Which broadest definitions of “life” might apply both on this planet and beyond? Which parts of our present Anthropocenic crisis might already have played out trillions of times across the universe? When I want to ask such questions, I pose them to Adam Frank. This present conversation focuses on Frank’s book Light of the Stars: Alien Worlds and the Fate of the Earth. Frank’s other books include The Constant Fire: Beyond the Religion and Science Debate; About Time: Cosmology and Culture at the Twilight of the Big Bang; and the textbook Astronomy: At Play in the Cosmos. Frank co-founded National Public Radio’s 13.7: Cosmos and Culture blog. He appears as a regular on-air commentator for All Things Considered, and an occasional contributor for The New York Times. He teaches at the University of Rochester, and you can sign up for his free Coursera course, “Confronting The Big Questions: Highlights of Modern Astronomy,” here.
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ANDY FITCH: I know publicly engaged astronomers constantly get asked “Are we alone out there?” And I appreciate your book’s efforts to reformulate this persistent question in multiple respects. To begin with, Light of the Stars redirects more open-ended ponderings by transparently calculating probabilities for extraterrestrial life and for technological exo-civilizations — and by including within these calculations our quite recent findings of potentially habitable planets existing in such immense quantities, over such extensive time spans, that, you say, the burden of proof now falls on pessimists “to demonstrate how, with so many worlds and so many possibilities over the whole of cosmic space and time, we somehow are the first and only.” But Light of the Stars also rewrites this somewhat self-involved “Are we alone?” question in broader astrobiological terms, by asking something more like: “Are we the only living species ever to have possessed the capacity to drastically alter planetary developments?” and by responding: decidedly no. So to open, could you sketch a brief summary stretching from say, Fermi’s Paradox of the mid-20th century, to contemporary theorizations of a “Great Filter” threshold, and outline some constructive ways to re-pose that “Are we alone out there?” question, and / or to re-think the well-rehearsed answers astronomers have offered to that question?
ADAM FRANK: Well, I first came to astronomy as a science-fiction fan (thinking about other civilizations ever since my dad put Isaac Asimov in my hands), but my own work on this subject actually started with thinking about climate change.
In between undergraduate and graduate school, I took a year off and just did a bunch of other things. I planted trees in British Columbia. I become a New York foot messenger (to give you a sense of the era). I was a bouncer at the Rocky Horror Picture Show on 8th Street. Then, finally, I ended up getting a job at the Goddard Institute for Space Studies facility on 113th Street and Broadway. It was a climate-research facility and my work there gave me my introduction to that field. I didn’t know anything — and in 1986, basically nobody knew anything about climate change. I was just a scientific programmer and one day I just asked my boss: “What are we doing here?” And she sat me down and explained: “Well, we think the climate is changing because of human activity. We don’t really know yet. We haven’t seen the signal in the temperature, but if we do, then we’ll be able to predict the following consequences…” And I sat there, 23 years old, hearing about how the world would end. And even though my own research soon shifted to astronomy, talking that day about the climate left a huge impression on me. I was so stunned I walked out of the building down to Riverside Park, just thinking: Oh my god, if what I just heard ends up happening, this transformation of the planet will define my whole life, and everybody else’s.
So even though I’m an astronomer I’ve always had climate change in the back of my mind. But the thing was I was an astronomer who always wanted to do popular writing. So once I got to NPR and really got started talking about science to the broad public, climate change just became a natural focus for me. This was during the rise of climate denialism, and I was watching this intense pushback. I couldn’t help but ask: “Why? What makes this so hard for so many people to accept? Where do they just refuse to engage?” Now part of the answer of course involves politics and money. But I also gradually recognized that people just couldn’t wrap their minds around the idea of our civilization having such a large effect on a whole planet. We just couldn’t yet imagine that. And this realization pushed me towards conceiving of our human influence on the planet as more of a generic phenomenon. Especially now, with the exo-planet revolution and our new sense of how many planets might have certain features in common with ours, I’ve come to this innate sense that: Well, with so many planets out there, life and intelligence could be common. Let’s start thinking about this more clearly. Let’s define a research project.
So it was climate change that really lead me to these broader astrobiological questions. That’s what led me to see that once a species becomes especially successful in its use of resources, it can’t help changing its planet. And when I started looking at that particular pattern, I recognized how often it has played out on Earth itself. I mean, think of the Great Oxidation Event. That was a couple billion years ago, when blue-green bacteria changed Earth’s atmosphere by producing so much oxygen. So we have at least a couple examples like that of life completely changing this planet’s atmosphere. And with the exo-planet revolution confirming that pretty much every star in the sky has planets, in 2014 Woody Sullivan and I decided to write our first paper on thinking about climate change from the astrobiological perspective. We wanted to show how you could get quite a different perspective on what’s happening to us now by considering this within the context of civilizations and planets in general. But that meant we had to do some thinking about how likely it is for civilizations other than our own to appear in the cosmos. That paper got a lot of attention.
We started from something like the classic probability question: “How likely is it that a civilization arises on any planet?” But we now had all this exo-planet data to help us with these calculations. We calculated the number of habitable-zone planets across the universe’s history, and came up with the number 10 billion trillion. Now every one of those planets is potentially habitable, and that means each can be thought of as an experiment nature is running on building life, or even civilizations. So for us to be the only civilization ever in the universe means the odds of the experiment working on any random planet has to be less than one in 10 billion trillion, which is so low that it starts straining credibility. Nature would have to be very biased in its evolutionary processes for the chances of making life and civilizations to be that bad. So I think pessimists actually now face the burden of proving why the odds of evolution occurring are low enough that 10 billion trillion planets didn’t provide enough positive outcomes.
In terms then of this broader astrobiological approach (an approach that investigates other planetary systems in part to better forecast and perhaps manage our Earth-bound fate, and that tracks intricate biospheric complementarity on Earth in part to speculate on extraterrestrial possibilities), could we also take up a couple late-20th-century precedents in which studies of Venus and Mars proved particularly illuminating both for confirming / refining our own climate models, and for demonstrating possibilities for acute atmospheric changes to drastically limit the potential habitability of a given planet? For Venus, for example, I grew up reading analogies between its atmosphere and Earth-bound climate-change mechanisms, but I hadn’t encountered the historical narrative in which studying our nearest neighboring planet actually served as the basis for theorizing global climate change. Similarly, I did grow up freaked out by The Day After and Threads, but didn’t know that researching the planetary consequences of dust in Mars’s atmosphere had prompted forecasts of our own potential nuclear winter. So could you offer two quick historical case studies here of how a comparative astrobiological approach prioritizing atmospheric pluralism already has, over the past 50 years, begun to shape some of our most significant civilizational self-conceptions and public policies?
Right. I love that idea of atmospheric pluralism, which I borrow from Conway Leovy. And again, for me this somehow all originated with dealing with climate deniers on our NPR blog’s comments page. Somebody would ask us: “How can you use such crap models? They don’t tell us anything.” But what people don’t understand is that our climate models have been tested out on more than one planet. Earth is just the start of it.
If we take a step back to the early 1960s, we see that over about five crucial years a cultural jigsaw puzzle about life, civilization, planets, and climate gets assembled. Astrobiology basically begins with Frank Drake, who offers the first framework for assessing the probability of intelligent life on other planets (and develops the ideas for how to search for this life). Then you have the emerging recognition of climate change already happening on Earth. President Johnson gives this amazing speech to Congress, where he basically says: “Hey, CO2 will soon become a really serious problem for us.” And finally, in those years we start sending robot ambassadors to other worlds, which eventually leads to explicit data about climate on other planets. The first one is Mariner 2, launched in 1962.
But even before Mariner 2 made it to Venus, we already had radio measurements from Earth showing temperatures so high nobody could explain them. Then Carl Sagan began to develop greenhouse-effect calculations for Venus. When Mariner 2 flew past Venus, it verified Sagan’s predictions — which is how we came to understand Venus as a world with a greenhouse effect gone crazy. So our very first success sending a bit of human consciousness to another planet was actually about climate and the greenhouse effect.
A few years later Mariner 4 gets sent to Mars. At the time everybody hopes for Mars to fulfil a long, long history of science-fiction speculation and show us a truly living world. Instead we see huge craters everywhere. People get bummed out. “Oh my god,” they say, “it’s just like the moon.” But then comes Mariner 9 a few years after that, where we actually can park the probe in orbit, and get lots of detailed pictures. That’s when scientists first see evidence that in the past Mars had quite a different climate. Today we see a cold and arid climate, with hardly any atmosphere. But there’s evidence all over for riverbeds and deltas and other features that must come from water flows. So again we recognize that Mars has experienced climate change in a big way. Eventually we start landing probes that let us collect day-to-day weather data, which leads to real climate modeling for Mars. After a while we have our first detailed climate models for a totally alien world. That’s how we started modeling planetary climate possibilities much more generally.
And one specific and very striking climate condition on Mars involves its huge global dust storms. In fact, when Mariner 9 first approached Mars, one of these storms enshrouded the entire planet. The only reason the mission didn’t fail was that some software flexibility had been built into the probe, which allowed NASA to wait until the storm cleared and then they could start taking pictures.
But the dust storm taught us something amazing about climate and climate change. Working out the physics of aerosols (tiny dust particles in the air) for Martian climate models became absolutely fundamental for debates about nuclear policy in the 1980s. That was when Carl Sagan and others developed their famous nuclear-winter model. A nuclear winter is when nuclear-weapon detonation ignites so many fires that massive amounts of particles are driven into the atmosphere. The skies darken, shutting down agriculture. The nuclear-winter models demonstrated how a useful and potent feedback comes both from exploring the astrobiology of other worlds, and from understanding our own world in much deeper ways — especially in relation to today’s climate change.
So with the threat of nuclear armageddon and the demonstrable facts of global climate change in play, we quickly arrive at today’s juncture of astrobiological investigations and Anthropocenic recognitions — with your book pondering the possibility that our present Anthropocenic crisis might provide simply one particular instance of a phenomenon already having happened trillions of times across the universe. So here, as one localized attempt to help push humanity beyond its adolescent, self-centered questioning (“What is happening to me? Doesn’t anybody out there care?”), could you start redefining the Anthropocene as a more generalizable planetary phenomenon in which any technological civilization perhaps inevitably reaches its biosphere’s carrying capacity? And how might articulating such a perspective help get us started on “thinking like a planet” (factoring into our own self-conception our dynamic, co-dependent relations with plants and other animals, with the Earth’s physics and chemistry and geology and climate and atmosphere), and all without overly anthropomorphized recourse to “Gaia” or to “Mother”?
So first of all, the idea of the Anthropocene, first appearing around 2002, gave us this really radical new perspective on ourselves and the planet. Scientists already knew about climate change, but the Anthropocene was proposed as a new geologic epoch we were just stepping into. The Anthropocene first got defined stratigraphically. Some geologists recognized that in the future, when people dig down, they’ll see indications of a fundamental planetary change happening in this era we inhabit right now. That idea prompted a broader recognition that humanity, in total, was now the principal driver of changes to the coupled systems of air and water (etcetera) that make up the planet. Climate change, we began to recognize, provides just one example of how large our impact has become. For instance, humans already push more phosphorus around the planet than the rest of nature does. We move more nitrogen around the planet than all other forces combined. We’ve colonized a huge portion of the Earth’s landmass in one way or another. So changes to the atmosphere provide just one part of a larger story about humanity changing the planet.
Now in the press today, this story typically gets framed as: “We completely suck. We’re a virus on the planet.” But I’ve come to understand that perspective as the wrong way to think about our planetary impact. If you look at Earth’s history, you can’t help but see that it has been many planets across its four billion years. We were a water world before the continents rose up. We’ve been a jungle world with almost no ice, and a snowball world almost entirely glaciated. The Earth has gone through many transformations and worn many masks — very often with life playing a key role in those transformations, such as with the Great Oxidation Event we mentioned. Our atmosphere didn’t have any oxygen when the planet started. Today oxygen makes a considerable fraction of the air. Life did that.
So I started to think of us as the blue-green bacteria of the modern era. And we don’t look back at the blue-green bacteria and say: “Oh my god, those ignorant greedy little bastards.” We need to rethink this notion of ourselves as somehow different from nature, or somehow separate from the Earth. The Anthropocene should actually make us see ourselves as just one of the latest evolutionary experiments the Earth has run. And the Earth has run many, many evolutionary experiments. I like to think about the example of grasslands. At some point our biosphere invented grasses. They were an evolutionary innovation. And that led to so much else, like a new biome in the form of prairies, which had a huge impact on how the planet functioned. Then the biosphere was like: “Hey, this is great. I’ll keep using this and move on to the next thing.” That’s where human civilization is at now. We are just the latest in a long line of experiments — but what we want is to stick around for a while.
Now let’s bring astronomy back into the picture. Let’s include those 10 billion trillion planets we’ve learned exist, and think about all of the experiments nature has run on those worlds. I like to say that planets are nature’s way of turning sunlight into something interesting. See, even on planets without life, you get something pretty interesting. Mars has snow at the poles. And there are winds blowing through its canyons. So, without a doubt, other worlds will have their own oceans and mountains and snowfall and rain. And odds suggest (unless you can give me a good scientific argument about why this just cannot happen) other worlds have life, and perhaps complex biospheres.
And given our understanding of planets, climate, and thermodynamics, I think we can assume that any time a biosphere generates a technological civilization, that civilization will trigger its own version of an Anthropocene. After all, a civilization really is nothing more than a way of harvesting a planet’s energy and then doing work with that energy. So anytime you have a civilization that gets good at harvesting energy, it probably starts to push up against the limits of its planet. When my collaborators and I modeled these generic interactions between a planet and an energy-harvesting civilization, we found Anthropocenes were pretty hard to avoid.
For me, this changes the way we should talk about what’s happening to our planet right now. Again, we basically have two ways of speaking about the issue at present. Either people say “Climate change isn’t happening at all,” or they say “We’re driving climate change and so we suck.” But neither of those approaches reflects an accurate understanding of Earth’s ongoing evolution. And once you can both acknowledge the Anthropocene and recognize it as a generic planetary transformation, then you actually can see it as an opportunity. If you really want to grasp this phenomenon as deeply as possible, you can even feel proud. We, as a species, can take pride in triggering this Anthropocene. It means we’ve reached a new threshold of success in terms of our capacities to harvest energy and build civilization. But now we face the next question: can we deal with the consequences of this success intelligently, so that we and the planet can thrive? That also means putting ourselves into the proper astrobiological context. It means recognizing the real possibility that this happens all the time. There have been all these planets out there where other civilizations reached their own Anthropocenes. They either made the right choices or didn’t and disappeared.
It’s here that a comparison to adolescence really comes into play. As an adolescent, at some point, you become old enough to drive. You get handed the keys to the car. At that point you either learn to be wise enough to handle this very powerful machine as a tool, or you don’t, and you drive it off a cliff. We as a species now have reached that level of maturity. We have the capacity to shape the fate of an entire planet. Now the question is: can we handle the responsibility that comes with such power?
But we also should keep in mind that the planet ultimately doesn’t give a shit. Nothing we can do will destroy life on this planet. Like every preceding transformation, if we can’t make it through our own crisis, then the planet will just pick up and move on. What feels to us like a disaster will be the fodder for the next round of evolutionary innovation. It’s important to see that every mass extinction launched its own round of evolutionary innovation. After all, that is why we’re here and the dinosaurs aren’t. So the planet will do just fine in the long run. We, however, definitely have our own future at stake, so it’s time to end the ecological hooliganism.
And here I particularly appreciate your book’s call for a re-invigorating pivot away from a moral (or moralizing) Anthropocenic self-reckoning (prompting not just questions such as: “How could a singularly destructive species like ourselves ever justify its existence?” but also “Who among us is to blame for this outcome?”), towards a more pragmatic comparative assessment of our present Anthropocenic circumstances (prompting questions such as: “What factors on other planets and on our own might make such a crisis inescapable, insurmountable, and / or survivable?”). And here in terms of telling ourselves a new story about Anthropocenic climate change, a few parallel rhetorical projects come to mind. I think, for example, of the Obama administration wanting to reframe terrorist attacks as criminal acts, in order to diminish the moral charisma of religious crusaders, and reduce the sting of seeming civilizational clashes — basically, so that we could just focus on addressing this problem as decisively as possible. I also think of contemporary efforts to shift divisive debates around Americans’ gun rights to less personalized campaigns to promote flourishing public-health outcomes. I even think of the basic absurdity, say in a moment of acute personal health crisis, of getting “mad” at one’s white corpuscles for letting one down, rather than concentrating all available resources in one’s whole being on getting better. Do any of those analogies help to illustrate your own approach for how to clarify at a societal level (not just a psychological or species level) our present Anthropocenic possibilities?
Well political polarization really does make people say the dumbest things possible. They’ll stand up in public and make these scientific claims that any high-school kid who took Earth Science can recognize as completely wrong. So how did we get to this point? And how can a new narrative take people off that ledge, especially by giving them some reason for hope? Let’s say we have, at most, a couple decades to solve this problem — though I don’t even like to talk about “solving” it. But let’s say we have two decades to implement strategies to really move humanity in a different direction. That will basically take a worldwide Manhattan Project-scale effort. That’s entirely possible, but how do we motivate it? It can’t just be fear. It’s important to remember we didn’t launch the Manhattan Project in World War II just because we were afraid of the Nazis. We also had a vision of something better. We believed in democracy as a better idea than German fascism or Japanese authoritarianism. We had a positive vision to activate and unleash the creative powers you need for society to undertake something like a Manhattan Project or the Apollo project.
Today, by extension, we need to reconceive of ourselves as a truly planetary species. This problem of the Anthropocene has been building since the Victorians. Now we have this instantaneous globe-spanning civilization. But really, we don’t know exactly what that means yet. We still struggle as new technologies give us new glimpses of our world. That’s why my book dwells on those first Earthrise pictures and their importance. It was our first glimpse of the planet as a planet. We’re still struggling to envision our new role on that blue marble. To do this successfully means talking about politics in terms that never forget the planet: how it functions, and its limits. So while I generally share progressive values, when I hear people identify as Democratic Socialists I can’t help thinking: Why use that word? Why evoke an economic theory born from smokestack-era industrialism? We can’t solve the problems we face now without a political philosophy that puts the climate (which means the biosphere) front and center.
Human beings have existed on the planet for about 300,000 years. We’ve had civilization for 10,000 years. But we’ve never faced a problem like climate change and the Anthropocene. Dealing with this will require a leap in thinking. So what’s the point of keeping these older ideologies? They no longer make sense in the face of this truly biospheric and planetary problem. We have to rethink who we are if we hope to survive and become a mature and thriving Anthropocenic civilization. So our politics has to not only start thinking like a planet — it has to celebrate this new way of thinking.
Here could we also discuss a bit this notion of a collective “we” contemplating the Anthropocene: with no-doubt praiseworthy economic gains in poorer parts of the world right now fueling an especially dramatic rise in carbon emissions, with the cumulative consequences from long-industrialized societies lurking alongside this more recent uptick, and with nobody hitting on the perfect perspective to address that uneven legacy all at the same time? Or when we say “We’ve known about climate change since the Victorians, or at least since LBJ spoke to Congress about it,” how can we nonetheless plot this Anthropocenic self-consciousness itself emerging unevenly — typically in response to more localized histories of industrial pollution, rather than to broader planetary phenomena?
That’s interesting. It goes to William Gibson’s point that the future already has arrived, and it’s just distributed unevenly. On the other hand, in our very recent history, we’ve seen a huge percentage of people across the whole world acquiring cell phones and connecting to the Internet, right? Back in the 1920s and 30s Vladimir Vernadsky and Teilhard de Chardin introduced the concept of the noosphere as a kind of next step beyond the biosphere. This noosphere basically was an enveloping vail of thought that would surround the planet as we evolved. But you know what? We ended up building a version of the noosphere with the Internet. I consider that pretty remarkable. So everybody doesn’t have the wealth to live in a three-bedroom house, or even to fly on an airplane, but they can connect to this version of the noosphere we built. And connecting to the noosphere happens at this very same moment when, whether or not you live in a developed country, you start feeling the impact of climate change.
And again, as you suggested, climate change is not binary. We can’t just pick between: “Oh, climate change is completely not happening,” or “This is a problem we can solve away.” It’s more that we’ve entered new territory, and can’t ever turn back. We can’t appeal to some ideal of the pristine perfect Earth, because the Anthropocene probably started about 10,000 years ago, when we began farming. And today, even the world that the older among us can remember has already disappeared to some degree.
So we can’t just think of the Anthropocene as a problem that magically arrived 20 years ago. But we also have to keep in mind the metaphor of an adolescent civilization. You can’t “solve” your 14-year-old kid’s adolescence. Instead, you have to give them the tools to navigate it wisely. In the same way you have to think of the Anthropocene, like adolescence, as both a powerful and a potentially dangerous transformation. We need to develop new tools of thinking and behavior to navigate our way to maturity. We’re never going back, but we can go forward with wisdom, compassion, and skillful action.
Well here could you also flesh out how a notion of biospheric co-dependence, driven by an intricate mesh of positive- and negative-feedback loops, has emerged from a visionary line of reflection and research by figures like Vladimir Vernadsky, James Lovelock, and Lynn Margulis? Could you outline how their work has shaped your own emphasis on reconceiving biological evolution, for example, not as occurring in a vacuum of inert matter, but as an active participant amid broader planetary epiphenomena (again factoring in physics, chemistry, geology, atmosphere, climate, technological civilization), or on reconceiving energy consumption as ongoing energy transformation (from solar energy to, ideally, a broader biospheric flourishing that incorporates energies of air columns, of falling precipitation, of living cells, even of perceptive consciousness)?
Sure. What your pointing out also lets us see how in all our arguing about traditional capitalism versus traditional socialism, we’ve missed a rethinking about life and planets that was happening through the work of Vernadsky, Lovelock, and Margulis. They showed us how life on Earth is not just a bunch of disconnected species, but an evolving interconnected whole that includes the evolving planet. You might be able to trace this line of thought back earlier, but the field of biogeochemistry really begins with Vernadsky. He recognized the need to see Earth’s evolution in direct relation to its biology. He designed very specific, experimental ways to conduct these investigations. In the process, he also realized that, just as we discuss the atmosphere as a blanket of gases around the planet, or the hydrosphere as the total system of water moving around the planet, we also need to include a concept of the biosphere. He saw that the totality of Earth’s life was strongly coupled to the rest of the planet: the hydrosphere, the atmosphere, and the geosphere. They all work together. They all evolve together. Vernadsky made it fundamentally clear why we can’t think of life as just some green scruff going along for the ride.
And then in the early 1960s we get James Lovelock, a brilliant independent chemist, physicist, and inventor. He gets hired by NASA to work at JPL, where they’re designing the Mariner probes and thinking about missions that can search for life on Mars. The other scientists basically want to send up little test tubes, but Lovelock has this amazing recognition. He sees that the atmosphere of a planet itself is a life detector. Depending on which elements you find in an atmosphere, you can determine whether that world hosts a biosphere. Why? Well if all life disappeared on Earth tomorrow, our atmosphere’s oxygen would quickly bind with other elements. The atmosphere would lose all its oxygen. That element is only in the atmosphere because of life.
Eventually Lovelock begins working with a brilliant biologist, Lynn Margulis, who is deeply interested in the huge role microbes might have played in Earth’s history. Together the work out the idea that life basically hijacked the planet. Life created feedback loops within the atmosphere, the hydrosphere (etcetera) that keep the planet in a range of conditions amenable to life. If I drop you in a hot desert or the freezing Arctic, your body works to regulate your internal temperature at 98.6 degrees. Lovelock and Margulis saw this kind of homeostasis working on a planetary scale. The famous Gaia hypothesis comes out of this idea.
Whatever you think of the Gaia hypothesis itself, it launched a rethinking of the relation between life and the planet. Now everyone agrees that the biosphere is a critical player in how the Earth functions and evolves. You can’t understand what’s happening with the Earth unless you factor life into the equation.
And here, as your book in fact points to the relative ease with which abiogenesis (the transformation from non-living matter to self-replicating life) can occur, I wondered when we might be operating with too rigid conceptions of “inert matter” and of “life” in the first place. If, over a billion years, elements from a given rock might grow into something more moss-like (accompanied by countless chemical and atmospheric changes along the way), where does life begin and where does it end? Or within that slightly less anthropocentric context, when does ascribing life, in Lovelock / Margulis fashion, to whole planetary systems actually begin to make more sense?
Yeah, that idea of seeing the Earth as a living being is how Lovelock and Margulis’s Gaia hypothesis got completely embraced by the New Age Movement. People start holding Gaia ceremonies and things like that.
With “Mother Earth” as some sort of folksy equivalent.
Right. There was a lot of silliness in some of that, and that’s why a lot of scientists pushed back against Gaia theory when it was introduced. But of course Lovelock and Margulis themselves had something less anthropocentric in mind.
Still I do think there’s a way that these anthropomorphizing tendencies can be useful. Politics is about making policy. But policy means advocating for what we value. So Christian conservatives might value life in an absolute sense, leading them to oppose abortions. Foreign-policy hawks might value the enlargement of freedoms, leading them to favor intervention against dictatorships. In each case, policy is driven by what we consider absolutely important — which, on the deepest level, is what we hold sacred.
Similarly, I do consider the astrobiological perspective innately spiritual. I have no problems using that term, because it points to a deep resonance inside us about what we believe most sacred, which is life. But adopting an astrobiological perspective also means seeing “life” and “the planet” as a whole. Some people see the hardship humans (and human-driven climate change) cause to other species, and say: “That’s why we suck. We’re destroying the planet.” But we humans are still animals. We’re still part of the biosphere. So here again, we need to develop a story that stresses these deep connections and builds them into something like a broader spiritual perspective.
One thing I have learned is that you can’t argue for political change based just on scientific evidence. You need to start from a strong value proposition. That’s what enables transformative action. Conservation can play an important part here, but we can’t think the goal is to just wall ourselves off. We can’t just put ourselves in some kind of cage so that we stop screwing up the environment.
The Anthropocene’s real lesson comes from thinking of ourselves as a part of the environment, as part of the biosphere. We’ve never ever been above it. We’ve never ever been separate from it. That means we owe it a profound debt of gratitude. Whatever transition we might make to becoming a mature Anthropocenic civilization (and I do believe other mature Anthropocenic civilizations exist out there) will have to emphasize the sacred value of life, and of our place within it. That’s what will let us build our (as yet unimagined) cooperative relationship with the rest of the biosphere. In that new relationship, all boats will rise. The biosphere can become richer and more robust alongside our own thriving.
Then to extend these questions about how we conceive of “life,” and at times problematically (or productively) anthropomorphize “life,” was I right to sense you making the case that at least one planetary system has in fact become (or has the potential to become) conscious of itself — that if we Anthropocenic human beings could begin to traffic less in an unexamined life of industrialized planetary evolution, and could instead implement earth-systems theory in more deliberative directions, then this planetary system (of which we are of course a part) can in fact become conscious of itself? Does that point parallel your Obama-esque aspirational notion that “we must become the agent by which the Earth wakes up to itself”?
Exactly. That’s exactly how I believe science still can serve as a gateway to the sacred for us. This goes to the point of my first book, which was about science and what I called “human spiritual endeavor.” When you see some NOVA program about our galaxy, and the NOVA producers include these beautiful graphics and a sweeping orchestral score, there’s a point to that. It drives a feeling we term “awe” or “wonder,” which are both inherently spiritual in the sense of lifting you, for a moment, out of your day-to-day mundane awareness. And I want to translate that feeling of awe into the story we tell about climate and about our planet waking up in a very explicit way.
Here let’s go back to that mid-20th-century notion of the noosphere. In de Chardin’s version, this can sound pretty New Age, as in: “The whole world shall be enshrouded by the one great soul.” But we’ve already built the wireless version with the Internet, in which waves of information (waves of consciousness) literally flow through each of us with every Google search somebody sitting nearby does on their phone. The noosphere has become that concrete. We have all these miracles of creativity and innovation right in front of us — alongside the beauty and power of life and of planets.
So then for a few future-oriented topics on the astrobiological horizon: first, most basically, in your own models, which planetary factors and civilizational choices do seem likely to have the greatest impact on facilitating Earth’s long-term flourishing? How, for instance, might we most constructively start thinking about human interventions to reinforce certain negative-feedback loops and help stabilize our biosphere?
Well first I should point out that those prediction models we developed provide just a first cut. Nobody had simulated these types of biospheric-civilizational trends before in an astrobiological context. So we deliberately started from a quite simplified set of conditions, to capture a few basic elements. But what I consider the most important finding to come out of these models has to do with the question: how do you know a sustainable civilization is even possible? I mean, many of us have been freaking out about developing a sustainable framework for our human technological civilization for the last 40 years, but we never even asked if the universe does that kind of thing. The universe makes a lot of stuff, from black holes to asteroids. But how do we know if long-term sustainable versions of energy-harvesting civilizations are on that list? So I found it extremely positive that these first models showed a lot of scenarios where populations increase and planets change, but the biosphere and civilization still reach a stable long-term state.
Always after a substantial die-off?
No sometimes we didn’t have a die-off. We generated three basic classes of outcomes with these simplified models. Sometimes you see a complete collapse, where everybody dies. Sometimes you see a substantial die-off, where a species overshoots a planet’s carrying capacity and then drops significantly before leveling off. And sometimes you see a relatively smooth landing where the population and its impact rise, and then level off. We’re working right now on a second version of these models, and I hope this will also stimulate others to pick up the ball and do their own work. But I most want to stress how important it is to find those smooth-landing scenarios in the model. When our results first went public, the work got a lot of press with headlines like: “Here’s How Aliens Destroyed Themselves through Climate Change.” But I thought that missed a really important point. I wanted to yell: “Wait a minute, we just showed that, within this model, the universe does sustainability. That’s really good news!”
Which specific factors made for the most likely sustainable scenarios?
In general we can say that the sooner you act, the better off you’ll be. But more precise models are needed. It’s going to be interesting to factor in the type of planet a civilization begins on. Some planets will show more sensitivity to, say, burning fossil fuels than others. But certainly it does seem that the sooner you act, the less likely you will reach dangerous territory. That’s because once positive-feedback loops kick in, you often can’t turn back. You’ve started the rock rolling down the hill, and now you can’t keep it from reaching the bottom.
For this question of localized planetary conditions, and with cross-pollinating research today teaching us more about neighboring planets, helping us develop increasingly precise models for Earth and comparable biospheres, further adding to the investigative potential for next-generation telescopes soon to come online (themselves giving us ever more detailed glimpses of a diverse range of solar systems and of exo-planet atmospheres): what new questions do you see us asking? And how might such insights gained along the way further advance our “theoretical archaeology of exo-civilizations,” and maybe even push us beyond the theoretical?
Good question. And again, I do want to stress how these discoveries drive unprecedented opportunities to reshape our thinking. NASA convened a workshop I attended last year where they asked us to outline some strategies for “techno-signature” hunting. Lots of effort is going towards the search for bio-signatures on exo-planets, meaning features in the atmosphere that show us life exists. But we also can look for evidence of technological civilizations in similar ways, in terms of pollutants in the atmosphere or the spectral signature of large-scale solar-ray deployment. Those would be techno-signatures, and who’s to say they won’t be more common, or easier to detect, than bio-signatures, right? All of that is becoming absolutely possible now — which I find really amazing.
As part of these efforts we’ll be exploring different kinds of atmospheric chemistries. We’ll want to see how planets’ location, relative to their star, produces different reactions. This will force us to conceive of biospheres in a much more comparative way. Scientists are already trying to imagine all the different biochemical pathways that hydrocarbon-based life might take. Maybe there are other ways to build proteins. Maybe there are other kinds of photosynthesis that might develop around, say, a star with a different spectrum. All of this means we have to start thinking about biospheres in a more generic way than ever before.
That thinking can feed back into our ideas about how to sculpt the Earth’s future biosphere with us in it. If part of becoming a mature Anthropocene civilization means working with your biosphere to enhance its biodiversity, we’ll need as many biospheric models as possible to help with this decision-making process.
This search for techno-signatures also makes me realize we still haven’t addressed one basic component of Fermi’s Paradox: the assumption that any self-sustaining technological civilization, given a more or less infinite time span in which to flourish, would so thoroughly have colonized the cosmos by now as to make its existence undeniable. Or Martin Rees made a compelling case to me recently for exo-civilizations most likely being electronic (and perhaps, I assumed, infinitesimal, at least in terms of our own conventional measurements), rather than flesh-and-blood civilizations. Would these still fall under the purview of “astrobiology”? And how again might our conception of “life” need to broaden as we further refine our theoretical archaeology of exo-civilizations?
Yeah, that takes us to the broader fact that when we pose these questions about the astrobiology of the Anthropocene, we end up focusing on quite young civilizations. We probably can’t help getting especially drawn to civilizations like ourselves — just climbing up the learning curve of energy harvesting. That’s because if you already have warp drives, you’ve probably already dealt with the sustainability problem. So at least for the astrobiology of the Anthropocene, this question of electronic life doesn’t really come up.
But to that great point from Martin Rees: yes, for a civilization that lives long enough, it might start off biological, but end up electronic. So how do we even imagine these possibilities? What tools will help us to understand civilizations that have existed for a million years (let alone a billion)? Do they still even think? Are they still conscious? I don’t know the answer. I’ve really just started working more on techno-signatures over the last few years. But you’re absolutely right to ask these types of questions. We did recently publish a paper on the Fermi Paradox, which tried to stay away from anthropomorphic understandings of agency. Our paper doesn’t ask what these beings might think, or how they might think, or how they might plan. Instead, we just try to develop a mathematical model for how they might spread through the galaxy.
That means we are taking up classic science-fiction-type questions, but without forcing everything into a human paradigm. It excites me right now to take part in developing formal methods for how to have these discussions, and to be very clear about our own biases. Our Fermi Paradox paper, for example, only focuses on the consequences of an exo-civilization’s attempt to settle other planets — not why they might want to do that. Asking about consequences (instead of intentions) makes it a basic physics problem. Assume the civilization can send out probes with a certain frequency and a certain speed. Now let’s work out how far they get, and then what the steady state of settled worlds would look like. Our results showed some really cool stuff. It was an example of staying within scientific rules, while recognizing that, ultimately, we don’t know all the rules.
