Ep 126: What does it take to change the world? (with Stephen Porder)

Ep 126: What does it take to change the world? (with Stephen Porder)
Big Biology
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How have organisms changed the Earth and what can humans learn from its deep past?

On this episode, we talk with Stephen Porder, a Professor of Ecology, Evolution, and Organismal Biology and the Associate Provost for Sustainability at Brown University. Stephen is also the author of Elemental: How Five Elements Changed Earth’s Past and Will Shape Our Future. On the show today, we talk about Stephen’s book and the importance of just five elements (hydrogen, oxygen, carbon, nitrogen, and phosphorus) in the fate of the  world, often with dramatic consequences. We also talk about sustainable actions that we all can take to reduce our impact on the world.

Stephen is also a fellow podcaster. He is a producer of the show, Possibly.

Cover photo: Keating Shahmehri.

  • Marty Martin  0:04  

    So Cam, do you remember the periodic table song?


    Cameron Ghalambor  0:07  

    Yeah, that's the one that goes there's hydrogen and helium, then lithium, beryllium, and so on and so on.


    Marty Martin  0:13  

    Ah, yes, that is the one. It's a key study strategy for helping students to memorize all known chemical elements in the universe,


    Cameron Ghalambor  0:21  

    Sure, although I always thought the periodic table was pretty boring and missing the element of surprise,


    Marty Martin  0:28  

    Ha, ha, ha, just like you're missing the element of humor. Yes, those elements might be missing, but the periodic table is a really useful way to organize the chemical building blocks that make up our world.


    Cameron Ghalambor  0:38  

    Right and it's also helpful for figuring out how those chemicals will behave and react with one another.


    Marty Martin  0:44  

    Elements are also critical for biological systems. Particular arrangements and transformations underpin life, as we've discussed with Sarah Walker, Nick lane and many others on the show. But they also have the ability to change the planet and the life living on it.


    Cameron Ghalambor  0:58  

    That idea is central to the book Elemental: How five elements change the Earth's past and will shape our future, written by our guest today, Stephen Porder.


    Marty Martin  1:09  

    Stephen is a professor of ecology, evolution and Organismal Biology at Brown University. He's also the Associate Provost for sustainability, where he works to make the university more sustainable.


    Cameron Ghalambor  1:19  

    Stephen is also a fellow podcaster and the executive producer of possibly a show that breaks down the science behind climate issues and presents action-based solutions to complex problems.


    Marty Martin  1:31  

    In Elemental, Stephen writes about how Earth's geological history inspires his drive towards mitigating climate change and other anthropogenic effects.


    Cameron Ghalambor  1:38  

    In the episode, Steven discusses several periods in the deep past


    Marty Martin  1:41  

    And we're talking millions or billions of years ago-


    Cameron Ghalambor  1:45  

    When organisms fundamentally changed the world through just five key chemical elements: carbon, hydrogen, oxygen, nitrogen and phosphorus.


    Marty Martin  1:55  

    For example, about 2 billion years after the Earth formed, cyanobacteria evolved a method to fix nitrogen and perform a more efficient form of photosynthesis involving sea water. This photosynthetic innovation produced oxygen as a waste product, leading to the great oxygenation event of Earth's atmosphere, which resulted in the extinction of many anoxic species and eventually a global ice age.


    Cameron Ghalambor  2:20  

    Then, a measly 400 million years ago, plants began to move on to land, evolving a lot of new solutions to get water and nutrients, in particular phosphorus.


    Marty Martin  2:31  

    400 million years ago, the Earth was really warm, a lot warmer than today- warm enough to swim near the North Pole, says Stephen.


    Cameron Ghalambor  2:40  

    And for the next, oh, 100 million years, plants came to dominate land, storing a lot of carbon dioxide in themselves. And when they died, the plants were buried under sediment, and that carbon was locked up in the ground.


    Marty Martin  2:54  

    This drawdown in carbon from the atmosphere cooled the earth rapidly, again, causing a huge mass extinction and leading to a major ice age.


    Cameron Ghalambor  3:02  

    And this, of course, isn't the end of the carbon dioxide story. When humans evolved and eventually discovered that all those dead plants in the ground-


    Marty Martin  3:09  

     oil, coal and natural gas, of course


    Cameron Ghalambor  3:12  

    -made for great sources of energy. But now that we're burning all this stored carbon, we're having a comparably profound effect on the planet.


    Marty Martin  3:20  

    Similar to other organisms in Earth's past, we humans are impacting the climate at a scale and rate previously unseen in geologic history, effectively introducing old carbon back into the modern carbon cycle.


    Cameron Ghalambor  3:32  

    Still, Stephen is hopeful that we can change Earth's warming trajectory, and we discuss some of the actions we can all take to help make this change.


    Marty Martin  3:42  

    And one quick note before we start the show, this is the first episode that we're releasing behind a paywall.


    Cameron Ghalambor  3:47  

    That means that if you want to hear the full episode, you'll need to go to big biology.substack.com, and sign up for a paid subscription.


    Marty Martin  3:56  

    And as a subscriber, you'll also get access to extras like our episode debriefs, our behind the scene content about how the episode art is made, and more material from our guests about their lives and hobbies.


    Cameron Ghalambor  4:07  

    Thanks for your support.


    Marty Martin  4:08  

    I'm Marty Martin.


    Cameron Ghalambor  4:09  

    And I'm Cameron Ghalambor


    Marty Martin  4:11  

    And this is Big Biology.


    Cameron Ghalambor  4:24  

    Stephen Porder, thanks so much for joining us today on Big Biology.


    Stephen Porder  4:27  

    Yeah, thanks. And it's great to be on the show. I'm really looking forward to the conversation. So


    Marty Martin  4:31  

    Stepen, I'm going to ask you one question because I'm really curious about it, and I think listeners would like to know. But Cam, after I do this one, if you want to sort of do the you know, launch into the book. Your bachelor's degree was in history, right? So, how did you get to do what you do now? Was there some specific experiences that you had during your training that took you down the path to a would you call yourself sustainability biogeochemist? I'm not sure what your label, your self imposed label, would be, right now, but it's not historian, I think.


    Stephen Porder  5:01  

    No, it is not a historian. Yeah, you know, I think that as much as I would like to say that there was a plan, you know, life is full of haphazard, haphazard events, and I just had a series of experiences that tweaked me in various directions. So I was a history major, you're right, but I fell in love with geology towards the end of my time in college, and I didn't have time to finish that major because I wanted to write a thesis, an honors thesis, and didn't have enough courses in geology to do that. And so I wrote a history honors thesis. And from that I learned I really loved research, but I didn't want to do research in the basement of the Vermont State House, which is where I did it.


    Stephen Porder  5:40  

    And so, but I was super excited about geology. So in part because I had lived in the I had taken some time off from college and lived in the American West, which is a good place to see geology up close, as opposed to the American east, where it's a little harder to spot. And so Iwent and got a masters in geology, basically the same kind of geology that had been interesting to me in undergraduate and from that, I learned that I loved outdoor field research, but that I wanted to do something that was more relevant to society, I guess in some way, like the rocks I was working on at that time were over a billion years old, and I kind of felt like if I was right or wrong about my hypothesis, there'd probably be three or four other people that cared, maybe, but not many more than that.


    Stephen Porder  5:40  

    And so I took some time. I was a high school teacher in New York while my wife went to medical school there, and I learned I really liked teaching as well. And then I stumbled across two books, the Beak of the Finch and the Song of the Dodo, both about for your listeners who might not know them, these are books about the first is about evolution, and in the Galapagos and Darwin finches and Peter and Rosemary Grant, very famous evolutionary biologist. The second is sort of a series of vignettes by David Quammen about conservation biology.


    Stephen Porder  6:57  

    And I called up the only biologist or ecologist that I knew, a guy named Dave who was the boyfriend of a friend of mine. And I said: "Dave, I think I want to get a PhD in either conservation biology or ecology. Where should I apply?" And he said: "Well, do you want to do conservation biology or ecology?" And I said: "I don't know the difference." I've never to so the last biology class I had taken was in ninth grade. And so this was just, you know, so this was in like, 1999 right? So the internet was just getting going. Wasn't like everybody had a web page. And so he gave me a list of seven schools, and I applied to those seven schools.


    Stephen Porder  7:34  

    And it just so happened that the person who ended up being my advisor was a ecosystem ecologist who had really started getting interested in geology, an intersection between geology and ecosystem ecology. And so the skills that I could bring as from the geology side were of some interest in him, even though I knew diddly squat about ecology or biology. I mean, I could barely spell DNA. So yeah, and I wrote that in my application, I basically said, like, "Hey, I don't know anything about this field, but here's why I think I'm interested in it, and why I think, you know, it might be good to take me." And as you might imagine, I applied to seven schools. I did not get seven acceptances, but, but I got one, and that's all that matters.


    Stephen Porder  8:13  

    And so from that, I sort of launched into what he studied, which was ecosystem ecology and biogeochemistry. That, as I said, that was what my graduate work was on. I worked on the interface between geomorphology, the forces that shaped the earth and the forests that sit atop that Earth, mostly in the Hawaiian Islands and also in Costa Rica. And then over time, you know, as one does, one finds more and more things to study. I had a graduate student who was super interested in agriculture in the Amazon, and so I launched into that for a decade or so and did a bunch of other things. And then round about 2016, 2017 I got really involved in the effort to help Brown University, which is where I teach, eliminate fossil fuel combustion and transition to a renewable electricity powered campus. And as part of that, they asked me to become this, this role called Provost for sustainability, which, as far as I know, is the first in the world to do that.


    Stephen Porder  9:14  

    And so my job now is sort of half time helping think about what sustainability means at the university level, both from the physical infrastructure, but also how that's integrated into the research and teaching and outreach missions of the university. And then the other half of my job is sort of still doing science. And yeah, so that's a long winded answer to how you end up professor of ecology and Provost for sustainability from being a history major, but that's that's the story.


    Marty Martin  9:40  

    Yeah, yeah, twist and turns. That's a common theme for many people we talked to. You mentioned Rosemary Grant. We had her on the show a little while ago about her autobiography. And so what I'm forgetting the name of the book, Cam, but it was very much. The name of the book was this sort of, you know, series of fortunate events kind of thing.


    Cameron Ghalambor  9:58  

    Yeah two steps sideways, one step forward or something like that.


    Stephen Porder  10:01  

    Yeah. I think anybody, anybody who gets to be our age and says that they planned it all out is just kidding themselves. I mean, right?


    Marty Martin  10:11  

    Right


    Cameron Ghalambor  10:11  

    Yeah, well, I mean, my background, Stephen actually parallels yours in some ways. So I was a geography major, and I was interested in geomorphology and geology and hydrology, and, you know, those sort of landscape processes and and then I took a biogeography course. And then I was like, Whoa, this is really cool. Like, why are plants and animals distributed around the world the way they are? And that kind of got me into ecology. And then I did a field course in the tropics, and I was like, Yeah, this is definitely what I want to do for the rest of my life. And but, you know, making that transition from geography to biology, I also had a little bit of kind of, well, not just a little. I had a major dose of imposter syndrome for many years thinking, like, do I really, yeah, I like, do I really belong here? Like, you know,


    Cameron Ghalambor  10:15  

    I still do.


    Cameron Ghalambor  11:06  

    Yeah somebody's gonna come in and, like, haul me away when they fight, they kept totally unqualified.


    Stephen Porder  11:13  

     I'm still looking over my shoulder. I completely hear that.


    Cameron Ghalambor  11:16  

    So, yeah, no, that's great. Good. Okay, let's, should we jump in? We're really looking forward to talking to you about your new book, Elemental: how five elements changed Earth's past and will shape our future. Let's kind of jump right in and talk a little bit about these elements and these major events which revolve around the appearance of cyanobacteria in the oceans, the colonization of land by plants and human use of carbon based fossil fuels. So at first glance, those seem really unrelated topics to me,  but you weave them together into this narrative. So can you sort of tell us a little brief kind of introduction about how you first kind of saw these different major factors in the history of life on our planet kind of connected through these elements.


    Stephen Porder  12:17  

    I guess the one or two sentence answer to that question is, I spend a lot of time thinking about how human changes to the environment today are, in some ways, unprecedented even in the history of the world. But when you look back through the depths of geologic time, you see that there are other organisms that have had really profound impacts on the planet. And what's so fascinating to me, and what I try to bring out in the book, is that those rare organisms that change the world always do it in a similar way, and that similar way is connected to these elements that make up the building blocks of all life. And not only that, but understanding how previous organisms have changed the world, and our link to them can actually show us a path towards a more sustainable future. So it's that thread that connects us to our world changing predecessors, that I find really interesting.


    Stephen Porder  13:14  

    And you know, you asked about the elements. So all life on Earth, from cyanobacteria to plants, to you and me and and everything else are made up of these five elements, hydrogen, oxygen, carbon, nitrogen and phosphorus, and then a few more after that, but those are the big ones, right? And so all organisms have this challenge of gathering those elements from their environment in just the right proportions, even though the environment is very heterogeneous and not made of stuff in the same proportions that we all need. So that challenge is the challenge of ecology and biogeochemistry, and it sets the stage for all this competition between organisms on the planet. But it's also the fact that those elements control the climate and the rhythms, the chemical rhythms of the planet, that that's where stuff really gets interesting, because now you have all these organisms fighting for these elements, trying to gather them from the environment. And when they succeed, they actually change the environment in which they're living. And it's that interplay.


    Stephen Porder  14:17  

    So one of the things that I came to realize actually in writing the book, or came to articulate in writing a book that I hadn't really thought through before. I mean, we're all taught as kids that Earth is a living planet, right? And I always took that to mean that Earth hosted life like there are living things on Earth, and that's true, but that's only half of why Earth is living planet. Earth is a living planet because it is itself shaped by life. So it goes both ways, and I think that interplay is at the heart of the book, and can point a way towards a more sustainable future.


    Marty Martin  14:50  

     Yeah, good, good. So, oh wow, there's so many things to do there. We'll try to walk through piecemeal. Let's go way back in time. Start with the cyanobacteria. And I'll ask a weird question, but when I saw it, you know, it made me think, we have to, we have to bring this up for the listeners, because the way that you framed it, it just turns to my brain in a twist. And so it was so much fun to follow from there. Why aren't old sedimentary rocks red? What does that have to do with cyanobacteria and why they feature in your book? Yeah.


    Stephen Porder  15:17  

    So that's a great yeah


    Marty Martin  15:20  

    That's your question.


    Stephen Porder  15:20  

    That's my question. Actually, actually, to be fair, it's the question of my undergraduate sedimentology professor Ed Belt, which is, by the way, the greatest geologic name Ed Belt, anyway. So that's, it's a very profound question, and as I write in the book, I didn't understand it at all when I was asked as an undergrad. But the reason it's a profound question is that that red is actually iron oxide. It's rust. And in order to get iron oxide or rust, you need oxygen around to react with that iron. And what we see in the geologic record is that there are tons of red rocks all over the place, but none of them are older than about 2.22 point 3, billion years old. And that's one clue. And now one clue among many, that the first 2 billion years of Earth had no free oxygen in the air or dissolved in the ocean. So what I mean by free oxygen is oxygen bound to oxygen, 02, which is what you and I breathe in and what any multicellular organism needs to be able to survive. But for 2 billion years, that wasn't the case, and it's only because of some really interesting evolutionary innovations by the cyanobacteria that we have free oxygen around for all the rest of us to breathe. And so that actually, that transition from no red rocks to Red Rocks is a marker of, really, the biggest change ever to occur on planet Earth, and it was precipitated by this group of organisms and their evolutionary innovations.


    Cameron Ghalambor  15:20  

    Yeah. So, so let's talk a little more about the cyanobacteria. So we go back to this time in the past where there's no oxygen in the atmosphere. All living life is unicellular in the oceans, and there is some capacity for photosynthesis among some groups of bacteria, but then the cyanobacteria come up with a sort of a novel mechanism for taking up carbon dioxide and releasing oxygen. So what was the magic combination of traits that made cyanobacteria so successful?


    Stephen Porder  17:29  

    Yeah, so we don't actually, I mean, this is a long time ago, and so everything is inference, right? I mean, I guess everything is inference, always, but everything is more diffuse inference when you're way back billions of years. But so photosynthesis probably evolved around three and a half, 3.8 billion years ago, but it was not particularly efficient. And what I mean by that is that for a given amount of sunlight, it couldn't produce that many sugars, you know, couldn't produce much fixed carbon. So CO2 changed into the sugars that then make up all, all are transformed into all living things.


    Stephen Porder  18:02  

    So there was photosynthesis wasn't particularly efficient. And sometime along the way, and I'm not, I don't, I don't think we really know whether it evolved first in the cyanobacteria or the cyanobacteria incorporated it later. But somewhere along the way, a more efficient photosynthesis based on the splitting of water, which of course, is very abundant in the ocean, evolved, and so in the early photosynthesis, you would use the reaction. Essentially used hydrogen sulfide, h 2s, and CO2, and that allowed carbon to be fixed and released sulfur, elemental sulfur, sulfur as a waste product, basically. The switch to using water is much more efficient. And what that means is more you can do more photosynthesis for a given amount of light using water, but instead of sulfur as a waste product, where you split h 2s and dump the s out, you split H2O and you dump the O out, right? And so that was a major evolutionary innovation that the cyanobacteria incorporated, but isn't the only one, because photosynthesis doesn't rely just on carbon dioxide and sunlight. It relies on enzymes, biological machines, to actually carry out the process. And those enzymes require a lot of other things, and particularly they require a lot of nitrogen.


    Stephen Porder  19:21  

    Nitrogen is another really wacky element. It's super abundant in the air. Right now, it's about 80% of the air we breathe. We breathe it in and breathe it out. Doesn't doesn't interact with our bodies at all, and that's because it's two nitrogen atoms bound to each other. Now, when two oxygen atoms are bound to each other, it's very reactive, but when two nitrogen atoms are bound to each other, it's super unreactive. It doesn't like to it doesn't like to break apart. It's very hard to break it apart.


    Stephen Porder  19:46  

    So in the again, in the early oceans, you have these, these photosynthesizers that are using water, but they're still limited, because they can't build enough photosynthetic machinery, because they can't get enough nitrogen, the cyanobacteria. Up, evolve or incorporate another biological innovation, and that is to build an enzyme that can break that nitrogen bond between atoms in the air, where it's super abundant, right? So what does that do? It allows the cyanobacteria to build a ton of photosynthetic machinery and then use that machinery in a hyper efficient reaction to fix carbon and so together, that allows them to wildly proliferate, right?


    Stephen Porder  20:28  

    Nobody really knows, but the estimate is life on Earth probably increased by 100 fold as a result of the combination of these two processes. Right? It's a lot more life. It's also, by accident, a lot more oxygen being dumped into the environment right now, oxygen is terrible for nitrogen fixation. This process of capturing nitrogen, it's called nitrogen fixation. Oxygen actually poisons the enzyme that does nitrogen fixation. Oxygen is also really bad for photosynthesis. It makes photosynthesis much less efficient, and so despite that, right it's such a boon to these organisms to be able to do both that they pay that cost and dump the oxygen into the environment. And for hundreds of millions of years, that oxygen just reacts with other stuff in the ocean. There's iron there, there's sulfur there, as I just described, that oxygen just gets consumed. But sooner or later, all that iron and sulfur kind of gets used up, and the oxygen begins to build up in concentration in the ocean and bubble out into the atmosphere.


    Cameron Ghalambor  21:24  

    I think in your book, you describe this transition as going from a Model T to a Tesla in terms of efficiency.


    Stephen Porder  21:33  

    Yeah let's just say an electric vehicle in general.


    Cameron Ghalambor  21:36  

    Yes, from a Model T to an electric vehicle.


    Stephen Porder  21:41  

    Yes, exactly. Yeah. And, and, you know, I think there's another lesson to be learned here, and it was sort of what I was trying to hint at when I said, you know, oxygen is bad for photosynthesis and for nitrogen fixation. This is just a waste product that the organism was dumping in the environment. It had no interest in creating oxygen. It didn't help it to create oxygen. It actually hurt it to create oxygen, but as long as the environment could suck it up and not change too much, it didn't really matter.


    Stephen Porder  22:07  

    But there's one more piece to this story, and it really sets the stage for the rest of the book. At the time, the sun was quite a bit fainter than it is now, stars get brighter as they get older, as opposed to professors who tend to go the other direction.


    Marty Martin  22:23  

    Well said


    Stephen Porder  22:24  

    I'm among friends. I know, so I can make that joke. So, so the earth had a fairly faint sun, and the only reason the earth was warm enough to be unfrozen was that the atmosphere, the greenhouse gas in the atmosphere at the time that was keeping everything warm, was methane. Methane is CH4. It's a very potent greenhouse gas. We talk about it a lot in the modern day, but methane, not CO2, was the major greenhouse gas at the time. The reason methane was there is because there was no oxygen in the environment. Methane is very reactive with oxygen, which is why gas burns, right? And so once that oxygen begins to bubble out again by accident, right? No benefit to the cyanobacteria, that oxygen begins to react with the methane in the atmosphere, which then forces the planet into a colder state, because methane was this really warm blanket, and now the oxygen has destroyed that warm blanket, and so you actually precipitate a global, almost global, nobody's really sure, Snowball earth a global Ice Age, because the blanket that was keeping the planet warm was destroyed, destroyed by a waste product, right? That was just being dumped into the environment as the cyanobacteria went about their daily business of photosynthesis and fixing nitrogen.


    Stephen Porder  23:33  

    So that really sets the stage, I think, for the whole rest of the book, which is sometimes the things that you're doing have unintended environmental consequences that actually might be bad for you, or might be at least or even neutral for you, but if the environment can suck it up, it doesn't really matter. It doesn't change things until it does, right? And that story then goes along to play out again in evolutionary history and then again in the modern day.


    Marty Martin  24:02  

    Yeah well, we could jump right into, sort of, what are we doing to create a similar scenario? But I don't want to leave out the plants.


    Cameron Ghalambor  24:09  

    Oh, I was just gonna say, and if we circle back, it was this oxygen that then, you know, this waste product that seeped into the atmosphere that then reacted with the iron that was in the rocks, which then led to the appearance of Red Rocks.


    Marty Martin  24:26  

    Yeah. Thank you for closing the loop.


    Stephen Porder  24:28  

    I think there's actually another lesson I'd love to pull from that story before we jump to the plants, if that's okay. So, you know, in the modern day, I hear a lot of people saying things like, well, you know, it's been a lot warmer in the geologic past, like, who cares about climate change? You know, it's been warm before. And it's definitely true, it's been warmer than it is now before in geologic history. And, you know, I think if you look back at the cyanobacteria, you and I and everybody else are very happy that they oxygenated the planet. We wouldn't be here, multicellular life would not be here if they didn't. So it's not that life can't exist with the earth in different states. It's the transition between the states that's really hard, right? So, so you know, in the with the hindsight of the last 2 billion years, I'm pro-oxygen, right? But if I had been an anoxic organism at the time of oxygenation, when the earth froze over, and all of a sudden, the environment that I depended on was gone, and there was this oxygen environment, right? That would have really been bad. And so it's not one state versus the other that's the problem. It's the transition, right? And I think that that also plays out in history again. So I just thought I'd raise it now . Yeah, yeah.


    Marty Martin  25:43  

    Well, likewise, I mean, I'm a big fan of carbon dioxide, and, you know, there's a way to sort of represent that poorly. But we can use that as a transition to these plants. How do we get from cyanobacteria and a very oxygenated atmosphere? The methane is gone. It's colder.But what are the things that facilitated the movement of entities onto the land, and how did the plants do it in ways that other organisms were not able?


    Stephen Porder  26:09  

    Sure. So let's just set a timescale for your listeners. So Earth is about four and a half billion years old. Photosynthesis probably evolves 3.8 billion years ago. The cyanobacterial transition is 2.2 roughly halfway through earth history, 2.3 to whatever somewhere in there. Right now we're going to fast forward all the way to a mere 400 million years ago, right? So nine tenths of Earth's history has already passed when the plants make their way onto land. So it sounds like a long time ago certainly is a long time ago for us, right? But in Earth history, it's relatively recent.


    Stephen Porder  26:45  

    So by the time the plants evolve, you're living in the world is a lot more like it is today, right? So pretty much all modern groups of organisms in the ocean are in the ocean, swimming around, doing their thing. You know, there are things that look like fish, and there are things that look like all sorts of other things. And you guys are real evolutionary biologists, so you probably know more about this than I do, so I'm gonna not say anything wrong and just move on.


    Stephen Porder  27:10  

    There are a few differences. CO2 in the air is the main greenhouse gas, as opposed to methane in the ancient past, and it's really abundant. So the earth is quite warm, and plants basically begin to move on to land around this time of 400, maybe a little less than 400 million years ago. And so we talked a lot about the story of carbon and nitrogen for the cyanobacteria. And I want to use the plants as an example of the other three elements that are critical to the book, hydrogen, oxygen and phosphorus. So let's start with hydrogen oxygen, together as water. If you are an organism made up mostly of water, as we all are, right? That's why there's so much hydrogen and oxygen in our bodies. Moving on to land is a real challenge, right? Because there isn't a lot of water on land compared to in the ocean. And in fact, it's even more of a challenge if you can't move if you're rooted in place, right? And you can't walk around. So the first problem that plants really have to solve when they begin to move to land, is how to stay hydrated in this new, difficult environment. In fact, we think for many millions of years, they basically were restricted to low lying, swampy valleys or coastal areas because of the water problem. But they evolve a couple of really amazing strategies to deal with this. The first is they evolve both roots and a partnership with fungi, which most all plants still have today, which allows them to explore huge amounts of the subsurface and suck up water and other nutrients. So that's one thing. They also evolve structures on their leaves, or not, there weren't leaves exactly at the time, but call them leaves for sake of simplicity, like waxes to help limit water loss and so forth. And so they evolved that. And then the last thing they evolve is seeds, which allows them to give their progeny both a way of moving around and looking for wetter places, and looking for in quotes, of course, but also sort of a little packet of goodies to start off with. So even if the environment isn't perfect when you get there, you can sort of start with your trust fund, and hopefully things will things don't get better, right? So that's a water innovation.


    Stephen Porder  29:20  

    We haven't talked at all about this last element, Phosphorus. Phosphorus is very different than carbon dioxide, which is in the atmosphere, or water, which is in the ocean. Phosphorus is really only found in rocks. And so any phosphorus in the ocean is comes from either rivers washing it into the ocean, off the land, or from dust blowing off the land. And so as a result, Phosphorus is very limiting to ocean life in many parts of the ocean. So fortunately for the plants, continents are made of rocks, right? So they move on to the land and their roots, and the fast to their roots, begin to mine the rocks. And that, in part, helps them get water, but it also helps them get phosphorus. And so they become and remain to this day, the world's best miners. And a lot of the mining that plants do is to break rocks and soil apart and get at those so-called "rock-derived nutrients," first, first among them, phosphorus.


    Stephen Porder  30:13  

    So that's the sort of two innovations of plants. They figure out how to stay hydrated on land, and they figure out how to get all this phosphorus. And that allows, essentially, forests to move across the continents. So all the continents, just for visualization, all the continents were in the southern hemisphere, at that time. The planet was so warm that you could have swum at the North Pole without a wetsuit. And so plants spread out across the continents. And over the next 100 million years, they sort of dominate the landscape, and they still dominate the landscape today, but about 300 million years ago, oh, I'm sorry, I should say plants are 50% carbon, trees are 50% carbon, right? And so they if you go from continents with no trees to continents covered in trees, you've pulled a lot of CO 2 out of the air. So plants begin to accumulate CO2 in their bodies. But there's another sort of trick to the story, which is all that mining the plants were doing that I was talking about just a minute ago, where they're mining for phosphorus and breaking down rock that actually, that weathering reaction, that breaking apart of the rock that too consumes carbon dioxide, again, not on purpose, like it doesn't help the plants that it consumes carbon dioxide, but it happens to. And so by about 300 million years ago, through a bunch of geologic coincidences, basically, but also plants sucking CO2 into their bodies, and plants weathering rocks, which also consume CO2, these plants managed to take the Earth from a global hot house back down into an ice house. And so by 300 million years ago, you have one of the five mass extinction events that biologists like to talk about, and it's another huge environmental change precipitated by plants, by living things.


    Marty Martin  32:00  

    So can you say something about I remember reading in your book, and maybe I just missed it, but what is it about this mining that consumes carbon dioxide?


    Stephen Porder  32:08  

    Yeah, let's see. What is it about mining? Well, it's a simple charge balance reaction, essentially. So plants, if you put CO2 into the soil, which happens as plants exude enzymes, or as they break down, and CO2 concentrations build up. That CO two forms carbonic acid, which reacts with minerals, and that bicarbonate is flushed out into the ocean, flushed out into rivers and down into the ocean, and it carries with it cations. So let's take calcium as the example. So for every two molecules of CO2 that you export to the ocean. So you've sucked two molecules of CO two out of the air, you flush them through the soil and out into the ocean. One of them then evolves back to the ocean as CO2, and one of them gets deposited on the ocean floor as calcium carbonate. And so the net flux of weathering of rocks is to take two CO2s and put one of them, one away into


    Marty Martin  33:04  

    One away, yeah, into coral reefs, or to shells,


    Stephen Porder  33:04  

    Or yeah just to inorganic limestone,


    Cameron Ghalambor  33:10  

    Limestone, marble, yeah.


    Stephen Porder  33:12  

     And so that's actually the process that, over millions of years, consume CO2 from the atmosphere, and that's balanced on geologic time scales by CO2 coming out of volcanoes.


    Marty Martin  33:23  

    Gotcha. Okay, okay.


    Stephen Porder  33:24  

    So you sort of have these three things going on that set the geologic time scale. Carbon Cycle. You have volcanoes pumping CO2 out. You have weathering of rocks, consuming CO two and depositing limestone on the ocean floor. And then you have burial of organic carbon, okay. And so it's it's this confluence of the weathering of silicate rocks and a geologic period that buried a lot of the plants and prevented them from being decomposed and returned to the atmosphere as CO2. It's that confluence that ends the the warm times with lots of CO2 and takes us into this time of low CO2, because you have a lot of carbon buried in the bodies of these plants that happen to be buried in swampy areas that didn't allow for decomposition, plus the weathering of those rocks.


    Stephen Porder  33:26  

    Gotcha okay. And I imagine for a lot of the rest of our conversation, we're going to do a bunch of treatment to carbon. So I don't want to ignore our buddy phosphorus, because we've only given it a little bit. I want to I want to hear


    Stephen Porder  34:20  

    No, no I don't want to. I spent my whole career on phosphorus, until about.


    Marty Martin  34:23  

    Yeah yeah exactly, but, but can you say why plants need phosphorus? I mean, they're mining for it. We need it. There's a magical trick here. But what is it that phosphorus is special for?


    Stephen Porder  34:34  

    Well, so phosphorus is, is basically important for everything, but, but probably the most important? Well, I don't know how you rank biological molecules in terms of importance, because it feels like without without them, they would


    Marty Martin  34:46  

    Without one the other doesn't make sense.


    Stephen Porder  34:48  

    Yeah ATP doesn't matter, right? But ATP, adenosine triphosphate, is sort of the energy, the energy engine of cells and so and the P in there is phosphorus. But phosphorus is in almost all biological molecules. And so you can't make a cell without it. And so it's in the energy, it's the energy driver, but it's also in many, in many other important biological molecules. So we, you know, it's just one of those things you can't live without. And again, it's, you know, you can't live without nitrogen, either or carbon or hydrogen or oxygen, but phosphorus is the one that comes from the weathering of rock, and so that makes it different. It's not, it's not that it's it's hard to say it's more important, since, like, you can't make a cell without all five or, you know, and people often ask me why I don't talk more about sulfur, because that also is an element that that is critical for life. And the answer is that we don't see human modification of the sulfur cycle on the same scale as human modification of the other elemental cycles. And so I focused on the five that humans have really, really been mucking about in the most of late.


    Cameron Ghalambor  35:58  

    Yeah. So before we kind of leave phosphorus here for a second.


    Stephen Porder  36:02  

    Well, we're going to come back to it when we talk about humans, I hope, because it's a very interesting story.


    Cameron Ghalambor  36:05  

    Yeah, no, definitely, definitely. Well, there's a big reason why we want to talk about phosphorus. But back to the plants and the symbiotic relationships that plants have with fungi that help them mine things like phosphorus out of rock. So I was curious, so were fungi already on land when plants arrived and what were they doing? Like was you know, I was kind of trying to in my mind as I was reading, you know, I mean, I'm imagining this, you know, landscape from 300 million years ago. And I was sort of thinking like, well maybe it was just covered in fungi. But then what were the fungi eating each other?


    Stephen Porder  36:52  

    Yeah, it's a really good question, and I allude to it only, only tangentially in the book, in part, because, honestly, I don't, I don't think I know, but I also don't think we know like we collectively know. So I don't think the continents were barren. I think there were probably the equivalents of lichens, which are symbiotic, you know, multi-phyla organisms, including fungi, probably there. You know, in the modern we call these things cryptic crusts in the desert. And you know, as I say in the book, I think anything that we call cryptic usually means we don't understand it very well. And so there were probably fungi there. What we do know is that if you look at the fossils of the earliest, or almost the earliest roots, you see fungi attached to them. So it's an interesting thing actually, it almost doesn't make sense to talk about plants as an organism without fungi. There are some plants that don't form symbiosis with fungi, but not very many, and they're not very abundant. And so in some sense, this idea that, you know, fungi are in a whole different group, a whole different right, than plants. I mean, it's true genetically, but in terms of the ecology of the system, there really haven't been, there has never been a system of land plants that wasn't also a system of connected fungi. And that's kind of interesting to think about. I mean, they think there's been a sort of revolution, and this is a tangent, and not really anything I talk about in the book, but there's been, you know, a lot of debate about whether ecologists and biologists in general have focused too much on competition and not enough on facilitation and mutualisms and things that help each other, as opposed to things that fight each other. And I think the plants and fungi story is, is, is one of those, right? These are groups of organisms that really have never lived without each other. They're a very old married couple


    Cameron Ghalambor  38:45  

    Well humans and their microbiomes, I think, and all animals in their microbiomes, I think.


    Stephen Porder  38:52  

    All animals in their microbiomes. And you know, to take it back to the cyanobacteria, the plants took the photosynthetic machinery of the cyanobacteria onto land with them, and that was actually an endosymbiosis, right? So this is our mitochondria. And plants chloroplasts are bacteria that got stuck in these cells, right? So even if you know, all of the most abundant organisms on Earth are running around as an amalgam of organisms, and this was the great insight of Lynn Margulis, long before anyone else believed her. And so, you know, we have a lot to learn, I think, well, I certainly do, but we as a field, have a lot to learn about the role of facilitation and symbiosis, as opposed to competition and structuring what we see out there in the world.


    Marty Martin  39:38  

    So let's, let's add humans to the mix, we'll roll the clock forward even more. But I want to, I want to try to tie the early sections to your book with the sort of you know, what are humans doing and what are we going to do about it? You talk us about your I think it's your friend, Sheldon, and his really, his really great question. And I think it just sets up things well, I think even one of my friends has asked me a question like this before. What's the difference between burning gasoline in a car and me eating an apple? If I mean biochemically, those are the same things, but there's a profound difference when you think about this, you know, in sort of the geologic context. So maybe share that with us. I think it's really useful to think about what we're, what we as people have done and are doing.


    Stephen Porder  40:19  

    Yeah and so my friend Sheldon, who's no longer alive, but was a really big influence on me growing up. He never made it past second grade, but he was one of the smartest people I ever met. And he asked me this question when I started to talk about climate change, and he said, Well, you know, we breathe out CO2 all the time. What's the difference if you burn gasoline and dump that CO2 out as well? And I didn't really know the answer when he asked me, but after I got, you know, a bit further in my training, I did, and so you can imagine, well, let's put it this way, every year, plants suck up a huge amount of carbon dioxide from the atmosphere, and when they die or and then we eat them, or whatever, that decomposes, and that CO2 goes back up into the air, and that that happens very rapidly. It happens all the time, and that happens in huge amounts, actually. But those amounts are roughly balanced, and so it doesn't change the total amount of carbon in circulation. It's just like this noise shuttling it back and forth between the land and the atmosphere, or in the case of the oceans, there's a similar exchange between the ocean and the atmosphere.


    Stephen Porder  41:22  

    And then humans come along and we find these deposits, actually the deposits of the land plants that I talked about just a minute ago. And that's coal, right? And so in China, 1000s of years ago, people were burning coal, but in the 1800s humans really start burning coal in earnest, in England and in industrial parts of Europe. And what is that doing that's taking a bunch of carbon that was taken up by plants 300 million years ago and has leaned out of reach and inert and not part of that rapid exchange between plants that's roughly balanced, and we start burning that and injecting it in, right? Think about a bathtub, right? And you're you, there's your kid in the bathtub, and the water's sloshing back and forth, and it's going up and down and up and down, but it's not splashing out. And then you turn on the tap a little bit, right? And the kids splashing around and but, but gradually, those splashes are all getting a little higher, and those troughs are all getting a little higher too, right? And after a while, as you start getting the floor wet, right?


    Stephen Porder  42:22  

     And so when humans are burning fossil fuels, of course, it's just putting CO2 back in the air the same way you breathe out, right? But the total amount of carbon that's splashing around in the bathtub, so to speak, right, that's going up and up and up and up. And you can actually see this if there's a very famous graph in ecosystem science, or atmospheric science, called the Keeling Curve. And this is an observation of the amount of CO2 in the atmosphere. And it's a record that started in the 1950s and so what you can see is in the northern summer, when, because there's a lot of land in the northern hemisphere, in northern summer, you actually see a decrease, a little decrease, in the amount of CO2 in the atmosphere. And that's all of the plants in the northern hemisphere, sort of waking up for the summer and doing their photosynthesis. And then in the northern fall, because there's not as much land in the southern hemisphere, so there's not as many plants to do their thing in the northern fall and winter, CO2 actually begins to creep back up, because respiration, the breakdown of those leaves and organic material is outpacing photosynthesis. So you see this up and down sawtooth pattern, right? And if you just looked over a year or two, it would just look like a flat sawtooth pattern. But what you see, if you look from the 1950s till now, is it's a very steep line going up and superimposed on that all that breathing by the plants and decomposing is just a little teeny wiggle sawtooth on that rapidly rising line, right? And that's the difference between eating an apple and breathing it out and dumping a whole bunch of extra water into the bathtub, right?


    Marty Martin  43:58  

    Yeah, that's well, really well done. It's very vivid.


    Cameron Ghalambor  44:00  

    Yeah,and so the so then, you know, I think the story that you really do a good job, I think, articulating in the book is that, in the same way that plants needed energy and a waste product of this exercise was oxygen that changed the atmosphere. Humans also needed energy and the waste product, in this case, is CO2. It doesn't, you know, help us, or necessarily, we're not using it any direct kind of way. But that's what's getting dumped into the bathtub. That's what's I really like the analogy used of thinking of it as a bank account where you're, you know, making withdrawals and deposits and these deposits are sort of exceeding the withdrawals in the atmosphere. And as a consequence, we're, we're changing the the climate, and in a big way,


    Stephen Porder  44:56  

    Yeah, in a big way. Yeah and I think it's kind of, it's worth pointing out, because it's hard to visualize. You know, people talk about this many billion tons of this and that. And the other thing, I think there are a couple things I really want to emphasize in the latter part of our conversation. And the first is that, you know, this book came out now. It came out in the fall of 2023 the paperback will be out in the spring. Despite everything, I'm more optimistic than I was when I wrote the book, so that's one thing. And the reason I'm more optimistic is because the energy transition, our ability to get energy without producing CO2, is advancing at an incredibly fast rate, and so I'm really, I'm really looking forward to talking about that in just a minute.


    Stephen Porder  45:40  

    But I also want to just give the listeners an idea of the enormity of the change we're making to the atmosphere. So humans produce more carbon dioxide than they produce anything else in the world by mass. So if you add up all the cement and all the steel that humans produce, it's not as much as the mass of CO2 that we dump into the atmosphere every year.


    Marty Martin  46:04  

     Wow.


    Stephen Porder  46:04  

    So it's invisible, and it seems like it's nothing, but it is the number one human product by a lot, actually, not not by a little. And so, you know, it's hard to visualize, but we are a massive industrial volcano of unprecedented size and we are doing that. And so it's like, not surprising that the atmosphere is changing as a result of that, right? Like it would be impossible to dump that much CO2 into the air and not change, like it doesn't make sense. And I think you know, the fact that it's invisible, and the fact that it's at still at low concentration in the atmosphere relative to oxygen or to nitrogen. Like, allows people to think, Well, how could it be that big a change? And so I just, I say that, I give that example of it's our biggest product, because I think it helps people understand, like, oh yeah, it kind of makes sense. And then the other thing I would say is, like, throughout geologic history, any organism that has changed the amount of carbon dioxide or greenhouse gasses in the atmosphere has impacted the climate. And so it would be completely unreasonable to think that we were doing the exact same thing as everybody else, all those other world changing organisms, or the few other world changing organisms, and then, by magic, there was no effect, right? Like that doesn't make sense.


    Marty Martin  47:17  

    Right. So, so which one. I mean, in the interest of time, we've got five elements to cover. We promised to hit the implications of phosphorus you just told us about. You know, carbon dioxide is the biggest product. Water ends up being something that's profoundly important for us and for our plants and everything. So, I mean, which one. In the interest of time, how do you want to frame those which which one are sort of the most consequential, the most tractable?


    Cameron Ghalambor  47:44  

    I think we should return to phosphorus and talk about fertilizing.


    Stephen Porder  47:48  

    Okay, yeah, let's do it. Phosphorus is a really interesting story, and I want to set it up, just to give people a sense, in contrast to carbon and nitrogen as sort of the other two elements we've touched on a lot here, and we can talk about water, if we have time. So if you think about what we use carbon for, we use carbon we eat food and to get carbon for our bodies, but the vast majority of carbon that we are dealing with is fossil carbon, right? So we're burning gas, we're burning oil, we're burning coal. That's, if you're an average American, that's 100 times more energy external to your body, then you use internally to your body, so the carbon story, and the beauty of that is we can get energy without burning these things, right? There's other ways to get energy, and so energy is absolutely necessary, but we don't need to mess with carbon in order for us to get most of it, right? So it's kind of like fossil fuels are replaceable. Energy is not, but fossil fuels are replaceable.


    Stephen Porder  48:41  

    Nitrogen is totally irreplaceable. We cannot build our bodies without it, and every extra person needs that same amount of nitrogen. And that's what we're altering the nitrogen cycle for. That's how like, we're basically dumping a huge amount of nitrogen fertilizer on our farm fields to try to grow more plants so we can eat more so, but we'll never run out of nitrogen. Nitrogen is wildly abundant in the air. After you use it, it goes back to the air. It can have all sorts of negative environmental consequences before it goes back to the air, but like running out of it is not a thing. So nitrogen is completely irreplaceable, but it's also infinite. Fossil fuels are finite, but they're replaceable. Phosphorus is both finite and irreplaceable, which is kind of a problem, right?


    Stephen Porder  49:29  

    So the vast majority of phosphorus deposits in the world are in the region of western Africa that is either called Western Sahara or called Morocco, depending on your political whatever. And I've gotten complaints when I've given that caveat, but I'm not an expert in the region, so I'll just say that part of West Africa that is called that, and there are deposits elsewhere around the world, but we are mining those deposits just like land plants had to, right? And we are then shipping that phosphorus all over the world, the most productive soybean fields in the world, for example, are in the Midwest, where we fertilize with phosphorus. They're in Brazil, where we fertilize with probably twice as much phosphorus as as is used in the Midwest, because the soils there really stick to phosphorus very strongly. And as with any finite element, right, we're going to need to figure out how to recycle that element eventually, because there isn't an infinite amount, and you cannot have life without it. What happens to that phosphorus after we dump it on our farm fields is it goes into our crop. Well, one of two, three things, it goes into our soils and gets stuck there, because the soils grab it and the plants can't take it up. It goes into our crops, which we then either feed to animals who then poop it out somewhere, or it goes into our mouths and then we poop it out somewhere, right? But in no case does it go back to the original deposits that we used. And so we're going to need to figure out a way to capture those waste streams and reuse that phosphorus, eventually. This is not a crisis of today. There's a lot of phosphorus in the world. I think more likely than not. What's going to happen is there's going to be geopolitical supply chain problems, not run, running out of the actual material, but over the next century, a truly sustainable if we, if we manage to transition to a really sustainable society that will have to include the recycling of phosphorus, because there isn't a way to get it. Those phosphorus deposits are not being created at the same rate as we're consuming them, in the same way that fossil fuels are not being created in the same rate that we're consuming them.


    Marty Martin  51:34  

    Right, so you can envision infrastructure to collect the phosphorus that's, you know, human waste or animal waste. But is there any, I mean, what's the promise? What's the technology? What's the thought about getting phosphorus out of the soils? Is this an intractable problem, chemically, or how do we stand there?


    Stephen Porder  51:51  

    Well, I mean, so we already do some things. So if you can change the pH of the soil, you can make it less acidic, you can bump some of the phosphorus off. And so in Brazil, for example, they dump enormous amounts of lime on the soil for that exact reason. I have colleagues who are working on genetic modification of fungi to help get the phosphorus.


    Stephen Porder  52:10  

    I think one thing that I think I should mention here is that one of the reasons that our crops are so bad at getting phosphorus in the soil is that they don't have the fungal networks that most other land plants have, because tilling destroys those fungal networks, right? And so forests, for example, and grasslands have huge amounts of fungi that help them get phosphorus from the soils. When you till up or clear a field, right? Then you don't have those fungal networks. Then all the phosphorus, the plants have to do it all themselves. And as we said in the earlier part of the story, you know, there aren't really plants without fungi in the real world, right? And so on our farms, we're basically making our plants work without their 4 million year old partner, sorry, 400 million year old partner. And so there are people who are working. So, for example, no till agriculture and better thinking about agricultural practices that can help cultivate fungi along with the plants, might be a very successful way to go in terms of because there's a ton of phosphorus and soil, it's just plants aren't very our crops aren't very good at getting it. So this is, I think, a solvable problem, and one I hope that students and industry will grapple with. Phosphorus fertilizer costs are high, and if you could have your crops get it from the soil, as opposed but having said that, to come back to the bank account analogy, you can't take, keep taking it out of the soil and moving it away without depleting the amount that's in the soil. Like that's a fundamental , you can't spend more than you earn, kind of thing.


    Cameron Ghalambor  53:41  

    So, so before we we talk about kind of more things that humans can do, I kind of want to ask a question, that sort of a thing Marty and I call these like 30,000 foot questions that, you know, but something that that I found myself often thinking about when I was reading the book, which is, and this is a bit of a digression from, I guess, what we've been talking about so far, but I was recalling a lot of the conversations that I've had in the past with my ecosystem ecology colleagues about kind of The the major factors that shape kind of the ecology and evolution and biodiversity that we see around us. And I mean, I think your book makes this very convincing case for the five elements and this sort of biogeochemical perspective as kind of the main drivers of the sort of, I don't know, maybe the template in which biodiversity sort of plays out on, especially with the interactions with climate.


    Cameron Ghalambor  54:53  

    But then, you know, from the world of biology that I come from, you know that's focused more on like organism. And thinking about how they evolve in response to the changing environments, which sort of impose selection pressures, and then causes, you know, the patterns of diversification, kind of within that, sort of those, those sort of two different views. I was just kind of curious, like, how you envision the the interplay between the sort of ecosystem, biogeochemical, kind of processes that are, in many ways, kind of I would, I don't want to say they're blind to the organisms, because we do think about the the kinds of functions and that that organisms have as being, say, nitrogen fixers or photosynthesizers or decomposers. But you know, if, if we're talking about like tigers and lions, you know, and just lumping them as like predators, we sort of lose that detail into the kind of cool diversity that exists, that has evolved on the planet. And I was just kind of curious, like, in your mind, how do you see that, that sort of interplay between these broader, you know, water cycles and carbon cycles and phosphorus cycles, versus the beak of the Finch and the evolution of Darwin's finches. Like, how do you how do you see those together?


    Stephen Porder  56:26  

    Yes, it's a really interesting question. I'm actually drawn back to our conversation at the beginning of the podcast about where I came from, sort of academically. And one of the nice things about geology is you can go anywhere in the world and mostly recognize the rocks, because there aren't that many different kinds of rocks that are common. And then, if you become a biologist, and you know, you try and go to the Amazon and identify trees, like it's just a nightmare. And then


    Marty Martin  56:52  

    Good luck


    Stephen Porder  56:53  

    And then if you all the trees there, and you go, like, 20 miles away, it's all different again. And like, they don't, oh my God. And so I think part of it, in all honesty, is like, it's too complicated for me to deal with all those species, you know, like, it's just like, and, you know, so I really, I wish I could identify all those plants. I really do. And I recently got, because I turned 50, I got into birding, like, like, everybody,


    Marty Martin  57:20  

    Everybody welcome


    Stephen Porder  57:21  

    Yeah, thank you. You know, never cared about birds at all. And then I hit 50, and I was like, "Oh, my God, that's so beautiful." But anyway, so I'm into all that stuff, and I think it's fascinating. And again, like, you know, it was the biology of the grants and the Darwin's finches that got me into this field in the first place. But I do think, especially if you're interested in thinking about human modifications to the world, this framework of what we all have in common is very, very powerful as an underlying principle. That doesn't mean there isn't fascinating stuff playing out, you know, at the molecular level, and at the symbiosis level, and at the species and competition and all that stuff. Like I'm I super think that's interesting.


    Stephen Porder  58:04  

    But to me, it's there's something really satisfying about principles that might pertain more universally. We all have to gather these elements from the environment, or we have to eat someone else and gather it from them. And that's, you know, that's kind of a good organizing principle that is the same in South Africa or Alaska, or, you know, Kamchatka, like it's, it's always there, and it allows me, you know, I always say that learning about something makes makes the world more beautiful. Like, I didn't ever know that rocks were interesting or beautiful until someone pointed it out to me. But having the understanding of why there are mountains in the Rockies, or why the Appalachians are less big than the Rockies, or why the Great Plains are the way they are, like that geology then becomes more beautiful to me. I think similarly, understanding what species are, what makes the forest more beautiful, or understanding what birds are what makes them more beautiful, and understanding these sort of basic elemental constraints that play out and make you know, the pond down by the river near my house is green a lot of the time. And I understand why, right? I know why there's a dead zone in the Gulf of Mexico, and I know why the plants in Hawaii, in one place are really, really low to the ground, even though they're same species as things that are growing as trees just down the road, you know, and that that that framework for me, allows me to go different places and sort of understand the beauty of it in a different way. And it's not that any of those other ways are less beautiful. This just happens to be the one I learned about. So, you know, I'm a great believer that I could have done, I could have been interested in almost anything. I think my academic path shows that I fell into a lab that worked on biogeochemistry. And so that's the path I went, have I almost, I was this close to studying penguin DNA for my PhD, because what the hell did I know it was all ecology, right?


    Stephen Porder  1:00:04  

     Wow.


    Stephen Porder  1:00:04  

    And, you know, I'm sure if I had done that, I would be sitting here talking to you about how exciting and cool penguin DNA is, you know, but I'm not. So there, here we are.


    Marty Martin  1:00:14  

    Ok well, whenever you finish that book, we'll invite you back on. We'll have that chat at some point in the future. Yeah, yeah, now that you're a birder, I mean, it's guaranteed to happen, right?


    Stephen Porder  1:00:21  

    Yeah it's guaranteed to happen


    Marty Martin  1:00:23  

    Okay, so, so last question, and this is it's I'm gonna frame it as a really open one, because there's so much that we haven't touched and you know, your book has so many great parts to statistics that you wrote about the average American uses more electricity in a week than a Kenyan uses in a year. There are twice as many pigs, cows, chickens, biomass wise, on the planet than there is human biomass. So this is a very different place than it ever was in its four and a half 4.6 billion year history. You advocate for a really unique sort of what are we going to do about it? And so I've read this from other people, and I'm very much of the mindset, and yet you emphasize that maybe this isn't palatable to a lot of different people. What is the future that we should aspire to have? And I guess let's juxtapose this against what you're saying that maybe we don't want, or what we don't want to try to recover, which is this idyllic Eden, like past that some of us have in our brains. I mean recovering some arbitrary point in the past, this absolutely wonderful in all ways, like your book sort of points out. Well, if you were that anaerobe that the cyanobacteria destroyed, I mean, that was not really so great, all these plants are running onto the land, and then the lichens are losing out. So you know, what is the future that we should aspire to, part one? And part two is for the listener. These are easy questions, Stephen. For the listener, what do we get? What are we going to do?


    Stephen Porder  1:01:44  

    Yeah wow and we have seven minutes.


    Marty Martin  1:01:46  

    You're totally welcome to take that in any direction. But what's reasonable and what can we do to get there?


    Stephen Porder  1:01:46  

    Yeah, so that's a great question. I'm very sympathetic to the idea of returning to an idyllic past, because I feel it in my core, but I don't think it's possible to have 10 billion people on the planet without having an impact. So we're going to have an impact. We're going to have 10 billion people, or close to it, by the middle of this century. Fortunately, that will probably flatten out and may go back down. I'm actually not at all worried about a declining human population. A lot of people are, but I feel like that's that would be just fine. I don't want to go to zero, but I don't think it needs to stay at 10 billion.


    Stephen Porder  1:02:23  

     I think there are a couple. So I don't want to answer the question, what should we aspire to? I'm going to, I'm going to reframe it in a different way. At its foundation, a sustainable society has to manage these elements in a sustainable way. So that doesn't mean that that's all a sustainable society has to do, I would, I would advocate for more equitable distribution of resources and all sorts of things and access to things that people don't have access to right now. So what do I mean by that? I mean we need to get our energy without accidentally heating the planet up so much that it significantly impairs our and everybody else's, all other organisms abilities to thrive, right? So that means a rapid transition off fossil fuels, which is already happening. So you know what I wrote in 2022 is no longer the case. We probably have peaked global emissions wise, this year, if not next year. China is peaking this year or next year. Europe's emissions fell 8% in 2023.


    Marty Martin  1:03:22  

     Wow.


    Stephen Porder  1:03:23  

    That's a lot for a big for a big energy user. So we are bending the curve. We need to bend it back to zero, and the great news is we can bend it back to zero. So there have been over 130 days this year that the California electricity grid has been fueled entirely by renewables, with no emissions for at least some part of the day. Western Australia, which is the biggest independent not connected grid in the whole world, is going to be 100% renewable. 24/7 by the end of this decade, right? These changes are coming, whether or not they come fast enough to avert really bad climate change, I think, is anybody's guess. But again, I'm more optimistic than I was when I started writing this book. So we need to get our energy in a way that doesn't accidentally pollute, and we need to get more energy than we're currently using, because there are a huge number of people in the world without access to the benefits that we all enjoy, like continuous electricity, like refrigeration, like the ability to have good medicine and connectivity around the world and travel, right? So these are things that are basic human needs, and we should supply them to everyone. And for that, we're going to need more energy.


    Stephen Porder  1:04:34  

    One of the nice things is that we're not going to need as much more energy as it sounds, because the vast majority of fossil energy is wasted. So if you burn gasoline in your car, 13% of the chemical energy in that gasoline goes into turning the wheels of the car. The rest is lost by heat. Okay? If you have an electric car, 80% of the energy from the battery goes into turning the wheels. So. You go a lot farther on the same amount of energy, and these kinds of efficiencies are all over the place. So, you know, I just want to say this is doable, and it's more doable and happening faster than I think most people anticipated. And by the way, it's not just California, it's also Texas, which is adding renewables faster than California, adding batteries to its grid faster than California, right? It's South Dakota, which is running on 100% renewables and is adding batteries. So, you know, this is, this is a big deal, and it's happening fast, and it's happening globally. And it's, it's, it's amazing, and it's allowing countries that have not had regular access to electricity to build out wind, solar and batteries, because they're now as cheap or cheaper than cold. So that's a lot of good news.


    Stephen Porder  1:05:44  

    We can't forget about the other elements. We need to rethink our agricultural system, which is where we use the vast majority of nitrogen, phosphorus and water. We need to rethink that system with the conservation of those elements in mind. And there's some really innovative work being done in the book. I talk about the prairie strips project that Lisa Schulte Moore is running in Iowa, but there are many others. Hers happens to be my favorite, and listeners should definitely look it up. It's called Prairie strips. Anyway, there are innovations happening in agriculture. Again. Will they happen fast enough? I don't know. I'm going to fight like hell to try and make it happen, just like I'm fighting to for the energy transition, and we'll see.


    Stephen Porder  1:06:22  

    But there's a possibility, and this is a maybe. I'll end on this note, or close to it. This is where we are fundamentally different from our world, changing predecessors. We share with them this need for these elements and the changing of the flow of these elements around the planet. But we actually know what we're doing, and we can innovate to avoid the consequences in a way that they could not right? If you're a cyanobacteria, you have to pump out oxygen. If you're a plant, you have to weather rocks, and that consumes CO two, and if you happen to get buried in a swamp, then you'll change the carbon cycle. We don't need to do that, right? We can be more efficient. We can use other sources of energy. We can recycle and learn from our world changing predecessors how to recycle. Forests are incredible recyclers, and so we have the ability to see what's coming, and that really differentiates us from our world changing predecessors, and gives me hope that we will become the first world changing organism that actually chooses not to change the world, right? And if we make that choice, it will be the single greatest success in human history, in my opinion, the most remarkable achievement that we were able to emerge from this, you know, consequences be damned phase of growth that has benefited us all enormously. We are the huge recipients and beneficiaries of these fossil fuels. A patient fertilizer, phosphorus, fertilizer, of water. I don't want those benefits to go away. I want to get them without the negative consequences. And if we can do that, you know, I won't be around by the end of this century, but, boy, I will be proud to have played a teeny, teeny, teeny, teeny little role in that transition. And I think we all should be if we are lucky enough to get there.


    Cameron Ghalambor  1:08:08  

    Yeah, no, that's great. Well, I mean, it feels like we covered a lot of ground, and still there was so much more ground to cover. But we usually like to give our guests the opportunity to kind of, you know, say anything that that you really wanted to say, but maybe we didn't touch on and give you sort of a last opportunity to kind of


    Stephen Porder  1:08:27  

    Sure I mean, I get, I tried to give my rousing speech there at the end.


    Marty Martin  1:08:30  

     Yeah, it was good. It was good.


    Stephen Porder  1:08:32  

    But one thing I didn't say that that you did ask me about, and I'd love to just send out to your listeners. So I spent a lot of time thinking about what individuals can do. And I run a radio show in part that talks about what individuals can do to lower their impact to help with this transition. And I'll caveat it before I even say by saying individual action alone is not going to solve this problem, right? Political action, economic action, governments need to play a very big role in this. But as we've seen, governments come and go in their commitment to this, and there's always something an individual can do. And I think it's best summed up on the energy side by the phrase, the phrase electrify everything and get your energy from renewable sources. That's the key to the energy story.


    Stephen Porder  1:09:19  

    So what does that mean for the average American? It means that there should be no combustion in your house. You should we are done. The Fire Age needs to come to an end. We need to start doing it differently, and that's very possible. So you can, when your air conditioner breaks, replace it with a heat pump that can both air condition your house in the summer and heat in the winter, put in enough capacity so that you don't need a furnace anymore. I live in Rhode Island. It's not that warm there. I haven't had a furnace since 2014. My house is very warm. Any climate that you're in in the US, you can run a heat pump, and you're up there already doing this. So no burning in the furnace, no burning on the stove. Induction stoves are now better than gas stoves. They don't require burning. They are not the old coil crappy electric stoves that burn your rice and your eggs and never turn down after you turn the dial down. Induction stoves are much more sophisticated, and also your hot water heater can be a heat pump. It doesn't have to burn things either. Okay? So electrify your house, electrify your car. There's absolutely no reason not to have an electric car in 2024 even more so than when I wrote the book. There's a lot of conversation about range anxiety and all that stuff. I'm going to just say if you run an electric car, you will have lower emissions than if you run a gas car of the same size in any grid in the United States, and your car will get cleaner every year as there are more and more renewables on the grid. Whereas if you're burning stuff in your gas tank, it will always emit the same amount per gallon no matter what. And then the last thing. So you've electrified your house. You've electrified your car, if you can, and this depends on where you live, sign up to purchase your electricity from renewable sources. Oftentimes you can do that. That's not true in every state.


    Stephen Porder  1:11:04  

    And then on the nitrogen, phosphorus and water side, the single most important thing you can do is eat less red meat. So if you eat a lot of red meat, eat less. If you eat not a lot of red meat, eat none. If you want to go vegan, great. But just remember that in terms of carbon dioxide emissions, at least being vegan will save you about one TransAtlantic flight a year relative to being a big meat eater. So like, if you want to go that way, all for it. I actually became a vegetarian because my students kept asking me, and I was ended up being embarrassed to say no, and it hasn't been as hard as I thought, but I'm not yet a vegan. So anyway, that's, you know, food's a very personal thing. That's the one thing if you're going to make a change to your diet. Less red meat is the key. And after that, I hope people will worry a little bit less and focus on institutional change or just living their lives, right? Electrify everything, renewable energy, less red meat, okay? And then just live and worry about the other things that you're passionate about.


    Marty Martin  1:12:06  

    Yeah, yeah. Excellent. Stephen, thank you so much. It's great. I mean, ending on a positive message, ending on a, you know, actionable things, that's just wonderful. We really appreciate your time and wish you a ton of success with the book.


    Cameron Ghalambor  1:12:17  

     Yeah, thanks.


    Stephen Porder  1:12:18  

    Thank you. It was a super great conversation. You're the first interview with with actual biologist that I've done for the book. I was very nervous that I was going to get something wrong, flying colors, because, you know, back to the imposter syndrome, you know, I really, you know, I'm not that kind of biologist, whatever kind it is, and so I worry about that all the time. So it's good. It was really great to talk to you. And this was, this was super fun. And, yeah, thanks for having me on the show.


    Cameron Ghalambor  1:12:42  

    Yeah, we really appreciate it. Thanks so much.


    Stephen Porder  1:12:44  

     My pleasure.


    Marty Martin  1:12:55  

    Thanks for listening. If you like what you hear, let us know via Bluesky, X, Facebook, Instagram, Tiktok, LinkedIn, wherever, or just leave a review where you get your podcasts, and if you don't, we'd love to know that too. Write to us at info@bigbiology.org.


    Cameron Ghalambor  1:13:09  

    Thanks to Steve Lane, who manages the website, and Molly Magid for producing the episode.


    Marty Martin  1:13:13  

    Thanks also to Dayna de la Cruz and Carolyn Merriman for their social media work. Keen Shahmehri produces our cover art. 


    Cameron Ghalambor  1:13:18  

    Thanks to the College of Public Health at the University of South Florida, our paid subscribers and donors and the National Science Foundation for its support.


    Marty Martin  1:13:27  

    Music on the episode is from Podington Bear and Tieren Costello.

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