The Great Simplification with Nate Hagens - Peter Brannen: "Deep Time, Mass Extinctions, and Today"

Episode Date: January 3, 2024

On this episode, Nate is joined by Peter Brannen, science journalist and author specializing in Earth's prior mass extinctions, to unpack our planet's geologic history and what it can tell us about our current climate situation. Humans have become very good at uncovering the history of our planetary home - revealing distinct periods during billions of years of deep time that have disturbing similarities to our own present time. How is the carbon cycle the foundation of our biosphere - and how have changes to it in the past impacted life's ability to thrive? On the scales of geologic time, how do humans compare to the other species who have inhabited this planet - 99% of which have gone extinct - and will we end up being just a blip in the fossil record? How can an understanding of geologic and climate science prepare us for the environmental challenges we'll face in the coming decades? About Peter Brannen Peter Brannen is an award-winning science journalist and contributing writer at The Atlantic. His work has also appeared in The New York Times, The Washington Post, Wired, Aeon, The Boston Globe, Slate and The Guardian among other publications. His 2017 book, The Ends of the World covers the five major mass extinctions in Earth's history. Peter is currently a visiting scholar at the Kluge Center at the Library of Congress and an affiliate at the Institute of Arctic and Alpine Research at the University of Colorado-Boulder. He was formerly a 2018 Scripps Fellow at CU-Boulder, a 2015 journalist-in-residence at the National Evolutionary Synthesis Center at Duke University, and a 2011 Ocean Science Journalism Fellow at the Woods Hole Oceanographic Institution in Woods Hole, MA. Watch on YouTube: https://youtu.be/3l81C_11D7A More information, and show notes: https://www.thegreatsimplification.com/episode/103-peter-brannen  

You're listening to The Great Simplification. I'm Nate Hagan's. On this show, we describe how energy, the economy, the environment, and human behavior all fit together and what it might mean for our future. By sharing insights from global thinkers, we hope to inform and inspire more humans to play emergent roles in the coming Great Simplification. I am very pleased to welcome Peter Brannan to the show. Peter is an award-winning science journalist and contributing writer at the Atlantic. He's particularly interested in geology, ocean science, deep time, and Earth's carbon cycle. So in this show, we kind of nerd out about the importance of carbon to Earth's prior mass extinctions.

Peter previously wrote a popular book about Earth's prior five mass extinctions called The Ends of the World. He is currently a visiting scholar at the Kluge Center at the Library of Congress, as well as an affiliate at the Institute of Arctic and Alpine Research at the University of Colorado in Boulder. This is a topic that I find fascinating and is relevant to all of our futures. Please welcome Peter Brannon. Peter Brannon, welcome to the program. Great to see you. Thanks. It's great to be here.

in your case I think you may be in Colorado but given your expertise of the world I put where I thought Pangia might have been in the past on my globe in the past in your honor okay I appreciate it I'm actually in DC right now for the fall for a for a fellowship but yeah I just moved out of Boulder Colorado which is sort of a dream for someone like me who's interested in geology and all things earth science so and bike riding and hiking and everything else. I love Boulder. Yep. We have a lot to cover.

Let me just first ask you right off the bat. You're an expert on Earth's mass extinctions. Why should viewers pay attention to this podcast? Well, I wrote a book about the so-called Big Five mass extinctions in Earth history. And the reason why I wrote that book is because I had sort of noticed that in the geology community, over the last few decades that the conversation had changed from how it sort of existed in the public imagination where with the success of the asteroid impact hypothesis in 1980 and when it was first introduced in a pair of papers written by the Lewis and Walter Alvarez

and another one by Jan Smith. And then a decade later when they discovered the crater, geologists sort of thought that they had this general explanation for why mass extinctions happen, which is, you know, they're what happened when big rocks fall out of the sky. And in the last 30 years, as geologists kind of fanned out across the world and looked into the earlier mass extinctions to try to tease apart the causes of those, they thought, you know, maybe they'll find a similar layer of asteroid dust or a big crater somewhere. And for the most part, in these other really sort of extreme chaotic episodes in Earth history, some of which were much worse than the extinction that wiped out the big dinosaurs.

There wasn't evidence for an asteroid impact really at all at any of them that's very convincing. And instead, people have been investigating these other sort of kill mechanisms intrinsic to the Earth system itself, that in some ways, each mass extinction is different, but the focus has turned more towards things kind of intrinsic to the Earth system itself, and things changing and in some of the same ways that the levers we're pulling today, you know, we're not quite at the level of devastation of these ancient mass extinctions, but it's sort of concerning that we're starting to see sort of the first check engine light signals that we know from Earth history.

If you go as far as you can in this direction, you can literally do the worst things that have ever happened in Earth history. So we'll get into the specifics of those. But I thought that was sort of newsworthy and worth bringing to the public attention that the conversation had sort of changed in the earth science community. So if the check engine light on earth is on, who are the expert mechanics? I would say it's geoscientists. I mean, and I especially people with a deep time perspective. So I think in my book, I refer to it as, you know, if you're having chest pains and you have

a history of heart attacks, like that's what we're experiencing now. sort of the first warning sign. So in a lot of the ancient mass extinctions, you see things like in some cases, huge eruptions of CO2 out of these kind of mind-bending volcanoes. You see evidence of warming and ocean acidification and the ocean losing its oxygen and a lot of the same things we're seeing today

in an extreme level in these ancient events. But what's sort of alarming is that, you know, it is in our capacity to kind of reproduce them if we really don't get our act together, that we're even in the same conversation as these sort of psychedelic horrors in the deep past is kind of amazing. Except most people have no idea about these mass extinctions. Right. So you mentioned the word deep time. I have a chapter in my book for students, reality blind on deep time.

your book is all about deep time, which for you and I, we can geek out on that. Can you define deep time and why is it important that we educate young people and maybe all people about deep time? Yeah, I mean, I think it really just sort of evokes this idea that in the same way that distances in space are kind of our, you know, when we evolved on the savannah as primates, we were not, we did not evolve to sort of intuit these, you know, quantum distances or distances between stars. It's just, you know, these are scales that we have no sort of way of reckoning with. So in the same way that astronomers come up with sort of mnemonics or aids to help them think about these expanses, so of geologists, because the time, behind us in the rear view is similarly expansive and mind-blowing and I think most people don't really appreciate this so yeah sorry no no no I mean the way that I talked to my students about it is our ancestors evolved to define and have words for one two three and many and even today I don't I think a million a billion a trillion right are just fancy words to represent a lot but a million

seconds is like 12 days a billion seconds sounds a little bit bigger is like 30 31 years right so when we think when we look backward it's very difficult for the human brain to comprehend these time periods on earth so what I do with my students is I hand out little pieces of amber with insects in them that were a lot 90 million years ago. Or I have, I think you've watched my podcast in the past, I show this.

This is two billion year old column of cyanobacteria stromatolites. And when you hold it in your hand and this thing was alive two billion years ago, it gives you a little emotional mnemonic to think like, holy crap, this existed two billion years ago. Right. I mean, that's one of the things that's so strange about.

the geologic record is you can have intervals in it so there's a fit this thing called the great unconformity um from it's primarily known from north america but a similar pattern exists over a lot of the world where something like a billion years has sort of gone missing and there's a lot of debates and fights about why that is but you see that it's just huge erasure of earth history in the fossil record there are outcrops here and there but it's way more rare to find things from that interval and then you can find an imprint of a raindrop that fell on a specific day uh you know two billion years ago. And it's just sort of this, these changing scales are just sort of mind-blowing. So how could we possibly find evidence of a raindrop that fell two billion years ago?

So you do actually, you, you, you, there are fossil raindrops. You know, they're sort of on a, you know, sort of a muddy, a muddy surface that got hit by a raindrop and then was covered in sediment. And it just gets preserved as this little impression on the rock. Wow. Yeah, but the way that I sort of, it's a tool that I use in my first book, and I often used to demonstrate sort of these expanses that we're talking about. I borrow from the geologist Robert Hazen at the Carnegie Institute, because I just think it's really evocative and sort of mind-blowing,

is that if you imagine every footstep you take is a century, and you go for a walk, and you guess how long does it take to get to the beginning of Earth history? You take one footstep back, and it's 1923, and the Ottoman Empire has just disbanded, and World War I ended, and the night side of the planet is still pretty dark because electrification hasn't really happened in most of the world. That's one footstep, and a lot has changed. You take 20 more, and the Roman Empire is there, 60 to 80 more, and there's woolly mammoths, and you haven't walked that far, and sea level's 400 feet lower, and there's Antarctica's worth of ice on North America, And there's camels and lions in North America. So the world's totally transformed. You've barely walked down the hallway. So you must think, oh, it's probably, I don't know, a mile to the dinosaurs and then a few miles to the beginning of Earth history.

But in fact, you would have to walk for 20 miles a day for almost four years to cover the rest of Earth history. So those are the expanses of time that we're talking about. And once you start thinking in those scales and you start to realize that we are doing things on this planet that are almost unprecedented, over a lot of that span, then it sort of brings home just how radical the experiment we're running on the planet really is. So that's why I think it's important to think about there it's on that scale. I happen to agree, which is why I invited you to share your research and your outlook on this. Okay, with some of my scientific experts that we have a a wide array of listeners.

Some may know your work a lot and some may not know it at all. Could we do a speed round of the five mass extinctions. Name them when they were. What was the general impact and what was the cause? Try to do it in under two minutes per, which as a science writer and someone who studied these things deeply is probably difficult, but go for it. Yeah, well, I think a helpful like sort of mileposts for people as the dinosaurs, because everyone knows the dinosaurs.

And the dinosaurs sort of evolved on pangia, but that is, you know, Pangaea started breaking up or about 200 million years ago and dinosaurs evolved about 245 million years ago. So we are, with the first few mass extinctions, we are way before Pangia. We're way before the dinosaurs. So the first mass extinction, so the Cambrian explosion has happened in about a half a billion years ago. And there's this sort of progression of life, and it really flourishes in this age known as the Ordovician period, where there's this thing called the Great Ordovician Biodiversification event and where species on Earth triple over, I think it's about 10 million years. And all the life is basically in the water. You might have a few little sprigs of archaic plants sort of on lake margins and things. But for the most part, the interior of the continent looks like, you know, the Mars Curiosity rover, feed, but the action is really under the waves. And you have this whole world of sort of invertebrates and

squid-like things with cone shells and things that sort of look like horsesy crabs. So that's sort of the world we're in. And the Ordovician ends in this devastating ice age where sea level dramatically falls and the ocean circulation's upended. And it's thought to be, that one's actually thought to be caused by declining CO2, possibly from weathering of the early Appalachians. So some of some of your listeners might be familiar with the idea of enhanced rock weathering to sort of of sequester CO2. And the planet does that all on its own. And it was very effective at doing that maybe in the lead up to this extinction.

CO2 passes the threshold. But it takes a really long time for that to pull CO2 down. Yeah, yeah. So these are on the order of, you know, 100,000-year processes. So, and in later mass extinction, when lots of CO2 goes into the air and it gets really hot, eventually the Earth is rescued by these weathering processes. processes that happen over hundreds of thousands of years that sequester that CO2 and cool it off again. And that's going to happen in our future too, like if you wait long enough.

So this was the first mass extinction. And what was happening on land there? Not much. Not much. There might have been the first sort of inkling of plant life trying to establish a beachhead. But for the most part, there's not much going on on land. And it's. And it was covered in ice pretty much.

at then, right? Well, when the Ice Age struck, this is so long ago that Africa and Saudi Arabia are over the South Pole. And so what's interesting is that, so I'm from New England originally, where you can go hiking and see remnants of the last Ice Age because you'll see these sort of scratch marks on the rocks from where the glaciers were. And that's from only, you know, 20,000 years ago. In the middle of the Sahara Desert and in Saudi Arabia, you see similar evidence for ice sheets,

only they're from 445 million years ago from this extinction. They've just, you know, Africa's not over the South Pole anymore. So it's, I hate to keep interrupting you, but sometimes I wonder which is more amazing that we evolved from the sea, from the universal, less universal common ancestor. and all the forms of life and navigated through all these mass extinctions and 99% of the species to ever live on Earth are extinct. Is that more amazing? Or is it more amazing that we figured all that out? And we can look backward in time and get clues.

And scientists like yourself can puzzle this together and tell a story about the history of this planet. I just find it amazing. No, I mean, I'm similar, I feel grateful, very grateful to live at a particular time on Earth where I have access to this story and, you know, can be reasonably sure that it is somewhat adheres to what actually happened. Unlike, you know, previous creation myths that every culture comes up with, we have a pretty, you know, rigorously sort of defined story of where we came. from. There's still a lot to discover. That was one of the sort of surprising things in reporting the book is how open-ended some of these questions still are, that we're looking at other planets for life, but we really don't understand kind of the steps that made this place habitable.

So it's a very exciting time if you want to get into the field to answer some of these big questions. As is my prerogative and frequently what happens as the host of this podcast, I have interrupted your speed round several times. Oh, no, that's okay. Okay, that was the first mass extinction, and that was called what? The end-Ordovician mass extinction, about 445 million years ago.

Okay, what's next? The next one, around 375 million years ago, is this thing called the late Devonian extinction. And the Devonian is a weird time because it's sort of an age of 25 million years where you repeatedly have pulses of mass extinctions and one really big one and another pretty big one at the end. And by the Devonian, the planet has changed pretty dramatically.

There's now trees sort of, and forests, first of all, in the middle and late Devonian period. Fish have started to waddle onto land, so our ancestors are showing up. Arthropods, things like, you know, insects are on land as well. So this whole land ecosystem is taking off in this period. But weirdly, it is sort of racked with pulses of extinction. And it's actually, it's, it's, it's, in many ways a mysterious sort of age and especially the pulses of extinction, but I would say the weight of evidence is on the, actually the evolution of trees and forests as driving a lot of

the sort of chaos that's happening. So I like to think of this one as sort of trees embarked on this incredible geoengineering project of, you know, where the land previously had been sort of uninhabited, spreading out all over the world, developing things like roots and breaking up rocks and seeds so they can push inland. And as they did that, they are releasing all these nutrients from the land, things like phosphorus that are washing into rivers, then out into the ocean, and they're driving these pulses of anoxia. So the ocean's losing its oxygen repeatedly in this age of extinction and, you know, devastating sea life. And sort of, I guess ironically in a way, a lot of that dead life that died in these extinctions is what we frack now. So in the Midwest, a lot of that stuff

is Devonian. It's from these pulses of anoxic seas that buried all this carbon in them because, you know, you have all this life that's dying and falling to the bottom of these seas, and there's no oxygen, so they don't decay so that that carbon just stays there for 380 million years until a weird primate decided to come along and dig it up and start burning it. But another sort of consequence of this extinction is, you know, trees are also very good at sequestering carbon, and when they're fueling these big algae blooms, that's bearing a lot of carbon. So there's evidence as well for pulses of ice ages in this one as well. So the first two extinctions are pretty weird. It gets more cinematic, I would say, with the latter three. But they show that it's not, you know,

it's really changed that is the environmental change on a pace that life can't keep up is the thing that's driving these things because you know you can pass these cold thresholds that can life out and then in later extinctions you see like incredible heating and life is adaptable and it can bend but it can also break and I think that's what's happening in these extinctions you know it's talking about theatrics and drama I have peter brannan on the podcast talking about Earth's mass extinction sitting in Washington, D.C. where the eye of Soron is directing its gaze around the world and there's a police car in the background during our conversation.

There's an allegory there. I don't know what it is. Okay, keep going. Okay. These next two I can sort of speed through because they're basically the same thing happens two times in a row. So 252 million years ago, you have the base. biggest mass extinction of all time. There's no real close second place. It's called the N-Parmian

mass extinction. It's also known as the Great Dying, and it lives up to its name. Life at this point, you know, it's starting to get a little more familiar, but we're still before dinosaurs. This is still sort of an alien planet. But there are reptiles on land. There's things that look like reptiles that are actually closer related to us that are on land. There's trees and forests, and life has recovered from these previous mass extinctions. And on land, there are these big sponge reefs or on the ocean there are these big sponge reefs and things like trilobites are still swimming around and you know a great place to actually see what life was like in the Permian is if you do what I did and you go

to the Permian Basin Petroleum Museum in Midland Texas they have this wonderful sort of reef diorama and the reason why there's a reef diorama in the petroleum basin or the Permian Basin Petroleum Museum is because all this life again left behind a lot of a lot of you know a trillion dollars of carbon in Texas But at the end of the Parmian, you just have this completely devastating mass extinction where you look for fossils in the millions of years afterwards. And sometimes, you know, the rocks are, you know, almost empty. And it takes about 10 million years for the Earth to fully recover.

There's all sorts of weird signals right at the mass extinction boundary, like this thing called a fungal spike, which might be the signal of, you know, and the most dramatic interpretation is it's just stuff rotting all over the world. It's the only extinction that really affects insects. And what caused it, people thought, you know, with a dinosaur asteroid, you know, maybe there's a big evidence of an impact in the Permian, and there really isn't. But what there is in Siberia is this incredible expanse of volcanic rock known as the Siberian traps, which they're one of these things called a large igneous province or when they happen on land, a continental flood basalt.

And it's really just the continent kind of turning inside out. It's the amount of lava that erupts in Siberia at the end of the Parmian is kind of mind-boggling. It was enough. So the volcanic rock that's, you know, the magma and the lava is enough to cover the lower 48 United States a kilometer deep in this stuff. So when we talk about Yellowstone, it would cover a few states and a few inches of ash. It would be very devastating to, you know, global industrial civilization. but this thing is just on a totally different scale. But as sort of dramatic as lava coming out in Russia is,

that doesn't explain why things at the bottom of the ocean on the other side of the planet are going extinct. And so it's not the proximity to the volcanoes that's killing things. It's the gases that are coming out of the volcanoes. And these things would have been emitting all sorts of horrible stuff. So, you know, mercury, maybe there's some mercury poisoning. they were on their way up through the Tunguska Basin in Russia. They were burning through a lot of gypsum and haylight

and putting all sorts of ozone destroying chemicals in the air. But what's really been sort of honed in on as the kill mechanism in this extinction is all the CO2 that came out of these volcanoes. And it truly is a mind-boggling amount. But on their way up, they would have burned through vast coal deposits from previous ages and natural gas and limestone. so they were, you know, igniting fossil fuels and limestone to an insane degree. And you see evidence of something like a 10 degree Celsius rise in temperature.

The oceans lose something like half their oxygen, I believe. There's evidence of ocean acidification. So all these things that we're sort of seeing today, this is like the RCP8.5. just, you know, a few hundred years out. You know, maybe we're not going to reproduce it, but it's kind of amazing that we could actually, it's in our power to sort of bring about another and Permian mass extinction. Well, we're going to get into the details of that. But just to be clear and a couple of questions, I don't think even RCP8.5 comes close to the amount of carbon that was emitted in that time.

because what happened was that was over thousands or even 10,000 of years. So we can't reproduce what happened, but what we could possibly do is reproduce the effects. Yeah, right. So it's interesting because we could never admit as much CO2 as the Siberian traps did. The estimates are on the order of tens of thousands of gigatons to some exceed over 100,000 gigatons. So that's just completely out of the question. but we are as far as we can tell we're doing it about 10 times faster so the rate is faster

and for things like ocean acidification it's the rate that matters and you know the earth has ways of washing CO2 out of the system on long time scales if you have a if you have a huge one of these big volcanic events but it takes tens of millions of years you're probably not going to acidify the ocean it's probably not going to get that much warmer because the planet is continually sort of scrubbing it from the atmosphere through these things like weathering it's when you jackknife the system in a short amount of time. But yeah, it's definitely an open question. How relevant are these analogs to what we're doing today? And the fact that it's an open question is what worries me, I would say. So slight tangent here interrupting you again, but I think it's

relevant because sometimes on social media, you, well, quite often, you hear, oh, well, a single volcano emits more CO2 than all of human industrial activities. So human CO2 is not a big factor. So what is the deal with volcanoes? And obviously there were the Siberian traps, which was thousands of years of giant provinces of lava basalts and CO2. But what about something like Mount Pinatubo or Montalaya or or modern volcanoes, how does the CO2 equivalent of volcanoes on land or in the sea

compare to the scale of modern industrial fossil carbon burning? Yeah. So, I mean, the best estimate I've seen is that humans emit 100 times more CO2 every year than all the volcanoes on Earth. CO2 is the second most abundant gas that comes out of volcanoes other than water vapor. So they are, they are, I mean, this is a good thing that volcanoes put CO2 up in the atmosphere. Earth needs CO2 so that it's not a snowball earth situation and so the plants can have food to eat. So it's, this is the planet that sort of is fundamentally, the behavior of CO2 on the

planet is fundamentally what makes Earth Earth. It's this thing called the carbon cycle. And it's supposed to come out of volcanoes, sort of move between the oceans and atmosphere and through life and then back into the rocks and then they get subducted and they come out of volcanoes again. But what we're doing is really, it's not like the background rate of CO2 emissions from volcanoes. And it's more resembles these once every 50 to 100 million year sort of crazy events that

you see in the fossil record. Leave it to those clever fire apes. Um, so those are, are, you still haven't, okay, uh, go to the fifth one then. Okay. No, the fourth one. So basically 50 million years after the N-Permian, life picks up the pieces and starts to look modern, which is a weird way to, uh, describe a world that has, you know, dinosaurs are evolving. But you get the first, you know, you get dinosaurs evolving and we still have, there's twice

as many species of dinosaurs today as there are mammals. So we're still sort of an age of dinosaurs. Yeah. The first modern... They're birds. 10,000 species of birds. Right, right. The first modern mammals evolve.

The first, you know, modern conifers and stony corals and, you know, the pieces of, that would eventually make our modern world are sort of evolving in the wake of the worst thing that's ever happened. So if you're looking for a sort of silver lining to the worst thing that's ever happened, it's we wouldn't be here having this conversation probably if it hadn't happened. And the world would look completely different. that's very that's very meta peter yeah yeah and i've said before i just as easily could have written a book about the mass radiations after the extinctions as the extinctions themselves because

it's just as spectacular sort of the rebirth that happens as the destruction is um okay so it's worst thing ever 252 million years ago and then to around 201 million years ago you have this thing called the entriassic mass extinction and basically the same thing happens it's It's not quite as bad, but as Pangaea is rifting apart, you have this thing called the Central Atlantic Magmatic Province starts erupting in another one of these big, huge continental flood basalts in the seams kind of where Pangia is ripping apart. So you find rocks that are a lot like that are these flood basalts that are dated exactly to the extinction in New Jersey, across from New York City and the New Jersey Palisades. Brazil, France, Morocco, Nova Scotia. So it's sort of this, another one of these sort of continent-scaled eruptions. Gets really hot.

Ocean acidifies, loses its oxygen. 75% of life on Earth goes extinct. And so that one, I've described the kill mechanism already. So we can jump to the Cretaceous, which is the one everyone knows about. And this is 66 million years ago when the most charismatic kind of creatures in the fossil record, the big dinosaur. get wiped out in possibly the most spectacular way imaginable when this rock the size of Mount Everest hits the planet going 20 times faster than a bullet. But what's strange about that

extinction is at the same time, there is another one of these big volcanic provinces in India this time. And I would say researchers are still trying to tease out the relative effects of the two things that are going on at the same time, essentially. And given the importance of these volcanic events in previous mass extinctions. It just seems like a bizarre coincidence that it's also happening at the end of the Cretaceous. To put it in some perspective, these are called the Deccan traps and enough lava erupted out of them. They could cover the lower 48 United States in 600 feet of lava. So nothing to sneeze at, but not quite as big as the Siberian traps. I'd say the smart money is still on the asteroid, but it's this still very much a, you know,

intensely researched area. Yeah, Peter Ward has been on the show before. I, Do you know Peter? I've interviewed him before. Yeah, I interview him in the book, actually. Yeah, so he thinks it's a combination that we were starting to see the effects of a carbon pulse and the asteroid was kind of the coup de grace. Yeah. Yeah, it's weird. As people have gone back to date both the asteroid and the volcanoes, you know, if you can get something within a few tens of thousands of years, the date down, that is incredibly precise.

And so I've seen papers where there's a warming pulse before and there's a warming pulse after. And, you know, we're still, yeah. So let me ask you that. As a scientist, I just got this bizarre self perception in my mind as I'm speaking. Did you ever see the movie Best in Show? I did a long time ago. Where Fred Willard is just asking these knucklehead questions of common, oh, it's a shih Tzu. I kind of envision myself in Fred Willard's role interviewing you as a scientist about this.

Like, I care about this, but I know a tiny fraction of what you do. So a lot of my questions might be naive, but I'm playing the role of my viewer who might not have heard this stuff before. So how do we know as scientist to date something within 10 or 20,000 years even of something that was 60 or 200 million years ago. Like how confident are we of that and what is the process? Right. Well, first I should correct you.

I'm a science writer and I like to think that I do translation from the science world to the general public. Perfect. I don't want to claim the mantle necessarily of scientists. But at this point, I feel like I've sort of earned an honorary membership in the geoscience community. How many hundreds and hundreds of papers have you read to get to where you could write these books?

many many hundreds and I would say that people have asked me or have said I want to write a book but I'm not sure about what and I've said then you don't want to write a book because it needs to be you know Saturday morning and all you can think about is going to read more papers on a topic like seriously when you were writing end of the worlds were you like oh god I got to I got to do this chat and I have to learn about that. Oh my God. I can't wait till this is over.

Or were you like, I want to find out the answer to this puzzle? Yeah, no, I was completely obsessed the whole time. And, um, I mean,

that's almost become a hazard of the job is that now I'm very in the weeds. And I think stuff is interesting that, you know, my editor would never find interesting. Right. Right. I feel the same about this podcast. But go on.

How do we know with, yeah. Um, so the, I mean, a lot of it is, is you need to get lucky finding a strata that is easily datable. And so like volcanic ash layers are really,

are sort of like the prize that you're looking for those, because those you can use radio isotopes. You know, you find these things called zircons, which trap a certain amount of, you know, uranium that you know decays to lead over, you know the half-life of it. So if you know this thing hasn't been messed with at all, you can tell when it came out of a volcano within, you know, I'm not sure what there are bars on those are, but within tens of thousands of years, I think. And there's other systems. There's like Argon, Argon, and there's a bunch of these. And so people sort of, you know, you're looking for an ash layer for sure. There's other ways you can do it too. You can correlate. You know, there's big, dramatic dinosaur fossils, bones and things. But most of the fossil record is these tiny little shelly creatures that you'll find in limestones and things. I thought it would my, my first, one of the examples I give. of my students is Lake Suigitsu in Japan.

Every spring they have the cherry blossoms, uh, um, that bloom and then they fall to the bottom, uh, and then the leaves fall to the bottom. So there's these alternate white and green layers and they drill down and they got a hundred thousand years of these layers. And then they did carbon dating to see. Uh, and they were like really, really close to 100, 110,000 years ago with carbon right. But what you're talking about goes way,

beyond what carbon dating could do, correct? Yeah, I think carbon dating sort of beyond like 50,000 years, I think it's kind of useless just because of the half-life of it. But you can find much longer lived radio isotopes. Yeah, and you can also. That's how we know, that's how we know all of the, the history of the one century per step going back for 20 miles a day for as long as you said, We know that from isotope dating of different elements.

Yeah. And, you know, I think the age of the solar system, we know because, you know, you get these meteorites that have just been pickled out in space since the formation of the solar system. And they preserve signals that go all the way back to the beginning of the birth of the solar system. Wow. But, yeah, I mean, another way you can do it is if you know you have a good, you know, extinction exposure, you can correlate. you can correlate the sort of like weird little life forms. You know, do they look like the one on the other side of the planet where you have dated it well? So it's been this, it's this huge sort of distributed global correlation game of, you know, what strata is when and where are the fossils, where in the strata and how is this one look like that one over there on the other side of the planet?

So it's kind of amazing that we've pieced together this story of the history of the planet through this. Thank you for all that. A follow up question, you have listed five mass extinctions. I would argue there was more than that because, for instance, I showed you this stromatolite before. Yeah. That was probably the first one, two billion years ago, where their waste product was oxygen.

And we had a CO2 nitrogen atmosphere then. and that killed off themselves because other things would evolve to eat them and they couldn't, you know, photosynthesize the same way that they used to. But were there lots, I assume that there were many, many extinctions that were not quite to the level of a mass extinction that we would refer to as minor extinctions. So what is the threshold to be called a mass extinction? And how many minor extinctions are scientists aware of? Yeah, I mean, depending on how you count, there's dozens of minor mass extinctions.

And some of them are pretty dramatic. The big five are sort of notable because they pass this sort of arbitrary threshold of, it seems like something like over 75% of life on Earth goes extinct, species-wise. Let me clarify that. 75% of species, which not necessarily 75% of life. Right. Although to wipe out a species, you know, you can have something that loses 99.5% of its individual members and it doesn't go extinct.

And you're doing this without hunting or any human. Like, you're making the chemistry of the planet so unpleasant that you are driving the majority of life on Earth extinct. So we're doing all sorts of bad stuff today over fishing and hunting. and habits to have fragmentation. And this has to be all kind of climatic and chemical. And to do that is pretty dramatic. So here's a question that will lead into your second book,

which you're writing now, and it'll be part of our discussion. Of all the mass extinctions and all the dozens of minor mass extinctions, how many of those were related to CO2 pulses? well they're all related to dramatic changes in the carbon cycle so like when I was describing the all of you know well yeah I mean just because life is made out of carbon so when the asteroid hit if it was the sort of darkness that did it it shut down photosynthesis so there was less energy available to flow through food webs through this organic carbon so that's but specifically the warm pulses from volcanic CO2, I would say the majority of them, there's, there are a lot of

large igneous provinces throughout earth history and a lot of them are timed really sort of eerily to all these, to many of these minor mass extinctions, or at least like reorganizations of life on earth, if they're not a major, if they're not a mass extinction, um, sort of dramatic changes. So, so most of the minor and mass extinctions in Earth's history were, eerily correlated with CO2 pulses largely from volcanic provinces? Yeah, I think that's fair to say. Why don't most people know that? Well, I think a lot of this research is fairly new,

or at least hasn't pierced the public consciousness, because in the 90s, all those asteroid movies got made, and there hasn't been a disaster movie. about her, I guess there have been, but sort of slow verbaling things. Don't look up is becoming eerily accurate the more I think about it. Yeah. I actually haven't seen it. It's one of those things where I'm sure I'd be preaching the choir, but I should probably,

I should probably check it out. But no, I think most people don't know. It's a little bit of a comedy and I thought you were going to say you haven't seen it because it's too painful for you. But that one wasn't really painful. It was kind of funny. But I can't watch like BBC Planet. at Earth anymore. I used to love those shows. I just get too sad. Yeah. No, I understand that.

Although there is a new Netflix series. That one you have to watch. It's narrated by Morgan Freeman, Life on Earth, is it called? Oh, yeah. Yeah. It's all about what you're talking about. I mean, it's about the evolution and they use computer AI to represent different dinosaurs. And it's, I've only watched part of it, but it's so good so far. Yeah, no, I have friends who have been consultants on that show. And so they definitely do it right on the BBC, bringing this stuff to life. Excellent. So, um, minor mass extinctions, CO2 pulses.

We are living through what I refer to as the carbon pulse, which also most people don't understand that we're drawing down ancient carbon, uh, millions of times faster than it was sequestered. Um, many, many more questions, uh, Peter. Uh, I wrote down some things as you were speaking. What are your thoughts on, you mentioned that after what, what did you say, uh, 10,000 years or 100,000 years after a mass extinction, um, things start to recover because the earth generates a life?

Um, what, what are your thoughts on the Gaia hypothesis versus Peter Ward's Medea hypothesis, which is the contrast that Earth is trying to get to an equilibrium in the service of supporting life. And Medea hypothesis is the opposite, which is the earth eventually finds ways to kill off life. What are your thoughts on that? I think there's truth in both of those. I don't think there's really a teleological end point. There's nothing that Earth is sort of straining towards. So in the book I'm writing now, my eyes have been open to this idea that life, ever since its origin, has sort of been this channel of energy dissipation through carbon chemistry that was opened at hydrothermal vents, you know, for 3.5, 4 billion years ago that was unavailable to the planet before. And when you have systems that are out of equilibrium, they'll find these sort of channels of energy dissipation. And life is really this planet. process that does that. So if there's any sort of like end goal, I think it's this sort of second

law of thermodynamics, straining towards equilibrium along with the rest of the universe, and life is just a channel that a planet sort of explores to relieve the frustration of systems that are out of equilibrium. That was all very abstract. But if I was going to think about the planet and sort of these broader, you know, what's the point kind of terms, I think that's, that is a sort of unifying concept for me increasingly, is that, you know, hurricanes relieve the upper ocean of the heat in them, and they're these complex dissipative structures that no one is there to organize, but they somehow make these, you know, beautiful structures to dissipate this heat. People have made the analogy that that is what life is doing as well, just in a different domain in carbon chemistry.

So I don't know if that was too left field, but... I caught the ball, the fly ball to left field, and now I'm going to throw it back to you. Okay. Are humans just energy dissipating structures as aggregate civilization? I've thought about that. I think there's a, like, yes, because we are, like all life, we find sources of free energy. and we dissipate it, and that's how we've, you know, stayed alive. But there's a risk of sort of naturalizing the last two centuries, which, you know,

there is human agency and there's historical contingency, and humans are sort of different than sort of just a blind, you know, thermodynamic process. But then sometimes I think, well, maybe we're not. And I think if you have this, you know, this disheas hugely out of equilibrium, system where you have tons of flammable stuff underground and you have tons of flammable air above and you have this fire creature in between them like it better not figure out how to reunite these these two reservoirs to interact with each other and that's sort of what's happened in the last few centuries but even if we are even if we are as a species as a modern culture an energy dissipating structure that is uniting the two don't unite these two areas. There is the possibility that there's a Heisenberg principle phenomenon at risk that knowing that we are uniting those two spheres maybe gives us the possibility to restrain ourselves, maybe, which is the purpose of this podcast. Right. No, I think that is the, you know, the reason

why I don't, you know, just become totally nihilistic is that, Yeah, in some ways we're like the asteroid or we're like one of these big volcanoes, but there's a steering, maybe there's a steering wheel on this sort of agent of chaos and destruction. And I think that's sort of the open question for the next few centuries is whether we can control this or whether, you know, we're just going to wait around for the planet to correct us and then figure it out. Why would you say next few centuries and not next few decades? Well, it'll definitely be focused in the next few decades. The sort of window to meaningfully, the window in which we can, you know, really change the trajectory and not get too far down this sort of scary dark path that we've seen before in Earth history really does depend on what happens in the next few decades. But I mean, I'm only now dipping my toe in sort of human history in this next book. And for me, even thinking on centuries is, you know, ridiculously short.

So I'm trying to think in shorter timescales. But the planetary process is like if we have any ambition to live into geological time into the future, we need to start thinking on how can we live in accordance with these cycles that take place over thousands and if not hundreds of thousands of years. So dinosaurs, if you include birds, have lived over 200 million years. Humans have been 300,000 years in our modern form anyways. So, yeah, we have a long ways to go. In theory, in possibility, we do. So we are 45 minutes in, and I have a long list of questions for you, Peter Brannon.

You are originally a science journalist with a focus on ocean. trends. What was it like working on that subject? Oceans? Did you, and do you feel like I do that a lot of the ocean related topics are underreported and under acknowledged by by mainstream media. Yeah. I think there's this tendency to sort of see it as happening out there and, you know, it's like learning about something happening in space, basically. It's this vast, unknowable thing. and it's hard to get people to feel much sympathy for, you know, the plight of a baitfish like Menhaden or, you know, even cod and things like that. But there is no division between, you know, life on land and life in the ocean.

We depend on the ocean for a habitable planet. Just as much as the ocean relies on, you know, mineral nutrients from land, there's no real disentangling. these two systems. But, you know, reporting on the ocean, I think anyone who does so, you know, learns pretty quickly that a lot's going wrong in the oceans in some pretty worrying ways. So, you know, you have coastal pollution and nutrient pollution and warming, which is driving this loss of oxygen in the ocean. So the oceans have lost 2% of their oxygen since 1960. And that might not sound like much, but when you're talking about percent of oxygen change in the ocean, again, these are sort of geologically rare to see a change that big in such a short period of time.

And the 2% I assume is accelerating. Yeah. What would happen if the oxygen on land dropped by 2%? I probably wouldn't be able to go for a bike ride the way that I do. Yeah, I think you'd definitely feel it. I'm not sure what the respiratory effects would be, but there would definitely be effects. I mean, we've changed CO2 by, you know, hundreds of million.

Yeah, but we're talking on the range of 100 parts per million. And already plants have 30% fewer pores on their leaves since the start of the Industrial Revolution. These things that they fundamentally use to mediate their relationship with the outside world. When CO2's high, they want to minimize their, their, water loss, so they reduce the number of pores on their leaves. And you see this in geological history during high CO2 periods, plants get fewer pores. And we've already done that since in the last 150 years, this huge physiological change in plants on Earth that has untold effects on the water cycle. And so like very small changes in these things, kind of dramatic effects on the planet

and life. Wait a minute. I didn't know that. So since the Industrial Revolution, all plants, many plants, a sampling of plants have fewer pores. The one thing. studied. So there are these, there's this global warming event 56 million years ago where it gets about five degrees warmer and CO2 briefly goes up from these volcanoes in the North Atlantic. And you see in ginkgo, ginko leaves in the fossil record, the number of pore, the density of pores on their leaves shrinks. And people have used this to try to reconstruct CO2 over time, just looking at the number of pores, usually on ginkgo leaves. So that would be the plant equivalent of me moving from Canada to Florida.

I would be shedding my clothes and wearing less clothes because the temperature was different. Yeah, it's an adaptation. It's evolution on such a rapid time scale that's driven by this injection of CO2 in the atmosphere. I forget how we get on this topic, but yeah. Well, you brought up this. I'm going to get back to your original question, but this is something relevant to, again, the memes that we hear in the news because people correctly claim that CO2 helps plants grow and is a natural fertilizer, but then the implications of that, making it out to be an expansion

from where we are today at 420-some parts per million, a further expansion to 500 or 600 or 700 parts per million would be good for plants. It would be good for crop yields with higher concentrations. How true is that? And what are the tradeoffs to that phenomenon? Yeah. I mean, as with a lot of these sort of cherry-picked things, there is truth to that. Plants do like CO2.

They photosynthesized by taking CO2 and through these pores I was talking about on the leaves. And in fact, actually, I look. look this up before we talked that there's there's at least one study that came out in 2021 that said that the global annual levels of photosynthesis have increased by about 12% between 1981 and 2020. So you can just look at that in isolation and say well what's the big deal? This seems like a good thing. But anyone who's looked into this, the big problem is the world's going to get a lot more erratic. So there's going to be worse droughts than there have been. it does rain, it's going to be, you know, worse storm than it's ever been. And, you know,

the grain belts will shift around sort of on, we're just making the planet more unpredictable. And I feel like our global system sort of relies on predictability and tomorrow looking something like it does today. But there's some, there's some crops like corn, I think, is expected to dramatically decline under future warming scenarios. So when we talk about this is the same way of looking at stock market returns. There's an average and then there's a standard deviation. And what you're saying is higher CO2 because of the impact on weather is going to change the standard, increase the bands of the standard deviation, which means we might have

really good yields or like no yields. On average, they might be higher. But here's another thing that I've looked into. I don't know if you are aware of this, but plants, when there's more CO2, it affects the distribution of where they put the energy within the plant. And sometimes we don't get the same nutrients that we would. Can you speak to that? Well, no, I've seen the same study you have, that there's this sort of prediction that

plants will become less nutritious. But I also think that I think there was a study that came out recently saying that even like yields in total will actually decline. So it's not my air of expertise, but I think if anyone confidently, tells you what, you know, the world's going to look like in a relatively geologically unprecedented level of CO2. They're kind of, they don't. So I don't know that you've watched it yesterday. I had a podcast released with Sir David King, a former chief science advisor to the UK. And one of the things we talked about,

is that and also I have a podcast that will come out in two weeks from this date, which is October 26 with Jeremy Grantham. And we also talked about people's attitudes towards global heating. And I said, well, half the people still don't believe in climate change and some of the things that you're talking about, Peter. And he interrupted me and he corrected me. And he's like, half of the people. in the United States, not half of the people. So I think there really is a misinformation, a lack

of education or some failing in our science communication, perhaps offset by different incentives to really understand what's going on here. Now, granted, once we agree what the problem is, the auto mechanics are diagnosing what's the problem, then there's a different, a totally different discussion on what to be done. That I understand that people might respond differently and it might affect their identity or their situation. I get that.

We still need to have that conversation, but I don't think we're even there. Like half of the people in our country do not recognize that we are alive during a carbon pulse. Prior carbon pulses led to minor and mass extinction. this is a big deal capital B and D. Yeah. Do you have any thoughts on that?

Well, yeah, I mean, this is, I might have sort of touched on this when I was talking about the importance of deep time, but I think most people don't really understand how rare and extreme the planetary experiment we're doing on the, as far as we know, the only habitable planet, you know, that we know of is in Earth history. And for me, that was the biggest sort of eye-opening thing. And it was actually reading Peter Ward's books in the early 2000s that kind of alerted me to this. And then actually when I was working on the oceans or writing about the oceans, I did this fellowship with the Woods Hole Oceanographic Institution.

And there people were looking at these sediment cores from tens of millions of years ago and showing this line and this chalky sediment that just turns to clay for 200,000 years during this ocean acidification event. And it's thinking on, once you really really, realize, you know, some people will talk about, you know, there's the little ice age, the medieval warm period, and there's Locky and Tambora, and these things are not even remotely on the same scale of the change that we're imposing on the planet now. And some of them are kind of spurious. Like the medieval warm period, yeah, it was in Europe, it was, there's evidence that the climate

was a little different, but it was sort of a reorganization of the climate rather than a complete phase shift, which is what we're sort of pushing it towards. So, yeah, I mean, for me, I've also found that talking about climate change in it from a deep time perspective has been a way, sort of a Trojan horse for some people who have their minds made up about it, where they've only heard about it as these things that happens on computer models and it's all in the future and it's theoretical. And if you start talking about, you know, these science fiction worlds from hundreds of millions of years ago and you explain how the carbon cycle on CO2 actually works on the planet,

People I found are more receptive to sort of this message. Well, that's why looking at human history and human behavior is so central because the way that our brains are as short-lived biological creatures is we have to see evidence of something before we change our minds and our behaviors. But in this particular case, if the carbon pulse fully manifests by the time we see the evidence, evidence of a mass extinction, we will have been part of a mass extinction. Right. Yeah. So that's a scary possible thing at play in some of these mass extinctions is, you know, you'll see these volcanic eruptions happening over the course of sometimes hundreds of thousands of years. But the extinction pulses usually pretty quick. Everything sort of goes to hell. And some people like Doug Irwin at the Smithsonian Institution is sort of trying to

figure out whether it's, you have this background stressor. And then once you switch in a mass extinction mode, it's more of a network collapse dynamic. So he compares it to this blackout that happened on the East Coast in the early 2000s, I think, where it goes back to a software glitch in a control room in Ohio, and suddenly the eastern seaboard all the way up to Canada went dark. And it's not that it was caused by that one thing, but it was because this plant this system was, you know, you take enough, you chip away at the different components and you're going to find that one that makes sort of the whole thing collapse non-linearly. And so we don't really know where, if that is how mass extinctions unfold, then we don't know where the

event horizon really is. Which makes concert. So I wrote this, part of my book was excerpted where I said, we're not in the six mass extinction yet because if we were, you know, it might be completely game over. And people sort of took that as like, oh, I'm saying it's not a big deal what we're doing. And I wasn't saying that. I was actually saying conservation is doubly important because we don't know where this threshold is if that's how these things actually unfold. Because by the time you're in mass extinction mode, it might be too late to do anything. And you're in a sort of like network collapse dynamic. What is your new book about? And do you have a title for that? And when's it going to be done and out? Yeah. So over the course of writing this book

about, you know, the bad things that can happen in Earth history when lots of CO2 comes out of the ground. I realize that there's this much broader story to tell about carbon dioxide and the way the carbon cycle works for a general audience to sort of show, reintroduce them to this thing they've heard about in the news as this, you know, random industrial byproduct that comes out of smokestacks as sort of fundamental to how the planet works, which is one of the reasons why you don't want to mess with it too much. And so hopefully the book is coming out next year. I'm finishing it up now. And the title is quite grandiosely. The story of CO2 is the story of everything.

So we'll see if I can. So good luck with that. When it comes out, please come back on the show. And we can talk about that. Yeah, I'll too. Lots more questions here, Peter. On the topic of CO2, I asked this question of Sir David King, and I will ask you, I'm sorry to use you as a sounding board for common memes.

that are minimizing this. But I think some of them take hold and I want to get your scientific answer. So pre-industrial CO2 parts per million were near the lowest of the last, you know, ever, really. About as low as it's ever been, yeah. About as low as it's ever been. 280 million of parts per million. Now we're 425, 430. So if you think about that, we've gone effectively from three parts per 10,000 to four parts per 10,000.

Big deal. And there are graphics showing little grains of sand and the white one is the CO2 and we added one per 10,000. How do you explain that that actually is a big deal? Well, I mean, this was science that we had a pretty good, you know, it was starting to mature as a science in the 19th century when we discovered that CO2 is a powerful greenhouse gas. And you even have people like Svante Arrhenius who, this Swedish chemist or physicist who made this calculation in 1896 that if you double CO2, it'll get about four degrees warmer, which is still roughly in line with our best supercomputer. So the physics of sort of the spectroscopic, yeah, sorry. But just why? Why would it like a doubling of a tiny, tiny thing?

Is it that potent in how it absorbs infrared radiation and keeps the thermal blanket on Earth? Yeah, it is that important. And, you know, an irony is. And it makes sense once you know Earth history that this is about as low as CO2's ever been. It got down to about 180 during the peak of the last Ice Ages. And then about 280 and as we came out of the ice ages, now we're up to 420. But we have pretty good proxies for what CO2 was in the geological past. And the last time it was at the level of it is today was the Pliocene when you had the north shore, the Arctic Canada,

look like Michigan, basically. And last time it was a thousand parts per million. There were alligators at the North Pole and sand tiger sharks in Alaska and palm trees in Alaska. And we know that water vapor is the most powerful greenhouse gas in the atmosphere, but water vapor isn't the primary knob. It responds to the level of CO2. And the reason is because CO2 takes so long to come out of the atmosphere

that, you know, warms planet up. And then the feedback is you get all this water vapor, which is a really potent greenhouse gas. But until you get that CO2 out of the air again, the temperature of the planet isn't going to come down, whereas water vapor cycles through the system very quickly. So it's sort of unusual in that respect. And one of the reasons why people describe it as the principal knob

governing the Earth's temperature. So I don't know if I answered your question, but... To answer my question would take the full... interview, but people who minimize these risks of human cause global heating frequently point out that CO2 levels and temperatures were higher to much higher in our geological pass without threatening life. So how do you explain that? Yeah, well, I've never really, I've never really understood this objection because, you know, they'll say things like what I just said, which is, well, 50 million years ago, CO2 was high and life was perfect.

happy with alligators at the North Pole and like how is that relevant and imagine if we jump from our world partitioned by borders and national creeds and language and global trade and within a few centuries you're in a alligator at the North Pole world it's true that that was the case 50 million years ago but that would be unfathomably destructive for us and it's again it's this thing about the rate of change that, you know, the early Eocene, when that was true, you're coming out of the greenhouse of the dinosaurs. And the planet had been pretty warm for a pretty long period of time. And then there's this slow descent over the last 60 million years or so where CO2's been declining, where suddenly you pass the threshold we're here in these glacial interglacial

cycles, which is the world that we evolved on. We did not evolve on the Cretaceous hot house of the dinosaurs. We evolved in this. We're an ice age animal. So we're really not evolved. for that older world. When it's true, life was very happy, but that's just not our planet. Well, putting on my Fred Willard best in show questioning hat, would humans even be able to live in at the CO2 levels of the late Triassic or the early Jurassic, not eight billion humans,

but would humans have been able to live and thrive? The early Triassic would have been really, the early Triassic is probably about as hot as it's ever been. I think things cooled down over the course of the Triassic, but then they get super hot again in the next mass extinction. But no, I think in the warm periods in Earth history, it would have been intensely unpleasant because there's also,

we have a sort of climate niche, and with each degree sea of temperature rise, the atmosphere can hold 7% more water vapor. So just imagine the most, you know, a brutal New Orleans summer day and then make that even worse. And that's sort of a, you know, the regular state of affairs.

So every one degree C, the humidity on average is going to go up 7% the water content in the air? The atmosphere can hold 7% more water just because it's expanded. So that's why you can have such more powerful storms when it warms up. You just have more energy and more water in the system and moving through it faster.

And I've asked a few people on the show about the wet bulb temperatures, so you don't really need to define that. But how worried are you about the combination of more humidity and higher temps on human health, especially in places that don't have access to air conditioning? Yeah, I think it's hugely worrying. And we're starting to realize that the thresholds are actually much lower because a lot of these things are theoretical. And you read how the wet bulb temperature is actually defined. You're imagining someone sitting in the dark, naked, doused in water with gale force winds on them. And that's not the situation. That is where the thermal sort of tolerance comes in.

It's what level beyond where even that doesn't cool you off. That's sort of the wet bulb threshold. But in the real world, these effects will kick in much sooner because people are working. People are outside. there. So I think a paper came out recently saying that, you know, even with two degrees of warming, we're going to start passing these thresholds over, you know, in pretty significant parts of the world. From a geologic perspective, you also see physiological adaptations to warm. So you have these transient warming events like this one of sort of offhandedly mentioned a few

times 56 million years ago, where horses in the interval of the warming, which is about, it takes about 200,000 years for this thing to play out. Horses get smaller briefly, and then they get back to their normal size because it's easier to dissipate heat if you're a smaller animal. So we see, you know, if we make the planet really warm for 200,000 years, there probably will be a fossil record of animals adapting to that. In fact, I think fish are getting smaller as well. So it's possible we will re-evolve back into Homo Florentzis.

the Hobbit man. Yeah. I mean, we can't imagine. I mean, we're doing a planetary experiment here in deep time in real time. I mean, this is, it's great. You and I can be in a climate controlled environment with effectively a zoom cameras and lights and do this, but it's really freaking profound the time that we are alive. Yeah, I think I'm sort of motivated in part in my work to show people that climate change is almost like this cosmic, cosmically important issue.

It's not just another, it's not the acid rain. It's not methylmercury. It's not the, you know, it really is this thing that's geologically pretty profound. And we don't know what's going to happen. But we do know that when you go down these roads, that things can go. pretty wrong. Some people talk about the conceptually the venusification of Earth. Can you briefly say what the CO2 situation is on Venus and how we know that? And is that relevant at all to Earth's future? I don't think it's relevant. I think we're actually too far away from the sun to cause a

runaway greenhouse effect. I'm pretty sure that's true. But the atmosphere of Venus is both 90 so we're 0.04% CO2 I think and the atmosphere of Venus I think is like 99.5% CO2 and it's also way more just a crushing atmosphere and it's hot enough to melt lead and so we don't have to worry about that but you think there's a long way between now and Venus that where it can get pretty unpleasant well on the way this is another Peter Ward thing on the earth clock of life. We have around what 500 million years left before the sun expands and the oceans boil and and all that, right?

But 500 million years is a lot. Potentially. I think that's still pretty kind of an open-ended question, exactly how long of a lifespan we have that the earth is habitable to, you know, complex multicellular animals. There's a study last week about how in the next supercontinent, which is 250 million years from now, it's mostly going to be an uninhabitable wasteland. So that's not too far. I mean, it's very far in the future. But, uh, wait, why is that going to happen the next supercontinent? Just because of all the tectonic shifts, uh, that happen on very small timescales are going to aggregate into some new pangia called, uh, Brannon. Yeah. I think it's called Pangya Ultima is the name they've given it. Oh, really? I mean, yeah. I mean, there's this thing called the, will. supercontinent cycle, which is we've had a few of these things. You had Pangaea, and then before then it's the continents, the continents are sort of disparate. But before then you have this thing called Rodinia, which is another supercontinent. And if you, you know, we've been breaking apart for

around 180, 200 million years ever since, you know, New Jersey and Morocco used to be contiguous, and they've been pulling apart since then. But it's projected that another 250 million years, we're going to be in another one of these situations. And what we know about from Earth history is supercontinants are not very pleasant places to be. Things usually go wrong and for all sorts of interesting reasons. But the sun will also be brighter. Sorry. I said the sun will also be significantly brighter than it is today.

So it'll be a pretty unpleasant place. So I think we need to get through the next few decades and centuries. Yes. Let's focus on that. Let's focus on that. So speaking of that, there are other cycles in addition to CO2 pulses. The sun also affects our climate, obviously.

As another debunking or another point that's commonly out there, that it's the sun that is responsible for our climate, not cattle or volvos. Could you describe the interplay between solar forcing and CO2s, and CO2 forcing over the last several hundred million years. Well, you know, you have these very regular solar cycles every, I think, 11 years or so. But over a cosmological time scale, the sun in the course of being a main sequence star is diffusing hydrogen to helium and increasingly getting brighter over time.

So it's about over the past 250 million years or so, I think it's gotten something like 10% brighter. And, you know, some people have said that this has, over time, sped up the hydrologic cycle and increased rock weathering and actually is responsible for this sort of secular decline of CO2 from hundreds of millions of years ago to today is actually if the sun's getting bright and to offset it, CO2 has been going down. which is an interesting idea. But there's a wild paper a few years ago saying that because the sun is slowly brightened over over the past few hundred million years, that if we actually did push CO2 up to, you know, an N-Permian level, it would be worse because we're also dealing with a brighter sun. So we actually could do something totally unprecedented, which is a little frightening. I think, you know, the ice ages are complicated to talk about because they are sort of paced by these astronomical things like, the tilt of the earth and the eccentricity of its orbit and the obliquity.

And so there are all these sort of things the planet is doing around the sun that changes the distribution of sunlight on its surface that can, you know, in certain latitudes are favorable to the development of ice sheets, which can account for sort of the rhythm of the ice ages. But to go in and out of the ice ages the last few, the last two and a half million years, it's also the CO2 feedbacks that happen that you can't explain why the planet warmed and cooled without these CO2 feedbacks included. But there have always been these orbital mechanics going on. It's just that CO2 and Earth's past has been high enough that it isn't really, you know,

relevant to ice sheets. So if you go to the Triassic Newark Basin outside of New York City, you can see these Rift Valley lakes from where Pangea was pulling apart. And you will see the lake level rhythmically change sort of over the same time scale that we have the have had ice ages and it's because these what are known as milancovich cycles which is the way the earth's orbit interacts with the sun to to sort of rhythmically change but you see the lakes get deeper and then you see sort of mud and then you see this deep layers and mud and so these things have always been there and you can't explain the the broader changes without CO2. The earth is complicated.

Yeah. Well, its complexity is one of the reasons that we're not doing anything about it. The other reason is we're addicted to our current consumption and comfort and convenience and status. But complexity is a huge challenge on all these things. The whole human ecosystem and the metacrisis, every time. topic is complex. And then when you integrate them, there's an even bigger level of complexity. I will say this, though, while you're speaking, I do think we need more of the following

integration. We need the science. And then we need a science journalist like you to amass everything. And then there needs to be a podcast or a communication vector. You need all three of those things because any one of those areas is not sufficient to get the complexity out to people to integrate in their understanding of our world. Yeah. No, and I'm, you know, struggling to explain some of these concepts just because I know them and they come naturally to me, but I forget what it took to build up to that point. And you can, you can pull out little, you know, cherry pick things here and there in Earth history, but unless you understand the the broader context

like the role of the son or yeah well I will say this that you are a brilliant and captivating and poetic author the the ends of the world is an excellent book could you

you know briefly opine on what the difference is between the end of the world and the end of civilization or even the end of civilization as as we come to understand it now yeah so So, you know, I think when I tell people I wrote a book about mass extinctions, and that is sort of a defined term in paleontology, but sort of more colloquially, people just think I'm talking about, you know, the collapse of civilization. And it might be that, you know, civilization is more brittle than the biosphere.

you might not need a proper mass extinction to bring down global industrial civilization. You just need one of these run-of-the-mill sort of climate events that happens once every few tens of millions of years rather than one of these apocalyptic things that happens once every 100 million years or so. So I don't know whether two or three degrees of warming is dramatically devastating to the current global network society we have. It is a complex nonlinear system that we don't fully understand in the same way we don't really understand the food webs that collapsed in some of these mass extinctions.

Or it could be that you really need to destroy the world to bring humans down. I do think humans are probably not going extinct anytime soon. We're incredibly adaptable and we made it through crazy swings in the ice ages. But can what we have come to know, know as modern industrial civilization, maybe that disappears much sooner than humans do. Well, and it could disappear much sooner even without any of the CO2 impacts that you're discussing. Right, right. If you follow my podcast.

So from a perspective of another carbon pulse on planet or Earth. This one caused by Volvos and Volkswagons and vacations as opposed to volcanoes. You as a science journalist that understands Earth's past, what do we need to do and how? Up until now, I've mostly been sort of writing descriptively and avoiding the prescriptive stuff. but i understand that i understand that completely yeah but i'm increasingly realizing and i think this is sort of one of the thrust of my next book is that human society is now a component of the carbon cycle and it really is impossible to extricate uh politics and economics from uh planetary science um So we need to negotiate a way of living on this planet that is in, you know, within the proper context of our role in the carbon cycle and not one that sort of drives it as far out of equilibrium as possible, as fast as possible, because we know where that leads.

So I don't know specifically. I mean, I have trouble up making heads or tails out of policy. I just know that we live in a very exciting time because something has to change. A real eye-opening paper for me was actually one of your former guests, Tom Murphy, where he just does this back-of-the-napkin calculation

that if you even have the most conservative relationship between energy and economic growth, and of course there is one, because we can't just hand things back and forth to each other forever. and see the economy, you know, go up forever. If you have this very conservative relationship between energy and the growth of the economy, within 400 years, the oceans are boiling away just from the waste heat of the economy.

And within a thousand years, it's more energy than the sun puts off in all directions. So 400 years, obviously, that's never going to become a problem because we're not going to make that much waste heat, but something is going to change. And 400 years, not even geologically, but in human history is not that. long. So whatever comes next is going to look dramatically different. And I don't know what it is, but it's exciting to be alive at a time where we get to sort of chart out that future, however scary and, you know, terrifying that prospect is. So I'm not answering your question sort of intentionally because I'm not smart enough to work on the policy stuff. Well, or you're too smart and wise

that you know that your role is to paint the picture. And as soon as you go into prescriptions, your audience is much smaller. So I get it. Let me ask you this, though. This you can give me your personal opinion. You've listened to this podcast. You've done a ton of research on the current unfolding CO2 pulse.

You're aware of some of the complexities and the, fact that probably RCP 8.5 and the other RCPs are maybe energy blind and they assume that all this stuff will be extracted because the molecules exist. But if you had to describe the distribution in your mind of the carbon pulse, what's the midpoint of your distribution of eventual temperature increase on Earth. You mentioned 2 to 3 degrees Celsius from pre-industrial times earlier. Do you have an opinion or are you just unsure?

I am totally unsure. And it's because I'm also completely skeptical of, you know, you'll see these a lot online passed around of these charts to 2100 about our CO2 emissions or our energy use. And I've seen, you know, very reputable versions of those graphs that are literally outside the range of uncertainty within their first year. And these go to 2100. Right. So I think the future is way more open-ended and the range of possibility is way kind of scarier and broader than most people think.

I mean, or maybe I don't know what I'm talking about. But I do think they're also, as you do, the link between energy and the economy. and the economy is, I think, an under-theorized sort of area. And I think the coming out of the pandemic was sort of a helpful exercise for humanity because it reminded us that, you know, the economy isn't just charts on a graph and price discovery and things. It's a physical, material world. It's flows of energy and it's a material.

And if a supply chain, you know, can't get a thing from this part of the world to that part of the world or you can't ramp up energy production fast enough, then you see this shock in the global economy. And there are people working on that that are, you know, making an understanding of the economy a much more physical thing. But I think that's sort of the cutting edge and something that we're really going to have to figure out if we're going to figure anything out. One of my deepest hopes is that your very distilled.

descendant, the Peter Jr. to the eighth power, 100,000 years from now, is not, if he or she exists, seeing a layer of nuclear residue in the geological record of the future. Because I think that is the most direct path to the next mass extinction. And I'm really hopeful that we can avoid that. Yeah. I think, I mean, the thing that really keeps me up at night is the unknown response of the carbon cycle itself. So there's this tendency to think that it's only going to get as hot as we let it, basically. And I think that is generally the output that you get from a lot of models.

But I know people who study geoscientists who study events deep in arts past, who actually attribute a lot of the chaos to pushing the carbon cycle sort of out of bounds enough that then it kind of goes on a on a bizarre trajectory and i think the more we push on the system the more chance that there is of something sort of unpredictable and like that happening i'm sure you've seen the data the last few months peter this is being recorded on october 26th um are we in a phase shift right now um with the uh reduction in ice the global temperature the storms the floods uh or is this just el nino linked and we're going to mean revert. I've tried to navigate the conversation among atmospheric physicists and it seems like there's some debate about about that exact question and I'm, you know, not equipped to come down with the

judgment, but it could be either. The fact that it's a possibility that we could be entering a new regime is certainly frightening, but I think, you know, it's possible that this is just El Nino and and, you know, the natural climate variability in the same way that the, you know, the, you know, the you know, so-called warming pause was natural variability that people sort of pointed to as indication that warming had slowed down. You know, these, there's a lot of noise in the system, and it's extracting the signal out of it that's difficult. But yeah, I mean, there was an op-in the New York Times by an atmospheric scientist the other week asking whether global warming was accelerating. I saw people debating that online, but it's definitely frightening that

I've heard people say, oh, what's all happening much faster than we thought, and not, it's not true at all. You know, James Hansen's testimony was 35 years ago or 25 years ago, so 35 years ago. So it's right on schedule. What I worry about is that that sort of linear trajectory gets a little steeper. So hopefully that doesn't happen. So given that I know a lot. and care a lot about this topic. I could keep you for three or four hours, but I want to be respectful of your time. If you have a few more minutes, I'd like to ask you some personal

questions that I like to ask all my guests. So you're a science journalist, used to live in Boulder, now in D.C. writing another book. You obviously think about living through the CO2 pulse, and you're aware of energy, the economy, geopolitics. As an observer of these systems, Do you have any personal advice to the viewers of this show at this time of what some call the meta crisis? I think it's figuring out what you lever you can push what your contribution is. There's a risk in just sort of being saturated by the news or refreshing your social media feed and just feeling overwhelmed. But figuring out what the pressure point is that you can. contribute to, whether it's answering these fundamental science questions or organizing, if that's

more of your skill. And if you give yourself a concrete goal, you can feel a little less helpless in the face of this stuff. For, I mean, I think especially with social media and sort of this just terribly addictive, you know, constant feed of, of, of, you know, constant feed of, of, dreadful news from all over the world, disengaging, not in a sort of apathetic way, but trying to step back from the news. I mean, that's one of the great gifts of, you know, earth science and geology is I'm able to think on longer timescales than just, you know, who's the next speaker of the house going to be. Because if you're constantly reacting and you're not doing any strategizing or organizing or difficult work, then

you're not going to have the most adaptive response to. This is all very vague. No, it's good advice to, to your podcast host as well. Because we are, I mean, everything is unfolding. It's not just climate.

It's geopolitics. It's interest rates are going up. It's affordability. It's inequality. I mean, there's, it's just a tragic and beautiful and amazing time to be alive. And I think you're right that knowing that this deep time perspective, it makes it a little bit more of a story.

And I don't know, it feels calming to me that we're part of this planetary evolving. Yeah. I mean, there's something consoling to know that the Earth will be fine in the long run. Not that that matters on human time scales. It's more just what an utter shame and embarrassment it would be to get this incredible. sort of cosmic gift here at the, where the planet's been handed to us on a silver platter, we live in this miraculously habitable place,

and within a geological eye blink, we could completely screw it up. You know, in 10 million years, even if we do that, there's going to be cool animals, and the Earth will be, you know, won't even have any signs that we were ever here unless you're really combing the Earth looking for extinction boundaries

where we disappeared. But yeah, we live on human timescales and we care about, you know, relationships in our lives and, you know, people we love. And unless we figure out how to live in concert with the planet's sort of cycles, then there's the chance for a lot of short-term misery in the next few centuries for human beings. Are you married? Do you have kids? I am not. I think that would also change my perspective. Yeah, well, I mean, I don't have kids either, but I used to teach kids or 19-year-olds. What recommendations do you have for a young person listening to this program? The world that I know best, which is the research community and the academic community,

it is increasingly the problems are going to be interdisciplinary. And there's a lot of resistance to that in academia. people who sort of try to make grand sweeping statements about that unite several different fields are often attacked for doing so, sometimes the good reason. But that's where all the big questions are, I think. And so if you're going into academia and I think it's good to explore, you know, not the well-trod territory, but sort of try to unite these different fields. like global geochemical cycles and human history or the global economy.

It seems like that's where a lot of the exciting kind of work is. So this is a question that I think I'm going to start asking my guests, which is I believe that one of the largest underutilized human resources in the world is grad students and postdocs that are following the academic superorganism and the linear reductionist worldview that could be asking really relevant questions in their research to the metacrisis and kind of the things that you were just mentioning. So in your field, climate, oceans, extinctions, can you offer a few big questions that postdocs should or could be working on that need research and answers, or is that field

relatively covered in that space? You know, you'll have these rock boundaries where the extinctions happen. You know what happens in a layer. You know what happened within 20,000 years. But the dynamics of how those things actually play out, we don't have a century by century sort of accounting, which is what's sort of scary about them. They're kind of black boxes where we know everything goes wrong. So that's still very much an area that's open. the how this planet became habitable if you're interested in that that is still very much a open question um the rise of animal life and the oxygenation of the planet all these things that you know from my perspective the more i learned about earth i used to be a total space nerd and

dream about going other planets and the more i learn about this place the more i realize just kind of how special it is and how what a bizarre series of accidents there is in our geologic past to get us to this point to have this conversation so if you're imagination is fired by these sorts of big cosmic questions. That's definitely an area to go into. And yeah, I mean, it's these interdisciplinary topics. So there are, I've seen conferences recently that are about how to energy and information structure society throughout human history. What is the relationship of how humans are organized and their interaction with the sort of physical and energy world around them?

And if you're in getting a history PhD and you propose that, you could be, you know, laughed out of the room because it's such an abstract and bizarre topic. But I think if we really want to understand what the phenomenon of humanity on the planet really is, it's trying to bridge these worlds. Because if we're going to persist into geologic future, we need to understand how we're how things like society and. institutions are now structuring the nature around us. Well, here's a specific one. I'm sure you're familiar with Jeff Bezos and Elon Musk's attempt to get to outer space to eventually colonize outer space, which given what you just said, we don't even know our own planet quite well enough. But you just mentioned you used to be a space nerd, but you've also studied the history of, of life on Earth, do you think there's life on other planets and what's the math and the logic

of your opinion? I think there's, I mean, depending on how out there you want to get, if the universe is extraordinarily big and possibly infinite, which there's some reason to think it's somewhere in that ballpark, then it's a mathematical certainty that me and you are having this conversation. It's just repeating at a certain distance over and over again because there's only so many, there's only so many arrangement of atoms that you can have in a certain space that you're eventually going to do all the combinations and start repeating them again. So physicists have actually I've seen a paper where it has the exact, just how many meters you have to go away. It's like

10 to the 10 to the 26 meters away. There's an exact replica of you. So that's the super out there question, or the super out there answer. But yeah, I think there's definitely, I think there's probably intelligent life out there. I would imagine given how unusual this plan. it is and its history is they're probably so far away that it's sort of we're not really going to talk to them because I do think intelligent life is very rare just given the number of contingent steps that took us to get here. I think life is probably a pretty general phenomenon, especially if it is this sort of channel of energy dissipation that planets is available to planets that yeah, if you have alkaline hydrothermal vents that somewhere else in the universe and the

chemistry is pretty similar to our early solar system, you'll get you'll get light. But getting energetic, aerobic, intelligent life is probably pretty difficult. And so for the indeterminate future, we are left with this pale blue dot, which is where we'll make our stand to quote Carl Sagan. Thank you for your research and your time today. And I really look forward to reading your upcoming book next year. and maybe we'll have you back for a CO2 or extinction roundtable. Yeah, that'd be great. Thanks so much for having me.

I'm a big fan of the show. And so it's an honor and pleasure to be able to talk to you today. So thank you. If you enjoyed or learned from this episode of The Great Simplification, please follow us on your favorite podcast platform and visit the great simplification.com for more information on future releases. This show is hosted by Nate Hagen's, edited by No Troublemakers Media, and curated by Leslie Batlutes and Lizzie Siriani.