The Return of "The Limits to Growth." An interview with Carlos Alvarez Pereira, Vice-President of the Club of Rome

 

Image from "Wired.com" Note that they call the report "infamous" -- they are still influenced by the defamation campaign against it carried out in the 1970s and 1980s. 

The interest on "The Limit to Growth" is returning. 50 years after that a vicious denigration campaign had consigned the report to the trash can of wrong science, we see the study resurfacing, reappraised, reviewed, being discussed again. 

And we are realizing that the study had been correct and that today is still relevant for us. It was never intended as a prophecy of doom, but its true message was drowned in a sea of irrelevant criticism, political slander, and plain insults that prefigured the current way of dealing with "science" in the media. 

The latest evidence of this new interest in the "Limits to Growth" is the interview with the vice-president of the Club of Rome, Carlos Alvarez Pereira, that recently appeared on "Wired".

Carlos does not keep a blog and he doesn't appear so often on the social media, so you may not have heard of him. But he is very active in various sustainability projects. Among many other things, he has edited, together with Ugo Bardi, the new report to the Club of Rome, "Limits and Beyond" that summarizes and reviews 50 years of history of the first "Limits" report. Carlos' interview on "Wired" is a deep and wide sweep at the many facets of the problems we face. Absolutely worth reading.

Here are a few excerpts from Carlos' interview. 


Fundamentally, it is about equity, managing the resources in an equitable way, knowing in advance that they're limited. Realizing that it's not higher and higher consumption which makes us live in a good way, have a healthy life and well-being. It's the quality of our relationships with other humans, with nature, that makes possible the scenarios in which you can decouple well-being and the growth of consumption.

............

We have to be in a good balance with the planet where we live. And that part of the message was completely lost, very rapidly. Jimmy Carter, when he was president, was listening to this kind of approach. And then of course, the political mood changed a lot with the rise of Ronald Reagan and Margaret Thatcher. Reagan himself has a discourse in which he says, literally, there are no limits to growth. So from a political point of view, there was a complete denial of what the book was saying.

...........

What the system has done, as a mechanism to continue with growth at all costs, is actually to burn the future. And the future is the least renewable resource. There is no way that we can reuse the time we had when we started this conversation. And by building up a system which is more debt-driven—where we keep consumption going, but by creating more and more debt—what we're actually doing is burning or stealing the time of people in the future. Because their time will be devoted to repaying the debt.

.......

The paradox is that capitalism is also based on the notion of scarcity. Our system is organized around the idea that resources are scarce, then we have to pay for them, and people in the value chain will profit from this idea of scarcity. Conventional capitalism is saying that while these resources might be finite, we will find others: Don't worry, technology will save us. So that we continue in the same way.

 

Limits and Beyond: the message from Dennis Meadows. A review of the 3rd chapter

Ian Sutton continues to review on his blog the chapters of the recently published new report to the Club of Rome, "Limits and Beyond" (Exapt Press 2022)

by Ian Sutton

We have reviewed the first two chapters of the new book Limits and Beyond. The reviews can be found at The Yawning Gap (Chapter 1) and No More Growth (Chapter 2). In this post we take a look at the third chapter, written by Dennis Meadows, a co-author of the original Limits to Growth. Dr. Meadows reports that he has delivered over a thousand speeches to a very wide variety of audiences. In this chapter the author summarizes “19 of the most common questions, comments and objections” that he has received over the years. Some of his insights are as follows:

• The World3 model continues to be more useful than the “many models advanced by economists who refuted our work since its first publication”.
• He distinguishes between physical and social models. We can predict solar eclipses or the melting point of ice with certainty, but we cannot predict how humans will act. Therefore, the fact that modern computers are much more powerful than their 1972 counterparts is not necessarily more helpful. (Engineers express the same distinction when talking about the difference between precision and accuracy. “When you’ve got baloney, it doesn’t matter how thin you slice it, it’s still baloney”. Or, “An engineer is someone who multiplies 2 by 2 on a slide rule, gets an answer of 3.9 and approximates to 4”.)
• “Climate change was not a serious concern 50 years ago”. Dr. Meadows argues that the model is nevertheless still valid because, “magically eliminating it would still leave other grave problems”. In other words, climate change is not a root cause; instead it is a symptom of deeper root causes.
• The biggest threat is to our social fabric.
• He concludes by saying that the, “. . . report did not make discernible changes in the policies of the world’s leaders”. However, it did influence the thinking of many individuals.

The fact that Dr. Meadows has worked so hard to deliver the message of Limits to Growth is impressive. The question remains, however, “Why has such communication mostly failed to make a discernible impact on the body politic?”

Dennis Meadows

Communication is, of course, a two-way affair. People such as Dr. Meadows speak, but others have to listen. And, as I point out in The Coffee Shop and Small Potatoes the vast majority of people don’t “get it”. At best, they see climate change as being just one problem among many. Maybe they sense that facing up to limits to growth involves making sacrifice, and most people don’t want to go there. 

One message that we have definitely learned that simply presenting well-researched information is not enough. It is possible that we need some type of '‘social tipping point’ as I discuss in Needed: A Tipping Point.

"The Limits to Growth" after 50 years: More relevant than ever

 

50 years after the publication of the first report to the Club of Rome, "The Limits to Growth," it is time to re-assess the validity of its evaluation of the destiny of humankind. Are we really destined to collapse? Or can we still make the right choices and avoid it? It is discussed in a new report to the Club of Rome titled "Limits and Beyond."

Can you think of a book published in the twentieth century that we still remember 50 years later? There is one that has left such an important mark that we are celebrating its fiftieth anniversary. It is the report to the Club of Rome published in 1972 with the title "The Limits to Growth".

"The Limits to Growth" was a study of the future of the global economy. Its basic message was that growth could not continue to go on forever on a finite planet. And not just that. It also said that if we continued to exploit natural resources without worrying about depletion, pollution, and overpopulation, things would start to go pretty bad: the economy would collapse. When? Maybe during the first 1-2 decades of the 21st century. 

The message of "The Limits to Growth" was hard to digest in the 1970s, an age of optimism and enthusiasm for technological progress and economic expansion. So, from the beginning, the study was criticized and demonized in every possible way, so much that many people, still today, are convinced that it was "wrong" for one reason or another. Actually, there was nothing wrong with the study: it was only affected by the unavoidable uncertainties in the parameters of the system. But the very fact that it was demonized so heavily means that it said something fundamental, relevant to our survival as a civilization and perhaps even as a species.

But what was so special about that book? Many things: perhaps the most important one was that it was the first study that addressed the problems of the future of humanity in a "systemic" way, that is, using a model that, for the time, was incredibly sophisticated. Let me explain: today there is a lot of talk about "artificial intelligence," but the concept was born in the 1960s. "The Limits to Growth" was part of the concept of using computers as a tool to help human intelligence. 

One of the problems we face when we try to manage complex systems, that is systems where many factors interact with each other, is that the human mind heavily relies on "intuition." We tend to focus on single parameters and consider them as the only relevant factor. Did you notice how people tend to interpret the world's problems on the basis of single factors? "Overpopulation!" "Climate change!" "Pollution!" "Peak Oil" "The public debt!" and so on. All these are relevant factors, certainly, but none of them is the only problem. But how can we estimate their effect when every single factor interacts with all the others? If you focus on the wrong parameter, you can make enormous mistakes. 

That's where a computer can be helpful. The computer is not intelligent, but for this very reason, it is not swayed by ideology or other kinds of personal biases. So, in 1972, the authors of the "Limits to Growth" created a computer-based model that analyzed the human economy according to various hypotheses on the availability of resources, pollution, population growth, and other things.

It was not a prophecy, not a political program, and not a religious revelation, either. The "Limits to Growth" model was simply an evaluation designed to answer the question, "what will happen if ……?" The results were stark clear. If the economy remained focused on growth at all costs, the global economic system would reach its physical limits around 2010-2020. And it wasn't just a matter of stopping growth. It was much worse: the model predicted the collapse of the system.

Today, given the current situation, we may legitimately wonder if we are finding ourselves at the beginning of the collapse that some of the scenarios of "The Limits to Growth" had seen in store for humankind. Is that our future? Maybe, but let me repeat that "The Limits to Growth" was not a prophecy: there was nothing unavoidable in the scenarios it proposed. And the authors never saw themselves as prophets of doom. The study was conceived as a roadmap to avoid collapse! 

Unfortunately, we didn't put into practice the solutions that the study proposed, such as reducing the consumption of natural resources, slowing down economic growth, and the like. But it is also true that today many things have changed. The revolution in renewable technologies has changed the rules of the game. With renewable energy, in principle, we can phase out fossil fuels and avoid the main causes of the coming collapse: depletion and climate change. Yes, but this does not mean that renewable energy comes for free: we have to invest in it and not a little. Unfortunately, up to now, we have not invested enough, not to mention the bureaucratic obstacles that hinder the new installations. 

Even if we could move toward renewables fast enough that we could smoothly replace fossil fuels, that would not be sufficient to avoid all problems. Never forget that the origin of collapse is its opposite: growth. Already long ago, the Roman philosopher Lucius Annaeus Seneca, noted that ruin is rapid after growth: it is called the "Seneca Effect." If we want to avoid the "Seneca Cliff," the rapid decline that arrives after the growth phase is over, we need to recognize the limits of our planet. Growth at all costs is a dream of the 20th century, that we must abandon now.  

So, we are facing difficult times, but we can muddle through if we make the right choices. Meanwhile, there is a new book that re-examines the whole story of "The Limits to Growth" and its relevance for our present and our future. It is titled "Limits and Beyond," a multi-author book that includes contributions from 21 authors, including two of the original authors of the 1972 "The Limits to Growth." It is edited by Ugo Bardi and Carlos Alvarez Pereira. Already available for purchase! 

The Age of Exterminations (VI): The Great Famine to Come

The third horseman of the apocalypse, hunger, is traditionally represented with a scale in hand, symbolizing scarcity. Famines are not normally considered exterminations but, in many cases, they have been provoked by human actions. Today, we tend to see famines as a thing of the past, but there is a rule in history that what happened once may happen again, and it usually does. By a mere coincidence (or perhaps not), the same day when this post was published, President Putin said at the Valdai Club that  "a number of countries and even entire regions are regularly hit by food crises. ... there is every reason to believe that this crisis will become worse in the near future and may reach extreme forms." There have never been nearly 8 billion people on Earth, and what the future will bring to them is all to be seen.

 

 

This is the 6th post of a series that explores one of the darkest sections of human behavior, that of mass exterminations. Previous posts dealt with the extermination of the witches in Europe, of young men during WW1, of elderly people, of the rich, of the useless, and now this one about famines as a weapon of mass destruction. From now on, I think I'll move to different subjects, although I may return to this one, a little depressing but surely fascinating.

Imagine you are an Irish peasant living in the early 19th century. You stay with your family in a mud or stone cottage. A single room under a thatched roof, no windows, no chimney, little furniture. You pay a small rent to your British landlord by working for him. You eat the potatoes you cultivate in a patch near your home and you warm yourself using the peat that you dig out nearby. You haven't seen much of the world outside your village, but that's the place where you live, where you were born, where you have your friends and family, and where you have your social life. You own nothing and you are perfectly happy.

But your happiness turns into chagrin in 1845, when you see your potato plants turning black and curled, then rotting. You can't know that it is because of a fungus that attacks the potato plant, but you know that soon you'll be running out of potatoes. By the end of the year, the great famine begins. 

You didn't imagine that being poor would mean being so wretched. Owning nothing means that you can't buy food or bargain for it. You have no power, no influence, no relevance to the British landlords who don't care about you and about your family.  And you have no weapons, nor the military training that would allow you to rebel against your masters. If you can't leave Ireland, you have nothing to do but wait for death to come. 

In the years from 1845 to 1852, Ireland lost a quarter of its population as an effect of the Great Famine (the An Gorta Mór). In a few decades, Ireland's population was reduced to 4 million, half of what it had been before the famine. 

Was it an extermination? Yes, if you define the term as the death of a large number of people caused by human action (or inaction). And there is no doubt that the Irish disaster was not just the result of the chance arrival of a fungus that liked Irish potatoes. Ireland was heavily populated, certainly, but not much more than most European countries. So, what happened? 

For some, the fault lies squarely with the Irish who merrily went on having children without realizing that the population was growing beyond the limits of what their island could continuously support. For others, it was because of the evil English who refused to help the Irish when they were starving. Some even claim that the extermination of the Irish had been planned in advance. They call it the"Irish Holocaust."

It is unlikely that there ever was a plan to depopulate Ireland, the British had no reason to do that. But it is true that they behaved abominably with Ireland and not just at the time of the famine, although not worse than other colonial powers did with their subjects. Ireland never was a British colony, but it was treated as a colony. The land was exploited to the utmost possible level and the Irish were despised and considered only as cheap manpower -- of which there was an excess. When the famine came, the British government did very little to help, sometimes acting in ways that worsened the situation. So, yes, the term "extermination" is appropriate, even though nobody had planned it. History is a great wheel that rolls onward and crushes whoever it finds on its path. It was the destiny that befell Bridget O'Donnell, one of the many victims of the famine, of whom we have a drawing showing her with her starving children.

 

 

 

Now let's examine our times. Remember that if something happened once in history, it can happen again, and it usually will. We have been already told that in the near future "we will own nothing and we will be perfectly happy." This may not be a bad idea in itself, but if you think of the destiny of the Irish peasants, then it is ominous. Even more ominous is the fact we completely depend on fossil fuels for our agriculture, and it is guaranteed that their production is going to decline in a non-remote future. Could we face the same destiny of the Irish of the 19th century? After all, we live on an island, too, just much larger.  

When discussing these matters, it is traditional to be pelted with rotten Irish potatoes for being "catastrophists", but the question is legitimate and the fact that some predictions turned out to be overpessimistic, such as those by Paul Ehrlich in 1968, doesn't mean that a great global famine could not happen. But to avoid past mistakes, we need more detailed models of the future. One of the first studies that dealt with the global population trends was "The Limits to Growth" study of 1972.

 

You see, above, the results of the "base case" scenario calculation, the one which used the data that were considered the most reliable and accurate at the time. You probably know that the study was widely considered overpessimistic, then demonized and consigned to the dustbin of the wrong scientific theories. It was not. But it may have been overoptimistic in its projections for the world's population. 

Note how, in the calculation, the world population decline starts around 2050, some three decades after the start of the crash of the industrial and agricultural systems. Why is it that the population keeps growing while people are starving? Unlikely, to say the least. 

 

It is hard to quantify people's intentions to have children or not have them, so the modelers used past data on birthrates as a function of the gross domestic product (GDP). It was equivalent to "running in reverse" the demographic transition that took place in the 1960s when natality had collapsed in many regions of the world in parallel with an increase of the GDP per capita. The result was that the model assumed that a contraction of the GDP caused people to have more children. 

These assumptions were later reconsidered and different results were obtained in 2004. 

Now, the population starts declining around 2030, less than a decade after that food production starts collapsing, and that looks much more reasonable. Yet, even this curve has problems: would you really believe that in the midst of the great turmoil of the global collapse the result would be such a gentle decline? 

More likely, all the four horsemen of the apocalypse would enter the game and generate a disastrous general crash. This is called the "Seneca Effect."  You see the typical shape of the Seneca Curve in the figure: decline is much faster than growth.

Models such as the one used for the "Limits to Growth" cannot reproduce a really sharp Seneca Curve because they do not consider the many possible "tipping points" that may affect the world system. But the historical data tell us that the Seneca shape is the typical behavior of population collapses. Here is an example with the data for the great famine in Ireland (From Ugo Bardi's book "The Seneca Effect.") You can clearly see the "Seneca Shape" of the curve, with a sharp decline following growth. 

 

Here is another example, Ukraine, as shown in an article that I published on "The Journal of  Population and Sustainability," 

The Ukrainians didn't really starve after the fall of the Soviet Union in 1991, but they suddenly became much poorer than before. The result was a lower quality diet and a collapse in the health care system. Add to that the general decline of the quality of life, then you can imagine that the Ukrainian population started to decline for two combined effects: the rise in mortality, and the fall of natality. Note how similar the curve is to that of Ireland. Other former Soviet Union countries show this kind of curves. It seems to be a general trend: when a serious disaster hits, the population starts declining almost immediately afterward.

If something similar were to happen at the world level, we would see it in just a few years after an economic or political crash. It is perfectly possible that it is exactly what's happening with the current crisis that sees a series of factors combining to bring the system down: health care collapse, food supply disruption, climate change, soil erosion and mineral depletion, financial crisis, and more. They are all pushing toward a global population crash that could start in the coming years. 

Could we call this population crash an "extermination"? That will depend on what governments will do. Surely, it is unlikely that they are planning a future famine, but how would they react if one comes? They might try to do their best to help, but they may also do nothing. Or they may well decide to actively push toward strengthening the crisis as a chance to eliminate people they do not like. 

If you are among those people who are not useful for the state (like the Irish peasants in mid 19th century) or, God forbid, a burden for the ruling elites, then you face hard times ahead. Your situation will be especially worrisome if you will be one of those "happy" people owning nothing, or at most electronic money that the government can erase at will. To say nothing about the electronic surveillance methods that leave you no chance to do anything they don't like or to go anywhere they don't want you to go. 

And, yes, it is perfectly possible that the coming crisis will appear in the form of an extermination by starvation: the third horseman on his dark horse. 

President Putin 's complete sentence at the Valdai Club conference: "Furthermore, a number of countries and even entire regions are regularly hit by food crises. We will probably discuss this later, but there is every reason to believe that this crisis will become worse in the near future and may reach extreme forms." Maybe he reads this blog?

A longer post of mine on the Irish famine subject was published on "The Oil Drum" in 2008. 

Mineral resources and the limits to growth.

Originally published on Cassandra's legacy on Wednesday, September 18, 2013

This is a shortened version of a talk I gave in Dresden on September 5, 2013. Thanks to Professor Antonio Hurtado for organizing the interesting conference there.

 

So, ladies and gentleman, let me start with this recent book of mine. It is titled "The Plundered Planet." You can surely notice that it is not titled "The Developed Planet" or "The Improved Planet." Myself and the coauthors of the book chose to emphasize the concept of "Plundering"; of the fact that we are exploiting the resources of our planet as if they were free for us for the taking; that is, without thinking to the consequences. And the main consequence, for what we are concerned here is called "depletion," even though we have to keep in mind the problem of pollution as well. 

Now, there have been many studies on the question of depletion, but "The Plundered Planet" has a specific origin, and I can show it to you. Here it is.  

It is the rather famous study that was published in 1972 with the title "The Limits to Growth". It was one of the first studies that attempted to quantify depletion and its effects on the world's economic system. It was a complex study based on the best available data at the time and that used the most sophisticated computers available to study how the interaction of various factors would affect parameters such as industrial production, agricultural production, population and the like. Here are the main results of the 1972 study, the run that was called the "base case" (or "standard run"). The calculations were redone in 2004, finding similar results. 

As you can see, the results were not exactly pleasant to behold. In 1972, the study saw a slowdown of the world's main economic parameters that would take place within the first two decades of the 21st century. I am sure that you are comparing, in your minds, these curves with the present economic situation and you may wonder whether these old calculations may be turning out to be incredibly good. But I would also like to say that these curves are not - and never were - to be taken as specific predictions. No one can predict the future, what we can do is to study tendencies and where these tendencies are leading us. So, the main result of the Limits to Growth study was to show that the economic system was headed towards a collapse at some moment in the future owing to the combined effect of depletion, pollution, and overpopulation. Maybe the economic problems we are seeing nowadays are a prelude to the collapse seen by this model, maybe not - maybe the predicted collapse is still far away in the future. We can't say right now.

In any case, the results of the study can be seen at least worrisome. And a reasonable reaction when the book came out in 1972 would have been to study the problem more in depth - nobody wants the economy to collapse, of course. But, as you surely know, the Limits to Growth study was not well received. It was strongly criticized, accused of having made "mistakes" of all kinds and at times to be part of a worldwide conspiracy to take control of the world and to exterminate most of humankind. Of course, most of this criticism had political origins. It was mostly a gut reaction: people didn't like these results and sought to find ways to demonstrate that the model was wrong (or the data, or the approach, or something else). If they couldn't do that, they resorted to demonizing the authors - that's nothing now; I described it in a book of mine "Revisiting the limits to growth".

Nevertheless, there was a basic criticism of the "Limits" study that made sense. Why should one believe in this model? What are exactly the factors that generate the expected collapse? Here, I must say, the answer often given in the early times by the authors and by their supporters wasn't so good. What the creators of the models said was that the model made sense according to their views and they could show a scheme that was this (from the 1972 Italian edition of the book):

Now, I don't know what do you think of it; to me it looks more or less like the map of the subway of Tokyo, complete with signs in kanji characters. Not easy to navigate, to say the least. So, why did the authors created this spaghettimodel? What was the logic in it? It turns out that the Limits to Growth model has an internal logic and that it can be explained in thermodynamic terms. However, it takes some work to describe the whole story. So, let me start with the ultimate origin of these models:

If you have studied engineering, you surely recognize this object. It is called "governor" and it is a device developed in 19th century to regulate the speed of steam engines. It turns with the engine, and the arms open or close depending on speed. In so doing, the governor closes or opens the valve that sends steam into the engine. It is interesting because it is the first self-regulating device of this kind and, at its time, it generated a lot of interest. James Clerk Maxwell himself studied the behavior of the governor and, in 1868, he came up with a set of equations describing it. Here is a page from his original article

 

I am showing to you these equations just to let you note how these systems can be described by a set of correlated differential equations. It is an approach that is still used and today we can solve this kind of equations in real time and control much more complex systems than steam engines. For instance, drones. 

You see here that a drone can be controlled so perfectly that it can hold a glass without spilling the content. And you can have drones playing table tennis with each other and much more. Of course they are also machines designed for killing people, but let's not go into that. The point is that if you can solve a set of differential equations, you can describe - and also control - the behavior of quite complex systems.

The work of Maxwell so impressed Norbert Wiener, that it led him to develop the concept of "cybernetics"

We don't use so much the term cybernetics today. But the ideas that started from the governor study by Maxwell were extremely fecund and gave rise to a whole new field of science. When you use these equations for controlling mechanical system, you use the term "control theory." But when you use the equations for study the behavior of socio-economic systems, you use the term "system dynamics"

System dynamics is something that was developed mainly by Jay Wright Forrester in the 1950s and 1960s, when there started to exist computers powerful enough to solve sets of coupled differential equations in reasonable times. That generated a lot of studies, including "The Limits to Growth" of 1972 and today the field is alive and well in many areas.

A point I think is important to make is that these equations describe real world systems and real world systems must obey the laws of thermodynamics. So, system dynamics must be consistent with thermodynamics. It does. Let me show you a common example of a system described by system dynamics: practitioners in this field are fond of using a bathub as an example:

On the right you have a representation of the real system, a bathtub partly filled with water. On the left, its representation using system dynamics. These models are called "stock and flow", because you use boxes to represent stocks (the quantity of water in the tub) and you use double edged arrows to indicate flows. The little butterfly like things indicate valves and single edged arrows indicate relationship.

Note that I used a graphic convention that I like to use for my "mind sized" models. That is, I have stocks flowing "down", following the dissipation of thermodynamic potential. In this case what moves the model is the gravitational potential; it is what makes water flow down, of course. Ultimately, the process is driven by an increase in entropy and I usually ask to my students where is that entropy increases in this system. They usually can't give the right answer. It is not that easy, indeed - I leave that to you as a little exercise

The model on the left is not simply a drawing of box and arrows, it is made with a software called "Vensim" which actually turns the model "alive" by building the equations and solving them in real time. And, as you may imagine, it is not so difficult to make a model that describes a bathtub being filled from one side and emptied from the other. But, of course, you can do much more with these models. So, let me show a model made with Vensim that describes the operation of a governor and of the steam engine.

Before we go on, let me introduce a disclaimer. This is just a model that I put together for this presentation. It seems to work, in the sense that it describes a behavior that I think is correct for a governor (you can see the results plotted inside the boxes). But it doesn't claim to be a complete model and surely not the only possible way to make a system dynamics model of a governor. This said, you can give a look to it and notice a few things. The main one is that we have two "stocks" of energy: one for the large wheel of the steam energy, the other for the small wheel which is the governor. In order to provide some visual sense of this difference in size, I made the two boxes of different size, but that doesn't change the equations underlying the model. Note the "feedback", the arrows that connect flows and stock sizes. The concept of feedback is fundamental in these models.

Of course, this is also a model that is compatible with thermodynamics. Only, in this case we don't have a gravitational potential that moves the system, but a potential based on temperature differences. The steam engine works because you have this temperature difference and you know the work of Carnot and the others who described it. So, I used the same convention here as before; thermodynamic potential are dissipated going "down" in the model's graphical representation

Now, let me show you another simple model, the simplest version I can think of a model that describes the exploitation of non renewable resources:

It is, again, a model based on thermodynamics and, this time, driven by chemical potentials. The idea is that the "resources" stock as a high chemical potential in the sense that it may be thought as, for instance, crude oil, which spontaneously combines with oxygen to create energy. This energy is used by human beings to create what I can call "capital" - the sum of everything you can do with oil; from industries to bureaucracies.

On the right, you can see the results that the model provides in terms of the behavior as a function of time of the stock of the resources, their production, and the capital stock. You may easily notice how similar these curves are to those provided by the more complex model of "The Limits to Growth." So, we are probably doing something right, even with this simple model.

But the point is that the model works! When you apply it to real world cases, you see that its results can fit the historical data. Let me show you an example:

This is the case of whaling in 19th century, when whale oil was used as fuel for lamps, before it became common to use kerosene. I am showing to you this image because it is the first attempt I made to use the model and I was surprised to see that it worked - and it worked remarkably well. You see, here you have two stocks: one is whales, the other is the capital of the whaling industry that can be measured by means of a proxy that is the total tonnage of the whaling fleet. And, as I said, the model describes very well how the industry grew on the profit of killing whales, but they killed way too many of them. Whales are, of course, a renewable resource; in principle. But, of course, if too many whales are killed, then they don't have enough time to reproduce and they behave as a non-renewable resource. Biologists have determined that at the end of this fishing cycle, there were only about 50 females of the species being hunted at that time. Non renewable, indeed!

So, that is, of course, one of the several cases where we found that the model can work. Together with my co-workers, we found that it can work also for petroleum extraction, as we describe in a paper published in 2009 (Bardi and Lavacchi). But let me skip that - the important thing is that the model works in some cases but, as you would expect, not in all. And that is good - because what you don't want is a "fit-all" model that doesn't tell you anything about the system you are studying. Let's say that the model reproduces what's called the "Hubbert model" of resource exploitation, which is a purely empirical model that was proposed more than 50 years ago and that remains a basic one in this kind of studies: it is the model that proposes that extraction goes through a "bell-shaped" curve and that the peak of the curve, the "Hubbert peak" is the origin of the concept of "peak oil" which you've surely heard about. Here is the original Hubbert model and you see that it has described reasonably well the production of crude oil in the 48 US lower states.

Now, let's move on a little. What I have presented to you is a very simple model that reproduces some of the key elements of the model used for "The Limits to Growth" study but it is of course a very simplified version. You may have noted that the curves for industrial production of the Limits to Growth tend to be skewed forward and this simple model can't reproduce that. So, we must move of one step forward and let me show you how it can be doing while maintaining the basic idea of a "thermodynamic cascade" that goes from higher potentials to lower potentials. Here is what I've called the "Seneca model"

You see that I added a third stock to the system. In this case I called it "pollution"; but you might also call it, for instance, "bureaucracy" or may be even "war". It is any stock that draws resource from the "Capital" (aka, "the economy") stock. And the result is that the capital stock and production collapse rather rapidly; this is what I called "the Seneca effect"; from the roman philosopher Lucius Anneaus Seneca who noted that "Fortune is slow, but ruin is rapid".

For this model, I can't show you specific historical cases - we are still working on this idea, but it is not easy to make quantitative fittings because the model is complicated. But there are cases of simple systems where you see this specific behavior, highly forward skewed curves - caviar fishing is an example. But let me not go into that right now.

What I would like to say is that you can move onward with this idea of cascading thermodynamic potentials and build up something that may be considered as a simplified version of the five main stocks taken into account in the "Limits to Growth" calculations. Here it is

Now, another disclaimer: I am not saying that this model is equivalent to that of the Limits to Growth, nor that it is the only way to arrange stocks and flows in order to produce similar results to the one obtained by the Limits to Growth model. It is here just to show to you the logic of the model. And I think you can agree, now, that there is one. The "Limits" model is not just randomly arranged spaghetti, it is something that has a deep logic based on thermodynamics. It describes the dissipation of a cascade of thermodynamic potentials.

In the end, all these model, no matter how you arrange their elements, tend to generate similar basic results: the bell shaped curve; the one that Hubbert had already proposed in 1956

The curve may be skewed forward or not, but that changes little on the fact that the downside slope is not so pleasant for those who live it.

Don't expect this curve to be a physical law; after all it depend on human choices and human choices may be changed. But, in normal conditions, human beings tend to follow rather predictable patterns, for instance exploiting the "easy" resources (those which are at the highest thermodynamic potential) and then move down to the more difficult ones. That generates the curve.

Now, I could show you many examples of the tendency of real world systems to follow the bell shape curve. Let me show you just one; a recent graph recently made by Jean Laherrere.

These are data for the world's oil production. As you can see, there are irregularities and oscillations. But note how, from 2004 to 2013, we have been following the curve: we move on a predictable path. Already in 2004 we could have predicted what would have been today's oil production. But, of course, there are other elements in this system. In the figure on the right, you can see also the appearance of the so-called "non-conventional" oil resources, which are following their own curve and which are keeping the production of combustible liquids (a concept slightly different from that of "crude oil) rather stable or slightly increasing. But, you see, the picture is clear and the predictive ability of these models is rather good even though, of course, approximate.

Now, there is another important point I'd like to make. You see, these models are ultimately based on thermodynamics and there is an embedded thermodynamic parameter in the models that is called EROI (or EROEI) which is the energy return for the energy invested. It is basically the decline in this parameter that makes, for instance, the extraction of oil gradually producing less energy and, ultimately, becoming pointless when the value of the EROEI goes below one. Let me show you an illustration of this concept:

You see? The data you usually read for petroleum production are just that: how much petroleum is being produced in terms of volume. There is already a problem with the fact that not all petroleums are the same in the sense of energy per unit volume, but the real question is the NET energy you get by subtracting the energy invested from the energy produced. And that, as you see, goes down rapidly as you move to more expensive and difficult resources. For EROEIs under about 20, the problem is significant and below about 10 it becomes serious. And, as you see, there are many energy resources that have this kind of low EROEI. So, don't get impressed by the fact that oil production continues, slowly, to grow. Net energy is the problem and many things that are happening today in the world seem to be related to the fact that we are producing less and less net energy. In other words, we are paying more to produce the same. This appears in terms of high prices in the world market.

Here is an illustration of how prices and production have varied during the past decades from the blog "Early Warning" kept by Stuart Staniford.

And you see that, although we are able to manage a slightly growing production, we can do so only at increasingly high prices. This is an effect of increasing energy investments in extracting difficult resources - energy costs money, after all.
So, let me show you some data for resources that are not petroleum. Of course, in this case you can't speak in terms of EROEI; because you are not producing energy. But the problem is the same, since you are using fossil fuels to produce most of the commodities that enter the industrial system, and that is valid also for agriculture. Here are some data.

Food production worldwide is still increasing, but the high costs of fossil fuels are causing this increase in prices. And that's a big problem because we all know that the food demand is highly anelastic - in plain words you need to eat or you die. Several recent events in the world, such as wars and revolutions in North Africa and Middle East have been related to these increases in food prices.

Now, let me go to the general question of mineral production. Here, we have the same behavior: most mineral commodities are still growing in terms of extracted quantities, as you can see here (from a paper by Krausmann et al, 2009 http://dx.doi.org/10.1016/j.ecolecon.2009.05.007)

These data go up to 2005 - more recent data show signs of plateauing production, but we don't see clear evidence of a peak, yet. This is bad, because we are creating a climate disaster. As you seee from the most recent data, CO2 are still increasing in a nearly exponential manner

 

But the system is clearly under strain. Here are some data relative to the average price index for aluminum, copper, gold, iron ore, lead, nickel, silver, tin and zinc (adapted from a graphic reported by Bertram et al., Resource Policy, 36(2011)315)

So, you see, there has been this remarkable "bump" in the prices of everything and that correlates well with what I was arguing before: energy costs more and, at the same time, energy requirements are increasing because of ore depletion. At present, we are still able to keep production stable or even slowly increasing, but this is costing to society tremendous sacrifices in terms of reducing social services, health care, pensions and all the rest. And, in addition, we risk to destroy the planetary ecosystem because of climate change.

Now I can summarize what I've been saying and get to the take-home point which, I think can be expressed in a single sentence "Mining takes energy"

Of course, many people say that we are so smart that we can invent new ways of mining that don't require so much energy. Fine, but look at that giant wheel, above, it used to extract coal in the mine of Garzweiler in Germany. Think of how much energy you need to make that wheel; do you think you could use an i-pad, instead?

In the end, energy is the key of everything and if we want to keep mining, and we need to keep mining, we need to be able to keep producing energy.  And we need to obtain that energy without fossil fuels. That's the concept of the "Energy Transition"

Here, I use the German term "Energiewende" which stands for "Energy Transition". And I have also slightly modified the words by Stanley Jevons, he was talking about coal, but the general concept of energy is the same. We need to go through the transition, otherwise, as Jevons said long ago, we'll be forced to return to the "laborious poverty" of older times.

That doesn't mean that the times of low cost mineral commodities will ever return but we should be able to maintain a reasonable flux of mineral commodities into the industrial system and keep it going. But we'll have to adapt to less opulent and wasteful life as the society of "developed" countries has been accustomed so far. I think it is not impossible, if we don't ask too much:

h/t ms. Ruza Jankovich - the car shown here is an old Fiat "500" that was produced in the 1960s and it would move people around without the need of SUVs