Dr. David Grinspoon is the author of Earth in Human Hands: Shaping Our Planet’s Future. He is also part of the team working with NASA on a proposed mission to Venus! On this bonus episode of Reversing Climate Change, David is back on the show with Ross to discuss the basic units of the geological time scale and explain why he proposes calling this new time marked by human impact and self-awareness the Sapiezoic Eon rather than the Anthropocene Epoch.
Full Transcript
Ross Kenyon: Hello and welcome to the Reversing Climate Change podcast. I’m Ross Kenyon. Today’s a bonus episode. We have an alumnus of Reversing Climate Change back on, Dr. David Grinspoon, astrobiologist, author of Earth in Human Hands and Chasing New Horizons, on which he is the co-author. Also a senior scientist at the Planetary Science Institute. Also some cool stuff going on with NASA. David, thanks for coming back. Oh, thanks for having me. Always a pleasure to talk with you. Indeed, we are big fans of Earth and Human Hands.
It’s made a big impression on us at Nori. We actually have a Patreon right now at Nori as podcasts like to do. And one of the things that we’ve been doing for patrons who have been pledging $10 a month or more is a book club. Every month we read a book. You get together with people who also like the podcast. We’ve been trying to get the authors of these books to come and hang out and answer some questions and do some dialogue with us, which has been great.
And David was the first author to do so in March. David, that was so much fun. And I’m really grateful that you came out for that. Oh, it was fun. I always enjoy talking with people who share my interests. Yeah, it must be fun to just walk into a crowd like that who have been already hanging out in your brain for a while and then them just flattering you by engaging with your intellect.
Dr. David Grinspoon: That’s one way to put it. I mean, it is really fun because, you know, writing a book is a very solitary activity and you kind of can go a little bit stir crazy and you’re sort of So much in your own brain. And then you put the book out and it switches to this very social activity where all of a sudden you’re communicating in all these different ways with people that have read your book or are interested. So yeah, it is really fun to talk to people who’ve read the book and want to explore further.
Ross Kenyon: Indeed. Yeah. I can’t imagine what that’s like. It sounds lovely. Well, I guess when people listen to the podcast, they’ve listened to dozens of hours of us yakking and then already know all the things that I have said, will ever say, because you’re just repeating yourself over and over on a podcast sometimes it seems. So. So maybe I have a little tiny taste of that. But yeah, if you want to participate, you can go to patreon.com slash noripodcast, plural, podcast with an S.
Come join us there at the $10 level or more. And this month, we’ve been reading The Wizard and the Prophet by Charles C. May. Also the author of 1491 and 1493. Trying to see if maybe he’ll come by for this. So it won’t always be like it is with David where he just pops in and makes it happen. But it is something that we’re trying to do. So if this interests you and you want to come hang out with us, you totally should.
It’s been a lot of fun so far. Okay, well, we should get down to business here, David. And I’ll only divert us for one brief little question here, which is that you have cool stuff going on with NASA. It’s too cool for me not to bring up. So what exactly is happening with you over there?
Dr. David Grinspoon: One of my other interests, in addition to Earth, which if I had to pick, Earth is my favorite planet, but probably my second favorite planet is Venus, which I’ve been studying my whole career. And in fact, my first research project as an undergraduate And I’m part of a team that’s proposed a new spacecraft mission. And this is something we’ve been trying to do for a long time. And it’s very hard to get a mission flown. It’s very competitive. There are other people proposing other really good missions.
But in the last round of competition, For what NASA calls Discovery Mission, which are the kind of relatively low cost planetary missions, which means, you know, under a billion dollars. So not that low cost. But then our mission, which is called Da Vinci Discovery. And then NASA is going to pick two of these four missions to actually fly. Has a real shot now at being selected, although it’s obviously still a competition. So it’s very exciting to be sort of in the playoffs, in the finals, I guess.
And now we’re working really hard to try to be the mission that actually gets flown because we want to go back to Venus and answer some of the outstanding questions that we still have about how that planet evolved and what makes it tick and why the climate is so different from the climate on Earth.
Ross Kenyon: That’s fascinating. Best of luck. Although I have to say DaVinci Plus, you would have thought you would have learned from Bodie McBoatface in the UK and gone for like Lando Calrissian and just gone for the Cloud City illusion. What’s wrong with you, David? You know, I’ll take that under advisement. Okay, take my stupid comment under advisement. Good to know. Well, I’m sure our audience wishes you well. Venus is super interesting too. I remember one of the things we talked about when you were first on is how much the study of Venus actually led to us looking back on Earth.
And saying, wow, actually these feedback loops can lead to some serious planetary changes if they run away. And this could happen to Earth too, although we’re not nearly in such extremis now. But that’s my understanding, right? Venus had a big impact on how we think about Earth.
Dr. David Grinspoon: Yeah, there’s a long history of insights we’ve gained about our home planet only from going and looking at other planets and realizing things that are unique about Earth or sometimes not so unique. And certainly the whole The modeling of carbon dioxide greenhouses. And there are other things about the way the radiation is scattered in clouds that really affects climate. You sort of see a really different example of these physical phenomena and you realize that you haven’t been thinking about it in a complete way. And it helps then us come back and do a better job with the Earth models.
And certainly Venus is... You know, it’s a very different planet in some ways, but it has these complex geochemical cycles as Earth does. And you realize that it’s not unique to our planet, some of these phenomena and getting this wider population. You have all these eureka moments that add up to just a better understanding of how planets work, including our own planet.
Ross Kenyon: Yeah, that’s fantastic. I’m very much looking forward to what might be learned from that. Well, okay, this bonus episode, my intention here, I’m going to set some goals, maybe we can try and achieve it. But we had Peter Brannon on a while back, and our objective I think Peter and I felt like, one, I think I needed a whiteboard to sketch out exactly how big these units of time are and how geologists and people who are working on deep time, planetary scientists, etc., So it’s one deep time is just hard to wrap your head around in general.
And I think a visual is useful. But since we don’t have that, I would love for people to walk away from this podcast, being able to understand what is an eon, what’s an era, what’s an epic, what might be an age. What is the Anthropocene? And then you also have this concept called the Sapiezoic that is an eon. So the Anthropocene is typically conceptualized as an epic. Sapiezoic is an eon. What is the relationship between these? How should we be thinking about the geological moment that comes after the Holocene, which is what we had left, which is prior to the Anthropocene or the Sapiezoic?
Dr. David Grinspoon: Yeah, I mean, it’s a great way to frame the question. And it is sort of hard to do without a visual. And, you know, I would encourage people who are listening a lot. I mean, you can just literally go and Google geological timescale. Click on the first thing that comes up and you’ll see something. I mean, anybody who’s been in a science classroom has seen something like this, this graphic with these different columns split into different units of time. But it is great. It’s great to unpack that and try to wrap our heads around what we’re really talking about.
Another visual just to picture is, think of a place like the Grand Canyon, where you’re looking at all these layers of rock, Without even knowing the details of what they’re all called and the details of what we know about how old they are, just picture the strata, the layers in the earth, and obviously the ones on top are more recent. They’ve been And as you go down deeper into the earth, you get to older times. Now, of course, it’s much more complicated than that because it depends on where you are and there’s been uplift and other things have happened.
But basically, when you look at one of The layers on the top are the more recent timescales and they represent geologic events and in fact rocks in the column that are made more recently and the layers down lower represent older times in Earth history. And then, of course, we break it up into these different, you know, just like in timekeeping in our lives, you have seconds and minutes and hours and days and weeks and years, you know, decades. It’s sort of something similar, although they’re not quite as regular, but we have the giant slices of time, which we usually represent on the left of that graph, which we call eons, which are really huge.
There’s only been five of them. And then there’s eras and periods and epochs. And I don’t think we should torture the listener with trying to memorize what each of those things are. But the thing to know is that as you go over to the right of that graph, Graph and you get over towards the epochs, those are the relatively smaller units of time that we break things up into. So epochs tend to last millions of years, maybe a few millions of years. Whereas when we get over to eons on the left part of the scale, the really giant units of time, those last for billions of years.
Ross Kenyon: Great. I think that is a very nice amount of groundwork that we’ve laid it out. And so you’re talking about eons and this concept that you’ve either originated or been popularizing the sapiezoic. That’s an eon. So this is a gigantic unit of earth history that So you think actually people aren’t thinking about it big enough, perhaps?
Dr. David Grinspoon: Yeah, let me explain that. So the Anthropocene is proposed as a new epoch. And the epochs are, again, over on the right side, the relatively small units of time, which is funny because for us in human time, they still seem unbelievably, unimaginably huge because they can be millions of years long. But supposedly, until the idea of the Anthropocene, the time that we’re now living in had been called the Holocene. And the Holocene, we pretty much agree on the beginning of the Holocene, it was more or less the end of the last deep ice age.
So it’s something like 12,000 years ago, which sort of almost corresponds to the beginning of human life. We’ve entered a new geological epoch. The Earth has gone into a significant new time and that is defined by a new geological force, which is the force of human beings changing the planet. And, you know, as you and I have discussed in the past and other people, including myself and many other people, written about, there’s plenty of evidence for that. If you just look at the, you know, quantitatively what human beings are doing to the planet, we’re in this new time where we’ve all Altered the carbon cycle and the water cycle and, you know, changed the nature of the surface of the planet and the chemistry of the oceans and the chemistry of the atmosphere in so many ways.
It’s undeniable there’s something new happening on the planet. So we can give that force a name and give that time a name and call it the Anthropocene. So that’s the idea that we’ve entered a new epoch. That’s being called the Anthropocene. And that’s controversial for a number of reasons that we’ve talked about and we could talk about some more. But the reason why I propose that maybe, in fact, it’s something more significant, and in fact, not just a new epoch, but a new eon, which I call the Sapiezoic.
The reason I proposed that is because I think that if you look at the nature of the changes between different epochs, In the past, there’s sort of these random changes in the Earth where, you know, there’ll be the climate will change for some reason and there’ll be sea level rise or sea level fall or there’ll be, you know, an episode of volcanism or, you know, something or there’ll be a mass extinction. Something will happen and change the planet. And in the long run, these are fluctuations that come and go.
But when you go over to the left of the chart, these eons, there’s only been four so far, and each of the eons represents a huge change in the nature of the planet, a sort of irreversible change, and they all have to do with a changing relationship between life and the planet. So there’s only four, so let me say what they are. The first one we call the Hadean, and it means it’s when life was hell. And that ended about four billion years ago with the origin of life, more or less.
And then that began a time that we call the Archean, which is the first time that Earth was occupied. And that lasted till about two and a half billion years ago. And the Archean ended really kind of with the rise of oxygen when life changed the chemistry of the planet. And that began a time that we call the Proterozoic, which lasted until about 500 million years ago, when we supposedly entered the eon that we are now in, which is called the Phanerozoic. And the Phanerozoic is when life got complex and made plants and animals.
So for roughly about five and a half billion years, we’ve been in the Phanerozoic, and that’s when life got more interesting and complex. And that’s All she wrote, those are all the eons that you’ll find in the standard geological column. The Hadean, the Archean, the Proterozoic, and now the Phanerozoic. But what I’ve suggested is that one way to think about the Anthropocene is that just as all those other transitions I just mentioned were massive changes in the relationship between life and the planet... You could look at the Anthropocene that way.
In other words, if you ask what’s really new and different about this time, this transition that’s happening to Earth now, In my view, it’s because it’s cognitive processes that are changing the planet. Cognitive processes have become planetary processes. It’s not just that we’re another species changing the planet. That’s happened before. It’s not just that we’re another species causing a mass extinction. That’s happened before. But this is the first time that there’s been a new geological force that’s aware of its own existence. We’re the species changing the planet and going, oh, wow, look at that.
Maybe we shouldn’t, or maybe we should actually find a way to integrate our activities gracefully with the planet. No other planet changer has had that choice that we have now to actually think about how we want to change the planet. So I maintain that this is then another major transition potentially in the relationship between life and the planet, in which case it would not just be an epoch, it would actually be a new eon, it would be the fifth eon of Earth history. And I call it the sapiezoic, you know, sort of aspirationally, that means the time of wisdom.
And the thing is, it will only be an eon if it really is the time of wisdom, because eons last a long time. Is this time of humans influencing the planet going to last a long time or short time? So far, it’s been ridiculously short geologically. Achieving a sustainable, stable state where we use our knowledge of planetary processes and we use our observations of how we’re interacting with the planet to choose those interactions in a way that ourselves. Then that could potentially be a very long-lived phase of Earth history, and so it could potentially be an eon.
So the sapiezoic is something I would say that hasn’t happened yet, but it’s an aspirational way to think of life. And if we achieve that, then I would maintain we’ve entered the new eon that I call the sapiezoic.
Ross Kenyon: That’s all super helpful. Thank you, David. I wonder how neatly it actually does break down along these optimistic or pessimistic lines because the Anthropocene is typically there’s a part of it that has a PR side where it’s saying like humans are now in control. They’re not doing a good job. They’re destroying everything. We have to change our behavior. And So some of the criticism of the Anthropocene as a geological notation of time is that Peter Brannon states this in Have We Earned the Anthropocene?
We would not probably make it into the fossil record because human civilization is so... So, so brief, especially when you take deep time into comparison. So if people think that an epic is already too grandiose for human involvement, they almost certainly would think the same for an eon. But I suppose you’re saying this is something that we live up to. We have to earn it. We don’t just get our own eon if we kill ourselves off very quickly.
Dr. David Grinspoon: Yeah, I mean, it’s an interesting question whether humans have made it into the fossil record already. I would maintain we have, that there are things we’ve already done to the planet that will be recognizable and detectable millions of years from now. But- I think the real important point about the Anthropocene is just simply that the processes of change on the planet are indisputably different from what they were a few thousand years ago before we ramped up our industrial act. And, you know, we can argue about when the Anthropocene actually started, but there’s no good argument really that the functioning of the planet is not radically changed by human activities right now.
Again, quantitatively, if just one example, the amount of water currently behind dams in reservoirs And stored in human built structures is now five times or six times the amount of water left in freely flowing rivers and streams. So that’s a huge perturbation to the water cycle. And you can go through and look. Look at the carbon cycle and all these other, there’s something, undeniably, there’s this massive change in the functioning of our planet. And if we give that collection of processes a name and connect them with the force, I think that’s the basis for the Anthropocene.
It’s not necessarily a belief that we’re going to be around a long time. It’s just looking at the functioning of the planet and how it’s changed and giving a name to that. I mean, there’s no minimum time scale that qualifies something from I think that argument that we haven’t been around long, so we haven’t earned epoch status, that just doesn’t make sense to me. But the more interesting thing for me, people argue about when the Anthropocene started, which is kind of interesting, but it’s even more interesting to talk about, well, when is it going to end?
Or is it going to end? Or what does that look like? And to me, it’s intriguing to imagine at least, you know, and this is partly my thinking as an astrobiologist, because I imagine, okay, here’s a new kind of planetary process, which is thinking, cognitive processes, technology, changing a planet. And As an astrobiologist, I want to say, well, this isn’t something that necessarily just happens here. Can one imagine that this is a kind of change that planets go through? Some planets that evolve life and where conditions are right, so life becomes complex and develops.
Develops cognitive processes. Is this transition to where a species is fundamentally changing the planet through technology, is that something that can happen to planets in the universe? And if it can, then is it possible that it’s something that can last? Not that it’s necessarily going to last here, but one can... Easily conceive of technology not just being something that’s self-limiting and self-threatening, but something that enables a new kind of long-term survival that’s never been enabled before. Because now, you know, you can stop those asteroids, right?
You can prevent the next mass extinction. If you sort of get a handle on your own behavior, one can at least imagine a state where technology and technological civilization becomes a very stable, long-lived phenomenon. And being able to imagine that makes one realize that, well, that’s actually a better idea than just self-extinction. So let’s try to figure out what that would look like. And then when you start to imagine survival on the long timescales that could enable, that’s when I go beyond just thinking of an epoch and my imagination wants to leap to saying, okay, so are there planets out there That have made this transition to self-sustaining, self-aware, stable technological planetary civilizations.
And if there are, they would have undergone a transition to a new type of planetary eon, which I, again, call the sapiezoic. And I deliberately, I like that term also because it doesn’t refer to us. It doesn’t have anthropo in it. It’s not saying humans. It’s just saying why self-aware life exists. Interacting with the planet over the long term. And so it could be some other species on some other planet, or it could be some other species on Earth. If it’s not us, maybe someone else in a few million years will start a sapiezoic eon.
So it’s a look at that phenomena that’s a little less attached to imagining that it has to be humans that achieves that.
Ross Kenyon: Wow, if this is your first time listening, if you can hear me chuckling, it’s because I think that these ideas are very important and very interesting and also underrepresented in environmental spaces, which could use this kind of perspective. I think it really snaps me out of how I think about things on a regular basis. And I also find it inspirational to something for humans to really aspire to. And David, career wise, you’re not just content to redefine stratigraphy and geological units of time. You’re also proposing an idea called the Terra Sapien, which is we can’t just be Homo sapiens anymore.
Now you’re there’s something more to it.
Dr. David Grinspoon: Yeah. So, I mean, it’s similar to the idea of the sapiezoic. It’s saying, what role can we imagine for ourselves on the planet? I think we do get caught up in the problems we have at present, and I certainly have no intention of minimizing them. We’ve got some Huge challenges on this planet as far as managing ourselves well as a global civilization and having energy supply that doesn’t wreak havoc on our climate. And those are very real problems. But I think it’s important to not just think about what we’re trying to evolve.
We know what we’re trying to avoid. We’re trying to avoid really dangerous climate change and sea level rise and collapse of agriculture and climate refugees, all this stuff we know. And it’s important to talk about that. But it’s also important to think... We need more than just fears and regrets and things we’re trying to change. We need an image of the kind of world we can imagine creating. And to me, that’s the value of terra sapiens, which again means wise earth. It’s the thought that we could use our scientific knowledge.
Our growing knowledge of self and our growing knowledge of how planets work, including our own planet, to create a truly sustainable global civilization. Obviously, there’s going to be some growing pains between here and there, but personally, I do think it’s possible. And Terra Sapiens is sort of the, again, the aspirational name I give to that. Because after all, Sapiens, I mean, when Linnaeus named us Homo Sapiens, that means wise apes. And maybe, you know, maybe he was being a little aspirational or giving us too much credit.
But I think we owe it to ourselves to imagine the role that we want to play on this planet if we’re going to be able to do a
Ross Kenyon: I think you did a very nice job here in explaining some of these basics, but I do have one question that haunted Peter and I on the episode we already did, which is how bad is it that I’m switching between Anthropocene and Anthropocene and Epic and Epoch? And I don’t know what to say, man. I feel like whoever I talk to about this, they always say it the opposite of me. And then I’m like, what do I do now?
Dr. David Grinspoon: It’s even worse because my British colleagues say Anthropocene. So it’s, yeah, is it Anthropocene? Oh, no, they say Anthropocene or Anthropocene. You know, honestly, to me, of all the different debates about the Anthropocene, the one about how to pronounce it is the one that I care least about. So. I think it’s, you know, we all know what each other means if we pronounce it differently. So I just don’t have a strong opinion on that. I can’t help you.
Ross Kenyon: Well, maybe next time. Well, great. Thanks so much for being here, David. If someone wanted to learn more about this, what do you think is a good place for them to start and follow your work and all of that?
Dr. David Grinspoon: Well, I think most directly applicable to the conversation we’ve been having today, I would recommend my book, Earth in Human Hands, which really is a book-length discourse on the topics we’ve been raising today. So yeah, I would start there.
Ross Kenyon: I think that’s a great, great place to do so. I love this book. I think it’s great. I think it’s due for... Every so often, David, I have to just like poke through it once again. Well, thank you. I really appreciate the positive feedback. Yeah, I feel like we overdo it with you sometimes. We’re just big fans. I hope you don’t mind we get too excited talking about these ideas.
Dr. David Grinspoon: Believe me, I don’t mind. It’s really nice to get the feel. Like I said, writing is a solitary experience and you start kind of wondering if you’ve completely lost your mind. And then so when you get it out there and people respond to it, it feels really good.
Ross Kenyon: That’s great. I’m happy to hear it. And you’re also on Twitter, DrFunkySpoon.com.
Dr. David Grinspoon: Yeah, Dr. Funky Spoon on Twitter. I’ve been starting to do, also if you’ve got kids and your kids are home right now because of social distancing, I’ve been starting to do a Wednesday afternoon kids science show on Facebook Live called the Funky Science Story Hour. So you can go on Facebook and just look for Funky Science Story Hour.
Ross Kenyon: That sounds very fun. One last thing, David, if I wanted to do a show on, what is it called? Abiogenesis. That’s how you say it, right? Just like life emerging ex nihilo and beginning to exist on the planet, if that’s even the right way to see it. You think you could help me with a good show on that? Is that your beat?
Dr. David Grinspoon: Sure. Yeah. That’s definitely something astrobiologists talk about. Yep.
Ross Kenyon: All right. Well, maybe that is something to look forward to in the future. It sounds like I have to do a lot of research to do a halfway decent job on it. But thank you so much for listening. Again, if you want to join the Nori Book Club, you can go to patreon.com slash noripodcasts with an S, podcast plural. Rate and review us on Apple Podcasts, iTunes, Stitcher. Tell your friends. Hope you enjoyed this. I always do. And thanks so much for listening.
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