Jeremy J. Schmidt: I’m thankful to have you here, Erle, and to discuss your work and its relationship to planetary boundaries. We were hoping to start with one of the ideas that you’re well known for, which is the idea of anthromes which help to capture the extent to which humans are reshaping patterns of the global biosphere. It’s a novel idea. I remember when it came out. I had just recently left McGill, where Navin Ramankutty was at the time, your co-author, and so I was really interested in the idea. I would like to hear more about why you and Navin thought the idea was needed, how you came up with it, and how you developed it.
Erle Ellis: It literally filled a need that I had to communicate with the ecological science community (see Ellis & Ramankutty Reference Ellis and Ramankutty2008; Ellis et al. Reference Ellis, Klein Goldewijk and Siebert2010). As an ecologist, I was an oddball. In 1990, I started working in China, studying the long-term ecological changes that had occurred in village landscapes during the transition from traditional agriculture to more intensive industrial agriculture. My interest was in the idea that we could understand sustainable agriculture by studying a place where you had this very long, deep history of agriculture. I focused on the nitrogen cycle in villages. I was doing village ecology. It didn’t really fit the same model as was used to incorporate people into ecological science at the time.
I would go to an Ecology of Society of America conference, and there was urban ecology and there was agroecology, and urban ecology was at the scale of urban areas, and agroecology was at the scale of fields. There was also landscape ecology, but it was mostly focused on ‘natural patterns’ or disturbance of the natural patterns – all those models. When I would give a talk, it just didn’t fit anywhere, and it was always this kind of marginal thing. It was so obvious to me from my work in China and in other places, that most of the planet is in fact transformed into different types of ecology shaped by people. Why wasn’t that more broadly recognized in ecology? It was something that bothered me. On my first sabbatical, I had a chance to think about how I could express this. How could I show the ecological community just how important the transformed ecologies were? Not just as a kind of degradation or disturbance of ecology, but as what the ecology is like everywhere.
I basically tried to bring in all the evidence I could get at global scale about human populations and different kinds of land use to just see what patterns I could illustrate from the data. Navin was one of the first people to produce a global crops and pastures data set. We started working together on this. I mostly did the analysis and came up with the results, but then when we were discussing how you present this, I was thinking about it in terms of anthropogenic landscapes – a kind of landscape ecology. Navin had also been working a lot on biomes. In a discussion, it kind of emerged, ‘Maybe these are really biomes.’ They’re anthropogenic biomes. They’re the global ecological patterns shaped by people. Anthropogenic biomes and then anthromes – as a contraction – emerged from that discussion. And from the beginning, it was remarkable how good the uptake was.
It was very interesting. I’ve never had an uptake like that before, or even after, in that it was very grassroots. It wasn’t just a lot of news outlets that were interested in it. It was every blogger. There were just hundreds and hundreds of bloggers who made blogs about it. People liked it. It fitted a lot of people’s thinking.
Jeremy: I think it’s fascinating, and it’s helpful to pick up on that history of the concept, especially given your work in Anthropocene Working Group that you were part of for a time but have now resigned from. Obviously, there are disagreements, significant ones around how to interpret human relationships to the planet and the impacts that people are having on how the planet functions and how to mark those functional changes. I wonder if you could speak about your approach to the Anthropocene more broadly: are humans doing something new to the planet or is this something that’s quantitatively different but qualitatively not something totally novel?
Erle: I think you’re asking that partly because I’ve written thoroughly on the deep roots of the Anthropocene. That’s my view. And I think it’s in many ways very healthy that there are many different viewpoints about this. I don’t think there’s ever going to be one viewpoint about human relations with the planet, or about human relations with nature. That’s just the way people are. There are a lot of diverse ways of thinking about things, and that’s not a problem. That’s kind of a solution in a way.
In terms of this relationship, when did people cross the line between just interacting with the ecology of the planet in the way that every other species does? No species can exist without altering the planet. It’s not possible.
What is different about our relationship with the planet is that it can just about continually scale up. That kind of scaling relationship, where people go from being a lot like a lot of other mega omnivores (which is our biological niche) to having a social niche. Which is also not so unusual. There are a lot of social insects that have a social niche – but becoming an open-ended social niche. So, how big can a human society be? There’s no answer to that. If you look at the other social species, they all have a limit to how big their societies get, and that limit is genetically determined. The behaviors of sociality in most species are genetically determined, like how big a wasp’s nest is going to be. Know what species it is, and you can know approximately how big that nest is going to be. That’s true of all social species except people. People have evolved the capacity through cultural evolution to have relationships with each other that are cultural – learned socially – and that means they can evolve very quickly.
Culture evolves much quicker than genetics, and it’s much more open-ended. Again, how big can a human society be? We don’t know. We’re discovering this all the time, but the scaling of human societies began a long time ago. You could argue it began around the time of agriculture. But that’s very debatable because there are hunter-gatherer societies that also scaled up pretty large – that resemble much the early agricultural large-scale societies. It’s not useful to put a simple date on it, but it’s that process of being able to scale that really matters. Of course, we do a lot of things to enable that scaling that are not unique, just unique in their scale. The most dramatic one is the use of energy from the nonbiological world. That’s exceptional.
That’s what’s happening right now in the transition to going beyond using the biosphere for energy, which all other species do except for plants. Remember, plants changed the entire planet – or rather ‘photosynthesis’, at first by cyanobacteria, the first photosynthetic organisms that changed the whole planet forever. By harvesting energy from the sun – a kind of abiotic energy – that process scaled up the entire biosphere. The biosphere could be much bigger when it is powered by solar energy, and that’s potentially true of human societies. There are also nuclear and other forms of abiotic energy. The scale of what’s possible energetically keeps increasing. From burning wood to cook food to coal to solar, I see this as part of a long process of becoming a planetary force. But arguably the most transformative process that really changes the relations between people and the planet is this kind of scalable sociality, this ability to scale up operations in a sense, including our metabolism, and all these other capabilities.
Jeremy: I think that’s fascinating: the focus on the scalability of the social. In the context of this book, the scalability of the social and how people cooperate, and the means to which they cooperate, become really important. In the past you have introduced these ideas using the idea of the electrical night – Earth’s night sky lit by human activity. The analogy was wonderful because this lit-up planet is an unintended consequence, as you put it, of one way that we’ve organized ourselves.
One of the things that you have also done is to contrast competing narratives of crisis versus a couple of different phrases of cooperation, innovation and so on. I wonder if we could have a bit of a conversation around your ideas about why crisis has limits on it or has certain kinds of connotations to it versus thinking about planetary boundaries themselves in other ways as well. The planetary boundaries concept kind of builds in a bit of crisis, but it puts risk at the heart of the framework.
Erle: It’s intended to form a crisis narrative. There are different ways to look at a crisis narrative. Crisis narratives obviously have utility. It’s not like you should never use a crisis narrative. The question is, does it fit the solution space? Is the declaration of a crisis and the use of a crisis narrative going to further the solution to the challenges that are raised in the crisis? If you have a crisis like a dam that is leaking, the idea of declaring a crisis is that everyone needs to respond. I think that’s fundamental to every crisis idea. People need to respond urgently to a crisis. That’s the whole point of it. To the extent that it encourages people to do this, to cooperate with each other to solve the problem, then that crisis narrative is serving a useful purpose.
If a crisis is declared over and over again, and even worse, if the crisis is not equally everybody’s crisis, it can become a very divisive thing: people who agree that there’s a crisis and people who have other things to deal with. Simply put, climate change isn’t the very biggest problem for people who don’t have clean water and people who have incomes below the global poverty line. They have a lot of problems to deal with. Their number one concern isn’t that the richest people in the world are emitting so much carbon into the atmosphere that the climate is changing. They’re not causing that problem. They can’t solve that problem because they’re not creating it and the idea of declaring that as a crisis of the planet – a crisis of humanity – is not actually a correct narrative. This is just a crisis for the people in power.
I wish it was more of a crisis for the people who are most responsible for causing this problem. In fact, the main aspect of the narrative is this idea that it’s a planetary crisis that humanity needs to deal with, when in fact it’s really just the failures of the elites of the world to solve their own problems. Instead, they’re making it out as if it’s this kind of broader planetary problem. The problem is they’re not taking responsibility.
It’s not a surprise that there’s a lot of division in discussions about things like climate change. The 1.5° narrative is intentionally developed as a planetary crisis narrative. At the time it was agreed upon by the different countries of the world, it was already known by just about every expert in climate change that it would be nearly impossible, if not actually impossible, to achieve a 1.5° planet. We were going to go past that. That was already known. So, you’ve got this set out as the boundary between safety and disaster and then you’re going to cross it. That’s a way of creating this kind of narrative of crisis.
Is it now leading to global cooperation to deal with it? Actually, what you’re seeing more and more of at these conferences is a clear dividing line between the developing world that needs more energy to just maintain very low levels of development versus the wealthiest countries in the world that are continuing to burn fossil fuels at pretty much the same rates, even as at the same time, they’re declaring a mandatory end to this. It just creates division not cooperation. The narrative of cooperation is not really there anymore. Of course, when we’re past 1.5° for the next 25 years, which will almost certainly be the case, it’s not going to seem like a climate crisis anymore. It’s going to just seem like a giant failure of society because that’s what it will represent.
Jeremy: One of the other normative ideas that has come out of discussions around the Anthropocene and around planetary boundaries has contrasted with the crisis narratives, the idea that we should be pursuing the recognition that we’re kind of entangled with this situation. There’s no escape route from the fact that we’re with the planet and we live with the planet. The goal is not to either leave in the physical sense unless you’re a billionaire or to restore it to some pre-human state. There are opportunities to make things better and to have a future that is a good Anthropocene, as many, including you and Elena Bennett, have called it (see Bennett et al. Reference Bennett, Solan and Biggs2016).
Erle: That’s been true for a long time. The only question is, what are we going to make of this? That can involve things like ambitions to have a large conservation area, a large amount of the planet that is managed just to restore or allow ecologies to exist that are not human related, that are dedicated to the other species there. That’s a model for a better Anthropocene for the rest of life. There’s not going to be a planet that’s not shaped by people. The question is just how we shape it and what kind of agency are we going to have in doing this. Most of the changes that we’ve made at planetary scale have occurred as unintended consequences. They have not been intentional. We’ve changed a lot of things intentionally, but the unintended consequences are most of the things that we discuss when we talk about the Anthropocene. Climate change is nobody’s project.
Jeremy: I wonder if we could push on this further. One thing that crisis narratives try to do is to connect these unintended consequences back to those who are responsible in different ways.
Erle: Let’s be clear here. You’re correct that crisis narratives can target the causes. Some of them can, but environmental limits-based narratives do not do this. They say that there’s something wrong, in a sense, with the relationship between people and the planet in this very basic way, without assigning any responsibility beyond humans in general. That’s the wrong model. Climate change is not caused by humans. Humans are involved in causing climate change, but not all people are creating it equally. The real problem here is not the biology of humans. Humans don’t emit carbon dioxide biologically at levels that are a problem. The problem is the burning of fossil fuels.
The problem is not that there are not enough trees taking up the carbon. That’s not the problem either. The problem is that fossil fuel combustion needs to end and the countries that are most responsible for emitting most of the carbon from fossil fuels need to invest in energy that does not produce this carbon pollution. That’s not part of the planetary boundaries narrative at all. It doesn’t assign responsibility. It only sets this kind of planetary level narrative. Let’s be clear, most people don’t even think about the planet as relevant to them at all. The planet is only seen as relevant by certain people, mostly people like me and you, who study global change, maybe some policymakers, but for the most part, the planet is not really what is actionable. You need narratives that are actionable.
You could talk about ozone depletion as a planetary problem. But that’s an example of where the problem – and its resolution – was not actually ever about the ozone layer. The problem was not even the ozone-destroying chlorine from CFCs in the atmosphere. The problem was the production of CFCs. The way that problem was solved is that the producing nations – not all the nations – the producing nations stepped up, took responsibility, and phased them out. Now, there are a lot of reasons why that happened and it’s not happening with fossil fuels. It’s true that fossil fuels themselves are inherently much more difficult as a challenge – because their use is much more widespread. CFCs were a patented product, and to some degree, it was much easier to assign responsibility. The bottom line is about assigning responsibility and going after those involved – and those involved actually taking responsibility and dealing with it. That’s what got the problem solved, not the planetary narrative.
Jeremy: I like the way that you’re framing how to assign or determine responsibility in terms of what is the relationship of producing or burning fossil fuels to the climate or where the production of CFCs is coming from. I wondered about your take on thinking about entanglements and a good Anthropocene. When it comes to this, there’s a certain group of people who have responsibilities or the capacity to address those root causes, and those people in addressing those causes, they’ll have lots of potential ways to do it. There are ways of addressing things that can also have effects on others. One way of addressing climate change, for instance, is not to stop producing fossil fuels, it’s to put a bunch of sulfates up in the atmosphere or something like that, to do some kind of geoengineering. For certain forms of solutions, there are also ethical questions that need to be asked. I just wondered if in your approach to addressing these kinds of root causes you see the considerations of responsibility working in those contexts around the solution spaces.
Erle: Again, that’s a good example of a planetary narrative: the problem is that the planet is too hot. The problem is not that some people are not dealing with their carbon pollution problem. It’s a different definition of the problem. The solution, when you start talking about ‘It’s a planet problem’ means the conditions are somehow not right on the planet – it’s just too hot. We therefore have to change the planet’s conditions. In this narrative, solar radiation management becomes a perfectly legitimate solution because it will solve that particular problem. It doesn’t solve the acidification of the oceans. It doesn’t solve a lot of the other really serious problems that are generated by fossil fuel combustion. This ‘planet is too hot’ narrative only demands a solution to the temperature problem, which is a classic example of dealing only with symptoms but not causes.
I would say that this is exactly the kind of thing that got us here. It’s an example of solving one problem by creating a bigger problem, which is something that human societies are really good at doing. We have solved so many problems by creating bigger problems and kind of pushing out the challenges to some other generation or this sort of thing. Think of it this way, people never had to manage the temperature of the planet before. That just never was something that you had to do. Just like you never had to plant seeds to get the plants that you wanted if you were in an early hunter-gatherer society. When some hunter-gatherer societies did do that, to propagate species that they favored, things began to change. To the extent that you become the ecology that supports you, it becomes more and more your responsibility. In the end, there’s no other way to support yourself than to transform the planet into agriculture, for example. You’re trying to solve this problem of food shortage by manipulating the plants, and ultimately the planet, to produce more and more.
That’s a kind of solution, and that kind of solution has been rolling out indefinitely. With solar radiation management, you’re basically going to do the same kind of thing. Instead of solving the problem of temperature increases by getting at the actual cause, which is the people burning carbon-emitting fossil fuels, you say: ‘Well, we’re just going to manage the temperature of the planet.’ There’s only one problem with that – because it could be successful in the sense, it can be done. There’s almost no question that sulfate aerosols could be manipulated to bring down the temperatures of the planet, and that it might even be okay climate-wise. It might not end up producing huge side effects. But also, it might. We just don’t know. That’s the big wildcard.
Even if it doesn’t produce terrible unwanted side effects like the end of monsoon systems in Asia or some of the other dramatic things that could happen, it does do this: humans will henceforth always be responsible for managing the temperature. If people stop doing it, it’s going to cause this really dramatic leap in temperature if you stop putting up the sulfate aerosols. It commits you to a path where you now have to manage the planet’s climate or face the consequences in the future. It just puts you on this kind of treadmill of endlessly having to solve the planet problem instead of solving the social problem of transitioning to clean energy and ends up getting us into a whole other ball game. That’s a dangerous thing. Plus, you’re not solving these other problems that are going to keep getting worse, like ocean acidification.
Jeremy: I think the clarity that you’re bringing to this distinction between the framing of a planetary problem versus the understanding of a social problem is key and something that I think is not often articulated.
Erle: I’ve heard a similar kind of thing with the Anthropocene. The problem becomes the Anthropocene itself. I’ve heard people say, ‘The Anthropocene is doing this. The Anthropocene is doing that.’ That is just so incorrect. There’s no Anthropocene doing anything. The Anthropocene is a description of a syndrome. It’s a description of a relationship between societies and the planet. When societies change, the planet is going to change as a result. It describes this entanglement of societies with the planet. We can’t operate without changing the planet. The only question is: how are we going to change the planet and in which way? It’s really about our societies. It’s not about the condition. We’ve been in this entangled condition for a very long time (see Ellis Reference Ellis2024). That is the challenge of the Anthropocene. It is how you manage that. It’s very difficult. Entanglement does not imply simple solutions, optimization, and these kinds of strategic options that you just do, and then the problem is solved. It is true that there’s pretty much no solution that is not going to generate some new problems. Just like fossil fuels actually solved a lot of problems. Fossil fuels have really been great for human societies in a lot of ways. They enabled a lot of possibilities that people wanted. Phasing them out is going to cause problems. It’s not going to be painless to do that. That’s one of the reasons why it’s not happening as fast as it needs to deal with climate change. It’s just like that and that’s not going to change as things go on. There are always going to be hard decisions to make between having one consequence and having another.
Then, of course, the unintended things, some of which are not yet known, just pop up. There’s no way to have such a big metabolic force on the planet without changing it. Every change you make to that force is going to change the planet, sometimes in foreseen and intended ways, and for the better as planned. But predictable changes like this are very difficult and rare – and almost always come with unintended things. We kind of have to accept that. That’s not a crisis. That is a condition. It’s a situation. And realizing you’re in that situation and not just treating it as some kind of unforeseen and unforeseeable crisis is pretty important. It makes for much better decisions when you understand the entangled causes and unpredictable effects of this condition – the challenges here – rather than simplifying the problem to just ‘the planet is too hot’ or something like that.
Simon P. Meisch: Could I come back to the question of novelty and anthromes? Would it be fair to say that anthromes have also emerged because humans have always introduced novel substances, such as fertilizers, into ecosystems? When we look at the novel substances that the planetary boundaries framework talks about, is that just a continuation of humans introducing novel entities into ecosystems? Or would you say there’s a difference between novel entities like nuclear waste or antibiotics and plastics?
Erle: First of all, I don’t really think of anthromes as being formed by humans generating and dumping these novel substances. That’s not really included in the definition. It’s obviously happening in those systems to some degree, but it’s not definitional. Think of it this way. The classic biomes – the original concept – describes the global patterns of life. Believe it or not, people learn about this in kindergarten. Even if they don’t call it biomes, you learn about tropical rainforests and deserts at that stage. These are the different patterns of life around the world, and these are shaped and defined mostly by adaptations to climate. It’s this kind of global ecological pattern shaped by climate.
That’s one way we can understand there are different patterns of life around the world. Yet, clearly if you look out of a satellite or aircraft window or whatever, you can see that for most of the planet, the patterns of life are also shaped by human societies in different ways. Agriculture is one of the very biggest ones in terms of extent but there are all sorts of others, including urban infrastructure and mining and all these other things that transform the ecology. If you want to understand the biology of the planet and why it’s not the same everywhere, climate patterns are not enough. You have to understand the patterns of the human world. That’s where it really comes from. Thinking of people not just as a kind of temporary disturbance, but as the shapers of the ecology of this planet, just like climate shapes the ecology of the planet, it’s just a different form. That’s where the idea comes from.
It’s not really from novel substances. The truth is that the novel term was introduced largely out of work on novel ecosystems, which was something that came from Richard Hobbs and his group out of restoration ecology. It was dealing with these kinds of recalcitrant ecosystems that people had altered in this way or that way and could not feasibly be changed back. Species invasions are often a big part of why ecosystems are getting defined as novel ecosystems, the idea that you couldn’t restore them to what came before. There was no real way to do it. That was the novel ecosystem concept.
One thing that happened out of that discussion was that we wrote an article and a book (see Hobbs et al. Reference Hobbs, Higgs and Hall2013). We had a workshop in Pender Island. This was 2010 or something like that. It was a long time ago. That resulted in a book. In one of the chapters, a few of us, Emma Marris was one of the authors, and Joe Mascaro (see Marris et al. Reference Marris, Mascaro, Ellis, Hobbs, Higgs and Hall2013). We just didn’t really think the concept of novel ecosystems needed to be made a permanent concept. It was a bridging concept. It was a way of helping restoration ecologists who had always used a kind of ‘natural baseline’ – the ‘natural ecosystem’ that we can restore in a place. It is essential to have a broader view of the different kinds of ecologies of the current time, with so many you really can’t call a ‘natural ecosystem.’ They’re shaped and sustained by societies. That’s the number one reason.
I don’t use the term ‘novel’ very much anymore. I’ve changed a lot of my narrative to now use the term ‘cultured’ to directly incorporate the idea that it’s the culture of the societies interacting with ecology that shapes different ecologies, not just this kind of ‘novelty,’ whatever that is. There’s nothing new about societies doing that. There are definitely new forms. Nuclear waste is a new thing, no question about it. Chlorofluorocarbons (CFCs): new thing to the planet, never existed before. So, novelty is definitely something that’s been introduced. A lot of the most novel things are new, but even some old things, like ceramics, are somewhat old but still unique – and therefore novel. That’s just one example.
Simon: So, does it make much sense for you to frame the novel entities boundary in the way that the planetary boundaries framework does: under the heading of novel entities, it subsumes the products of social practices and social problems that are actually unrelated?
Erle: A planetary boundary neither defines the problems correctly, nor does it say anything about the solutions at all. Actually, it seems like that issue has become an even more important part of the planetary boundaries narratives. If you read the more recent papers, they are even more careful not to say what needs to be done, but they focus more on measurements relating to these arbitrarily defined numbers – these numbers decided by a small group of scientists. You can’t decide boundaries like this without having some form of social decision-making. This is just how these things are done. For example, when scientists and society deal with the problem of lead pollution, and need to define allowable limits, it’s not just a group of scientists that decide how much lead is allowable in water or food or whatever. This is done as part of society.
Society must decide what it can do and what’s optimal, and this gets decided by a social group. Science is informing that, and it’s extremely important to inform that – not an optional part. But the idea that politicians, NGOs, industries, and other representatives of society are optional parts of deciding what a boundary is, is also not correct.
The 1.5° planetary climate boundary, the only good thing about it, is that it was decided that way. It was a collective decision. Those are very difficult to make. Very hard and involve a lot of negotiation. But that process is the only process we have for building larger scales of agency to deal with these challenges. So, the good thing about 1.5° is that it was produced in that way. It’s not just a small group of scientists making this declaration in a scientific paper. It’s a collective process of important actors at the global scale. I don’t have a problem with deciding that. But I think that choosing to put our focus on the temperature of the planet and a number like 1.5° was probably a mistake. It should have been focused on the amount of carbon emitted per person, or the percentage of energy in a nation that is clean energy. If it had focused on something like that, this would have more directly assigned responsibility to those who are actually emitting the carbon and causing the problem, rather than making it this planetary discussion.
Yes, it probably would have been harder to negotiate a target like that. That might have been one of the reasons why they chose to talk about 1.5°. But it doesn’t really matter. In the end, you can see the product. Yes, they negotiated something, but it’s not leading to the solutions that we need.
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