It's a colloquium included in the program of the international basic science for the scientific for sustainable development. And so I think we have two distinguished speakers today, and I think they are really role models for addressing issues which relate to sustainability. So the first one is Sir Partadas Gupta, is the Frank Ramsey Professor of Emeritus of Economics at the University of Cambridge. He is actually was born in India and did his undergraduate studies in India actually in physics and mathematics. And then he moved to Cambridge where he got his PhD in economics. And Sir Partadas Gupta devoted his professional life, professional career to understanding welfare economics, development economics and in particular the interaction between population and environmental resources and the ecology. And he's a leading figure in this field and yes he's a long friend of ICTP because he has been one of the leaders of a program that we have had since from 2002 to 2006 on environmental and ecological economics which included also the Bayer Institute with Carl Gordon Mahler and Simon Levin who is also involved in this workshop. And Fondazione Enrico Mattei, Carlo Carraro was mostly dealing with the interaction between economics and climate. So without further ado I would give the floor to Sir Partadas Gupta. Thank you very much. Thank you very much. It's a pleasure to be here. That's great. Thanks. To those of you who are young, younger than I certainly, you'll find gradually as you grow older that academic life really amounts to becoming a slave to institutions and they're not necessarily your the institution which pays your salary. So I've been a slave in turn at the Bayer Institute as was mentioned, ICTP, the Santa Fe Institute, Sandy, the South Asia Network for Development and Environmental Economics. These are institutions of the greatest importance at least from where I stand for my kind of work I do and whenever they ask me to do something I do it. There's no questions about it. So everything else falls apart. So it's a great pleasure to again assume my role here at ICTP. Right. I was asked by Matteo to speak in to the review of the economics of biodiversity that I published. I submitted to the UK Treasury in February 2021. It took about 15 months to complete it. It's on the Treasury's website. My wife told me that a 600-page document with appendices and boxes with mathematics in it is not going to make it readable to people that I was really interested in addressing, which was a common citizen. That's the concerned citizen is the person I was actually wanting to address. And she was right of course. So she told me that she wouldn't let me submit it until I completed a short version, a 100-page version with no maths in it, but which I did. So that's also in the Treasury's website. Then there was also a document that my team produced, a very brief one of the urgent things that need to be done, that the review appointed to. That's also on the site. And then the Treasury produced a response to it. That's a substantial one. And I was very pleased with it, more than I can say. And that's also there. And then they did me the honor of keeping my team for an additional year for dissemination purposes. So I've been doing that a bit. What I want to do today is to give you the heart of the argument in it, from which emanates the policies that we ought to be thinking about. I'll be keeping attention today to global aggregates. The review goes into distributional issues from the global down to the individual level, via nations, communities, villages, households to the individual as well. And that's where the richness of the subject, of course, is drawn. But I can't do everything here today. I'm going to stick to the global patterns in everything in aggregate terms. And occasionally I'll point to some significant distributional issues that crop up that the basic fundamental model draws our attention to. And the reason I want to spend some time on the model itself, the fundamental core idea, is that this is ICTP. And they like things to be simple. Physics has developed from simplicity, not mixing everything matters. And you don't get anywhere. Okay, we have been living in unprecedented times. And I guess I would be seen in future, our generation, my generation will be seen in the future as being the luckiest ever on earth. If you go down to 1950, you will see a turning point. The first of my slides gives you time series of global GDP in real terms, PPP, prices of all ours in 2011 prices. Everything's normalized so that it's not. It's from 1750 to 2019. And you will see a sharp break as far as these models of these data can tell you in 1950. Huge acceleration. You've seen this kind of curve from emissions, carbon emission curves, you know, the famous hockey stick. It draws GDP, global GDP in real terms, increased by a factor of about 15 from 1950 to today. It's about in PPP, it's about 110 or so trillion dollars a year of GDP. I'll come back to the issue of why we concerned with GDP here. And of course, because it's the most commonplace index of economic performance. So this has been unprecedented, but of course, along with it is the fact that per capita GDP has also increased. Now, I want to be able to do that, show you that. Here we are, global real GDP per capita. Again, you will see a break roughly speaking in about 1950, going up, hooting up. It's gone up by a factor of five or so. So today's per capita GDP in PPP terms of about 16,000 dollars PPP. Okay, about five times in 70 years. And correspondingly, population has grown from 1950, about 2.5 billion. Then just think of it, only 70 years ago, 2.5 billion global population. Today is of course, we're hitting 8 billion. So you had a rise of great more than three fourths. Life expectancy has increased from 46 years approximately at that time 1950 to today about 72 life expectancy at birth. Poverty, proportion of people in absolute poverty has reduced from about 60% of the world population to about 10% today. Now these tell us we've been living in an unprecedented good times and not for understandable reason. The past 20 years has generated a large number of books telling us how we've never had it so good. And they're right. It's no good pretending that these figures are lying. We are better off in the aggregate. And as I suggested, even distributionally in terms of absolute poverty to be reduced. However, birth scientists have reminded us that 1950 or discovered through the signatures that the earth system offices that 1950 is also probably about the year where it could say we have entered the Anthropocene, the human dominated. Now that's of course completely consistent with what I just now said, these data here. We are dominating the sense that things we're increasing our footprints, so to speak, and I'll come back to that. So that's alarming the Anthropocene story that there are scientists and of course, ecologists as well. So we've, these are giving us hints that this great divergence, if you like, from the past that I'm now shrinking into 70 year period is accompanied by a short changing, possibly short changing the future. Possibly not yet, not yet understood. This one is telling us something else. This is taken from an Aegean Kumar's United Nations Environment Program, a UNEP has been published in 2018, inclusive wealth report. And I'll come back to this issue. Let me just go through it. They were looking at, it's this is a time series from 1992 to 2016, 2014. And during this period, the estimate global per capita stocks of produced capital, that is buildings, roads, machines, all the stuff that we think amounts to investment accumulation, produced capital, that's the top curve, increased, doubled in size in these few years from 1992 to 2014, doubled in size. Human capital per capita, education, health, and there are ways of trying to estimate these. I mean, I'm not going to belabor the estimation problems. This kind of area is, if you really want to be sophisticated, don't enter it. This is really requires crude, dirty hands at work. But they're not going to mislead you. This is all consistent with the earth science stories, ecological stories, and now the social science economic stories. And that's what I'm telling you now, the latter. Human capital per capita health, health, education index increased by about 15% per capita. And remember, the population has been growing hugely too. So there's been an accumulation of human capital, but natural capital per capita. And I'll come back to that person. But for the moment, think of the earth system as creating services on a regenerative basis, potentially regenerative basis per capita natural capital stock has declined by about 40% during this period. Now, population didn't grow by a factor of 40% during this intervening period, 1990 to 2014, that alerts us that the stock of natural capital has declined. Now, that's not, of course, picked up in the GDP curves that I showed you time series because GDP is gross domestic product. It does not take into account depreciation of capital. So that's the first alarm bell every scientist should hear when he hears GDP figures. And that we must grow in GDP. Nothing wrong with that, except for the fact that you need to know correspondingly whether we're eating into it in order to be able to produce that output. So what we need is something like NDP net, but net or depreciation. And this is one of the biggest drawbacks of national accounts in not taking depreciation series. Now, of course, there are reasons for it.  My statistician friends in the Office of National Statistics in the UK will say, well, it's down difficult. And in any case, you could have crude estimates for physical capital produced capital buildings and so forth saying, well, let's say these stocks depreciated about 5% or so. And you can firms, of course, keep depreciation allowances. So in the past 30, 40 years ago, when I raised these matters over the weaknesses of national statistics, they would say, well, look, all right, so it's 5% less big deal. Problem is natural capital is not quite like that. We can actually tear apart natural capital without thinking, which we are actually doing, and I'll come back to that in a few minutes. So depreciation is extremely important. It's not a question of 5% issue. It's a question of becoming greater and greater as you share. Now, notice in this figure, I moved away from GDP, which is a flow. GDP, remember, would be dollars per year into stocks. This move from close to stocks is absolutely crucial because our parents thought in terms of stocks, it's only economists who moved away to close. They would say, well, we are educating you. We're leaving behind assets for you. We leave for our descendants, our children, our grandchildren, assets, and those are stocks.  And income is essentially a claim to the stocks that you have, low claims over time. So your salaries and your wages are returns on your human habit. That's one way the economists think of the matter, and we're correct in doing that. So we moved to stocks, and it tells us that if we were looking at stocks, we ought to be asking what's the aggregate stock of assets the global economy has moving through time, which means in effect, we ought to be adding these three curves and looking at the path that the stocks have taken. Now, how do you price those stocks? Well, of course, you're going to take a bunch of market prices, but for reasons that are absolutely clear, we need to work harder. We need to use accounting prices, shadow prices. That is something like the social worth of these assets. And I'll come back to that later if we have time, but just for the moment, let's glide over that problem because that's a gigantic set of issues on their own right. Okay. So that's the first point. The second point is when I say accounting price, it doesn't, there's a common criticism, which I'm sure none of you would be asking, but I faced initially when the report was, is that you're monetizing the damn thing. Well, I'm not at all. I'm not monetizing. Everything is in real terms. Goods. The thing is, you have to compare the goods, chair and the table and the desk and so forth. They have to compare. And so you look at rates of exchange between them, not market exchange, but real exchange. Okay. So accounting prices normalized are in real terms. So when I talk about stocks, I really mean stocks. And of course they would all reduce to something unambiguous if there was only one kind of capital asset. We're trying to create one kind of capital asset out of the billions and billions and trillions of capital assets. Okay. So we want to add them up. Some of these stocks we call inclusive wealth. And of course that immediately rings a bell. Adam Smith in his great book called it The Wealth of Nations, An Inquiry into the Wealth of Nations. He didn't write this classic of a GDP of nation talked about the wealth of nations. So when we talk about sustainability, its sustainability is whether you're carrying wealth across time, whether that's increasing or declining. And of course that means you need to take a balance between the three. The problem is, the problem is that we haven't got the balance. The rate at which produced capital and human capital is increased has been compensated adversely by the decline in natural capital. So total wealth if you like per capita would have been in many, many parts of the world. Right. So what I want to do, having talked about inclusive wealth, one final thing.  There's a theorem. It's very simple to prove, but it's very deep. It says, you tell me what your conception is of intergenerational equity. The notion of welfare across the generations. You tell me what you think. You may be utilitarian, you could be a Buddhist, you could be whatever. But you have some notion for the fact that tomorrow matters, day after tomorrow matters, our grandchildren matter, great-grandchildren matter and so forth. And I will give you a set of accounting prices with which to estimate inclusive wealth, such that the two will move in the same way. Inclusive wealth will move in the same way as your notion of intergenerational welfare or well-being. What do I mean by that? I mean that one goes up, the other goes up. If one goes down, the other goes down. It's an if and only if statement, which means that instead of talking about intergenerational equity, you could be talking about wealth, which is of course what the people do with GDP. They say, well, GDP is not happiness or well-being, but it corresponds to it. And I'm suggesting to you that's not right. What is right is inclusive wealth. Okay. Having told you that, this has been the one success of the review so far. Statistical offices throughout the world are now moving in that direction of creating parallel accounts on natural capital. Not perhaps they won't be adding up. I think that's a bad idea. Inclusive wealth is still a sort of an ideal system, but the component of natural capital will be included. And it should be included because of the reasons I mentioned, we need to keep an account of stocks. How are the wetlands doing? What's the oceans doing? What are the rainforests up to and so forth. Okay. This has been a success. I think this is uncontroversed so far. Now comes the controversy. Not in terms of theory. You can't beat me on that. But whether we have the guts to follow through what the analysis is pointing to. Obviously, if natural capital, which has been understudied by economists, by long chalk, is to be taken seriously, we ought to concentrate on that. Now, what I'm going to suggest is, having talked about inclusive wealth, we're now ought to be concentrating in a firefighting situation, the plight of natural capital. And I'm going to give you the, oh, how am I about this, right? Ah, wrong thing. Right. So I wanted to think of the biosphere. And that's a reasonably good approximation, the kind that I think ICTP and Santa Fe Institute love. It's really simple. Which is, I wanted to think of the biosphere as a regenerative finite regenerative. That's it. Maybe like a fishery, like a forest, you can introduce complexity, of course. That's for sure. But the idea we want to catch here is that it's finite, it's bounded, but it's regenerative. In principle, unless, of course, you tamper with it in a huge way, and you can create thresholds and so forth, multiple thresholds to talk about tipping points and all that. That's easily done. And others have done it for me. And I want to talk about the demand we make on it, humanity makes on it, and its ability to supply. And that's the global impact and equality. And that's the inequality that I've written down to begin with. Okay. What are we talking about? We look at the right-hand side. That's simply boring from the notions, notations we use for fisheries and forestry. That is, G is the flow of services that Mother Nature offers. It's a function of the stock, the health of the biosphere. What are these services? There are two types of services, and this is an introductory lecture, so I'll give it immediately. There are two types of services and goods that the classic millennium ecosystem assessment of 2005 defines and pair it on with the idea. One is provisional goods, which are water, timber, food, fibers, pharmaceuticals, and non-living material, which are the ingredients of GDP, by the way. With human labor, we transform those objects into GDP. So that's one kind of service, provision and goods. And the other, the much deeper ones, conceptually deeper, which ecologists have explored at great length, are what are called maintenance and regulating services, so that they involve climate regulation, nitrogen fixation, water cleansing, air cleansing, decomposition of waste, solid, soil regeneration, pollination, and so forth. Those are like what we economists call basic industry. They're basic to everything else. They're the ones which manifest itself into the growth of trees, plants, and so life in general. Now, the defining characteristic of many of these provisioning, sorry, of these regulating and maintenance services is that they're both silent very often, and they're invisible. Think of what's going on under our feet in the soils. Think of what's going on in the deep oceans. So they're easily missed. And the second characteristic is, of course, that Mother Nature is never, are still, she's on the move all the time. Wind blows, the water currents, and so forth. These three make nature extremely vulnerable to economic activity because you can't price, the new property rights are very difficult. So that's a classic story behind the tragedy of the common city life. These are adverse externalities we inflict on others, which got transmitted over time and space, which perhaps lead to this inequality, the basis. And I'll assume that there's the hallmark of what's going on. So G is the supply of these primary, these maintenance and regulating services as a function of the health, which I'm going to call capital S, the stock. Now, remember, this is an imaginative aggregation. If you don't want to aggregate, that's fine, then you'll have a string of inequalities, not just a scalar. So that's not a problem. You can do that. You can say, how are we doing with climate regulation? How are we doing with regard to pollination? How are we doing it with regard to many of the others? In each of them, we'll have a supply function and there'll be a corresponding G. That's the right-hand side. And the left-hand side, I wanted to model the idea of human activity. And one simple way of thinking of human activities, of course, measuring GDP. And I'll suppose that, of course, it doesn't capture everything because so many of our activities are not included in GDP. But that doesn't matter if the proportion remains the same approximately, then you can use one against the other. Anyway, we have to do what we can with what objects we have in hand. And I'm going to call global GDP, decompose it in the way Holdren and Ellick, Paul Ellick and John Holdren did in a classic paper in 1971 in terms of population, global population, and per capita income, small Y. Thought logically, the product is global GDP. The thing is, global GDP is in terms of provisional goods and we are looking on the right-hand side with regulating and maintenance services. So we need to have a dimensionality issue crops up. And I'm going to clear that one by talking about the efficiency with which Mother Nature's good services are transformed into final goods, which is, of course, the left-hand side. And I'm going to call the efficiency parameter alpha. The higher the alpha, other things equal, the left-hand side is lower, which is a good thing that when we're being more efficient. And that's one way of looking at the climate literature, move from fossils to say solar, it's more efficient. That's the meaning of it. But you can get back for back, you can get more equal amount of energy, but without tampering into the earth system. That'll be like alpha increasing. And I would suggest that in some sense that's been the weakness of the economic, the literature on the economics of climate change. The weakness has been in drafting onto standard models of economics. And I'll be giving you this discussion of standard models and how to go beyond it. And my lecture on Thursday, Matteo asked me to give a more specialized lecture on that. And I will do that. The weakness has been standard models do not have Mother Nature in it. I mean, I'm talking about both models. I'll come to that on Thursday. But what they've done is to have incorporated, drafted a climate system onto the standard model. Now that has enabled them to talk, continue to talk about growth in GDP. So long as we increase alpha by investment in clean energy, alternative for us. So you don't have to tamper with capital N. You don't have to worry about small y. All you have to do is to keep on increasing alpha. And that leaves a pressure on the gene, the right hand side. The trouble is, and this is the point of the fundamental importance, and I'll be using it on Thursday, that the regulating and maintenance services of Mother Nature are complementary to one another. They're not substitutes. You tamper the climate system sufficiently and the rainforests go under or are transformed in a different way. These complementarities mean that the alpha is going to give you very little mileage. We really have to go in for the other parameters. Now, the global impact inequality is the demand that we are making exceeds the nature's ability to supply it. And we have five parameters here or five variables. And of course, it's a snapshot. There's dynamics at play, and they relate each of the parameters, the factors here to the others. I'll do that on Thursday. Here I'm looking at a snapshot, no dynamics. And I'm going to be looking at each of them separately, as I have been. I've been looking at the right hand side. Increasing the right hand side would mean to close the gap between the impact inequality. You have to move from, you can do it by raising capital G or by declining, reducing the left hand side. The increasing the right hand side is like saying investing in nature. And investing in nature or investing in natural capital involves, the mindset is very important. It doesn't involve lades and bulldozers and people in hard hats drilling and so forth. It involves waiting, letting modern nature recuperate. So the financial outlay in green investment, if you like, can be very low. The cost will be the waiting. And even now I can suggest that we overdo the cost. If you follow economics honestly, it doesn't violate your informed intuition. It violates informed intuition only when you cheat. You might say, well, waiting is costly. Trees, low trees take 100 years.  There are other ways of doing it. The thing is, when we do cost-benefit analysis, it's common practice to keep the relative prices of the flows constant over time. And you do it because you don't know very much else. So what you do is you have, let's say a project of 50 years duration and you look at gross benefit investment outlay, gross benefits each year, net benefits each year, and you regard them as constant. Then if you discount, then of course the future net benefit looks small. But in this world that we are looking at, the relative prices, relative accounting prices will not be constant. Natural capitalist price relative to reduced capital will be increasing because the balance is going in the reverse direction. One is being accumulating, the other is accumulating. So the relative price of the accumulated one will be rising to the others. So the future value of oak trees relative to ICTV building will be growing up, growing. And if they grow fast enough, then the discount rate will look like negative. In other words, the future value of these oak trees will look even larger. This, of course, what intuition tells us is just getting scarcer. This must be more valuable. Okay, so that's the right side and I'll not belabor any further. What about the left hand side? I've spoken a little bit about alpha, but I want to give you one more thing as to why, why this kind of analysis is really worth it. The United Nations published, produced the Sustainable Development Goals to be reached by 2030. It's been probably the most publicized piece of work coming from the United Nations. I can think of in recent decades. And yet the one question they did not ask, I have seen no paper on it, is whether the Sustainable Development Goals are sustainable even if they're reached at 2030. And this inequality tells us how we ought to be thinking about it. We ought to be asking whether if we were to reach the Sustainable Development Goals to 2030, would they be accompanied by an equality of this impact in equality? Because if it's AR, if it is, and it can be maintained, that's sustainable. So long as the inequality is positive, of course, you're not in the Sustainable Development Goals because your S is declining, your demand exceeds supply. And what's happening is you're shrinking the biosphere. It's helpful. Well, very crude calculations have told me that if we wanted to have this equality, the inequality transformed into an equality by 2030, you would require alpha to grow at a rate four to five times higher than it has been in the past 30 years. I don't believe it can be done. And yet this is a crucial question in the SDGs. So that leaves me with the few minutes I have left with the numerator, N times Y. I will not speak about N today too much. I'll just hint at it right at the end, because I should have the scope that we'll be speaking on in population. This is an absolutely neglected field amongst the social sciences. It's come with the news to SFI and ICTP because your scientists and your field population is a perfectly good thing to talk about. But social scientists, particularly those with the sociological event, humanities event, do not wish to discuss it for reasons which I have not understood, given the fact that the world's poorest women suffer enormous from a lack of access to family planning and reproductive health services. And these are the world's poorest women. I'm talking about 220 million women in Africa and elsewhere in the world's poorest countries who have no access to the tools they need in order to be able to space births, determine how many children they have, and so forth. And then we talk about women's empowerment. So I won't speak about capital N. I'm going to speak about small Y. Well, small Y is too large. Other things equal for the reason of the prices are missing. Two examples of how economics can go wrong when we think about these matters. If we go to supermarkets and steal food and imagine that their ability to screen customers for pilfering is weak, then of course, your take home income is large because you're not spending much money on food, because you're stealing. But that can't be sustainable because the supermarket will go broke. And if they increase, you know, if they raise the ability to catch you, then of course, you will feel poorer because you now have to pay, but the system will survive. What we've been doing is pilfering from mother nature because she doesn't have a tail when you take things. So that's the adverse externalities and we're not paying for the stuff. So if we started paying, then small Y in terms of goods, provisional goods that we transform into final products will of course have to go down. So instead of saying we need to cut our expenses or goods that we buy, which is the standard way of thinking about how to save the earth system, we should be asking, who should we, how do we organize payments for the stuff we take from mother nature? Give you two examples now and then I'll conclude. First is the open seas and we, and of course, the atmosphere as a sink for our pollutants. The open seas is the interesting one because nobody discusses them quite as much. They certainly don't in comparison to the atmosphere as a sink because all you have to do is to look out and see all the container ships, which will be sailing across the seas. And they don't have to pay rent for the access to the seas as a transport means. And yet they're doing that. So that's like pilfering. And on top of that, there are ocean fisheries. I'm talking about now beyond the 200 mile EZ, talking about the open seas. Then the fisheries, which are causing devastation. And then, of course, we use the oceans as a sink for our pollutants. So you're using the oceans as a free good, reducing the quality of the oceans s, that component of it. And keeping our small y high. We ought to be paying for it. How do we pay for it? One of the suggestions I made in the review, and it's not going to happen because we don't have the appetite for international would be to have an international organization, organization created for the management of the oceans, open seas, as well as the atmosphere. But the atmosphere has has taken, of course, a dynamic of its own climate change discussion international negotiations over limits to emissions, but the seas have not. That would be the natural thing to do. But the argument has been that we haven't got the appetite for an international agency. On the other hand, at the end of the Second World War, there was urgency, and the national community came to the problem by creating the United Nations, the World Bank, these are all global public goods. And they were designed to meet them. Okay, so that's one possible. That's one example. And the second and the final one I want to give you has to do the Sub-Saharan Africa. It is not a surprise. It's not a coincidence that the world's poorest countries are in the tropics. And it's not a coincidence that the world's highest biodiversity points are also in the tropics. The two coincide and they're an explosive conflict. Because these poor countries, they rely on their livelihood, on the aid of course, but also in exports of primary products. But export of primary products involves externalities, domestic externalities, which are not paid for. So if, for example, you're deforestation in the highlands, then the damage caused in the lowlands of the same country will not be paid for when the object is the timber is exported, typically or not. Which means what? Translated into a notion of wealth, it means that there's a wealth transfer every time poor countries export primary products to rich countries, from the poor countries to the rich countries, because they're underselling. Okay. Now you put it that way, it looks like a distributional issue. And yet we are all in favor of openness or trade.  So you can see the narrative, which bypasses everything that has been talked about. So I think I will stop here. This is now time for our next lecture. But on at the moment, I should just conclude by saying at the moment, the ratio between the left hand side and the right hand side, I forgot to mention, because it's on my note here, is been estimated to be about 1.6 from which we get the metaphor that we need 1.6 to meet our demands. So this is a firefighting situation. We mustn't allow ourselves to go along, which have been echoed in the talks this morning. But what this does is to make it concrete what this firefighting situation is. And the reasons we need to close the gap and the sustainability can only mean have a meaning other than just dinner table conversation. Close this gap between the impact in the policy. Thank you very much. So thank you very much. So I suggest that maybe we can have 10 minutes of questions before moving to the next talk. Yeah, yeah, yes. And then maybe we can have questions at the end. So is there any maybe I can start? Yes, okay, we have one question from Max. Thank you very much for your very fascinating presentation. You refer to the SDGs and you said something very thought provoking that they didn't ask the question, will they be sustainable if they were ever reached? I would like to ask you if perhaps you think there might be another issue with the SDGs, perhaps some internal contradictions. For example, SDG number eight talks about economic growth. And I'm always puzzled. How does that match or counterbalance SDG 13, 14 or 15 or even others? So I wonder what your opinion is, since you have thought so much about this. Well, you know what my view is. My opinion, you do know. Well, you're quite right. Of course, you're quite right. It's a, it's a, as a, as an academic, I find it just incredible that they can, but what they've done is essentially borrow from the intuitions of climate economics. Intuition in climate economics is, roughly speaking, the intuition backed by the climate models drafted onto standard models of economic growth. There's been no criticism. That was the weak point of it, not recognizing the complementarities is that about 2% of GDP spent on investing in raising alpha, increasing alpha will enable to have growth. So that's where the intuition at least is not, is consistent with the economics of climate change. The economics of biodiversity is very, very good. For a very good reason. Mother Earth is a lot richer in complexity and what she does for us than simply climate. Climate is one extremely important, but there are complementary so many other things. I agree with you. Thanks. Thank you. Really fascinating talk. I wanted to go back to your very start when you said that your wife forced you to make a short accessible version of a hundred pages of the report. And well, I thought that that chimes with my familiar experience of, you know, my wife bringing me on planet Earth, but I wanted to ask you, you know, in your experience, what is the right level to pitch it? So why a hundred pages and not an illustrated book for children? Sorry, let's have that again. So I wanted to ask you, what do you think is the right level at which we should communicate these issues? So why a hundred pages and not say an illustrated book for five year olds where you explain these concepts at the very start? I think the thing is that science is technical, has to be, and the 600 page one is technical, has to be. I tried to lace it with a lot of non-technical expression, but, you know, average reader will be frightened. So the hundred pages way of giving us sort of a sense of what the other 600 pages were doing, that's why I did it that way. Does it have to be that or I mean, unless I misunderstood your question, do you think that should be something intermediate level of? Oh, I'm so sorry. Yes. Yes, absolutely. Look, like most people, most of us, I'm schizophrenic. I have many targets. I really wanted to address the concerned citizen because I'm convinced that unless she gets into the act and creates collective action as it were, through the community, through a community work, to put pressure in democratic society, government's own. And the thing is we keep on blaming the government, but in democratic society we ought to be blaming ourselves, not getting our act together. So the concerned citizen was the first, my real aim. And of course I wrote the 600 page, which my wife then told me that, look, what you say you want to do, you're not delivering. So that's why you produced the short one. But on the other hand, I also want to address the student, graduate student of economics. And so the 600 page one is now going to be published by Cambridge University Press and I'm adding some sections to it to make it more of a text. Now, that doesn't mean they'll read it because it has to be on their curriculum before their teachers have to assign the text in order for them to read it. I wouldn't know about it, but there's so much I can do. Okay. So you have a question? Thanks again for your wonderful presentation. I'm coming back to your last remark about the fact that when we import natural goods from poor countries, we're actually transferring resources from them to us that we're not paying for. And yet it seems as if, for example, the European policies in this area are going exactly into that direction. I mean, the from far to fork strategy has been accused of offshoring production of goods to other countries. So how can you explain this dichotomy? Or how can we make the voice of those countries heard more so that our policies don't damage them even more? Well, look, there many ways of thinking about it. I've said very, very good question you've asked, by the way, and very complicated one. And I can only just sketch it. The contradiction that you're pointing out happens because we're using wrong economic model to build. I mean, globalization and the free trade argument is built on a theorem. Okay. Without the theorem, it wouldn't have flown economists, obviously, because you need a theorem to show that that's efficient. But it assumes the theorem has an implicit assumption that every commodity has a competitively perfect market price, every commodity. And of course, we are looking at a world in which, of course, so many prices are missing. So that's pre trade arguments simply does not stand in this world. Okay. So that's the first point. The second point is what biases does it lead to. And that's what I was alluding to the biases are transfer of wealth from the poor to the rich when they export primary products, put it on the other way after all, we don't know in advance, but that's the argument that was given. Now, the question is, what do we do about it? Well, there are many things we could do. For example, governments in poor countries, and they're so minded, but they're not so minded, would be to would have it that they would actually tax, have an export tax on there, which then go to compensate those who are being hurt. That would be the standard story. From the OECD point of view, the U point of view who want to help poor countries, their argument, their state would be to get their companies, which are importing the products, not the products, but the primary factors, to coordinate and disclose what they are doing to the ecosystems from which they're importing the primary products. Disclosure is extremely important because of course, without the disclosure, you have these missing markets and disclosure would be a substitute for missing markets. This is what's something I have been talking to good deal with companies, because many private sector, age CEOs are concerned about their profitability. If the ecosystems start collapsing, are going unhealthy tendencies, if you like, then of course, their profits, they're their supply chain. And if that starts rocking, and their profits fluctuate, and there's a risk associated with the collapse of the ecosystems. And so that's another possibility would be for them to collectively agree on disclosure and then get their governments to force disclosure. And the way, for example, now firms do that over food.  Why? Because we consumers insist they tell us what we are eating, whether they're healthy or not. If consumers and the concerned citizen that I was mentioning is concerned about these issues, they should insist that companies now disclose what they're doing on their supply chain, entire supply chain, in order to remove the moral hazard and adverse election problems that are involved in this trade. Thank you for asking. So we have our question for you. Thank you. Fascinating talk. I was wondering what you think on how we generate metrics that are simple enough to understand. Sorry. How do we generate? Metrics or definitions that are simple enough to understand, but also not so simple that they had adverse consequences. For example, many climate solutions have been collapsed down to the level of trees, which means that we're investing in the Great Green Wall in the Sahel Desert, while simultaneously deforesting old growth rain forest across parts of the planet. We have mechanisms that provide genuine solutions like supply chain tracking. There are ways that we could have that on every product. And yet governments often default to the most parsimonious solution, even when in the long term we know that there will be adverse consequences, there will be perverse subsidies that support bad outcomes. How do we find that balance and communicate it in such a way that governments can understand it? That's it. 64 million dollar question. I wouldn't be able to answer it other than the fact that the ecologists and earth scientists and we social scientists who are working with them, and there are only a few of us, by the way, who really do work in a harness, continue to probe and identify these leakages, which you're pointing to, and you're pointing to these complementarities. That's exactly what you're pointing to, that you push one button and there's a leak there. One last question from David. Thanks, Partha. Let me just poke at you a little bit. In writing down this inequality, you've done what economists do, which is you've separated human agency that lives on the left from evolutionary dynamics that lives on the right. Sorry, from evolutionary dynamics, what you call mother nature, this somehow this existentially independent set of processes. Isn't this part of the problem that we have to completely rethink our constitutive role in natural processes, move into GS, as opposed to think of ourselves as somehow separate from them? That's a very, very good question. Again, all of these questions have been very good. This is a hard one. We are embedded in nature. We are part of nature. We are part of capital G. That's what you're saying. And you're right. I guess what I would argue as a first, what I was doing was using a first approximation to say, we don't matter. Mother Earth will be just fine. In fact, finer if we were to be extinguished. So we're a small component of capital G. That's, I think, scientifically correct, even with 8 billion of us. That's still a small pride. So the separation of capital G from us, you're absolutely right. There is inconsistency. It's not in the book, but in my talk here today, there is. And I'll just plead the case by saying we are so small, a part of capital G, that I'm ignoring it. Okay. Thank you very much. I think now it's time to move to the next talk of this session. So we thank again, partner for this wonderful talk. So the next speaker is Pablo Market, is a Chilean ecologist, worked in many disciplines of macroecology, theoretical economy, applied to global change. He's also, I think, a role model for many scientists. And essentially, he has given very important contribution in deriving, scaling law in ecology, connect phenomena across different dimensions to the interaction between landscapes and ecosystems, the dynamics and also the biological dimension, evolution, and also the social structure. So he was born in Santiago, in Chile, and he did a PhD in the University of New Mexico. And now he's a full professor at Pontificio Universidad Catolica de Chile. And he's fellow several academies, including the National Academy of Sciences, and twice the World Academy of Sciences. He's also an external professor at Santa Fe Institute. So please join me to welcome Professor Pablo Market. Hello. Well, thank you very much. It's a real pleasure to be here. Actually, I'm a big fan of a alum. I share with him his vision of creating fostering science in the third world, but also his conviction that through science, we can try to make and work for a better society. And I think this workshop, to some extent, is leading to that. And I would like to sign the organizers for this. And I define myself like a scientific homeless. You know, I don't have a discipline. That's why I get associated with Santa Fe Institute, where there are many more homeless looking for disciplines there, or forgetting disciplines as they stand. But when I echo some of the words that David said in the morning regarding this, that we're kind of working in this sort of scientific establishment that is not working very well. But we keep publishing papers and doing the thing we do. And we realize more and more than we have to do different. But we don't know pretty much what different is. So at some point, we should find out hopefully it's not going to be too late. So I'm optimistic, as you see. And what I want to do today is to compliment some of what Professor De Gupta said. But I wanted to ground it in a real narrative about a particular group of humans that live in the Atacama Desert starting 9,000 years before present. And I want to do that because they represent an anomaly which anomalies are great in science because provide an opportunity to try to understand what are the driving forces of, in this case, cultural evolution. So I'm going to talk about the Chinchoro culture. I'm an ecologist by training. And I became interested in this culture because my association with different scientists among them are the archaeologists that work out this discovery in the desert. So the question is how so-called simple hunter-gatherer society actually developed the level of complexity that led by 7,000 years before present to intervene their death and modify them in a way that you wouldn't anticipate for a simple society that hunters and gather. That by definition, if we follow some of the paradigms in archaeology should be very simple kind of egalitarian societies. So in trying to understand this phenomenon, we came out with some hypotheses regarding the interaction between demography, environment, innovation, community cultural evolution, and ideological innovation too, and how they play together in order to bring the world we live. So that's what I want to talk today. This is supposed to be a very kind of a general talk for a general audience. To outline some of the topics, many of them will be, I presume, touched upon by different of the speakers. And on Thursday, I will kind of attack some of the modeling we have been doing of this process. So let's get started. And this is a culture that inhabited a particular part of the world, which is the Atacama desert, going all the coast, part of the southern coast of Peru, a northern part of Chile, in an area that you can presume is very devoid of everything, just, you know, one of the extremist deserts in the world. And some resources are concentrated in the river mouth, and as well as some water areas where you can find some particular freshwater wells that show up in the coast. So in this context, these societies start to modify their debt, and it looked like part of this tradition, which actually evolved during this 7,000 years. It went through different phases, black mommies, red mommies, different kinds of designs. And you can see here a characteristic mortuary assemble in a particular site. I think this is Camarones 4. And as you can see here in this picture, the elaboration, I mean, pretty much the techniques was taken out all the skin, removed the muscles and put some skin up on it, although all their animals make a complicated mask phases. They were also modifying their embryos and adults and kids and so on, and develop kind of a diversified cultural toolkit, too. So the major thing that we realized is that this community, this culture actually arose in a time when the environment was very productive. And a productive environment, this desert region means that you have more humidity to support life. And as you can see here, let me explain you this very quickly, we have different, these are different kind of proxies for the environment. Okay, this is measures of temperature, very fluctuation, measures of water table levels, and these are measures of humidity based on the vegetational response in some particular deposits, which are rodent middens in the desert. And all of them coincide with these two phases where you have high productivity, which are wet phases in this area. And the second one between 7,000 and 4,000 coincides with higher population density estimated by just the amount of C14 or carbon, radiocarbon databases, you know, radiocarbon dates. So you basically each ready carbon data is a PDF. It's a probability distribution of age. So you add up all this PDF, and you end up with a rough proxy of abundance or number of individuals in the record. So basically what happened is that high productivity was correlated with high number of individuals. And we then start keep running this argument a little bit further. And this is what you see here. So this artificial modification time coincides with this increase in aquifer recharge and high humidity in the region. So to link this causally, we came out with this hypothesis that is the socio-ecological loop that basically said that the environment created opportunities for higher demographics of this group. And the larger number of individuals doing social learning actually came out with innovations to actually increase the flow of the natural contribution to people or ecosystem services that they used to be called. And that created more people, more innovations and eventually also changes in the way we think we are in the world. So ideological innovations that led to these people to intervene their death. Why is that? Well, this graph shows that the living population for different growth rate, but pretty much led or growth to 100 individuals, which is kind of the doubles of the size that you would expect for the kind of others at that time. But the thing is, and bear with me because this is the fantastic part of the story. It's not central to my talk, but I just have to tell it to you. Bear with me. You know what happened in the desert? Things do not decompose. So you have part of the natural cycle of decomposition, which is mute. And that creates two human populations, one of living humans and another one of dead humans that are there, but never disappear. So our estimate is that there were at least 100 mummies per living habitants. You would say that that's a lot. And indeed, I myself have discovered a couple of mummies just by turning a stone to find a bone, you know, and it's quite amazing that these people was everywhere. There was dead bodies. And in fact, the archaeologists do not excavate because there's so many they don't have where to put it. It's just rescue, what they do. Whenever someone is building something and they found a particular mortuary site, they call the archaeologists, they go and they collect things because of a rescue. So let me give you an example. Here you see how this is taken from a Google shot in Arrica, the city of Arrica in the northern part of Chile in the border with Peru.  And here you see the bodies there. You know, the people was excavating this. That's my daughter, by the way. I should point out she never she didn't turn out to be an archaeologist though. She's a lawyer. She wants to sue us for doing this, but just kidding. But you can see that this is a very fantastic backyard. You don't want to have it in your house, but it is fantastic indeed. And this is what it was under the floor of the house. You know, quite an enchanted house, I would say. So it was a huge cemetery and that's something that repeats everywhere. It's full of bodies and people know it and they are okay with it because they are somehow the current residents of the same habitat. So the explanation I was anticipating to you was this socio-ecological look. And in truth, it's not just one loop. There are four loops, you know. And this is the interesting part, I would say. Because you have this is the typical demographic loop which is built on social learning, community cultural evolution, you know, that leads through to from biodiversity and ecosystem through the services and a national contribution to people to an increase in population size, which led to technological innovation, which affects the delivery of the flows of capital G to populations. But this does not end here because it does affect the settlement pattern. When you have a flow of services, you want to keep yourself in that flow because that flows put you out of equilibrium and then you can start doing things, fantastic things, inventing a world for yourself and creating ideological innovations. And settlement pattern for these hunter-gatherers meant a change where they are now called complex hunter-gatherers. You know, that's for some reason of bands that used to kind of move around the landscape became more sedentary and anticipating what will be the formative period where agriculture will discover people gather in kind of centers and start making a living together. But this was anticipated because of the surplus of resources. And as I said, here we have the ideological innovations that created narratives that made this living together possible. And here are all the inventions we have made, including economy, including science, and which obviously affect the delivery also of ecosystem services and the nature of contribution to people. So this is basically the slide of this talk because I think it contains several key messages that first, it is not, I mean, we cannot address the complexity that this entails by just looking at particular components. We need to have a kind of a big picture analysis where we take care of all the loops because each of them can potentially make the system crash. We need to know about this delivery and technological innovations, but we need to actually find solutions here and actually, which is that I will say is the tough part, because that's where governance systems are, that's where philosophy are, that's where economics is. And so we also have to think about the settlement pattern. And I think that Luish is going to illuminate us on this in terms of how this enters into this picture and affects the whole thing. And just to give you a glimpse of some of the drivers and some of the things I've been talking about, I just want to show you this very old graph by the anthropologist Robert Carnado back in 1967 where he classified different cultural groups based on traits, organizational traits of different cultures. And just to make the point back in 1967 that there was a positive relationship between social complexity and population size, more people, more complex. And the mechanism, it was based on the things that we can do together through social learning, we can solve complex tasks, we can create different ways of being and imagine and create narratives regarding that. And more recently, we see the same patterns when we actually doing on other sort of proxy for creativity like patents, income, well GDP, and also the bad things which is crime. This is a picture from one of the paper by Luish on the scaling cities. So living together brings new and interesting things, but also problems. But the social ecological loop is fragile and can go wrong very easily. And there are many examples, I just want to talk about one which is close to the area where I was talking to begin with, and this is the Nazca culture. It's a very simple example of how things can go wrong. And still we are in the desert and seeing of a culture which is growing, formative period, 1500 years before present, and they start, they are agriculturalists, they are expanding and creating more and more and more agricultural fields. But they don't realize that they are creating this field at the expense of cutting the forest, which actually was providing soil fertility and was a barrier against mega-nino events. Mega-nino events in the desert means a flood of debris and water, and that forest contained it. When forest no more, people no more. And the thing is gone and the culture is gone. And it's one of the examples, which is very simple. Cut the forest, bye-bye. And it doesn't have to be very complicated. So things can go wrong in many ways. And it looks like after 50 years of this book, which has a very interesting story, when it was one of the first reports to the club of Rome, which was the project was the predicament of mankind, which has extended to the present day. And it was committed to the middles, the MIT think tank, to actually came out with an assessment of this predicament. And what they came out with, and this is just to illustrate our current predicament, came out with something that is very familiar now, becoming that Professor Dagusta showed that back by 1950, there was an exponential increase in GDP. And so there was an exponential increase in many other social economical processes across the biosphere. And they just showed here the world fertilizer consumption was going up. The industrial production and arable land, there were different scenarios, but also going up, as we know. And they produced a model, probably the first, we know those, these are now called integral assessment models. And it was the world three computer model that put all the pieces together to interact, and came out with the projections for possible futures. We have many of this. IASA has been one of the major players on this model. So the evidence, the projections are there. We know pretty much what might happen in the future. And they did some projections, and they came out with how industrial capital will affect other sources of capital, and how this might eventually affect the state of the world. And the conclusion was that population and industrial output, if they are limited, and if technologies are added to abate pollution, because that was one of the major problems. This is abating pollution through time. This is not abating pollution through time. And this leads to actually population crashes. This leads to population stabilization, and a possible future for everyone. And there were potentially pathways ahead for us that make a sustainable world possible. Since then, the last 50 years, we have revisited the same estimate. And now we have what was mentioned by Professor Dagoop that we have this great acceleration back in the 1950s of every socioeconomic trend that you can think of, which also affect similar trends in different earth systems, compartment like capture of fish, aquaculture, nitrogen in coastal areas, acidification, methane, nitrous oxide, carbon dioxide, etc. So, yes, we are embedded in nature. We are part of nature, and we have to take charge of that to some extent. And land change has been one of the major components. And I just want to play you this harmonization of different satellite products to see the extent of the transformation of planet earth, starting, and as you will see in 1950, also the protected area expanded, are the yellow polygons that you will see. And the red is the intensity of the impact of human activities in different continents. This is spreading and eventually 1950 protected areas become more fashionable and become more enforced. That was the thinking that we have to protect nature and that was the salvation. Just enclose a particular area and we will be fine. It hasn't worked that well. We're still behind, but we should be. And what we have, we don't know if it's working. Many of those protected areas are not well funded and probably they are not fulfilling the objective we respect from them. And all the notion that came across at the same time is the planetary boundaries. We talk a little bit about that. There are boundaries estimated for different kind of components of proxies for what you will say a working biosphere. There are safety areas, but most of the different ones are exceeded in terms of their boundaries. And this is just for one country, Chile, the country I came from. The assessment is pretty much radical. We are an extractive economy. We export products and our wealth, as was saying, and fisheries are, many of the fisheries are already, the stocks are crashed. Chemical contamination from the mining industry is rampant. The amount of phosphorus and nitrogen that is poured into agriculture and aquaculture because of the salmon industry is incredible amounts. So the limits are exceeded and the impacts on biodiversity. And we know that for most of the nation contribution to people, from 18 of them, 14 are exceeded or are in decrease. And we have Professor Dias, Sandra Diaz here who was one of the leaders of this assessment. And she will probably can talk more about this. And this is going to lead to the extinction of millions, one million species in the next 50 years. We don't change the course. But we do have an option, at least by some optimistic economics, like Jeffrey Sachs, in terms of he put a lot of weight on economic growth and sustainability that can change the world. He is the person behind also the sustainable development goals of the United Nations. And this is a very influential book, highly criticized by some members of the ecological community because for many of the assessments there is no scientific evidence that things will work that way. And some of us believe that even though it's pessimistic, but this is one scenario that the state of the biosphere in the future could actually be quite different from what we are experiencing right now. This is the state of the biosphere. This is the present moving from 1700 to the present. And this is the number of people. And the dark green is how much of planet Earth we have transformed. And if you take from basic physics percolation phenomena, there is a chance that there is a transition probability at 0.59. If you change a kind of a you play in a lattice, pretty much that particular probability things might percolate. In this case, what percolates by our prediction is 2045 is humans percolate in the biosphere, which means that you can walk or this is the analogy, you could walk on a sidewalk of cement from every single point on Earth to every single other point just by a sidewalk. But you can walk from Santiago to the Manaus in the heart of the Amazon rainforest just in a sidewalk or you can cycle there. And if we percolate all the services and all the national contribution to people will not. Deep trouble. That's a warning. So it looked like order, we make something, we do a transformation, not an adaptation. I think the word adaptation is not fulfilling what we have to do and the speed we have to do it. But we have to aim for a transformation of some sort to actually achieve some of the sustainable objectives or we might, there is a possibility for a drastically changes ahead. Solutions, yeah, there are some solutions that the most discussed ones are nature based solutions that might eventually fulfill 30% of what we need in term of abatement of CO2. But that requires a complete change in the way we do business in agriculture, business in livestock and the way we protect wetlands and forests and so on and so forth. There are chances to do it, but that's only 30%. Certainly the most important thing is to change the way we produce energy. If the energy sector is not with us on this, I mean nature based solution will be just a minor component that will not lead us to match that. There's an assessment by Griscum that's saying, especially those solutions associated with this song here with reference station avoid the forest conversion and management will lead us to somewhere. Protected areas, yes, can be also a solution if they're well funded and if they are created, thinking of how by the birth they will respond to climate change. There are proposals we did this work for the whole tropics in the world not too long ago and show that if you go to 30%, you will decrease the aggregated extinction risk in more than a 50% in most of the continent. So there are chances, but we have to do protected areas respecting local people and have to be in a justice oriented way and we can eventually try to use this socio-ecological loop so we have a better chances of changing the way business are going. And just when I end up by saying that one of the risks of forest fragmentation and change is also the risk of extirpating a huge part of our biodiversity and language groups across earth. This is the distribution of language diversity and this is the distribution of forest loss from 2000 to 2016. Some of the hotspots coincide, there is a risk of losing them, but we can also protect this biocultural heritage. We can maintain this loop going on for many cultures by including biocultural traits in our assessment and in our prediction of where conservation areas should be. The question obviously is we can succeed in conserving the species and while relatives of current crops, but the issue subsists that we need to pass from the diagnosed to the action and we can use the social ecological loop because it enshrines things that are fundamental to the human phenomenon like social learning, community culture, evolution which are quintessential. We can use those things which are quintessential to us in order to foster the transformation we require. I think that's the point and the other is that we need to take care of this integrative view of the socio-ecological loop. I would like to end with these words of Jim Brown that says that it is not enough simple to assert that what should be done one must show quantitatively what needs to be done and how it could practically and politically be accomplished in time to a very catastrophe. Thank you very much. Okay, so Sandra we have a question. Thank you very much for this hot provoking talk Pablo. You show the importance of both technological and ideological innovation in your diagram and I think we don't need many more details about technological innovation because it's stressed by everybody. I wonder if you could elaborate a little bit more on the role of ideological innovation. Well that's the 60 was a 64 million dollar question. I think that's it. Well let me give you an example that comes to my mind kind of recollecting the history of science and when we moved from the ancient to the modern time there is a great philosopher which is Alexander Coiret which actually made a very critical account of that period and showed that one of the things that led to modernity was a philosophical change you know because inspired by science by the way which because we passed from Aristotelian kind of a arithmetic geometry to Euclidean geometry. People discovered Hilbert space you know infinite dimensions and but also we passed from a close universe where we were the center of it to something that was infinite you know and that's the kind of change we need I would say now. How can we explore something similar to that that will actually generate this oh on that like you know that's that that that's sense of getting this sense of wonder and appreciation for the human condition is that we are completely lost. It is difficult to say it is this or that you know that doctrine or this other doctrine I think is much more fundamental is something that we could all share which I think is this oh this kind of wonderful feeling about being alive whatever that means sharing this mystery with others and be humble and wanting that everyone's will do well and how we achieve that difficult but I think that's the key if we can change the whole other stuff I mean we can do technology we can do policies and so on and so forth but the other it will be the other sphere that the the kind of a more ideological part will be wanting and have to be up to speed that's what I can say. Yes so I'm reading this question from Karim Aoudia so he's asking Achilles the most the most seismic country in the world site of the 1960 Valdivia earthquake largest even recorded the earthquake worldwide and there's over 2000 volcanoes each 60 years you have a magnitude eight and each 25 you have a magnitude 9.5 plus related tsunamis in between Anodomini 13,000 and 15,000 earthquake and tsunamis recorded exceptionally to be died that toll and devastation, blindundation and continental level. This is a great accounting it's a beautiful country despite this being here. Are you accounting for this transient in your economic trends let alone volcanic eruptions have a long-term climate consequences? How do I account for for these transients for these exceptional events which are not so acceptable? Well you know it's difficult to account for that I can tell you what it means and it means probably little in terms of technology I mean I would say that seismic control of buildings is a huge area that has been very well developed in Chile and for obvious reasons and the other thing is we are somehow accustomed to extreme events. I have recently learned that Italy is experiencing 400 percent increase in extreme events due to weather. Sicily had a really hard time last two years ago in terms of extreme weather events and it looked like temperature is getting high and high and these heat waves are swapping through Europe too so but but we are used to that and probably the other consequences that he has had is inspiring a lot of poetry you know if you know that you can die or you can start singing you know like your last time and that we don't have novel prizes in science but we have two at least in poetry so that might be is an all of enchant to the nature and the volcanoes so that might be something and but he hasn't had any kind of a true impact on on economy. Thank you. So we have a question from David. Yeah this is my guess to both of this morning speakers it's well known and has been for decades that the percentage of either you can view it as the total global biomass or net primary productivity that basically is monopolized by humans is now well over 50 percent and which I think actually has a huge consequence implications for whether we want to say that humans are in nature or not we are now most of nature but here's another question that I'm not seen directly addressed or can't find easily in the literature has the total bio I could imagine that because of our use of fossil fuels that actually since the Anthropocene the total biomass on earth may have actually increased is that true and if that is true is it only due to our use of this one time only resource of petrochemicals or is it actually are we becoming also more efficient at harvesting which was originally the only source of productivity which is sunlight is actually sunlight the efficiency of it has transformed through our crops and so on I would assume that that's gone down but that's due to the use of petrofuels that the total biomass may have gone up but don't know I'm curious I can I can try a provisional answer and professor the group that might compliment if he wish um here's my my provisional answer is the evidence we do know uh about the working of ecosystems there is it's it's interesting in pointing out that biomass is you can reach a limit you know in terms of how much biomass you can have per unit area independent of the number of species it has been pointed out for you know analysis of forest plots all over the world um it looks like we might um have um a reallocation of that biomass you know and that there is a sort as van veilen li van veilen predicted this a long time ago there was kind of a ceiling to the biomass and you can reallocate it it's like a zero sum game and it looked like a big chunk of it is being reallocated to us and our natural kind of friends that we eat you know chickens and pets and I think that the latest estimate is is about like 96 percent of the biomass is allocated to to to to us and um our kind of uh cultivars and um friends so um I don't think in particular cases it has increased the biomass of particular for example crops because we have become more efficient you know at uh and juicing and juicing also genetic engineering to actually engineer crops and making more predictable more so we increase the productivity of some yields but I think overall the the biomass is fixed at the ceiling I would say that's the the scant everything we have I know there is a a group of scientists in Israel working on this they're doing the the global biomass for different kind of organism they already did a paper in pns last two years ago I think on the global biomass and but there are some some some movement but my hunch and the the evidence I managed is that there's a ceiling and we are uh taking up on the biomass I think it's a partner is a question or an answer actually well I'm just taking up your uh invitation to to address the question you're absolutely right of course that the composition of biomass is all important it's not just a biomass alone so let me give you a calculation which I think gets hard of the matter and it's consistent with your worry that just simply looking at biomass is not going to do which is to look at primary productivity and the Israeli research that you are pointing out is one piece of it which is to try and estimate the stock of biomass of primary producers okay and there is independent uh using similar techniques of trying to estimate the a production of net a net primary production see if you divide one by the other in other words the net primary production by the stock then you get something like the rate or own rate of return on that asset namely of primary producers and primary producers is the key here because of course that generates so much more and it turns out that the I mean in my in my review I tried to do the calculation it's pretty straightforward it's about 20 percent now 20 percent own yield on it okay so you might say well if anybody who knows finance here and SFI is full of people who know know the financial would say well it depends on that that alone compared to let's say five percent or four percent on yield of government bonds of whatever that doesn't really say very much because you need to look at the capital gains to the relative price of biomass of primary products primary producers to the rest you know like buildings and so forth and the thing is that if if we had been efficient imagine that we had been efficient in our dealings with all different types of natural capital of all types of capital then the own the the yield plus capital gains should add up to the yield of government bonds let's say but the trouble is the company gains terms works in the wrong direction because if government yields yield is five percent let's say and is 20 percent is the other then you need a 15 percent gap and that 15 percent gap would be the rise in the value of government of of produced capital relative to natural capital which of course goes just the reverse way as I was arguing we are eating into natural capital so it means we're absolutely off the kilter even you don't have to do any of this either your wonderful lecture or my wonderful lecture if you like because none of this is needed just look at that gap between the rates of return and you see that we have made a huge eating into natural capital and creating the problems that you so brilliantly have exposed to us so you're quite right it's the composition of biomass which is important and the primary producers is the right one to target because we all depend on the primary producers we mean animals and pigs and so I hope that helps yeah now that you have the microphone can I ask you a question yes so the the the equation you showed this global index of this global inequality um I was wondering what what is the theory behind I mean is there a theory that can predict you or can give you a prediction in terms of what is the optimum value for the ratio because you said we are 1.6 biosphere okay so I yes I'm assuming that you I mean you will say well the optimal would be just to need one but maybe one is too close to it's too edge it's too an edge how how much biosphere should we need or Paul Ehrlich will say 50% kind of the biosphere should be allocated to human so because it's a number that we don't really kind of a tie with biodiversity what does it mean uh you know can you expand a little bit on that well I'll try and do that on Thursday when I try and produce a dynamic describe a dynamic model which carries these variables that I had in the impact inequality over time so how they interrelate it and of course you can human economy could and we do choose the control variables like how much to invest in this and that and human capital and natural capital and how much to consume and so forth and investment in R&D investment in mother nature and so forth to see what the balance would look like now nobody since I don't know the values of the parameters because these models have not been estimated I wouldn't know what the optimum rates would be but just to point out one thing which is that at some time at some at some date we need to have equality of these and you're suggesting that initially you may want to have demand go below supply so that nature can reject and that's entirely possible sure yeah I was asking a much uh easier question which was how much what would it need for us to get in 2030 to inequality never mind it reverse the inequality and alpha will not do it because it would require an alpha we haven't seen historically increasing alpha historically so we really have to do other things like put a price on things what about let me kind of build on this and since you are a Fran Ramsey professor and Ramsey one of the thing that I think he believed because he was a kind of a socialist kind of person he he believed in that discount rates were outrageous I mean unfair unjust you know and now you point out of the possibility of thinking in negative discount rates and I find that fascinating but I was thinking that we should put it on negative not because nature will be a scarcer and higher value in the future but because we value so much the next generations and we have destroyed or spoiled so much that we have to invest now to actually assure that they will have or they will be an equal food to us because we we need to invest in restoring nature for the future so would that also imply a negative this absolutely right if you I mean you should be you should be a professor of economics that was absolutely right you're the intuition here is the following Ramsey so there's a famous famous paper by Frank Ramsey 1928 as you probably know he died at the age of 26 having written six extraordinary papers in mathematics economics and philosophy this one is to do with intergenerational well-being the point that I was raising previously I was using Ramsey's framework to prove the equivalence between inclusive wealth and intergenerational well-being okay but the question Ramsey was concerned with asking the question should we discount the future simply because it's in the future should we discount well-being of the fourth generation not beyond this simply on grounds that it's the fourth beyond generation beyond this and suppose you say no we should just for the sake of argument conditional on their surviving by the course and we're assuming that we know that they'll be there all right so let's make that zero but the point that professor here is making is deeper he's saying all right suppose it's zero doesn't mean however we when we do cost-benefit analysis we discount future income the benefits that we get should those benefits be discounted at zero rate or maybe even a negative rate assuming if it is the case that the future will be poorer than us and the answer is exactly right that you would it be a negative because you'll be giving a greater weight at the margin to the consumption of somebody your great-grandchild who you know is going to have half your half your income because of depleted earth let's say just for the sake of argument then you will say well no at the margin we want to give him when I sacrifice one dollar now of consumption of some kind then you know even if he gets less than one dollar I should make that deal because he will need it more or she will need it more so yes the answer is yes if you if your forecast is there's going to be a declining consumption then the social discount rate would on that would be negative not possible you're quite right thank you thank you very much and it's great that we started this new idea of having by the speakers question answer themselves so I have a question myself so looks like the example of this civilization that you discussed is one where essentially collapse of the civilization was driven by ecological collapse so are there examples of civilization that developed institutions that were able to avert this type of collapse or to cope with the so are there positive examples or all the examples that we have are just negative yeah let me try to I'm gonna I don't have a particular one I know there are and but one thing that really kind of got my attention in the Andes which is on this very widespread kind of practice it has to be to be it has is related to how they manage water in a desert you know and they created a very sophisticated way of conducting water so averting this kind of flush floods that might have different problems and and the way they do it is was based on collaboration among the members of the community you know and a collaboration is so enshrined in this human group living in this extreme desert that they have rights they have different ceremonies for example when a young adult becomes a transition to adulthood they have to pay the community for what everything that the community gave him through his life until adulthood and he has to organize a party he organized a big party and he pays the party to everyone and then everyone's put kind of bills you know and give him against things you know for the party and that's amazing I saw that what doing my my my my sophomore thesis up in the Andes and I saw that this is astonishing this great this people collaborate you know and then I realized that it was it was a widespread practice everywhere in the in the Andes and also in southern Chile where they have these rights where they clean up channels like water channels and they move houses in in in Chile island that they move is the community the whole community moving the house and I mean the house you know they take the house and they put a oxen cart and 40 50 people from the community moving the house from one island to another and collaborating on that it's like that's what I think is it's it's lovely about this socio-ecological loop there's so much there you know that we have to learn about ourselves about how we are and collaboration I think is a key point and I think that the ethnographic evidence is very well kind of clear that we have to collaborate and I would say that that's part of the the the self-organization of community is has been this collaboration to face complex difficult times and and and we have to foster that collaboration I don't know how but we should thank you okay so I think this was a very great set of talks and very inspiring you can close this session here thank you all and we have now lunch we will reconvene at 2 p.m. here for the start of the workshop