 Hello, everyone, and welcome to the Circular Metabolism podcast. I'm your host, Aristide from Metabolism of Cities. And in this podcast, we interview thinkers, researchers, activists, policymakers, and practitioners to better understand the metabolism of our cities and how to reduce the environmental impact, their environmental impact in a socially just and context specific way. With today's episode, we go back to the topic that we hold dearest to our hearts, which is, of course, urban metabolism. And if you have ever explored the topic of urban metabolism, one of the first pieces of text that you will encounter is the article, The Changing Metabolism of Cities, which quantified the energy, materials, water, and waste flows from eight different cities, which was co-authored by Chris Kennedy. In fact, Chris has been one of the main driving forces of the renaissance of the urban metabolism field, let's say, in the mid-2000s. Chris is a professor and director of Industrial Ecology Program at the University of Victoria. And he has worked for over 20 years in the fields of climate change, industrial ecology, accounting elements, and how to reduce the environmental impact of cities. Now he has developed a standard approach of city-wide greenhouse gases accounting, developed mitigation strategies, et cetera, et cetera. What is very interesting is I think that he has academic background, both not only from engineering, but also from economics and management. And I think this will also bring some interesting insights. He has worked with the World Bank, with NL Foundation, and many other prestigious foundations. So with all that being said, I'm extremely happy to have Chris Kennedy with us. Chris, welcome to the podcast. And could you please let us know who you are and what is your work like? I'm overwhelmed by your introduction. I don't think I need to say too much more about who I am. But that's fabulous. I love the way you use the word renaissance, because it really was. I was fortunate to be at the beginning of a restart of urban metabolism studies. Woolman had done it in the 65. And there was others between 65. And when we started looking at Toronto's metabolism, but it was fortunate and timely when we started piecing together the data from those eight cities around the world. And also tried to put a definition on metabolism, or urban metabolism, which was possibly why that paper gets cited so much, because it's got something there for people to say, what is this thing? Yeah. So you define it as the sum total of the technical and socioeconomic processes that occur in cities resulting in growth, production of energy, and elimination of waste. Wow, that's a difficult definition. Yeah, maybe I should say a little bit more about where that definition came from. And I basically looked up a dictionary. I think it was Colin's Dictionary, Definition of Metabolism, which sort of gave the common person's definition of metabolism as opposed to this more technical, biologist, anabolism, catabolism type of definition of metabolism. And I said, hey, you know, this applies to cities, but it's about sociotechnical processes. It's not just about biological and chemical processes. And so it really was an adaptation of that. Yeah, that's the root of the definition. So there's not a lot of genius in that. It's just practicality. So I'm wondering, so you are a civil engineer. You also did economics. And as you said, there was, you know, in the accounting realm of sustainability in cities, there was already a woman back in the 60s. And then there was this phase in the 70s, let's say, where we had autumn, where we had the Newen Brussels, where we had a couple of people. We had the Hong Kong with Newcombe as well. So we had, I think, five cities that kind of did their homework quantitatively. And there seemed to be a lot of emulation as well. I mean, they seem to discuss with them between each other. So there was something happening. And then it kind of died off. And then you brought it back up. Do you know what happened there during these 20 years or so before you started again? No, I never really pieced together how much those other authors knew each other. I mean, there was Giraudet. I may be mispronouncing that he was working, not as an academic. He sort of, he wrote about metabolism of cities. I don't know to the extent to which those other four paper authors really knew each other. Maybe you've discovered things I don't know. But what was striking about them was just how different they were. I mean, one was a chemical engineer. One was a geographer, a civil engineer. Even the way they drew their diagrams of metabolism were very, one was very organic. The Brussels metabolism was beautiful. I use that slightly years as a way of introducing the complexity, right? Whereas the chemical engineers, it was just a flow-through reactor of Tokyo, right? So no, I mean, and there were others as well. I mean, I discovered years later getting into some of, there was some work on Barcelona and I think it was maybe Prague or something like that that was done under some European studies, not necessarily in mainstream literature. I mean, I was fortunate when I was doing that review paper with Josh and John, the other two authors. The University of Toronto where I was at that time had a fabulous library. It's the third largest library in North America. And I was able to find print copies of some of those relatively rare publications. And that's how I dug them out and pieced them together. And obviously the reading, what we're writing of Brunner and Buccini was also an influence because Paul Brunner had, he gave me some clues in some of his writings just where to go look for things, right? So it was a piecing together. But yeah, and then of course, putting everything into common units was important. And that was actually, if anything, the meat of the paper really. So yeah. But you did, before you worked a bit on infrastructures and transportation, if I remember correctly, before, I mean, before going into this review, but how did you say, okay, that's something that I might be interested to look at this or what was so appealing that you then, spent 10 years almost working on the topic? I thought you might ask me about why I started working in urban metabolism. So I spent a lot of time thinking about that. And I mean, we could talk a long time about this. And I was thinking, there's really sort of three things. Actually, three cities that influenced me. I gave London, Leipzig, and Toronto. And there's a story behind each of them. We can go into them if you want. But I mean, the first one is London. London's where I did my undergraduate degree as an engineer in civil engineer at Imperial College in London. And the fact that I even chose to go to London from I was living in Lincolnshire in the English countryside. I was obviously drawn to cities. I was something about the big cities that fascinated me. I always, and when I finished as a civil engineering degree, I decided I didn't want to be a civil engineer. And I went to study economics after that. Why? What was the, what did you like and why did you expect to find with economics? I think it was something about the left brain and the right brain. I think that engineering is very focused, it's really detailed. And to me, economics was an ability to sort of see the world in broader terms, but still using analytical skills, which is obviously where I guess my strengths lay at the time. So, yeah, that was it. Although I guess ultimately I went back to engineering and used my engineering degree to go to North America and do a PhD at the University of Waterloo. So you went to London, you said? Yeah, London, then Leipzig. Leipzig is a quirky one here. Many people probably don't know that I went to the Ombel Fortune Centre in Leipzig. And that was after my PhD. I did my PhD in groundwater contamination and then went out to what was East Germany or Eastern Germany. It was mid-90s, so it wasn't so long after reunification. And I worked on cleanup of environmental catastrophes, really, that were in the former East Germany. And I love the city of Leipzig, because this is a city where Gödel and Escher and Bach, you know, sorry, not Escher, that's a book. Gödel and Bach had visited and it had a great rich culture. But what I really got out of it was a witness firsthand, just how horrible man's treatment of the environment was, the environmental pollution that we had caused. It really, it was something that I really saw firsthand. Over there in the city? Yeah, not so much in the city, but just in the area around the city. It's in, Leipzig is surrounded by the brown coal lands of Eastern Germany. So there's these large areas where they've just done stripped surface mining to get down to the brown coal. And I worked on one particular site where they'd, there was a house in a little town called Sibling or something like that, or a row of houses, and across the road from them was this big pit. And you know, the grandfather's generation would have seen this big pit created by the coal surface mining. And then the next generation, they took the brown coal and they processed it to get these cocoa briquettes. And then they took the waste from that and put it back into the pit. So there was this big black lake of organic nastiness, right? And then after that, they finally, it drained away and they turned it into a landfill. So it was, I just saw, what a horrible, what a horrible kind of existence of the generations of people. Yeah, yeah, it's just, it's unnecessary, right? If we're clever and smart, so yeah. Yeah, emphasis on if, yeah. Yeah, I saw that Leipzig itself, the city was fabulous. It was very entrepreneurial, it was growing. It was really responding from the opening up to the West really well and it had all this great culture to learn about. So I loved Leipzig, but it was this surrounding area that I just like, ooh. But that's what I was working on, right? That was my area at that time. And so groundwater pollution when you were looking at this was from, let's say, contamination. Was it from these, from coal or was it from other elements? In this particular case, it was pyrolysis wastewater. So it was from the manufacturing of core briquettes. But there was lots of other examples of waste sites in Eastern Germany. There was an area, they called it the black triangle of Europe because it went into Poland and the Czech Republic as well. So, and the Germans were really, it was great. They were working at different ways of remediating these sites from forestry to creating natural lakes or and other processes. I worked with a limnologist while I was out there which was really cool because that's got a different discipline to mine. So, yeah. And the third city? Well, the third city was Toronto, right? So I returned back to Canada after my stint in Germany and got a job as a assistant professor at the University of Toronto. And there were several things about Toronto that really influenced this work on urban metabolism. One was, I started reading the work of Jane Jacobs who was very famous for her several of her books on cities including life and death of American cities. And I'm not sure everyone knows but Jane Jacobs had been a New Yorker and she'd sort of written about amazing insights as to how cities economies work from a framework, from a grounded social, on the street, eyes on the street perspective. But she'd moved north with her family to Toronto and stopped some highways going into downtown Toronto as part of her work there. So she was an icon of Toronto and I, and Toronto's a confidant. It's sort of one of those wannabe city-states. It's a capital of Ontario. It's not the capital of Canada, but it's a wannabe city-state. So I read Jacobs' work and it kind of, I got on, there's an urban vibe that Toronto's got very strong that I really picked up. And also, I got this job as a faculty position and it was fairly open. It was actually a call on something to do with sustainability, which was, there was some really well-minded professors at U of T as we used it. And I'd gone in as a groundwater researcher, but within two years I decided, you know what, I want to do something different. And so I was quite brave, you know, in the middle of tenure track, I switched my disciplines, right? I did a part-time MBA just to cover myself in case I didn't get tenure. And I had an old colleague called Rodney White who'd written a book on urban environmental management. He was a geographer. And I'd seen in his book, there's a few attempts to sort of quantify energy use in Toronto. And another colleague had actually given me a stash of papers on sustainability that he'd collected, but he'd just gone off to become the chair of the department. So he didn't have time to do any work in the area. And amongst it was the Hong Kong metabolism paper. And I just thought, I think I put two and two together. I just thought, you know what, wow, someone's tried to look at metabolism in Toronto and they've not really done it. And this is a framework that as an engineer, it's very quantitative, it's a framework we could use as an engineer to take on this topic of urban sustainability. So that was really the genesis of that, right? And you can also see the groundwater is an influence because in that changing metabolism, the city's paper, I use groundwater as a way of talking about storage and flow processes, right? Which is a little bit more in-depth than the most urban metabolism researchers would go into, right? Sorry if that's too long, but there's a lot, you know? I'm always curious what's the story because there's no, of course, let's say, curriculum on urban metabolism or there's no single way to get inside of it. And I think each one of us have a different entry path to the discipline and it also explains why some people are more interested in some parts of this field than another, let's say. But yeah, when I discovered this topic, someone told me about this metaphor and because I wanted to do quantitative stuff for a city but I didn't know what to do and a friend of mine did LCA of buildings, I think. And I said, okay, let's do an LCA of a city. Well, how would that work? And I couldn't understand how to do it. And then someone talked to me and said, well, perhaps you're looking at urban metabolism and well, you know, everything was clear after that. You know, I just, but of course, I then discovered the work from Matthew Gandhi and from urban political ecology. And then I said, whoa, wait. Yeah, that's some good, that means very interesting work in the geography or literature, right? And even going back to Marx and the others who talk about metabolism. Yeah, which makes it more, so it makes it more interesting, right? Yeah, definitely. I mean, it's not something that I feel that we comprehend still. I mean, even if the principle is easy, let's say, we still are, I guess, perhaps not at the genesis but there are so many things to be done at least in its implementation, not its implementation because, you know, it's just a lens to look at cities but at least that how to use it to do stuff or to use it for policy making. I feel we're still at the very beginning but perhaps you have experienced this very much over the last years. Yeah, yes and no. I mean, just to pick up on one thing you said, you use it to our metaphor and some of the early papers did use metabolism as a metaphor but I learned from Maria Fischer-Kowalski that it's not a metaphor, right? Cities really do have energy and material flows through them but the policy side for me, I think the importance of urban metabolism is that it's brettz, it gives you a broad view of the city and the real policy lesson for me or breakthrough for me was really when it came to the greenhouse gas accounting work because when I was writing the urban, doing the urban metabolism study of Toronto and doing the comparison of cities worldwide, at that point the literature on urban greenhouse gas accounting was very weak. There was a few, I think there was pockets in different nations of people that did it and there was competing, similar but competing frameworks that were kind of, they were hidden, they were really, they were sort of businesses and they weren't wanting to give that method away. And so I then moved on to do this comparison of the greenhouse gas emissions of these cities because as you well know, the greenhouse gases, it's all about multiplying emissions factors by activity levels, right? And the activity levels are all in the metabolism, right? So the metabolism provides all this data which goes right into your greenhouse gas calculations, right? So I did this work comparing the greenhouse gas emissions of 10 global cities, largely was industrial ecologists and people that you know quite well, and you may have probably interviewed a few of them on your part, right? And at that time I got to know this guy called Dan Horvig who was the urban anchor at the World Bank and he was from Canada, so I met him in Toronto and he said to me, you know, the bank has been wanting this for five years what you just produced because you've used a consistent methodology, it's transparent, you've collected data from all the cities, you've given all your data sources, you've done a rigorous scientific approach to greenhouse gas accounting from cities. And we can use that. And I tell you now, within a month of us publishing the results paper in ESNT, the World Bank made a $75 million investment to Bangkok on the basis that they had, Bangkok was one of our 10 cities. And I didn't get a cent for this from the World Bank, right? At that point it was like, hey, we've arrived in the policy world, the World Bank built its financing mechanism for funding cities, I mean, they actually deal with countries, but they built it on that accounting message which basically came from the metabolism and that was really the sort of the connecting of the dots from the metabolism, which is kind of science through to the policy. So yeah, that's the experience there. But what type of funding would they then provide? Was it for infrastructure? Was it what type of, yeah? Yeah, it was, they had a larger package of funding for Thailand, I guess, and they added an extra $75 million in. It was for funding public transportation infrastructure. I guess the Thai government had said, we want to put this transit in and it will reduce, it's part of our strategy to reduce greenhouse gas emissions. And the bank was able to say, hey, yeah, okay, we've got a measure of your emissions. We know how much you've got from transportation and the message is consistent with that that New York and London are using, right? So we know the New York and London, so yeah, okay, we can go ahead and do that. There's probably a bit more to it than that from a financial perspective, but anyway, that was my insight into it, yeah. And it wasn't the last time you compared cities, right? So you compare them in the changing metabolism of cities, you compare them then for the greenhouse gas emissions. And then you also compared the 27 mega cities and this mega paper that is, well, very condensed actually, but it probably took a lot, a lot of time. And it was, so I think it was in 2015, it was called, what was it? The energy and material flows of mega cities. And I think it was like a bomb when you dropped it, it was, wow, 27 cities compared at the same time in terms of metabolic flows, well, that was a lot. And I think most of the field was very excited to read it. So what happened there? Well, I'm pleased to hear that, that's a great way of describing it. It was, yeah, I mean, it was a fabulous journey. I mean, first of all, you know, Angelo and others at the Angelo Ficcini of the Enel Foundation were a big part of that. It was, yeah, no, it was a fascinating project. There was the Enel Foundation who, they didn't just sponsor the work, they were inherently involved in it. They, it was a new foundation created by Italy's National Utility, that's basically a global renewable energy entity today. I'm back then. They actually reached out to me. I think they'd been speaking to some people in the Industrial Ecology Network about, they had an interest in urban metabolism. They had an interest in mega cities. In particular, South South American mega cities, which came out. And they reached out to me. They said, hey, we're gonna be in North America next month. Would you like to meet us in New York City, right? So here's, I'm in Toronto. So I did a short flight and we met for lunch on this Avenue in New York, which was all kind of very kind of, enjoyable. It was just a lovely experience, right? And basically, the Enel Foundation said to me, hey, we wanna study metabolism, mega cities. Would you like to propose something, you know? And I said to them, well, how much do you wanna spend, you know? What's the scope of the project? Yeah, and it was interesting because they said to me, I'm trying to think, I've forgotten someone's name, if he's terrible, but Angelo wasn't there at that meeting. But they said to me, yeah, maybe just study 10 cities. And here's a couple, we're interested in the South American ones, so make sure you include them. I mean, that's because Enel was the electricity provider for some of the mega cities in South America, plus cities that weren't quite mega cities yet. They were including Lima, and I was like, well, Lima's only nine million. I'm sorry, that's out of bounds, right? And I convinced them, or I wrote a proposal to say, look, for us to, you know, if we study 10 mega cities, that's kind of interesting, but if we did all 27 mega cities, if we did all of them, then that's a landmark, that's a real piece of science, right? Because, you know, there's no kind of holes or gaps. It's comprehensive and complete. So I made a proposal to them to study all 27 mega cities. And we devised, the challenge is the data, obviously, you know really well, I mean, just doing 27 cities, but 27 mega cities where we're going beyond the central city into the suburbs, and you know, some of the cities were like 20, 100 municipalities, you know, we're in there. And so we, but I'd learned enough that really the trick is you need a person in every city, or at least a person in every country, right? So we devised a mechanism whereby every, every, we found a partner in every city, just about, and that was really using the industrial ecology network. We used the World Bank network at that as well. And I had a colleague, Patricia McCartney, who was running the Global Cities Institute in Toronto, right? We used her network as well. So that was an effort just to get that network of people together. And we offered honorariums. I can't remember this, $1,000 or a couple of thousand dollars, it was not a lot. It was an honorarium to say, hey, you know, just, you provide the data, we'll give you an honorarium, but you'll also, we want you to contribute to the paper. We want your reflections on the data. We want you to give us insights. We want you to co-author, not all the papers, but the PNAS paper was so. So, and, you know, amazingly it worked, right? I mean, I had a post-doc Ian Stewart and the project went twice as long as it was meant to go. Not that we got twice as much funding, but it was, you know, and now had a reorganization of the foundation halfway through the project, which we survived, which was tricky. But yeah, at the end of the day, it produced this paper with some really neat insights into the working in mega cities, I think, yeah. Yeah, and what was interesting is, I don't know, I guess it was within this whole project you had also this indicator set that you developed so that you could really compare, let's say the cities have comparable data within, well, or comparing all of these cities. And of course that's always the bane of the existence of urban metabolism studies. What do you account for and what do you exclude? You know what I mean? Because we could always include more and more and more or, you know, what's in and what's out in the quantifications. And so what we also have inherited in metabolism of cities in our global datasets and all of that is this layering system. I think that speaks a lot to have layers on explaining the context and then layers on the flows themselves and different layers. And as we see fit, we can add or subtract some layers. And so I think that this was perhaps even most interesting is how do we build something that, you know, all cities can be compared at the end of the day because just the flows is something but then we also need, you know, how do you compare Tehran with Paris? How do you compare Buenos Aires with Bangkok? You know, I mean, it's very difficult to actually do that. Oh, absolutely. I mean, those layering of those layers, actually I think it was Angelo or Renata. That Renata was a colleague at the NL Foundation who were really sort of keen on that layering approach that we know. And yeah, I think you've got it absolutely right. It's, you know, there was certain data you really want to get. You want to energy use if you can. I mean, that's kind of natural. But some of the material flows are pretty difficult to get. Some of them are a bit quirky, right? Much more difficult actually than energy and water, right? Yeah, yeah, I mean, I was amazed. We didn't really make a lot of it, but we got some data on steel, which was for about, you know, if you got data for seven or eight cities, that would be enough. Yeah, and you know, it sort of made sense that the cities that were growing fastest, not necessarily the largest mega cities, but the ones that were doing lots of construction, you know, you could see the correlation with steel. We also tried to get data on food and it really, you know, it was really completely inadequate. We didn't, I don't think we ended up reporting it in the paper at all, but you know, I just remember sort of, I think it was Cairo, we got sort of like someone reported the numbers of tins of hot chocolate or something like that. It was really quirky and I was like, yeah, I'm not sure that we can do much with that, but you know, others have gone on to do really good work on food, but we really didn't get it at all, you know, in our data set and that was okay, right? And what do you, I mean, because you've compared so many times different cities, what's, how do you approach this very extremely difficult task to compare cities and to what insights do we bring out of it and how can we really compare cities? I was gonna stare. Yeah, no, I was actually, I was sort of, I wanted to twist the question a little bit. I mean, let me say something that's kind of a response but isn't exactly a response. I think what I love about doing it is you actually learn something about the city, right? You know, you can read about the history of the city and I've written books on the evolution of cities, right? Which is another topic, but- We have a cheer, yes. I have some questions later on, yeah. Sure, but it's like, you know, as an economist, you can find out about the GDP of a city or you can look at a map at the geography, you can look at the map of the city and you sort of know where the main subway stations are or the main squares are. You learn the architecture of the city. And when you study the metabolism of the city, you learn something else, right? You complete that picture. You add the physiology to the morphology, right? That's what you do. And you think, you look at a place and you go, yeah, it makes sense that this place has all this energy used. Look how spread out it is. Look how big the buildings are, you know? Or look how cold it is here. You know, it adds something to sort of the understanding, the understanding of a city that could be amazingly lost. I mean, I remember if we go back to the greenhouse gas paper, one of our 10 cities was Denver. You know, Anu Ramaswamy, of course, I'm sure you know well, she was based in Denver at that time. And she and one of her grad students were the co-authors of the paper. And Denver is a little bit, I don't say off the map, but it's a relatively bad North American city in terms of its greenhouse gas emissions. And I just remember going, I did a number of radio interviews around that paper. One of them was a radio station in Denver itself. And I just remember the presenter introducing me and saying, we the people of Denver think we're living in the greenest city in the world, right? Because we have these beautiful Rocky Mountains behind us and it's clean living. And I had to explain to him, but you've got an interior continental climate. So you've got a lot of energy for the heating and cooling and you're running off coal power. That doesn't help, yeah. Doesn't help though. And you've got this really spread out, typical North American sprawl. I see you're driving an awful lot, right? So it's your heating, your high carbon electricity and your transportation emissions, which are the big three, right? That's why you're over 20 tons per capita. And it was like, it was news to them. You don't perceive that, right? Until you've sort of studied the metabolites of city. So I don't know whether that answers your question, but it kind of worry, it took me I suppose. No, you're right. I think it always goes back to some similar insights, let's say, each city, their main flows or energy, water, construction materials and food, let's say. Of course, water dwarfs them all in terms of mass. And on the output side, it's more or less the same thing. So we have, I think now some generalizable insights, which are good because at least when we start a new urban metabolism study, it's not from scratch. We already have some habits and some insights that are comparable from one city to another. Of course, then there is some specificities. And this is why we're also very attached to context-specific elements is how do we start then doing policies which are perhaps not exportable and are very context-specific? Or is there something that, are all policies universal or should we ground them all and how do we start grounding them? And I think that's the next level which we're right now in or something like that. Yeah, I mean, that provokes a couple of responses to me. Just first one, again, and going back to the mega cities paper, I remember when we were collecting the data for Karachi in Pakistan, how a big part of Ian Stewart's work was actually proofing the data and checking it was right. I mean, I remember the electricity used for Karachi was coming out way, way much bigger. I mean, it was like we had Delhi and Mumbai and then like, and then Karachi was like way, way bigger. I was like, no, that just can't make sense, right? No, let's double check that number. And so, you know, we went back and it turned out they'd given us the electricity used for the whole of Pakistan, right? So, it was like, no, we spotted that one because, you know, we'd expect it to be similar to those other types of cities. Not like the difference would be interesting, but, you know, we knew that those South Asian cities were really low metabolisms, right? In per capita terms, right? So, we'd learned something there. I can't remember what my second point was gonna be. That was about policy. I know we're talking about, yeah, exactly, about universality or context specificity. Yeah, I mean, I guess maybe this is moving on to some of the last work that I've, more later work I've done on cities where it's not really doing full metabolism studies, but just sort of drawing upon the learnings of 20 years working on cities. We did some work for the Wood Resources Institute on called Shifting Currents. It was about electrification of cities. And that's, you know, that's a big topic on, you know, big strategy for dealing with reductions in greenhouse gas emissions. And we were able to look at, you know, the whole planet of cities and say, you know, electrification is a major strategy, but it doesn't necessarily apply everywhere. And, you know, one of the two key variables that we should look for in understanding which cities are really good places to electrify. And, you know, one is the carbon intensity of electricity, which, you know, we use a lot in the greenhouse gas accounting, which is something, it's an addition to the metabolism, but it's an important part of the impact of the metabolism. And the other is just to what extent is a city using electricity? What percentage of the population actually have access to electricity? Because when you're looking in the global south, it's, you know, you can't sort of start professing that everyone should drive electric cars if only 10% of the population actually have electricity, right, it doesn't, it's just, it's social equity right grounds. This just doesn't make sense. But we were able to pick out a whole number of cities across the world and in different countries where actually electrification was a really good strategy for reducing emissions or growing without so much large emissions. So that was a, I think that would be an example of something that's useful for policy people in a very simple, you know, two very simple measures nicely displayed on a map of the world with some tables in the back, which really came out of the understanding of metabolism, you know, I think. Yeah, I remember, I think it was perhaps in 2017 or in one of the conferences you said the future of cities is electric cities or the future is electric cities, something like that was the title of your presentation, I think, and you had like a nice futuristic diagram, I think, or neon signs, I don't remember, yeah. I think there's a rock band called Electric City and I think I stole their logo or something. Might be that, I'll go have a listen, yeah. But, and how do we get to electric cities? Is it the, so we electrify all of the appliances, I guess, and electrifying all of the needs of energy into electricity, that's the main, or is there something else that I can think of? Yeah, and you're on the right track. I mean, the main ones are electrification of the vehicles, which is here today with automobiles, obviously. It's a bit harder for freight and larger trucks, but also the building stock, the, you know, in the last 10 years, air source heat pump technology has really progressed. 10 years ago, ground source heat pumps, you know, what people would talk about and there's always challenges with the unknown geology and, you know, going underground, but the uptake in air source heat pumps means that electrifying buildings is a major strategy that is and can be pursued, right, or can and is pursued. What I find interesting about that is though is, and again, this comes out of, I did some work with David Bristow in his PhD thesis on resilience of cities and we quantified energy stored in cities as a measure of resilience, right? So it's a slightly different angle, but it's actually had some really important insights for the strategy of electrification. The challenge is if you electrify your city, then you're going from, you know, most Western cities have maybe five or six predominant forms of energy, your diesel, your gasoline, your natural gas, a little bit of coal where it's still used, wood a little bit and electricity, right? If you go from six down to, you know, to just one, then you're much more vulnerable to shocks, right? You're totally dependent, you've drastically reduced resilience. So it's important when talking about electrification of cities to also think about local generation, building scale generation versus the larger scale, external wind and solar plants. And as you know, the nature of cities is such that you can't generate all the electricity you need off your roof because, you know, unless they're really spread out, but then if they're spread out, they need more electricity. So I do think there's some important subtleties in how you go about that. And I think, I don't think that's been necessarily well well written on or I don't think I don't see it getting into policy very much. I don't think that the utilities or the people who govern utilities have really caught on to that yet. And they need to, that's really important. Yeah, you're right, because I've never thought of this of, you know, homogenizing or going to one vector of energy is actually a risk, of course, of resilience. And of course, seeing how the grid today is vulnerable and we're all freaking out with blackouts how this risk gonna increase in the future. So it's a, it must be quite daunting for grid operators, this type of electrification of cities. Yeah, no, actually I think I'm going back to the, to the sort of the comparisons between cities. It's interesting actually, I always remember looking at Bangkok's energy sources and it was much more diverse than any of the Western cities. They had, they were burning rice husks and all sorts of stuff, you know, to, you know. And in a sense, as they become more developed, they actually become less resilient in some respects. I mean, there's a bit more to it than that, right? But it's, so yeah, no, I think it's an angle that I'd like to see more work on. I'd like, yeah, so. We, you mentioned briefly your book, The Evolution of Great World Cities, which you kind of wove through how big cities happened and how they made wealth back in the day and how the old cities that were wealthy are not the new cities that are wealthy and how this wealth moved around. I guess, of course, when we translate wealth into flows, wealth into flows, of course, there is, or wealth is, or there is capital and then there is money flow. So of course, it's very metabolic as well. So I'm wondering how, why did you, was that the culmination of engineering and the economy that's brought you to write this book or what did you have before writing this book? What was the rationale that you had in mind? It's funny, you should ask that. I was reflecting on that, not so much because of the podcast, but I'm doing a book review of some of a latest book by John Arenfeld, who's such an amazing leader of the field of industrial ecology going way back. He's the founding executive director and his academic work is fabulous. And John had, John was helping me arrange the 2007 ISIE conference in Toronto. He was one of the four of us, very much the steering hand. And I learned a lot from him. And he was him that really got me interested in complexity and was big on looking at complexity in industrial ecology. And in some respects, it's only the second last chapter where I look at cities as ecosystems. And I bring in a bit of the complexity theory where John's influence comes in. That book, Evolution of Great Well Cities, really relates to my work on metabolism of cities and industrial ecology. The rest of it is really another me. It's that guy that didn't wanna study civil engineering and went off and studied economics. And yeah, but there is a weird, I mean, there's a weird story to it too, because I, after I finished my first seven years as an assistant prof or, I guess the six and then I got my tenure at University of Toronto. I went off in my sabbatical year and I went to Switzerland, which is where you are now, right? Actually, I went to Oxford first. I had six months in Oxford in the geography department. And then I did six months, I actually attended up to before because my son was born, so I had to go. But complex these here. But anyway, I reached out to Peter Piccini, who of course was just a fabulous writer, all the things he was doing. And it was all because he just finished his professorship and he was working for the Swiss Science Foundation. I probably not got the correct term there. But he said, you should come anyway and you can mix in with my old group. So I still went and I, and so, and on my sabbatical, I'd written that I was gonna take, I used to teach a course called Infrastructure Economics. It was a graduate level course. And I was going to write a book on infrastructure economics. And the infrastructure economics had sort of all the economics and then engineering needs to know not just the micro-economic stuff or the cost benefit, but to understand economics and its broader context and macro and those kind of things. And after one month of trying to write this book, I said, this is boring. I wanna write something on cities instead. And so I started, at some point, there was some ideas came together that, it'd be way more fascinating to talk about the economies of cities at these different levels from micro to macro rather than just infrastructure for engineers, right? So that's probably the genesis of it. And so I just started writing a different book and it took me another five years actually. But it was an adventure. I mean, it was quite a mission. And I mean, I did the foolish thing, which was I wrote a book before I had a publisher. But then, I got to know Richard Florida when he came to U of T and he read it and he loved it. And so he really went out, encouraged U of T press to publish it. So yeah, no, it's a... That's a big second matter, having Richard Florida as well, pushing your book, so... Yeah, no, Richard was great. Yeah, no, he was a really good colleague at U of T. It was a shame to leave the... There were some great colleagues doing work on cities at University of Toronto. It was the right place for that type of work. It's not... Victoria is a very different type of city. So I don't quite have that same kind of group of people around me here. But... That's perhaps... So now you work on biophysical economics perhaps. So Victoria has something to do with the biophysical element of this? Maybe. That's a nice theory, but no, I mean that's... I mean, my main, really the last five years in Victoria have been about building this green civil engineering department. So I've been hiring professors. I've hired a dozen people. That's a lot of work and just building a department. But the biophysical economics actually has come out as something else. I mean, I've... I've long... For a long time, I've read broadly across industrial ecology and economics, ecological economics and other similar types of fields. And... Actually, I mean, I don't know how long... It's a little bit off-way from the topic of cities. So we can do this maybe concisely. But I actually started writing another book. Again, without a publisher, and I've actually stuck... I've got this other book that's been written, which is all about Malsusian struggle. It's a very big picture. It's sort of a 250-year look at sort of... Not just a population problem, but the whole package of environmental challenges that the globe faces, right? And in this book, I go into the roots of industrial ecology and I go and explore the roots of ecological economics, including the whole chapter on the roots of thermodynamics. So it's roots of roots of roots, right? And one thing that I... In that process, I went back and I read a lot of original writing. So I read Georgesco Rajan's work. I read Daily Steady State Economics. I read similar types of books. So I really... And it just kind of occurred to me that Georgesco Rajan had this whole thing about the entropy law and the second law of thermodynamics that was kind of what all the ecological economists and some industrial ecologists to extent, sort of go back and draw upon it. And I thought, you know, it's a bit of a red herring because it just confuses everybody, right? And really, you should just stick to the first law and think about, you know, energy plants. There's a connection back to metabolism in the cities there. And I think I saw a different way of interpreting with what Georgesco Rajan was trying to say. He was just trying to say economy is a subject to the laws of physics. I think that's what he's just trying to say. And of course, I also all this stuff on de-grows and steady-state economies. And I just thought, and Hall's work on biophysical... Well, he called it biophysical economics. He's really looking at energy return and energy investment. Basically what I did was I've come up with a method for replacing general equilibrium models of neoclassical economics, using an equilibrium between capital, labor and energy. So I've got working on this method and I applied it to the Industrial Revolution as a way of developing it. And now I'm applying it to 20th and 21st century North American economies, really as a way of dealing with greenhouse gas emissions. So I got pretty excited by it and it's pretty much my main thrust of my work, at least, you know, just now. Things change, but just now it's really where I'm at. So this model, could you elaborate a bit? How does it work? I'm a bit aware of CGE in general, how they work, but now you have, so capital, stocks and then energy flows that you combined the three together to kind of see what was the outputs attached to these three? Yeah, let me elaborate a little bit more on that, for sure, I'd love to. So the CGE models basically, this is going back to Walrus and the idea that economies can be described by this general equilibrium where prices and outputs, you know, the balance of supply and demand for multiple products in all markets all can sort of come into this great big general equilibrium. And it really has no physicality to it at all. It's very much, it's a social science model, derived from physics, right? But without using physics, if you use a mass of the physics, right? And various people have actually built CGE models of the industrial revolution, which was, I chose as my target period or era because it's a relatively simple economy. There's a bit of data, and it's not too contentious either, you know, there's not a lot of people working in the space. It's an easy space to develop new ideas, I think anyway. I've got some interest in that area, but, you know, you come across these people who've written these, come up with these general equilibrium models, and one of them in particular was a researcher at University of Chicago, and what she had done is she'd put energy into the model. But energy was just an intermediate variable, you know, energy was just something that was used in industry and energy was dependent on capital and labor to generate the energy. And that's, and there's more to energy than that. Energy flows through the entire economy. You need energy to produce capital. It's a two-way interaction. There was a feedback loopy there, yeah. Yeah, and so I said, well, and I'd rest, I mean, and Bob Erz has written a lot on, you know, Bob Erz has got some great work on, on the role of energy in putting it into neoclassical production functions. But I went further than that. I actually, I wrestled with the neoclassical production functions for the Industrial Revolution and they don't work. And I was reading this guy, Alan, who's a great scholar of that, he'd found the same thing, right? They don't work for the Industrial Revolution. So I kind of had to throw them away. So then, so then here's the story of how capital, labor, and energy come together in the Industrial Revolution. And actually cities comes into this as well, which is kind of neat. So we can tie it back to the pod. We're not getting too much of a detour, right? So what happened in the Industrial Revolution is you've got these great increases in agricultural productivity. So I'm looking at, you know, Great Britain from 1760, actually up to 1913. So I'm going up to First World War. So it's actually two periods of the Industrial Revolution. You've got an increase in the productivity of agriculture, which frees up labor. You've got, you've got more people than you need to produce your food, right? So you've got this labor. And the labor, I had a simple sort of four sector model of the British economy. One sector is agriculture, which I've just described the key thing of. The other sectors are coal mining. And then the sector for construction and materials, or it's construction, but it's got materials layered into it. And then the four sectors is production of goods and services, which is obviously a very big sector, right? But it's sort of a last down the line, right? And textile would go there, I guess, right? Because there was a lot of, yeah. Yeah, so the textiles are under the goods and services, yeah. So I don't really focus on, obviously, you know, textiles, the cotton mills is a big part of the Industrial Revolution, but I'm more interested in the energy side of it, right? And so the idea is that you've got this excess labor and they could go and work in any one of those other three sectors. But you can't, they can't get a job until there's a capital infrastructure in place. You know, there has to be mines for them to go do the coal mining, you know? And there has to be factories or shops for the goods and services. So you need to build the capital and obviously the construction of material sector is the sector that does all the capital construction. And there's no IT in those days, right? So it's all structural and mechanical engineering, basically. But then to build capital assets, you need energy. So you need the coal miners, right? So what you end up is this neat little equilibrium model where your labor from your agriculture, your energy from coal mines and your capital that's produced, physical capital produced from, excuse me, your construction and material sector all kind of play out and you actually grow, you grow your cities, you grow your infrastructure, you grow your goods and services capital, right? So that's, I mean, the math is actually really, really simple. It's almost embarrassingly simple, but because actually it's a very different way of looking at how economies function. And I've since, I mean, the beginnings of applying it now to the more complex economies of today, which is an interesting direction that I'm headed just now. Yeah, I mean, it's funny because as soon as you said that in the agricultural sector, we had surplus and thanks to that we could do all of the other things. That's how cities were born. I mean, we need the surplus from somewhere else to have cities, right? I mean, that's kind of the social and spatial surplus that we need to make cities, they don't exist elsewhere. So I'm curious to see how that would fit in as well. Like we need extra space outside to make cities happen. And then to make cities, we need, you know, more material. So yeah, I'm curious to see how that would evolve. Yeah, I mean, that's the, I mean, just tying a few things together there, that's, you know, the amazing thing about cities, we were talking about complex systems before and John Ehrenfeld's influence. And yeah, cities are this things that emerge, it's emergence, right? The complex systems that emerge. We free up the labor, people need jobs and cities are actually a creation of higher order structures. There are this complexity and with creating complexity, there's roles of people, there's people to fix potholes, there's people to work in gas stations, there's people to build buildings, there's people to fix buildings, you know. And that all comes about, and you need an energy supply to do that too, right? So it's the combination of the labor, the excess labor from the countryside, the ability to access energy sources that creates these amazing entities, these cities that we, the many of us or more than half of us these days live in. And again, just a connection to this was, I was really fortunate to supervise the PhD thesis of David Bristow, who again is another industrial ecologist and he did his PhD on sort of the sermon dynamics of cities and he was so far ahead of me. I didn't understand what he was doing. I came out of his first defense. I worked closely with him, but I came out of his first defense. And I said, oh, Dave, I finally got, I finally understand what you're doing. You know, and he had seen this idea of the role of energy and the emergence of cities. It was in his thinking. He needed a little bit of help to kind of pull it out, right? But I find the penny dropped for me at what he was getting at, right? And so it's all buried in his PhD thesis. So that was something that I really felt like I was learning about cities through that work and that perspective. But again, metabolism is in there, right? It's the role of energy. Is it really critical? Yeah. So you have these two current projects like biophysical economics and global infrastructure. What is kind of your small secret project that you're working now for 2021, 2022? Is there something that you really want to explore? Is something that you want to discover still? Something new that you want to embark on? Well, on the city's line, I did a recent conference paper looking at this question of jurisdiction for responsibility for electricity supply tied into the question of resilience. I was looking at British Columbian cities and just pointing out that we really need the building codes to have PV on the roof of every building, I think. But the building codes don't say that. Building codes don't touch electricity supply or storage, which is important too, right? The rules governing municipalities sort of say that there's lots of things pointing to the fact that municipalities have a responsibility for the well-being of people and provision of infrastructure and almost worth light resilience. But they're superseded by the utilities, the electrical utilities, right? The electricity utilities have this power to sort of put their poles and their lines wherever they want or sort of telling the municipalities that who's in control, right? And so there's, I think there's some tensions to be worked out there. I'd love to see some more work done in there. I'm not sure I will do it, but it is something about cities that's interested in me a lot. I'm mainly working on a biophysical economics model of the United States just now. I was an old colleague from WRI. That's one thing. I've actually got a new postdoc starting with me today, which is really exciting, because we're gonna, you know, he's gonna do some of that work, but he's also just come out of a PhD with Peter Victor in ecological economics. So he's got some really great talents. I'm looking forward to seeing what he produces. And then again, I've got this other book that I've been beavering away on. So we'll see whether I find a publisher for that. I don't know where that might be. It might still be a few years away before that sees the light of day. Is the topic also something in between civil engineering and economics or? No, this is the one on the Malthusian struggle. Ah, yeah, yeah, sorry. Yeah, yeah, yeah, yeah, yeah. So yeah, no, it's got, it's actually way too ambitious. It's just, that's the problem with it, yeah. So. But you know, I mean, you need something ambitious to get excited to write it. And then when it's too ambitious, it's difficult, I guess, to see where it ends or? Yeah, and actually that's just something about what you just said, which is sort of almost like my learning in life, my learning as an academic, that I found myself about 20 years ago when I was transitioning from groundwater into sustainable cities, that I was looking at the advection dispersion equation which describes solute transport, right? And I was looking at its inability to describe tail effects. So I was looking at a tertiary phenomena. What is this pollution to that it goes along and it spreads out? And three, I'm looking at as deviation in how it spreads. And it was like, maybe this is just like way, way too fine a detail. And my world almost turned upside down. And I started working towards larger and larger scale, a larger phenomena. And this is the whole realm of interdisciplinary research. And what you discover when you start saying was, well, how does this whole realm of ecology relate to economics or physics, whatever it is? And you find these chasms where there's so much to learn, right? And it's such an exciting space to throw yourself into and work out connections between things. It's not reductionist science. It's something else, but it's fabulous for learning about the way the world works, I think. Yeah, yeah, for sure. So we generally have a last question, which is we want to recommend other people to, well, we want you to share something you would recommend other people to read or to watch or to listen to, probably in your work of writing this new book, you probably have encountered many interesting readings. So do you have anything that's really kind of shook you and you want to share that with everyone? Oh, yeah, there's a lot in that book. Well, I'm going to reiterate something I just said, actually, because it's very much top of mind just now, but it also is very impressive. And readers, listeners or readers can't actually read it yet. But again, John Ehrenfeld's new book on flourishing. He's got one already out on flourishing. So maybe his old book on flourishing they should go to, but he's got a new book coming out. I'm looking at the pre-proof copy just now to write my review of it, but it is an amazing piece of work. I mean, it's got brain science and philosophy and sociology and business and ecology and spirituality wrapped into it. It is a really clever, sophisticated deep look at humanity. And our challenges, right? So I'm in awe of John Ehrenfeld just now. So there's a pretty good plug for his book on flourishing. I'm not sure I can top that. With this level of ambition, yeah, I can imagine it's difficult to top that. Yeah, yeah, no, it's a fabulous, I mean, yeah, in terms of the stuff I've been writing on in my other book. No, I mean, there's so much, it covers so much ground. I mean, it's been interesting to sort of look at the history of discovery of global warming by, you know, the challenge of diversity, biological diversity globally is something that I worry a lot about. And there's a new Tuscupta report which maybe people should look at if they haven't. I think that's worth looking at. I mean, you know, some of the foundational stuff on thermodynamics still interests me a lot. I'm just trying to remember the name. There's a researcher who moved back to Germany from Maryland whose work is Clyden, Axel Clyden. Yeah, so Axel Clyden, he's, I think he's at Jena in East Germany now, but he's done these wonderful workpapers on understanding the whole of systems through non-equilibrium thermodynamics, not too deeply technical or not too deeply mathematical, I should say. His writing is really good. There's several papers in pretty prestigious journals that I came across in the last few years. David Tillman's work actually, I mean, he gave a presentation at a Gordon conference not too far away from you probably, I don't know, 10 years ago, but his work on understanding the future challenges of biodiversity loss to provide food for a growing and more affluent population is really quite hard hitting. And I do think it's almost scary, but I think he's a very accomplished academic too. So there's just a couple of names I could throw out. But yeah, that's probably enough to wear the appetite of listeners to this, I would imagine. Yeah, they'll be covered for a couple of months, I think with his list of, because you need to digest them as well. It's not just reading them. You also think there is knowledge to be understood and then linked with each other. So thanks so much, Chris. I think we covered many things. I learned a lot from this renaissance. I learned a lot from what are some interesting topics to also start researching again, some others to rediscover as well. Thanks so much for taking your time, Chris. And I think we, I hope we're gonna meet very soon in another conference and discuss this over. I'm really looking forward to reconnecting with people again. I've had my jabs. It's been fabulous to talk to you, I see there's a lot of fun. Yeah, and kudos to you for doing this part. It's great, you know. I hope you can edit that down and have a really good, some good insight from our conversation, so thank you. I always enjoyed, thanks a lot for sharing all of these insights. And thanks everyone for listening until the end. We'll see you at the next episode. Cheers.