1. The publisher is the World Publishing Company (in Singapore). The ISBN is 978-9814273930.

2. See for instance Michael T. Klare, The Race for Whats Left (Henry Holt, 2012). This is one of several kindsof currently notable environmental degradation. The other kinds include: overshoot in the use of renewable re-sources; pollution; unduly fast climate change; troublesome changes in the locations of certain kinds of material

2(e.g. of H O which has, on the one hand, melted from the polar caps and is, on the other hand, flooding Bangla-desh); mass extinction of biological species, and yet also new super bacteria and more virulent viruses capable ofcausing epidemics.

3. In order, for instance, for a force to qualify as having done mechanical work on a physical object, the force musthave caused a displacement of the object. The amount of the displacement is measured in terms of distance. Theamount of the work is equal to the distance times the amount of resistance that the object poses to being displaced.With the same amount of work you can either lift one cup of tea 20 cm straight up or else two such cups 10 cm.

4. The flow of energy radiated here from the Sun in a week is more than the total stock of terrestrial energy (ther-mal energy, fossil fuels etc.).

5. How much energy is there in the aimless molecular stirrings and reboundings which we perceive as heat? The

A Method for Assessing Thermodynamically the Depletion of Nonrenewables

Mark Lindley

Antonio and Alicia Valero, a father-and-daughter pair of professors at the University of ZaragozasCentre of Research for Energy Resources and Consumption, have published recently (2014) a magnumopus more than 650 pages long, and with 81 tables and 132 figures about the ongoing decline in1

worldwide availability of non-renewable, abiotic (i.e. not living) natural resources vital to modern soci-eties: the fossil fuels and various kinds of minerals. The book has a poetic title, Thanatia: The Destiny of2

the Earths Mineral Resources: A Thermodynamic Cradle-to-Cradle Assessment (yes, cradle-to-cradle!),and contains a fascinating and sometimes daunting array of explanations and technical information,much of which is based on a new theoretical concept (grave-to-cradle) which is described thoroughlyand complemented with practical suggestions for addressing the economic problem.

A quick way to get the drift of the theory is via an analogy between the well known concept in phy-sics of an isolated system in a dead state and a salient aspect of the new concept for which the bookis named. Thanatia is an imaginary geological condition in which (along with some other features speci-fied by the authors) the Earths various minerals, though not absent they have, after all, nowhereelse to go as long as the planet remains coherent would be distributed quite evenly (no longer con-centrated in ores or recycling repositories) throughout the land and water. On the other hand, in anisolated physical system in a dead state, all the energy in the system would be distributed evenlythroughout it with for instance the heat (haphazard zigzag stirrings and reboundings of molecules)at uniform temperature throughout and there would thus be a physical equilibrium whereby no workin the physicists sense of the term could take place.3

(The Earth is, thank heavens, not isolated, as plenty of energy is radiated here from the Sun. But4

no minerals are radiated to the Earth.)

Exergy is a term in physics, and important in this book, for energy which in a system with dis-equilibrium yields work if it is kinetic or can do so if it is potential and is then released. The applefell on Newton that was an historic kinetic event when the potential mechanical energy of its highposition on the tree was released by the stem breaking; he could then, by eating it, use some of thepotential chemical energy in it. The difference between exergy and the energy that would be presentthroughout an isolated system at uniform temperature, pressure and chemical composition is qualita-5

authors mention that Whilst a calorie is a really small amount of heat, namely that [which is] needed to warm agram of water by one degree centigrade, it is also the kinetic energy of that same mass at 327 km/h! Hence, smallfluctuations in system temperatures result in considerable energy expenditures. (They mean exergy expenditures.)

6. Herman Daly and Joshua Farley, Ecological Economics: Principles and Applications (Island Press; 1st edition,2004; revised 2nd edition, 2011), Glossary.

tively just as notable as, say, the difference in our emotional life between love and boredom, or thedifference in a market economy between legal tender with and without galloping inflation. (Inflationisnt a lack of money, but it affects the quality of money.)

A basic law of physics says that the exergy in an isolated physical system with disequilibrium wouldexpend itself in the course of time, and the system would thereby approach equilibrium. A well knownterm for such self-expenditure of exergy is increase of entropy. The authors explain that the funda-mental idea underlying the concept of entropy is that in an isolated system everything degrades orbecomes dispersed by and by as the systems exergy is gradually expended: sooner or later fluids willstop flowing, [relatively] warm bodies will get colder, [and] pure substances will become impure.... Thisis an experimental fact and constitutes the Second Law of Thermodynamics. The reason why it is calleda law of thermo- dynamics is that the earliest formulations (in the 19th century) of the principle werejust about the fact that heat is spontaneously transferred from warmer to cooler parts of the system,and did not say anything about, for instance, substances becoming dispersed and thereby immersed inimpurities. In the 1970s, Nicholas Georgescu-Roegen (who was a sharp economist but not a thermo-dynamicist) proposed an additional theoretical law in regard to dispersion of substances. The Valerosderive it from the Second Law, and Georgescu-Roegens most accomplished former student, HermanDaly, has likewise held that the Second Law covers the fact that things left to themselves ... tend to getmixed up and scattered. 6

According to the Valeros, dispersion of raw materials has not been sufficiently considered in eco-

[ ]nomic analyses. It has been ignored as a materials availability loss , and it is viewed [instead] as a pollu-tion problem, more than anything else. The purpose of the book is to show, without belittling the pol-lution problems, how to analyze correctly the materials-availability losses. The Valeros note that nowa-days,

technology is employing all [the] elements of the periodic table and their use is growing exponentially.Yet this fact is barely discussed in conventional ecological discourse that preferably focuses on climatechange, loss of biodiversity, deforestation or ecosystems destruction. Instead, the problem of a futurelack of abiotic resources is readily solved [in the writers imaginations] with the ideas that the Earthscrust is almost unexplored (oceans, the poles, deep underground mines, etc) and that technology willovercome any potential market disruption. The truth however is quite different, with mining companiestelling another story.

Thanatia is defined as a theoretical, quantitatively formulated model of an economically deadcondition of the Earths atmosphere, hydrosphere and upper crust, whereby all the fossil fuels would

2have been burned, leading to an increase in atmospheric CO concentration (the authors reckon itwould be some 70% higher than now) and hence in mean global surface and atmospheric temperaturedue to the greenhouse effect, and, all commercially exploitable [mineral] resources [would] have beenconsumed and dispersed (my italics) throughout the upper crust and hydrosphere. This model providesa theoretical baseline against which the authors venture quantitative assessments of what would berequired theoretically to restore the minerals from thanatia to useful conditions of concentration (like,for instance, in economically feasible ores).

7. The Valeros tactfully refrain from mentioning price fluctuations due to mob psychology rather than to rationalassessments of value. Instead, they say (p.xii) that if Economics is used to explain value creation, Thermo-dynamics can describe and quantify the resource destruction [in regard to mineral resources] that comes aboutin the creation of that value. Some relevant but woefully mistaken modern laissez-faire precepts are that theeventual unavailability of any one kind resource can always be dealt with by paying more money for a substituteand that the price system thus communicates to the scientifically ignorant man on the spot all the informationbeyond the limited but intimate knowledge of the facts of his immediate surroundings that is needed in orderfor society to make wise decisions. (These phrases are from Friedrich Hayek, The Use of Knowledge in Society,American Economic Review, XXXV (1945), p.525.)

The assessments are in terms of physical exergy costs (although data for monetary costs etc. arealso amply cited). Prices depend on psychology, whereas physical exergy cost in regard to minerals7

depends only on the techniques of mining, processing, using, recovering and/or disposing of them.Monetary sums are at least latently akin to microeconomic thinking, partly because the quality of socialpower in the money in the employers pocket depends on the employee wanting to have some of it inhis. The Valeros are making macroeconomic assessments of Humankinds mutual relation with the abio-tic content of the outer layers of the planet, which doesnt care about social power.

They use the noun grave to refer metaphorically to thanatia, and they use cradle to refer to (1)the corresponding, not economically dead condition nowadays (as there is still nowadays a modi-cum of naturally concentrated mineral deposits) and (2) an economically equivalent condition after arecuperation from a dangerous (and perhaps disaster-laden) historical approach to the theoreticalthanatia. Hence the books subtitles, The Destiny of the Earths Mineral Resources: A Thermo-dynamic Cradle-to-Cradle Assessment.

The following schematic chart (slightly simplified from one in Chapter 4) represents flows of exergy(except that its dissipation, represented by the lowest arrow, is loss of exergy and hence growth ofentropy) in the global economy:

Use includes all the uses by consumers. The Stock in Landfills block overlaps with Thanatia be-cause in some of that stuff in the landfills, the minerals which had previously been economically usefulare so utterly dispersed that to restore them, by urban mining, to a feasible degree of purity and/orconcentration would be unfeasible. The Valeros envisage estimating (a) the exergy costs nowadays ofextracting and processing fuels and minerals, and also (b) the potentially smaller such costs if there

8. What is said here about geological (vs biological and sociological) realities reminds me of what Kenneth Boul-ding said in 1981 (in his book, Evolutionary Economics, p.44) about the solar system: The only reason why pre-diction is so successful in celestial mechanics is that the evolution of the solar system has ground to a halt in whatis essentially a dynamic equilibrium with stable parameters. Evolutionary systems, however, by their very naturehave unstable parameters.... If, of course, it were possible to predict the change in the parameters, then [this wouldmean that] there would be other parameters [structurally deeper] which were unchanged; but the search for ultim-ately stable parameters in evolutionary systems is futile, for they probably do not exist.

were wiser and more expert uses of technology (as well as wiser patterns of consumption and re-cycling). These exergy-cost estimates would presumably be helpful for figuring out the best ways ofslowing down the dissipation and conserving more of the valuable stuff.

The book has 16 main chapters, as follows.

1: The Depletion of Non-Renewable Abiotic Resources. This is mainly about how the currentlyincreasing demand for certain minerals may hinder the development of a green economy as proposedby the U.N. The discussion is rich in geological data and engineering savvy, and contains the equivalentof a two-hour graduate-level seminar in environmental economics for people who expect windmills,solar photovoltaics and bioenergy to supply consumable energy as plentifully in the 21st centuryas fossil fuels did in the 20th. Three facts which leap off the page are that (a) in order for half of theworlds electric power in 2030 to be generated by windmills of the types that we now have, an amountof copper equal of that which could be obtained by mining two-fifths of the worlds current economic-ally exploitable reserves of copper ore would have to be mined just to supply the copper for the motorsin those windmills and the transmission lines from them (Would you call this green?); (b) the depend-ency of new-fangled solar photovoltaics on critical chemical elements is just as drastic; and, aproposbioenergy, (c) the global supply of phosphates will not meet future demand without drastic changeswithin the recycling sector [and] in the application of fertiliser, improvements in food chain produc-

[ ]tion , and alterations to the Western diet. The authors point out that Plants and other biota require

[ ]phosphorus to live , with no possibility of replacing it with an alternative.... [T]he amount of biomassthat can be produced is absolutely limited by the phosphorous resources of the planet and mankindscapacity to recycle it [i.e. the phosphorus]. Any solution will almost certainly sharply raise future foodprices....

This can be understood without the Valeros theoretical innovation. (Toward the end of the chap-ter they say a little about why they think the innovation will be useful.) The next two chapters providesome historical and intellectual background against which they will, in some of the subsequent chap-ters, survey more thoroughly and in a more long-term context the material facts that have beensampled in this prologue.

2: Economic versus Thermodynamic Accounting. Economics professors who are familiar withthe modern history of their discipline can readily understand a good deal of this chapter. It describesvarious concepts which (a) economists, (b) accountants (in a broad sense of the word) and (c) sci-entists have devised for assessing environmental degradation in general and mineral-resource deple-tion in particular. At the outset the Valeros mention the well-known distinction between economiccapital measured in terms of money, social capital and material natural capital, and describe thislatter idea as a useful conceptual bridge that can help economists and thermodynamicists to under-stand each other ... especially in [regard to] quasi-static geological systems as opposed to the moredynamic biological ones. Later in the book they will suggest that natural endowment would be a8

more valid concept than natural capital.

9. According to Harold Barnett and Chandler Morse, Scarcity and Growth: The Economics of Natural ResourceAvailability (Johns Hopkins University Press, 1963; p.11), Advances in fundamental science have made it possi-ble to take advantage of the uniformity of matter/energy a uniformity that makes it feasible, without preassign-able limit, to escape the quantitative constraints of the earths crust. Daly has perspicaciously detected herethe alchemists dream of converting lead into gold. (See Dalys brief essay, Georgescu-Roegen versus Solow/Stiglitz, in the journal Ecological Economics, 22 (1997), p.263.) V. Kerry Smith has correctly remarked (inScarcity and Growth Reconsidered, Johns Hopkins University Press, 1979; p.69) that it is not the uniformityof matter-energy that makes for usefulness, but precisely the opposite.

10. Such precepts are not mainly what business schools teach as environmental economics. Some of the lessonsin those schools are, for instance, about how to pollute without paying.

11. The idea of discounting when assessing the present negative monetary value of a future cost is that if youknow that the cost at a certain future time will be a certain amount, you could put a smaller amount now in, say,a savings account with a guaranteed annual interest rate, such that the account would yield the full amount by thetime you have to pay.

(a) Economists. After noting the radical views of Ludwig von Mises (It is vain to provide for theneeds of [future] ages the technical abilities of which we cannot even dream) and Friedrich Hayek([T]he conservationist who urges us to make greater provision for the future is [thereby always] infact urging a lesser provision for posterity), and Harold Hotellings less radical precept (1931) thatmining companies would inevitably extract non-renewable resources at a rate which would maximizesocial well-being indefinitely, the Valeros outline some subsequent opinions of market economists(from Barnett and Morse 1963 to Krautkraemer 2005) and mention that fluctuation in the price of oil9

in the last fifty years has often been due more to political manipulation than to a new objective findingas to how much is left in the bucket. They then distinguish between the ideas of environmental econo-mists (such as the polluter-pays precept and the application of cost/benefit analysis to economic-environmental tradeoffs) and those of ecological economists such as Georgescu-Roegen (who is10

discussed at some length), Daly, Kenneth Boulding and Kozo Mayumi. These ecological economists arefound to have deeper transdisciplinary inspirations and a larger time-horizon in mind (i.e. deeper andlarger than has been characteristic of the environmental economists), but even they have lacked, theValeros maintain, the quantitative instruments to convert economic statements into global vision andpolicy for a sound management of planetary resources. (The work of certain other ecological econo-mists is treated under the Accountants and Scientists headings.)

(b) Accountants. Some of the concepts described here are the SNA (System of National Accounts);GNP (Gross National Product); EW-MFA (Economy-Wide Material Flow Accounts); NPV (Net PresentValue, i.e. with discounting from supposed future monetary values); the SEEA (System of Environ-11

mental-Economic Accounts; the Valeros praise this for the way in which the statistics are universallyorganised permitting well established procedures for their analysis, but they also criticize it, partlybecause its recommended method of valuation is in terms of imaginary market prices (estimated NPV-wise) for non-market assets an accounting technique which harbors implicitly the absurd notion thatif one could extract and use all present environmental capital and convert it into money it would bebetter than having [any] physical assets yet to be exploited); the Net Price Method, User CostMethod and Hartwick Rule (all of which fail, in the Valeros opinion, to seriously look at the con-sequences of production and [indicate] whether it is sustainable on the long term); Wouter van Die-rens precept of Environmental Defense Expenditures; and Roefie Heutings concepts of PreventionCosts, Avoidance Cost, and indefinitely extending [non-renewable] reserves. The Valeros discussstrong-sustainability thinking (i.e. thinking about each kind of natural resource in its own right, with-out assuming a priori that if it is used up, a substitute can replace it), and this prompts them to exam-ine critically the common-sense notion of natural capital and to list some misconceptions hidden in

12. See Bruce Hannon, The role of inputoutput analysis of energy and ecologic systems in the early develop-ment of ecological economics a personal perspective, Annals of the New York Academy of Sciences, 1185(2010) pp.30-38. The account begins as follows: The idea of combining economics and ecology into a singlediscipline has it roots in the ideas of Robert Costanza in the mid-1970s when he was completing his PhD thesiswith the Energy Research Group ... at the University of Illinois in Urbana....

13. See Mauro Bonaiuti, ed., From Bioeconomics to Degrowth: Georgescu-Roegens New Economics in eightessays (Routledge, 2011), p.237.

the analogy with industrial capital. (Natural endowment would be, they say, a more suitable term. Iagree.) They warn against supposing that substituting one mineral for another is going to be routinelyfeasible in a high-tech era of clever uses for this and that specific mineral resource. They mention thatrecycling often requires a lot of exergy (a fact which Chapter 14 will explain in detail). And they pointout the paradoxical fact that since the overriding mentality [nowadays] is that ecosystems are subjectto irrevocable death whilst minerals are not, modern society likes to use up, in order to restore localecosystems, the non-renewable kind of natural endowment which is the subject of their book, withouttrying to use inherently renewable (though evolving) ecosystems to help recover certain non-renewablemineral resources from degeneration into useless waste.

(c) Scientists. This part of the chapter is a bridge between its earlier parts and the next chapter.The Valeros say that ecological footprint (Wackernagel and Rees, 1996; this concept is based onreckoning in terms of surface areas of economically and environmentally valuable parts of the globe)explains well the demand for the regenerative capacity of biotic systems but provides insufficientinformation when dealing with abiotic resources. (Indeed. How could you guess at the value of anabiotic resource on the basis of square meters? Its not like a field of wheat.) They are ambivalent aboutH.T. Odums emergy analysis. It is, they find, too inexact (and I agree), even though it does addresseco-centric problems that other methodologies are unable to, and is based on the resources [own]physical characteristics, and measures all resources ... with a single unit, and is therefore useful(notwithstanding the inexactness) for ecosystem analysis. They find that Friedrich Schmidt-Bleeksproposed method (1993, 1994) of assessing by weight the material input per unit of [economic]service is a sustainability-indicator which is easy to understand but takes no account of irreversibili-ties like material dispersion and depletion, nor of the costs of dealing with contamination throughheavy metals, radioactive materials and persistent [noxious] organic compounds, and thus yields in-sufficient clues for prioritizing among possible remedial measures. They are likewise ambivalent aboutembodied-energy analysis (with estimates of how much consumable energy has been consumed inthe course of creating various commodities and delivering them to customers), which Bruce Hannonin the 1970s had used in drawing up input-output matrices for the U.S. economy (with the numbersrepresenting amounts of consumed energy rather than dollars). They say that this kind of analysis12

often provides valuable insights but is to some extent methodologically weak because it lacks thermo-dynamic fundamentals and therefore lacks good rules for allocating [the supposed] energy inputs [i.e.exergy costs] among [the resulting] co-products, by-products and wastes common in many mines.

Georgescu-Roegen had, on the basis of his own regard for thermodynamic fundamentals, criticizedthe concept of embodied energy more sharply than the Valeros do. I see two interesting analogies13

here. One of them is with W. S. Jevonss famous rejection (1871) of the classical economists labourtheory of economic value. Labour and embodied energy are, alike, aspects of the history of the com-modity up to the moment when it is ready for sale to consumers, whereas (a) Jevons pointed out thatits market value routinely depends on how much people are thereupon willing to pay for it (regardless

14. William Stanley Jevons, Theory of Political Economy (1871 and several later editions; my reference here is tothe 1931 edition), p.164: [L]abour once spent has no influence on the future value of any article.

15. Different writers have offered somewhat different definitions of virtual water. The definition best suited tomy point here is in A.Y. Hoekstra and A.K. Chapagain, Water Footprints of Nations: Water Use by People as aFunction of their Consumption Pattern, Water Resources Management, vol.21 (2007), pp.35-48): the volumeof freshwater used to produce the product, measured at the place where the product was actually produced.

16. The concept of Pigouvian taxes was first set out in 1920 in A.C. Pigous The Economics of Welfare. TheOrganization for Economic Co-operation and Development defines them as tax[es levied on an agent causingan environmental externality (environmental damage) as an incentive to avert or mitigate such damage.

of how much labour may have gone into producing and delivering it), and (b) the Valeros will estimate14

losses of the thermodynamic rarity of mineral resources on the basis of assessing how much exergywould theoretically thereafter have to be spent to recover them from thanatia. The other analogy thatI have in mind is between the concepts of embodied energy and virtual water (i.e., water used toproduce a commodity which may or may not then actually contain it): In each case a qualitative quali-15

fier should be recognized as being crucial to the argument, since the energy is really exergy and thewater is practically always freshwater.

(Given that the Valeros see, just as clearly as Georgescu-Roegen had seen it, a lack of thermo-dynamic fundamentals in the concept of embodied energy, why do they say that it often providesvaluable insights? The answer has to do, I think, with the fact that retail consumers shouldnt have tostudy exergy etc. in order to make environment-friendly microeconomic choices. For that kind of pur-pose a thermodynamically inexact concept such as embodied energy will suffice. What the Valerosare trying to provide, however, is a more exact kind of guide for engineers and the like. They dont gointo political science, but I imagine that if they did, they would mention Pigouvian taxes. )16

After discussing in this chapter several additional ways of assessing environmental impact, theValeros prepare the reader for the next chapter by introducing the concept of thermoeconomics,the basic precept of which is that the role of exergy in our material activities ought to be understoodnot only by means of the Second Law but also in terms of such criteria as the efficiency and benefits(health-wise, for instance) of the various mechanisms for capturing and utilizing exergy to make com-modities and perform other services.

(If this basic precept of thermoeconomics is worth applying to all our material activities, why shouldit be especially pertinent to our uses of abiotic natural resources? The answer lies in Alfred Lotkas dis-tinction (1945) between endosomatic and exosomatic instruments. Endosomatic is a tag for thingsinside the body of a given creature; exosomatic refers to things outside it. A birds wings, beak andfeet are endosomatic; a beavers dam and a [wo]mans gun are exosomatic. We humans have, however,far more exosomatic instruments than other creatures do. Whereas all creatures with skeletons needcalcium phosphate endosomatically for their bones, we humans also need calcium carbonate (lime-stone) exosomatically for building stones and cement; we need calcium sulfate (gypsum) for plaster;etc. Whereas all red-blooded animals need iron endosomatically in order not to become anemic, wemodern humans also need it exosomatically for steel. And so on; the examples are legion.)

The latter part of this chapter and the entire next one are philosophically the most interesting partsof the book. In order to serve up a taste of the philosophy (and, in particular, the concept of qualityas a characteristic which can be found in our lives and in the inanimate world) let me mention first thatin physics, the word system is a term (i.e. a word with a standard technical meaning) for any given orimagined portion of the universe that has been chosen for studying the physical changes which takeplace within the system in response to varying conditions (that is, it doesnt have to be something

which would be described in common-sense talk as systematic; it can be anything physical, big orsmall, that a physicist wants to study); the properties of a given system are said to be either exten-sive or intensive; and, its extensive properties include its total energy as well as its mass and vol-ume, whereas the intensive properties (i.e. properties which can be estimated quantitatively withouthaving first got estimates of the extensive ones) include the systems temperature(s), level(s) of pres-sure, and chemical composition. The Valeros theory depends on the fact that the systems intensiveproperties can each be converted into exergy; but they appreciate also the fact that the qualitativeaspect of a systems energy which determines what proportion of it is exergy (i.e. to what extent theenergy can perform work) is hardly the systems only quality that is likely to be important to us. Theypoint out that a certain morsel of food could to some appear repugnant, whilst to others [it might beof] extraordinary [value,] but regardless of opinion it will always maintain the same exergy value, andthat a work of art will have aesthetic as well as physical qualities, and the former will of course have alot to do with its value. They decline, therefore, to put forward exergy as a physical measure of thevalue of things as an alternative to their market price.

In regard to Humankinds uses of minerals and fuels the Valeros are seeking to define and identify(and here I will italicize some of their words that imply quality) the true efficiency [exergy-wise, andtherefore macroeconomically in the long term] of processes in a given system, once the desired flows[of goods] to be produced are identified. They want to show how to increase the true efficiency.

3: From Thermodynamics to Economics and Ecology. This chapter is about some aspects ofthermodynamics which are relevant to macroeconomic assessments of all kinds of environmentaldegradation. It starts out with detailed accounts of the laws of thermodynamics, of the concepts ofexergy and irreversibility, and of thermoeconomics. Then it gives, in preparation for the next chapter,an introductory account of physical geonomics, which is an application of thermodynamics that theValeros have devised in order to be able to make their quantitative evaluation[s] of mineral resourcesfrom a Second Law perspective. Exactly how they would do this for each kind of mineral is explainedlater in the book; Chapters 5 and 6 will meanwhile provide an introductory account of all the valuableabiotic stuff that is currently accessible to mining companies etc., or which may become accessible infuture if inventors devise new ways to get and use it (and if civilization is not meanwhile destroyed).

4: Physical Geonomics: A Cradle-Grave-Cradle Approach for Mineral Depletion Assessment. Thekey idea here is to consider, in assessing quantitatively Humankinds current and likely future relation tominerals, not just how much pollution etc. is caused by mining and by industrial uses of minerals, andhow much exergy will sooner or later have to be expended to prevent the pollution from rendering usvery sickly or even extinct, but also how much exergy would theoretically be needed to return each eco-nomically valuable kind of mineral from an utterly dispersed, crepuscular condition of thanatia to acondition of a certain degree of rarity thermodynamically equivalent to what it was when the stuffwas in the mines where Humankind found or will have found it. This latter amount of exergy is equalto the natural bonus of having minerals concentrated in the ores in the mines rather than being dis-persed evenly throughout the Earths crust.

This chapter culminates in a set of three graphs in each of which the curve looks as though it wereplotting commodity price (on the vertical axis) against market demand (on the horizontal axis), butactually the difference in height between any two points on the curve represents an amount of exergywhich has somehow been expended on work (in the physicists sense of the term) causing a certainbatch of a certain mineral to have a certain degree of thermodynamic rarity, while the resulting eco-nomic quality of the ore the ore grade is plotted horizontally in the graph. Of particular interest

Care the situations (a) in the dire crepuscular conditions of thanatia (x ), which are, however, infinitelybetter than before the cosmic Big Bang (we would need an infinitely tall graph to chart the situation

17. The mining consists of extracting ore from the deposit and transporting it (inside and outside of the mine).The ensuing beneficiation would characteristically consist of crushing and grinding the ore and then separatingthe sought-after stuff (by such techniques as flotation, magnetization, sieving, washing etc.) from other stuff in theground-up ore. (That other stuff is called "gangue".) The resulting valuable stuff then transported to a treatmentplant, where metallurgical treatment would consist of "smelting" (chemical reduction of metallic oxide to obtain(unpurified) metal(s) and then "refining" the metal(s), e.g. by electrochemistry or carbochemistry, to whateverdegree of chemical purity the manufacturer requires.

18. There is no arrow of time from left to right in these graphs. Instead, the points further to the right representhigher grades of economic quality in the stuff at a certain stage (indicated by the subscript to x) of the process.

Mbefore that), and then (b) in an ore which is more or less feasible for mining (x ), and then (c) post-

Bbeneficiation (x ), which is economically better than before the beneficiation but is still prior to the17

refined minerals use in manufacturing to make commodities such as houses, airplanes, hair dryers,diet-supplement pills etc. The firstof the three graphs, which can betaken as being about a momentarysituation in regard to a certain mineand a certain mineral taken from it,includes a note to the effect thatwhile the difference in thermo-dynamic rarity between the stufftheoretically in thanatia and actuallyin the mine is a natural bonus(since our heritage from Nature in-cludes the existence of this batch ofore suitable for mining), the subse-quent difference between the ore (a)in the mine and (b) after extraction,beneficiation, etc. is the mine-to-market cost (reckoned here interms of exergy):

The second graph indicates that the mining process itself diminishes the natural bonus, since more exergyhas to be expended to dig deeper (or

M1 M2whatever). In this graph, x and xrepresent earlier and subsequent con-ditions, given a certain mine and acertain set of techniques for miningit and processing the stuff:18

But what if better techniques couldbe devised and applied, such that (a)the mine would yield more from thesame Human-administered amount ofexergy, and (b) the processing becamelikewise more efficient exergy-wise? Inthat case, we would have a new curve, Ore grade

in which each distance rightwards would be at a lower height:

19. Appendix B in the book provides, for economists and other readers who may not have had college-level educa-tion in chemistry or geology, the equivalent of undergrad-level lectures on the minerals and the chemical elementsand their characteristic economic uses.

20. Topsoil is not included in this survey, as it is teeming with worms, insects, plant roots and microorganisms hardly abiotic; and, the moisture in the topsoil (which amounts to a tiny portion of the hydrosphere, but is ofcourse vital for the plants on the land) is not included in the hydrospheric reckoning.

(And yet there would be, of course, a steadily increasing mine-to-market cost to be charted on thisnew curve as time goes by; and the mine would eventually be exhausted, and the natural bonusthereby lost.)

* * *

The next four chapters make up a section of the book which is entitled Over the Rainbow: FromCradle to Grave. It goes into detail about the chemical and mineral makeup of the Earths abiotic stuff,about the global distribution of the various substances, and about how they are taken from the naturalendowment to Industry en route to their consumption and toward the theoretical thanatia. These chap-ters are like handbooks inasmuch as they include 29 tables (as well as 30 figures), some of them severalpages long; but virtually all the data is in one way or another needed to help provide a reasonably solidbasis for the important (though somewhat speculative) assessments set out in Chapter 13.

5: The Geochemistry of the Earth and 6: The Resources of the Earth. These chapters reviewthe planets geological and geochemical characteristics, focusing especially on the quantity and qualityof the useful mineral resources. Chapter 5 is equivalent to a graduate-level lecture on geology and19

account of the make-up of our abiotic natural endowments in terms of all the important kinds of min-20

erals and of 77 chemical elements which are potentially available for extraction and use. It describesthe composition of the various layers of the atmosphere, of the hydrosphere (i.e. the various forms of

2H O, including the atmospheric water vapour, the renewable freshwater resources, the ice caps, ice15

21. N.A. Grigorev, Average composition of the upper continental crust and dimensions of the maximum con-centration of chemical elements... (in Russian), Uralian Geological Journal, III (2007), pp.3-21.

22. Nancy E. Carpenter, Chemistry of Sustainable Energy (Boca Raton (Florida, USA), CRC Press; 2014).

23. I put this word in quotation marks in order to avoid implying that Humankind is not part of Nature.

sheets and glaciers, and the 97% of the hydrosphere which is salt water) and of the continental crust,with detailed attention to the chemical and particularly the mineralogical composition of the upperpart of the crust. (99% of this upper part can be accounted for in terms of eight chemical elements. Theother elements are rare.) The history of the methods of making such estimates is described in somedetail. The Valeros regard the findings of N.A. Grigorev (2007) as being a significant improvement21

upon those available in the compilations published by Wedepohl (1995), McLennan (2001) and Rudnickand Gao (2004).

Chapter 6 is mostly about the various possible resources of consumable energy: nuclear, geo-thermal (i.e. from heat radiating ultimately from the innermost parts of the Earth to the surface), tidal,hydroelectric, from windmills, and more or less directly from solar radiation, as well as from burningvarious kinds fossil fuels and of biomass. Remarkably detailed data are set out, for instance in regardto ores, petroleum etc. of various different qualities. The reason why is perfectly obvious when it comesto fuels: the higher the quality, the less is needed to provide this or that amount of consumable energy.

An excellent recent textbook by Nancy Carpenter describes in detail the theoretical chemical as-22

pects of various industrial methods of producing consumable energy, and she is clearly attentive to thefact that even if a certain method may appear to be inherently sustainable, the materials needed to usethe method may be too readily exhaustible. The Valeros go into far more detail about this latter point.

7: An Introduction to Mining and Metallurgy and 8: Metallurgy of Key Minerals. Chapter 7describes the main physical processes, costs exergy-wise, and environmental impacts of the mining andmetallurgical industries (exploration, extraction, smelting, refining), and also the reclamation, rehabili-tation and post-closure treatment of mines. This serves as an introduction to a set of more specific anddetailed analytical descriptions, in Chapter 8, of the processes in regard to each of a dozen differentdemetallurgical categories (iron and steel; aluminium; copper; copper-related metals; nickel and cobalt;etc.) and to each of several subcategories within some of these categories.

* * *

Having thus discussed taking stuff from Nature to Industry en route to the theoretical grave23

of thanatia, the Valeros devote Chapters 9-12 to a theoretical reversion from grave to cradle, areversion which they also tag metaphorically as down the rainbow, i.e. back to a useful degree ofconcentration. Their quantitative study of such theoretical reversions will provide data for a compre-hensive set of provisional assessments, in Chapter 13, of how fast the natural endowments of the non-fuel minerals their economically feasible natural concentrations in the Earths upper crust could wellbe exhausted in the next ten or twenty decades.

(Chapters 14-16 will then suggest how to develop and adopt more efficient ways of extracting, pro-cessing, using and recycling nonrenewable abiotic resources. To cultivate a rational management rational for Humankind of mineral resources would be, the Valeros say, like tying the rainbows: re-routing the stuff away from the last part of its journey to thanatia. These Spanish-style poetic touchescarry messages of admonition and of hope.)

24. See apropos Kozo Mayumi, The_Notion_of_Substitution..., at www.academia.edu/12516509/The_No-tion_of_Substitution_Reconsidered_Economical_Biophysical_Epistemological (downloaded 27 May 2015).

25. M. King Hubbert, Nuclear Energy and the Fossil Fuels (Houston 1956), p.10 (and p.22), and Energy Re-sources: A Report to the Committee on Natural Resources of the National Academy of Sciences NationalResearch Council (Washington 1962), p.73.

9: Thermodynamics of Mineral Resources. This is about which particular thermodynamic con-cepts are useful for exergy-cost assessments of mineral formation, separation, scarcity and mining,and for exergy-calculations in regard to the resulting fuel and non-fuel minerals.

10: Thanatia and the Crepuscular Earth Model. This is about how to assess quantitatively thetheoretical baseline for exergy-assessments of mineral resources. It includes accounts of how much ofeach kind of the various mineral resources (defined in terms of their differing chemical compositions,which are described in detail) would exist in thanatia.

11: The Exergy of the Earth and its Mineral Resources. This chapter provides definitions and dis-cussions of enthalpy and of Gibbs free energy. These mathematically formulated concepts of physics closely related to, but not the same as, exergy are of use in the next chapter.

12: The Exergy Replacement Costs of Mineral Wealth. This is about how the replacement costs ofdepleted mineral resources compare, exergy-wise, with the current consumable-energy costs of miningand metallurgical processing. Replacement here means recovery, not substitution. (You may recall24

my having mentioned that Chapter 1 includes a remark to the effect that plants and other biota re-quire phosphorus to live and that there is no possibility of replacing it with an alternative, i.e. ofsubstituting something else for it.) Phosphorous is not the only such indispensable stuff.

A notable fact brought out in this chapter is that while more than 60% of the physical exergy costsattributable to the total worldwide production (as of 2008) of the main non-fuel mineral commoditieshad been in the form of fossil fuels being burnt up in order to get the stuff, some 33% of the exergycosts was in the form of a resulting loss of the bonus of having the minerals concentrated in feasibleores instead of being spread thin in a crepuscular worldwide landfill. (The Valeros havent used thisphrase, but it seems to me suitable.) No wonder recycling will be discussed at length in Chapter 14.

13: The Exergy Evolution of Mineral Wealth. This is to my mind an especially impressive chapter.Back in Chapter 2 the difference between quasi-static i.e. non-renewable resources and the moredynamic biological systems has been mentioned. A well-established way of making predictions in re-gard to the rates of extraction and (hence) exhaustion of the non-renewables is by means of Hubbertcurves. Hubbert was a geophysicist in Texas who devised the following kind of graph and used it tomake a remarkably accurate prediction that peak production (i.e. the historically fastest overallannual rate of production) from oil wells within the USA would occur in 1970:25

The area under the curve represents the stock. The height of the curve at any given moment (time isplotted from left to right) represents the rate of its extraction at that moment. The left half of the curverepresents an historical progression from a gradual start-up to a kind of feeding frenzy as the curve ap-proaches the peak production phase, some halfway through its historical course. For any given realstock, data must be available (if this method of prediction is to work) for a fair amount of the left half ofthe curve (which will therefore be less smooth than in the idealized version); the method entails usingon the one hand an estimate of the total natural stock and on the other hand a presumption, based onsome historical observations which Hubbert had made, that after half of it has been used, the rate ofextraction will slow down pretty much in reverse to the way it had sped up.

Chapter 13 includes more than 70 Hubbert curves (as well as dozens of other graphic figures) pro-viding easy-to-read assessments of when the peak-production years for each of the various kinds ofuseful minerals are likely to have occurred.

Some words of caution are called for. If the estimate of the feasibly available natural stock is toohopeful, then the peak-production moment will come sooner, and vice versa if feasible ores prove to bemore bountiful than expected. If the estimate is to be made in terms of exergy costs, then good data inregard to the history of the ore grades is also very desirable; and yet only patchy data are at hand forthe assessments in regard to some of the minerals; and so, many of the Valeros Hubbert curves repre-sent merely provisional assessments. (They acknowledge this and discuss various ramifications of theuncertainties.) But the method is informative even so, because if the stock that is feasibly availablefrom natural endowment is really twice as big as estimated, then the rightward shift of the peak-production moment is a matter of only some 35 years.

The chapter culminates in a set of five graphs, on each of which several Hubbert curves are placed.The first and last of this set are shown below. (Note that the amounts represented by the heights of thecurves in the first graph are far greater than in the second one. All the stuff for which data are plottedin the second graph is merely part of what is covered by the hardly perceptible curve labeled Rest ofminerals in the first graph.)

26. Let us recall here that radical shortages of nonrenewable abiotic resources comprise only one aspect of loom-ing environmental degradation, and that some of the other aspects may be of more urgent significance. The effectsof climate change are likely, IMHO, to cause agricultural havoc already in this century. Newfangled epidemicsdue to superbacteria etc. will meanwhile draw immediate attention. The timescale of the effects, dangerous toHumankind, of diminishing biological diversity may be comparable to that of the diminishing natural endowmentof mineral resources: a well-qualified Canadian ecologist has estimated (Peter F. Sale, Our Dying Planet: An Eco-logist's View of the Crisis We Face (University of California Press, 2011; p.233) that by the end of this century,Most larger species (coyote size and up), other than those directly cultivated by humans, are likely to be extinctor to exist only as threatened populations.... Environmental goods and services [needed by humankind] will bemuch reduced simply because of the loss of diversity of organisms. With the increased homogeneity and overallreduced diversity, there will be a much greater risk of pandemics that severely impact particular species and createmassive change in ecosystem composition as a result. The risk of a species extinction that has major ramificationsthrough the ecosystem will become ever greater as diversity falls, and our own population will be precariouslydependent on just a few species to sustain its vast size.... [Probably] it could be a sustainable world for a time,as long as we engaged in a fair amount of environmental engineering to help it along until it neared the pointof final collapse.

The general take-away message is that all the peaks will probably have occurred before the nextcentury and that a great number of shortages will become drastic before the end of it. 26

However, the Valeros purpose is not just to sound an alarm about looming shortages of nonrenew-able abiotic resources but also to outline a well-designed basis for mitigating the effect of the short-ages. The next three chapters are about that. The following graph shows what percentages of theestimated original natural endowments (i.e. as of the birth of modern industry) of ores for 42 eco-nomically important non-fuel mineral commodities had been exhausted as of 2008:

27. Tailings are ground-up waste from mineral processing operations. Slags are waste from metal smelting.

28. The term exosomatic means outside the body of the organism (in this case human). See p.@.

14: Recycling Solutions. Some of the points covered in this chapter are that the only way to elim-inate extraction from natural endowment would be to increase recycling and reduce demand until thelatter no longer exceeds the former; that this is not going to happen very soon in regard to strategicmetals (the recycling of which has seldom amounted to as much as half of the fast-increasing demandin modern times); that even so, to recover economically valuable chemicals from tailings, slags and27

post-consumption waste is beginning already to gain importance as the ore-grades of natural depositscontinue to decline and as extraction from this or that kind of waste tends therefore to become cost-effective; that dispersion should therefore be assessed as the replacement cost from thanatia not justto traditional mines (as described in Chapter 12) but also to potentially useful technospheric waste;that while we cannot improve the levels of concentration of valuable minerals in natural-endowmentsources, we can by means not only of technology but also of lifestyle-alteration improve the levelsof concentration in various kinds of anthropogenic mines, while also improving the techniques ofanthropogenic-mine as well as natural-mine beneficiation and metallurgy; that all forms of recoveryfrom technospheric waste are subject, however, to the Second Law, and the waste from a consumedrecyclate is likely to contain more entropy than the recyclate had contained; and yet that there is none-theless a huge potential for material and energy savings and for reducing pollutant emissions. TheValeros call for a holistic view of life-cycles [of consumable minerals] and recycling chains, for furtherresearch in process and in end-of-life recovery, eco-efficient design [and] disassembly, for systematic

[ ] [ ]account of [exergy] losses , ... a new way of promoting and managing material streams , ... and an eco-nomic paradigm shift.

15: The Challenge of Resource Depletion. This chapter discusses (in a somewhat rambling way, itseems to me) why mineral resources are being poorly managed. It identifies accurately (in my opinion)some big defects in the neo-classical economic theory which has focused so much on material socialexchanges that it has neglected environmental externalities and has incorrectly taken as for grantedthat everything in our natural exosomatic endowments can be substituted for. The Valeros call for a28

paradigm shift whereby (a) since money is not an absolute and universal magnitude, as it is subject toboth inflation and monetary revaluation..., the unit of measure employed for [natural-]resource use

[ ][would] be physically [rather than monetarily] based , and in this respect Thermodynamics must playa prime role, (b) economists and the politicians whom they guide would realize that the substitution

[ ]of materials, unlike that of money or [sources of consumable] energy , is limited and case-specific, and(c) long-term thinking would become embedded in economic theory.

16: The Principles of Resource Efficiency. This chapter is rich in engineer-type professional chatand sets out 12 basic principles, together with an ample number of corollaries to them, which theValeros propose that businessmen as well as engineers adopt in striving toward sustainable resourcemanagement. The text includes many references to other authors similar proposals. The references inChapter 2 to writings by other authors were part and parcel of an historical narrative (complemented bycriticisms and critical appreciations) and I therefore mentioned some of them; but here I will just give aprcis of some of the ideas:

To take seriously the Second Law (i.e. that even though energy is, as the First Law tells us, never lost,every expenditure of exergy entails some irreversible loss of exergy). Since the various processes forobtaining purified materials from mixtures of materials cost gobs of exergy, two of the corollaries for

industrial engineers are do not mix, purify, clean, heat, cool, pressurise or depressurise more thanstrictly necessary and segregate polluting flows; do not mix them.

To think about replacement costs and to reckon that the greater the cost of replacing a resource, i.e.the greater its rarity (exergy-wise), the more it should be preserved.

To attend to the difference between efficacy (getting things done) and efficiency (getting them donewithout wasting resources). One of the corollaries is that getting things done faster in industry meansmore heat, more chemicals, more water, more effluents, more solid waste and special hardware re-quirements. Consider time as a resource that ultimately saves more resources.

To design products to last and to be easily repaired, and then extend their viability through upgradesand careful maintenance. Two of the corollaries are to upgrade [factory] systems through replacingobsolete components, instead of replacing the system in its entirety and to personalise possessionsas this may augment their endurance.

To repair things efficiently and to reuse them with due revisions when appropriate.

To exercise intelligent control for maintaining, in the economy, the required quality of purified min-erals with as little expense of exergy as possible. Two of the corollaries are: know your process andinvest in appropriate equipment in order to know it all the better and predict the accident, dont justreact to it.

Since the storing and transmitting of electricity as well as of heat (i.e. of a temperature higher thanthat of the surroundings], costs a lot of exergy, to instantaneously couple supply and demand ofconsumable energy, and avoid unnecessary distances of transmission. One of the corollaries is:Undertake intensive research in [better methods of] energy storage.

To be alert to the fact that since each physical system on Earth is part of a greater system, all thesystems are somehow connected. One of the corollaries is: The industry and urban system must be[regarded as] part of the natural system. The [deliberate] connections must be multiple and ongoing,not discrete, aggressive and/or ill-considered."

To be aware that the malfunctioning of a subsystem is likely to render the broader system inefficient(but also that the proper functioning of a subsystem doesnt ensure proper functioning of the broadersystem!). One of the corollaries is to design flexible and resilient systems.

To feel that all waste symbolises defeat in the design of some system in the economy and/or in itsconnection with other systems. Here the Valeros mention that in the biological world, one organismswaste is another ones feedstock. Two of the corollaries are: Embrace Biomimicry in product designand Energy must come from renewable sources (as should the materials used to generate it).

For society at large, to evolve toward paying a larger share of money for goods and services that cost,directly or indirectly, a lot of exergy, and hence toward paying relatively less for those that cost lessexergy. (The Valeros mention, as a notable example of imbalance between monetary and exergy costs,the fact that in the entire process of creating a residence, the deed-signing entails the highest financialexpenditure per unit of energy effort.)

17: Epilogue. Some of the theoretical points restated in this chapter are that exergy can serve asa universal measure for resource accounting, that the concept of decreasing degrees of thermo-dynamic rarity (reckoned in terms of exergy) can be used to indicate the hidden but eventually realdepletion-costs of producing industrially useful minerals, that cradle-to-grave technologies constituteonly half of the theoretical material cycle for each industrially useful chemical element, and that theconcept of thanatia provides a baseline for calculating the other half, i.e. for assessing depletion in

terms of grave-to-cradle exergy costs. It would be sane to use up the fossil fuels sparingly (as they can-not be recycled) and to recycle efficiently the other ingredients of the Earths natural endowment ofmineral resources, realizing that for them as well, an actual grave-to-cradle process would take too long millions of years to be of use to Humankind.

There are five appendices (labeled A, B, etc.):

A: Discussion of which kinds of materials, and how much of each, are used up in green tech-nologies (electric and hybrid vehicles; flourescent and LED lighting; newfangled information andcommunication technologies).

B: Descriptions of seven main groups of minerals in our natural endowment (the silica minerals, thefeldspars, the pyroxenes, and the amphibole, olivine, mica and chlorite groups) and of the geochemistryand various industrial uses 77 of commonly produced minerals (from Aluminium to Zirconium).

C: Detailed description and discussion of the parts of the U.N.'s internationally accepted System ofEnvironmental-Economic Accounting (SEEA) that are directly relevant to the subject of the book: i.e. theasset accounts for mineral and energy resources.

D: Additional Data and Calculation Procedures. The topics of the data and/or calculation pro-cedures are: standard redox potentials (i.e. how much voltage is needed to cause certain industriallydesirable chemical reactions with minerals to take place); how much exergy is needed (it is a lot) forcommunition (i.e. to reduce chunks of various kinds of ore to small particles by cutting, grinding, vibra-ting etc.); the estimates published by (a) Rudnick and Gao in 2004 and (b) Grigorev (2007) of how muchof this and that chemical element is in the Earths upper crust; Australian fossil-fuel production; andworldwide fuel production.

E: An account of a philosophical interview in November 1991 with Nicholas Georgescu-Roegen. Hisreason for advocating conservation was that with conservation we gain time, and in gaining timewe make it more probable for a [new] Prometheus to arrive if it is to arrive; we dont know what isto come next.

* * *

29. Cited in Alan O. Ebenstein, Friedrich Hayek: A Biography (2001), p.273. Friedman went on to say, If yourealways going back to your internal, self-evident truths, how do people [i.e. economic theorists] stand on one an-others shoulders? And the fact is that fifty, sixty years after von Mises issued his capital theory which is whatsinvolved in Hayeks capital theory so-called Austrian economists still stick by it. There hasnt been an iota ofprogress.... If you and I disagree about whether some proposition or statement is correct, how do we resolve thatdisagree ment?... We [would] have [on the basis of allegedly self-evident truths] no way to resolve it except byfighting, by saying youre wrong and Im right.

30. Robert Solow, The Economics of Resources or the Resources of Economics, The American EconomicReview, LXIV/2 (1974), p.1.

31. The term social metabolism came into use in the late 19th century as a translation of the German term Stoff-wechsel. It is a misleading translation, since (a) only organisms have metabolisms and (b) societies are not reallyorganisms. A phrase conveying correctly the meaning of Stoffwechsel is transformative exchanges of matter.

32. Sudhir Anand and Amartya Sen, Sustainable Human Development: Concepts and Priorities (U.N. HumanDevelopment Report Office, 1994; 2nd edition, 1996), p.11.

I can see two main problems in regard to the reception and usefulness of this book. (1) It is full ofdata which will soon be outdated. An occasionally renewed online version should be published for adecent subscription price. An ancillary advantage of this other way of publishing would be to allow forrefinements (as well as updatings) in the presentation. (2) Meanwhile, however, it is clear to me thatnearly all economics professors are, alas, too ignorant about science and technology to understand thetheory and reckoning which the book offers. Perhaps some of them would, even if they could under-stand the argument, belittle the Valeros projections somewhat as Robert Solow in the 1970s belittledthe projections prepared at MIT for the Club of Rome. Many of those dismissive professors would beimplicitly content with von Misess and Hayeks precept (let me cite here Milton Friedmans descriptionof it) to base economics on propositions that are self-evident ... because they are about human beings,and were human beings. So we have an internal source of final knowledge.... Their intellectual level29

would match that of Solows famous declaration that The world has been exhausting its exhaustibleresources since the first cave-man chipped a flint, and I imagine the process will go on for a long, longtime. (So why worry?)30

The ecological economists do worry, but even they, by and large, dont know enough about therelevant aspects of chemistry, engineering and industrial production to understand a great deal of whatthe book says. An abridged and simplified edition for them might be worthwhile. It might help their suc-cessors who will have studied scientific topics at graduate-school level (which 21st-century ecologicaleconomists ought anyway, IMHO, to do) upgrade the level of discourse in the field and bring it well be-yond rudimentary concepts like throughput, social metabolism and happy planet. It could also,31

with luck, prompt attentive welfare economists to deconstruct the tragically misleading postulate ofsustainable human development endorsed by Amartya Sen and promoted by the United Nations inthe 1990s that The fact of substitutability (in both production and consumption) implies that whatwe are [morally] obligated to leave behind [for children and future humans] is a generalized capacity tocreate well-being, not any particular thing or any particular resource.32

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