going to be looking at more of those from what this sounds like, and then conservative estimates, even like the most conservative estimates about climate changers, saying we're looking at more droughts across our land, as well as more natural disasters things like storm surges, wildfires, and heat waves. So in terms of our larger question here,

when will the Earth become uninhabitable? From a climate change perspective, it all seems to come down to how high the temperature will rise and how quickly within the next hundred years. But it does seem like there are current parts of the world that are inhabited that will no longer be habitable. But the good news again is that there are efforts in place. There are plans in place that can mitigate the effects, that can slow it down if we have the willingness to stick to them and to and to

insist that they be inactive. Yeah, exactly. So there's a matter of policy involved here. There's a matter of communication. I I definitely think go back and listen to the episode that Robert and Joe did on Science Communication Breakdowns, because I think that is crucial right now with this stuff, because hey, the sun thing, that's a billion plus years

off right this we're talking about a hundred years. All right, We're gonna take one last break, and when we come back, we're going to discuss one final threat to the habitability of the planet. And I imagine you can guess what it is. Thank Alright, we're back. So there, of course, a number a number of other scenarios to consider here, various technological threats. AI is certainly a crucial one and one that we're hoping to explore in a future episode

of Stuff to Blow Your Mind. But then there's there's also good old nuclear war to consider. So okay, combined, we're talking about Skynet and Judgment Day. Yeah, but but let's let's just focus on on just the sheer destructive power of nuclear weapons for a minute, and the sheer number of nuclear weapons. This brings us back to our earlier episode from this year about the doomsday clubs. Yes,

indeed it does so. According to the Federation of American Scientists, as of early two thousand seventeen, there are still fourteen thousand, nine hundred nuclear weapons in the world. Now you can compare that to the maximum number we've ever had, and that was six where there's we're seventy thousand, three hundred. But even because Superman threw them all into the sun down. Um. So The important thing, though, is no matter how many nuclear weapons you have, even a small scale nuclear war

would have intense effects on climate. So NASA scientist Luke omen He's predicted that the detonation of one hundred hiroshiumist sized bombs would inject upwards of five mega tons of black carbon into the upper tropic sphere and result in a one degree celsius or one point eight degree fare kneit fall over the three years to follow, and for two to four years afterward, rainfall would decrease around the world by ten percent, and then larger exchanges it gets

even more terrifying. So this is this is this is interesting. In Lost Alamos Laboratory, scientists they predicted that the detonation of a mere ten to one hundred super bombs what we'd call a hydrogen bomb today or a thermonuclear weapon. Uh, they said that that would be enough to to do

just significant um irreparable damage to the planet. Um. So not only like as we're recording this, like we're in the middle of again like heated rhetoric with North Korea about nuclear weapons, right, and like not only are we worrying here about the fear of nuclear threat, but we're also like we we need to worry about like the effect that this is going to have on the planet afterwards, Like what what's the world gonna look like? Afterwards? And this has been this has been all a longstanding uh

warn from scientists. So one issue here is that you have so you have one hundred mega tons of fission per bomb, you have one hundred bombs. That's enough to generate ten thousand mega tons necessary to raise the background radioactivity level to dangerous levels. According to the nineteen fifty three Project Sunshine study, the exact predictions as to how a nuclear war would impact the environment these have varied

over the years. Using modern climate models, scientist Brian Tune and Alan Roebok, they theorized that even a regional nuclear war would cause a marginal nuclear winter for everyone nuclear winner. To remind everybody this, the idea here is that the the the mass the burnt carbon ejected into the atmosphere by these explosions, by that by the burnings of cities and forests, that this would have essentially shroud the Earth

and reduced the amount of sunlight reaching the earth. You know that this is an aside just to bring a little levity, I guess to the but so stranger things. We've talked a lot about it on the show before. Everybody's talking about it right now because the second season just came out. The upside down is essentially like a nightmare scenario of of post fallout, right, because you're looking at everything's blacked out, there's constant it looks like Dan Driff is kind of falling from the sky. But it

does have a nuclear waste land kind of feel to it. Yeah. According to the two thousand seven findings from Robot and Tune, they said they did Indian Pakistan, for example, where did each launch fifty nuclear weapons at each other. The entire globe would experience ten years of smoke clouds and a three year temperature drop of approximately uh two point five degrees fahrenheit one celsius. What this is like real gallows humor here. But like, so is that going to counteract

climate change? Then? Um, you know, I've I've seen people make that joke in the past, and I'm and you can make the argument, yeah, that it's like one bad thing counts the other bad thing. But but but then you have all these other effects too. I mean, obviously the loss of life involved the radio active pollution. Uh So I think it's very it's very difficult to make

up a straight faced case for that. But this study, this two thousand and seven study, uh, this was one of the factors that the Bulletin of the Atomic Scientist took into account when they advanced the doomsday clock two minutes closer to midnight at the time. Yeah, which is, you know, part of what we were talking about earlier this year. All right, So we've just presented you with all the scenarios we could think of, from the sun

to asteroids hitting us, to climate change in nuclear war. Yeah, I know, Grant, there are a lot of a lot of possibilities that we didn't get into. We didn't get into your gray goose scenario, your green goose scenario, or some of the more exotic ideas. Uh, you know, destruction by an alien force which is a planet, things of that nature. Uh. And there are other there are also a hope there are a number of other cosmic scenarios

as well that have been thrown out. But I feel like this gives us a nice overview of the long torrent term, the short term, uh, and the random events, the sort of irreversible cosmic threats, as well as the the man made of threats of nuclear war and climate change. So what should we believe the worst case scenarios that are prevented in front of us, or the hopeful messages that will get human beings to hopefully be more proactive

about their part in this. I mean, the big takeaway I've got from this is that we need to be even more proactive about climate change than even the Paris Accords. And nuclear weapons are a much bigger problem than in terms of just uh war, right, Like they're they're going to have like an overall horrible effect on the entire planet. Well, I think one way to look at it is to think of it in terms of per and all human health.

And this is an example that I think gives hope and also is um concerning too, because you could think about all, right, so worst case scenarios are presented for human health all the time. You know, if you if you drink NonStop or and or smoke NonStop, then this is what will happen to your body. Here are some examples of what has happened to other bodies, and in some cases those can be helpful. They can say, oh, well, I better not do that that I'm gonna I'm gonna

cut it off. I'm gonna cut this level of my destructive behavior off at this point so that I don't

get to there. And you know, that that can that could be helpful for for human society if we realize, yeah, we definitely don't want to get to this point, so let's figure let's figure out a way to at least scale back and uh, you know we've seen that, say with with the with the reduction of nuclear warheads in the world, even though we still have way too many, especially when you think like the relative short amount of time that it's actually been in which we got rid

of like uh doing this off to the top of my head, but basically sixty warheads. Yeah, yeah, I mean, it's it's it's impressive, even though there's a lot more work to do. I mean, but the other side of the coin is that we see countless examples of human health where when presented with the data, we still don't do anything, you know, because we're still so shortsighted in how we interact with our lives and that applies to

our personal lives as well as as globally. So we could think, yeah, climate climate change is a threat, nuclear weapons are a threat. I hope somebody does something about that one day. It's kind of like saying, yeah, one of these days, I'll get into shape and start eating right right, Yeah, that's what it makes me think of from personal perspective. You know, maybe I need to lay off the pizza. Also, maybe I need to lay off

the carbon emissions. All of this reminds me of that episode I'm gonna circle back around the one that we did way back in May on mass extinctions. Uh. In that episode, I talked a lot about this book by Anneleine Knew. It's called Scatter adapt and remember how humans will survive mass extinction, And her argument there is that we need to a scatter from Earth in the long term, be adapt to climate change and see remember our history so that we can ensure our species survival. This reminds

me of the Expanse, which we've done episodes on as well. Right, So where do we go? Well, NASA conducted a two hundred million dollar study in the year two thousand that reported a colony could be dug under the Moon's surface and covered to protect its residents. Now we're talking about short term here. Remember we talked about way in the future, the Moon isn't going to be an ideal place for

us to go to. But if not our Moon, then there's other possibilities such as the moons of Jupiter, Saturn, Uranus, Neptune or Mars might be a possibility, or even more possible, an orbital habitat that's constructed from resources that we extract from near Earth asteroids. But again, you're getting closer and closer to Kardashio of scale level that we just don't

have that kind of technology right now. Yeah, I mean again, it comes back to the Goldilocks UH conundrum though, where you have all these things that are just right on Earth, and when we start expanding outward and trying to imagine ourselves establishing humanity on other planets or other cosmic bodies, we're faced with just how imperfect all of our options

are compared to what we evolve to thrive in. How much more work it's going to be too, and then and and how how does that work stack up with the work we're faced with now to just add some more years to the planet shelf life? You know, like, what is what? What's what's easier? I mean, granted, neither of these things are are easy. Both all these things

are hard. But is it easier to to reduce the number of nuclear warheads in the planet to uh, to admitigate the effects of climate change, or to figure out how to establish a new Earth on it, like a radiation scathed planet elsewhere in our solar system. Yeah, that is a very good point. Yeah, when you weigh the cost benefit analysis there, it really, you know, from a capitalist perspective, becomes obvious what the answer is. There's also the question which we always bring up on the show,

what if we've become transhuman? You know, we could develop technology or genetics that could change us into another species that could totally survive these changes. Well, okay, Wallace Wells, though this is interesting. This is an interesting one to leave you with, he said in that piece, And again

remember his piece was a little scaremongery. He spoke to some scientists with a point about the Fermi paradox, which is another thing we talked about on the show a lot, and they said, maybe the reason we have an encountered intelligent life yet is because the natural lifespan of a civilization is only several thousand years old. Remember I started this off by telling uh the stats on how long mammals are known to survive for. That's not talking about civilization.

Civilization brings with it its own complications that namely the risk of self destruction. Yeah, so maybe civilizations have emerged, developed and then burned up, but it's all been too

fast for them to ever find one another. Uh So, while we can start seeing the devastating effects from climate change and as soon as the next one hundred years, it seems like the actual planet won't be uninhabitable to us for five hundred million years, right, Like, the climate change effects are going to be bad, but there will

be parts of the planet we can live on. It's just going to be a matter of even more disparity than we're already looking at here, right because the rich are obviously gonna want to live in those parts that are nicer. So it's the it's less the prospect of an uninhabitable earth in the prospect of a less habitable earth, I think so, And that can be pretty, uh pretty terrifying in its own way. Absolutely, Okay, I hope we did this topic some justice. It was a little bit rough.

They're going through all of those statistics and just kind of looking looking at the sort of damocles hanging over all of our heads. But I'm glad we did it. I think I think I learned something. Yeah, Yeah, so we'd love to hear from everyone out there. What are your thoughts on these various threats to the planet we call home. You can get in touch with us a number of different ways. Find us on social media. We are on Facebook, Twitter, Tumbler, Instagram, uh who knows where else,

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