Global constraints and a new vision for development—I

TECHNOLOGICAL

Is

FORECASTlNG

AND SOCIAL

CHANGE t&211-297

(1974)

277

Constrai ts and a New Vision evelopment-

YOICHI KAYA and YUTAKA SU%UKI

ABSTRACT The object of the work rcportrd here (Part I) is the limited supply and forseeable depletion of the world’s mineral resources. including fossil fuels, as well as the effect their consumption will have nn the earth’s atmosphere. In particular, wc have studied how the discharge of carbon dioxide and heat from fuel combustion will affect the atmosphere. In projecting the dcplction of mineral resources, we have limitci I~~lrsclvcs to the next thirty years or so, up to the year 2000 A.D. To attempt to look beyond this was, we felt, unrealistic. ‘lecausc WCcan optimistically expect that technological advances in the rc-cycling of resources, the utilization of solar energy, and the development of nuclear fusion will completely change the energy picture for the human race by the year 2000. Part II, in the next issue, deals with the growth of developing nations.

Introduction In recent years, the human race has become increasingly aware that its progress is being threatened by the limitations of our finite earth. The Limits to Growth drew the conclusion that not even significant technological advances can sufficicnrly roll back these limits. Food resources, water supply, available Imd, and other factors are presented as major growth-limiting factors. To attempt to analyze each of these f-actors thoroughly would be such a vast project that we have restricted our attention in Plrt I of this report to only one of these limiting factors. The object of the work rcportecl here is the limited supply and foreseeable depletion of mineral resources, includin, 13fossil fuels, 3s well 3s the effect their consumption will have on the earth’s atmosphere. In particular. we have studied how the discharge of carbon dioxide and heat from fuel corn lustion will affect the atmosphere. In projecting the depletion of mineral resources, we have limited ourselves to the nxt thirty years or so, up to the year 2000 A.D. To attempt to look beyond this was, we felt, unrealistic, because we can optimistically expect that technological advances in the rc-cycling of resources. the utili/.ation of s6ar energy, :md the development of nuclear fusion will completely change the energy picture for the human race by the year 2000. The approaching limits of our earth, however, compete for our attention with another equally, if not more serious problet.1: the poverty and inadequate economic growth r-ate of the developing nations. In thc.
YOICHl KAYA Japan Work Team Committee and the .E&?orial Note: Journal.

(Univ. of Tokyo) and YUTAKA SUZUKI (Osaka University) arc members of the of the Club of Rome. This work was sponsored by The Club of Rome Japanese Japan Techno-Economics Society. This paper is presented in two parts, with the second part in the next issue of the

0 American

Elsevicr Publishing Company,

Inc., 1974

278

YOlCHIKAYAANDYUTAKASUZUKl

Ame,rica, where over half of the world’s people live, development is made extremely difficult by rapid population growth chronic malnutrition, and often by an unstable political order. Furthermore, if we look some distance into the future, we can easily see that the developing nations will run into anlIther impasse when their manufactured goods begin to compete with those of the advanced nations in the world market. On this point, at the GATT meeting here in Tokyo in Sektt-nber 1973, not only the delegates from the Philippines, Indonesia, and other developing nations, but even one from an advanced nation like Holland insisted that to help the developing nations effectively, tike :. lvanced natio;ls must take positive steps to reform the structure of their own industry. We have made an attempt tlo investigate exactly what kind of reform in the indust,, pattern of the world would be m1:)z.tdesirable. Because for each local area the limiting factors such as available land, climate, the people, natural resources, and available capital are different, an industry pattern must be sought which, while respecting these limitations, will practically and effectively contribute to the progress of the nation. To find the optimal world industry pattern under so many local conditions and restraints is such a formidable problem that we have resorted to the techniques of mathematical programming. We have also tried to estimate what the realization of this plan would achieve. Our work on this problem is contained in Part II of the report. Our work on these tw_ problems is not yet complete, but we would like to offer some of the conclusions we have fc.rmed thus far. l.MlNERALRESOURCES (1) The overall amount ol’ natural mineral resources is so great that their exhaustion does not seem imminent. In fact, the available amounts still unexploited are quite considerable. (2) Nevertheless, the rapidly growing demand folr energy, which shows no signs of abating, threatens to precipitate a temporary energy crisis at about the end of this centuq, before nuclear power generation has been developed enough to fill the gap. To bridge .this temporary crisis immediate steps must be taken to develop new technologies for using the abundant coal resources available. (‘3) The effect of d’ISCh arging carbon dioxide al:d heat into the earth’s atmosphere is, with our present knowledge, very difficult to predict. We can, however, affirm that, if we continue to consume energy at our present rate, the earth”s environment will be greatly affected in ways and with results which we are not able to foresee. The absolute limit to the energy generation which our atmosphere can sustain may be as low as 20 to 30 times present levels, but certainly not much higher than 200 to 300 times our present level. (4) Considering both the available resources and the effect on the earth’s atmosphere of ener?] consumption, :>ne is forced to the conclusion that the human race should try to reduce rts demand for energy. 2. WORLD-WIDE REDIISTRIBUTIONOF INDUSTRY (I) I.:notir plan, industries suitable to a developing nation would be fostered there, and at the same time, markets would be provided in the advanced nations by re-structuring their industry. (2) In t?ur platl. relatively high capital effective types of industry could be, with suitable restrictions. transfeerrpd from the advanced to the developing nations. This would also make capital aid to developing nations much more tffective than in the past. (3) In this way, while the economic ;::owth rate of the develc ping nation would be

CLOBALCONSTRAINTSAND

ANEW

VISIONFOKDEVELOPMENT-1

279

accelerated, that of the advanced nations would be slowed down. and so the global economic growth rate would not be accelerated. This would partially satisfy one of the demands made of the human race by our limited earth. (4) This plan could be called a new type of international division of industry. From this viewpoint, light industry should be promoted in Asia, and agricultural industry in Middle and South America as well as in North America and Oceania. (5) A policy of economic self-sufficiency is unfavorable in our plan, for if each nation should strive to maintain or develop economic self-sufficiency, the plan would be largely ineffective. Thus plan would impose sacrifices especially on Japan and Western Europe among the developed nations, and on all of the developing nations. (6) The method we have employed in our research is one that, taking into account the physical and economic restraints of each area of the world, searches out a feasible and advantageous world distribution of industry. International organizations also might be able to make use of our method as one mesns of forming an overall vision of the world we would like to live in in the future. 1. Global Limitations:

Natural Resources

and the Environment

l.l.TH9:EARTH'SNATURALRESOURCES:THEPRESENTANDTHEFUTURE In The Limits to Growth [I], simulation runs of the world model are s!:trwu which indicate that, if the industrial productive activity of the human race continues to grow at present rates, the earth’s natural resources will be depleted by the middle of the 21st century. It is obvious to anyone that the present exponential growth rates i:annot be maintained forever on a finite earth with limited natural resources. The problem is whether we are really in proximate danger of reaching these limits in the very near future as 7?re Limits to Growth indicates. In 77TeLimits to Growth, the maximum amount of reserves (amount still useable) is taken to be a tixcd value five times the amount of the known, or “proven reserves.” it is precisely this assumption which we would like to question. We will first present our view about the reserves and the demand for natural resources, Resource Reserves are Changing The amount of new resources discovered each year and the rate of th9r consumption determines the changing picture of the reserves. Up to the present, the annual newly discovered amount has exceeded the consumption, and so, as shown in Fig. 1. the reserves have been growing year by yeas. As the search for more resources goes on, however, the annual newly discovered amomrt has been decreasing. On the other hand, the consumption of reserves has been incrcdsing exponentially, and so one can reasonably predict that the growth of our reserves will not continue much longer. Although this view seems sound, an important consideration has been neglected. When we speak of “reserves.” we always mean the amount of resources ihat can be recovered at an economic profit. But if the price of the resource rises, and if there is progress in the technology of recovery, then lower-grade ores can be used and even resources found in adverse locations will become “reserves” in the full econom:l: sense of t:te word. Thus, we see that the amount of the reserves of natural resources i; by no means a fixed and unchanging figme. But how much of an increase in our reserve r can we expect:’ 1’0answer this question adequately, we must consider metallic resources such as iron. aluminum, and copper separately from fossil fuel resources such as’coal and petroleum.

YOICHIKAYA AND YUTAKA SUZUKI

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FIG. 1. Ten-year trend in the reserves of important resources (from U.S.B.M. Commodity Data Summary Sheet-2).

Reserves of MetallicResources As a way of estimating the amount of metallic resources we can first look to see how much of these various metals actually exist in the earth. Now, and probably in the future a!:,~, the metallic resources which can be recovered are those found in “the continental cnlst” which is made up of the crust of the colltirlerltal laxI masses and the earth’s crust

GLOBAL

CONSTRAlNTS

AND A NEW VISION

l:OR DEVELOPMENT-I

. 8 -2% IO

9

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5

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281

SIllcOn oxygen lr3n colclum others tltonfum potoss~um soai urn mognesrum olumlnlum

FIG. 2. Principal elements in earth’s crust (96 by weight) (from K. K. Jurekiam, 1969)

under the continental shelves. The percentages of the various metals found in the continental crust are shown in Fig. 2. Iron and aluminum are abundant metals, but lead, copper, and other metals belong to the rare metals which constitute less than 0.1% by weight of the continental crust. Ry multiplying these percentages into the total wei&,t of the earth’s continenial crust, we arrive at figures which represent the absolute existing amount of these resources. If WCgraph the absolute existing amounts of each metal versur the percentages of’ the total we get the dotted straight line shown in the upper part of Fig. 3. If, now, we plot points on the same scales for the proven reserves of each metal, we find that they fall very close to a straight line parallel to, but below, the existing amounts. Now, instead of considering the reserves of each metal separately, let us consider the ratio of the proven resources, taken as a whole, to the ab:olute existing amount. This ratio is indicated by the vertical distance between the two lines measured on the logarithmic vertical axis. Since the distance between the two lines is 5.6 X 106, we can say that, roughly speaking, the existing amount of each metal is 5 million times greater than the proven resources of each. Thus, if it should ever become possible to recover metals from ordinary rocks, our metallic reserves wou”ld be almost inexhaustible. But, even if only lower-grade ores become usable, we can greatly increase our reserves.

FIG. 3. Relation between the proven reserves of metals and their absolute amount.

282

YOICHI KAYA AND YUTAKA SUZUKI

Qualip und Reserves 4t present, the quality of the iron ore we use is about 60% and that of the aluminum ore about 30%. Even with our present tec!mology, under favorable conditions, we could use iron ore of only 25% quality [2]. Thus, since iron constitutes 5.8% of the continental crust and aluminum 896, we could recover iron and aluminum from ordinsrv rocks if we could lower the acceptable ore quality by a factor of about one-fourth. When: we consider copper, a metal whose supply is vey tight, we see that at present we use ores of d quality of less than 2% (see Fig. 1); the iowest useable quality is about 0.5%. Since the overall perkentage of copper in the continental crust is a mere 0.0058%, it would be necessary to r-educe the acceptable quality by a factor of 100 to be able to use vrdina y rocks as a source for copper. For the future, ive want to know most of all how much our reserves will increase as we gradually lower the acceptahlc grade of ores we use. For small changes ic acceptable quality, the relation between the 0192quality H and the reserves I: is given :Ipproximately by the well-known equation of La&y ]3] :

It is reported (see Appendix 1) that the reserves could be expected to increase by about 40% if the acceptable quality of ore should be lowered by 0.4% to 0.8%. Whether this equation would still hold for a larger reduction, say from 0.5% to O.OS%, in the acceptable quality, is not clear at present, although the subject is being investigated. Even the reserves of copper would almost certainly increase considerably if ore of one-tenth the present acceptable quality could be used. Quality and Cost How much does the cost of recovery increase as the quality of the ore decreases? If the rise in cost ,is excessive, then the potentGal new resources cannot be called “reserves” in

FIG. 4. Cost of the principal metals vs. ahe lowest acceptable quality art’. Prices am for 1968 taken from J. K. B. Booth [4].

GLOBAL CONSTRAINTS AND A NEW VISION FOR DEVELOPMENT-l

203

the previously stated economic sense of the word. The problem of relating cost and ore quality can be approached in the following way. For iron, aluminum, and other natural resources. Skinner [2] has investigated the lowest acceptable quality of the corresponding ores. For the prices of the various r:letals we rely on a report of Booth [4]. if we plot the data of both these reports on a graph as in Fig. 4. we see that the data points fail approximately along a straight line, which indicates that the recovery cost and the quality are inversely proportional to one another. For example, a reduction of the qllality of an ore by a factor of i/IO would raise the cost of recovery by a factor of 10. The straight line in the graph. of course, only represents a kind of overall average for all metal resources. but still no particular metal resource would deviate greatly from the line. Even an elementary consideration tjf the recovery process would indicate that, to recover a given amount of metat from ore, say only l/IO as rich, ten times as much raw ore would have to be mined, ground up, and then processed, at a cost ten times as great. Therefore, if we are willing to accept the increase in price indicated by the inversely linear proportion, then we can rest assured that the vast quantity of metal resources in the continental crust will not be exhausted in the near future. However, notice that we are assuming that the enormous supply of energy needed to recover *ie metals ir available and that the proper steps can be taken to dispose the vast amounts of discarded waste. l3e Euerg?yNeeded up to The Year 2000 to Recover Metal Resources As will be explained in more detail below, the supply of energy resource*; will be very tight up to the year 2000. If, into this dark picture, w-e should introduce another rapidly increasing demand for energy to recover metal resources, the energy supply would be seriously affected. Fortunately, there is no great need for apprehension on this account. The production of iron and aluminum, which takes a significant part of all the energy used at present, holds the key to the future prospects for ener,gy needed for metal lecovery. The total amount of steel which will be produced up to the year 2000 is projected to be about 30 X 10’ tons. and that of aluminum about 1 X lo* tons. The ore needed for this total projected amount can be supplied by our present proven reserves, and so a significant decrease in the quality of the ore used is not foreseen. Consequently, we can project the energy needs of steel and aluminum production from the energy per ton needed at present. The tot21 energy needcJ for steel production up to the year 2GO$ can be thus estimated to be zquivdent to 30 X IO* tons of coal; that for aluminum production, 7 X IO8 tons of coai (AppenJix 2). This is about 10% of the total projected energy consumption of 320 X lOa tons; just 2% more than the present level.

Fossil fuels, whi,il constitute, the principal sources of energy at present, were formed from living plants and animals. Coal. consisting primarily of carbon, was formed in the earth over Iong ages by the transformation of dead vegetation. Thus. since vegetation is formed by the photosynthesis of carbon dioxide and water, we can consider coal to be formed from carbon and light energy. in view of this process, we cannot ex.pect to find coal in the vast quantities in which we find metals. Less is known ab#out the formation of petroleum, but the theory that it was formed from living matter has loug been accepted. Consequently, we can hardly espect to find enormous amounts. Since the process of coal fol mation is very well known, geologists claim that they have ascertained all of the places where coal exists and have also been able to estimate the amounts. Experts [5, 6, 71 give the total amount as from 6 to 8 X IO’* tons. The

YOICHIKAYAANDYUTAKASUZUKI

224

variation in the figures given is due primaribi to different estimates of how much coal is in the Soviet Union. Because the origin of petroleum is less czrtain, and also because it is liquid, there is less certakay about its location and quantity. Many experts have attempted to estimate the amount of petroleum existing, but some estimates are L.3much as three Limes greater than others. A fairly representative estimate is about 2 X 1OL2 barrels, equivalent to 0.35 X 10” tons of coal [7, 8,9] .’ Aboslt one-third of this amount has already been proven to exist. bratural gas has not been in use as long as petroknn, and so the search for it has not been as thorougr.. Present estimates put the total existing amount at 175 X I@* cubic meters, equivale.rt to 2300 ‘4 10s tons of coal [7]. One-third of this amount has already been proven to e>:ist [lo] . In conclusion, we note that when the absolute eGsting amounts of both coal and petroleum are cfnverted to potential calories, the amaunt of coal is about ten times that of petroleum. Projection for Emrgy Resotrrces

‘Charreserves of fossi fuels are especially threatened by two factors One is the fact that, different fr(Jrn metal resources, the absolute existing amount is not so much greater than the proven reserves. Another great threat is the rapid rate at which world energy consumpGon is growing. A widely held hypothesis [7] maintains that after the energy consumption of a nation has reached a certain level, the demand for energy will gradually level off. The overall picture given by Fig. 5 [S] , however, shows that, in recent years. as

4000 per

coplto

GNP 1 $ U S 1

FIG.5. Energy consumption and its growth related to GNP [S]. ’ Tks figure comes from a conside:ation recoverable.

that about

30% to 35% of the existing petroleum

is

GLOBALCONSTRAINTSANDANEWVlSlONFOR

DEVELOPMENT--I

285'

the per capita GNP increases, the per capita energy consumption also steadily ir creases. Furthermore, the growth of energy consumption for the countries with the highest per capita GNP is not noticeably leveling off. Neither does a long-range look into the future of energy consumption offer much encouragement. For example, to mention just some of the many factors at work, the energy requirements of the populace will grow with increasing and better distributed income; fossil fuels will be increasingly converted into electrical energy2; to recover metals from lower-grade ores more energy per unit will be needed; and the re-cycling of waste and the prevention of pollution will make new demands on our energy suppli;s. If present trends continue, what will be the situation from now until the year 2000? In making a projection of the energy consumption, we first noted that there is a great difference between the various nations of the world in per capita energy consumption as well as in the per capita GNP which determines it. Also we noticed that there are considerable differences in population and its growth rate. Consequently, to study the energy problem, we formed four groups of nations: USA and Canada, the free-market advanced nations, the planned-economy nations, and the developing nations. For each group we computed the growth in the population and in the per capita GNP, and from these we projected the future growth of.the per capita energy consumption For the growth rates of population and GNP, as well as for the quantitative relation between energy consumption and GNP we have used the averages over the few years before and including 1970 [5]. 0 ur results are displayed in Fig. 6. The per capita consumption of USA and Canada wil! havIe increased by 2.4 times that of 1970; the free-market advanced naticns will increase by 4.7 times. At first this 4.7 times increase 30 t

under-developed P I970

7

--: ,990

countrrer 0

: 1990

2000

yeor

FIG. 6.Projected incre;lsein per capita energy consumption. 2 The generation of electrical power fr’.)m the primary energy produced by burning coal and oil is reported to be only 40% efficient; t!le othi:r 60% of the heat energy is. at present, d:scharged into the water and the atmosphere.

YOICHI KAYA AND YUTAKA SUZUKI

286

might seem implausible, but when we consider that the level attained will be only t .34 times the 1970 level of USA and Ca;lada, then it becomes quite realistic. Another point to be watched is the widening gt. By 1985 we will have consumed an amount of energy comparable to the entire 1970 proven reserve of petroleum (crude oil and natural gas). Furthermore, during the next thirty years up to 2000 A.D., we will use TABLE I World’s Projected Energy Consumption (unit: log tons) 1970

1975

The authws

6.73

8.55

U.N. Energy projection [6]

6.8

1980 _--_--_ -

- _.

32.1

496.0

11.2

28.0-30.2

486.0

36.4 6.80

8.50

Cumulative

11.0

U.N. Energy projection io 2000 prtijection I.191

2000 -~.

10.71

total

GLOBAI. CONSTRAINTS

AND A NEW VISION FOR DEVELOPMENT-I

350 -- ..(2

287

: 7000 110’~borrels):

(

I

230 175 “80’2

m’

)

100

“Ill’)

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(24~10~tons

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I

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projected

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,,-‘I

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1970

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for

1985

/ Cumulotlvz

I59

Q

i

energy consumptton 1970 - 2000

\ for

\

14 2

CT7 The

onnuol

world

energy consumption In 1970

FIG. 7. Energy consumption

The

Dnnuol

consumption 1985

energy In

The onnuol consumption

energy an 2000

and reserves of energy resources (unit: I x log of coal equivalent).

an amount of energy comparable to the entire absolute existing amount of crude oil and natural gas. This enormous projected increase in world energy cor?sumption does not immediately spell the exhaustion of our oil reserves. Coal is also an important source of fuel: in 1970, 35% of the primary energy was from coal. Also the amount of energy generated by nilclear power is growing. Nevertheless, the ever-increasing dependence on petroleum is a cause for concern. UsingCoal in Place of Oil The fuel sourccs of world energy consumption for the past twenty years are shown in Fig. 8 [7]. It is obvious from the figure that the use of coal is leveling off and has only increased by about 5% each year. It is also strikingly clear that the great increase in energy consumption is due almost exclusively to crude oil and natural gas. Crude oil use has frown 8% a year; natural gas, 8.6% a year. If this tendeiacy continues until 1980, petroleum (crude oil and natural gas) will have become the major source of energy, providing 75% of the total. If this growth rate continues, there is a real danger that our present proken resources will be consumed soon after 1985. In view of this situation, it seems inevitable that supply restrictions will be experienced within this century. Exactly when the sup.~ly will begin to be throttled is hard to say, but it is difficult to see how it could come la :er thar. 1985. The development of nuclear power is being pushed forward, but c:tn we really expect that nuclear energy will soon provide a substitute for energy from petroleum? The existing amount of uranium which, with our present technology, could be used for nuclear f Jel is shown in Fig. 7. If 1 kg of uranium should be completely used up in the

YOICHI KAYA AND YUTAKA SUZUKI

288

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1980

FIG. 8. Fuel sources of the world energy consumption (in coal equivalent).

nuclear fission process, an enormous 1.85 X 10” kcal (equivalent to about 2.85 X IO6 tons of coal) is given Ioff. Most of our present reactors, however, are of the light-water type which utilize only about 1.5% of the uranium fuel. Therefore, I kg of uranium is actually only equivalent to 4 X 10’ tons of coal. Using this actual energy conversion rate, the figure of 100 (unit is 1 X 109 tons of coal equivalent) given ia Fig. 7 was arrived al using the published figures for uranium resources. Since uranium resources have a great military significance, one should not too naively accept the published figures, but still for our purposes these published figtues can be used. From this one can see that the power generation to be exrecfed from the present t:;pe of reactor is surprisingly small. New converter reactors, now under development, can double the utilization of uranium to about 3%. A ur;anium utiliT,ation rate of about 80%50 times that of our present reactors-can be attained by the fast-breeder reactors also under development. If fastbreeder reactors could be used in the future, the area of the uranium encrgv circle in Fig. 7 would become fifty times larger: comparable to the entire absolute existing amount of coal. Like the other metals, the possibility of expanding the reserves of uranium arc very good. If, then, the fast breeder reactor is successfully develcped, the long-range outlook for the energy supply is bright. It looks, however. as if the development and building of a large number of these reactors will take many years yet, and so nuclear energy will not be able to save us from the energy crisis of the near future. There arc also c*?er masons why nuclear energy can not be expected to save the oil situatioil very much. The sheer physical difficulty of cl,,mging over from a heavy de:?endence on crude oil to a *zicler use of nuclear energy is very great. According to the nuclear e!lergy development plan of the free-market countries, for example, the goal for

GLOBAL CONSTRAINTS

AND A NHV VISION FOR DEVELOPMENT-I

289

nuclear energy is 500 X 10” kW for the year 198.5. Even if this goal is reached, nuclear energy will produce only 40% of t!le total electrical power generated, and only from 12% to 15% of the total amount of primary energy generated 1121. The enormous expansion in petroleum use and its dominance as an energy fuel, which is evident from FJ6. 8, tells us plainly that if our oil supplies should be restricted in the near future, the newly developing nuclear energy could not step in to replace it. Due to a number of causes, the erection of nuclear power plants is falling behind schedule. The system for manufacturing the reactors and their equipment i: still inadequate; also, because the safety :,nd nonpollution standards for atomic power plants are not yet agreed upon, it is often difficult to find a suitable site [ 131. When one considers all the above points, it is obvious that we must find some source of energy other than petroleum to bridge over the years until massive nuclear energy generation is ready to take over. Here naturally we look again to that energy source that we already use quite heavily and of which vast reserves are at hand, namely, coal. In the immediate past crude otl and gas have been replacing coal in bearing the major burden of our energy consumption growth. This path, as we have seen above, is leading us toward dangerous shortages. We must rzversc this trend and make every effort to replace petroleum with coal as an energy source. To that end we must make efforts to develop new technologies to utilize coal. There are perhaps ways, for example by converting coal to a gaseous form, in which we could use coal as a fuel without polluting the atmosphere. We have, fortunately, a large fund of expsrience in the use of coal. Therefore, we can, in a sufficiently short time, develop new technologies for the use of coal; for the development of the fast breeder reactor or nuclear fusion much more time will be needed. I .2. GLOBAL RESTRAINTS:

THE WORLD CLIMATE

Once we have attained neN ways of generating energy, especially after we have learned to utilize nuclear fusion, can we then securely use energy without limit? Most people imagine that the earth is still large enough for man to expand his activities considerably. The meteorologists, however, are becoming worried about the changes which man’s activities will soon bring about in the earth’s climate. The principal factors they are studying with anxiccy are: tile increasing discharge of carbon dioxide and to heat into the atmosphere, and the change in the “albedo” of the earth. The Heat Balame of the Earth The earth is constantly receiving energy from the sun in the form of visible light. The amount of such energy that reaches the outer layer of the atmospl!ere is, on the average, equivalent to 0.5 calories per square centimeter per minute. Of this energy about 33% is reflected back. out into space from the surface of the earth, especially from snow and ice. Forests, jungles, alld thl: darker colored bare earth reflect back very little of this energy. This light reflcoting ability of the earth is called its “albed,- .” When forests are cut down to make farm land, and when cities with their expanses of white concrete are built, the albedo of the cart11 is increased. When (desert land is converted to farm land, the albedo is decreased. If t’le cloud coverage of the eaith increases, the albedo increases very much. At the present tine we do not know whether the earth’s albedo is constant or changing. Only by gathering data over a long period and on a global scale with earth satellites can we answer this question. Of the r57R>of the solar energy which is not reflected back into space, about 22% is

YOICHI kAYA AND YUTAKA SUZUKI

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absorbed by the a!mosphere. The remaining 45% r:aches the surface of the earth where three-fourths of it serves’ to evaporate water. The rest warms the earth; photosynthesis in plants is produced by less than 0.1% of the solzr energy. Besides reflected light, the earth also radiates ‘heat {infra-red rays) out into space. The temperature of the earth remains constant because the absorbed light energy and the radiated heat energy balance each other. The hfluencc of Carbon Dioxide Gas The earth‘s atmosphere allows light to pass through, but absorbs heat. Thus, the warm atmosphere surrounding the earth exercises a “green house” effect. Of the gases in the atmosphere, carbon dioxide gas and water vapor contribute most to this green house effect. Even a small increase in the amount of carbon dioxide can cause t’he temperature of the atmosphere to rise. The combustion of fossil fuels or the burning away of large forests for farmland throws carbon dioxide out into the atmosphere. Actual measurements show that from 1958 to 1969 carbon dioxide gas in the atmosphere has been steadily increasing by C.ZS a year. This increase is attributed primarily to the corn1 ustion of fossil fllel. According to reported calculations [14], half of the carbon dioxide from fossil fuel combustion is reabsorbed by the sea and by vegetation; the other half accumulates in the atmosphere. Based on these reports and on the hypothesis that the projected 5% increase in energy use would be sustained only by burning more fossil fuel, we projected the amount of carbon dioxide which would accumufate in the atmosphere. The results of this projection are displayed in Table 2. Assuming that half of the carbon dioxide thus generated should remain in the atmosphere, the cumulative effect will be that by the year 2000 carbon dioxide will have increased 27.2% lover the 1970 level; by the year 2030 it will have become three times that level. As will be explained in Part II (following issue), it is projected that about 20% of the tropical forest areas will be converted into farmland to produce more food. The carbon dioxide thrown off by burning off these forests will increase the carbon dioxide conccntration of the atmosphere by 13.5% (Appendix 3). If this burning off of forests with the accompanying production of carbon dioxide takes place before the year 2000 during which period fossil fuel combustion will increase the carbon dioxide concentration in the atmosphere by 27.2%, the overall concentration will increase by about 43%. One expert TABLE 2

Year

Increase of (‘0, Gas in Atmosphere -__ --__ --Energy C‘3, discharged Concentration of consumption CO, in atmospherr” (kg)

1970

0.673 x 10”

--

0.0197 x 101s

321 pprr

4 :!OOO 0.496 x lOI

1.455 x 10”

415 ppm, 29.8% increase

2039

9.155 x 10’5

939 ppm, 194% increase

0.322 x lOI

aHalf of the CO, gas discharged is assumed to remain in the atmosphere.

GL0BALC'I)NSTRAINTSANDANEWVISI(ONFORDEVELOPMENT-I

FIG. 9. TempeMure variations over 100 years. Curve 1: Annual Smoothed by 100 year averaging.

average temperature;

291

curve 2:

[ 131 has, using computer simulation, estimated that a 25% increase of carbon dioxide would raise the average atmospheric temperature by 0.75”C.; and a 100% increase would raise it by 2.3”C. From this result we can say that the 40% increase projected above will raise the atmo.;pheric temperature by about 1°C. To grasp the significance of this 1°C increase, we have in Fig. 9 presented data showing the gradual rise of the temperature over the last 160 years. A glance at the graph sholvs that the tempe ‘ature only rose from -0.2’C to tO.4’C during 100 years. Here the warming of the atmosphere by increased carbon dioxide has been projected while assuming all other factors to be unchanging. Actually, when the atmospheric temperature rises, water evaporation with consequent cloud formation increases. More cloud coverage of the earth would increase its albedo. Since more of the sun’s energy would now be reflected back into space, there would be a cooling effect countering that of the increased carbon dioxide. The calculations we have made. however, are enough to show that by burning fossil fuels for energy, man can cause rather significant changes in his environment . 7he Effect of Wasted Heat What is the effect of heat thrown off rnto the atmosphere as a by-product of burning fossil fuels? At present, the total heat en. rgy from the sun is over 10,000 times as large a$. the heat waste from fossil fuel combustion, and so the ;ffect can be said to be negligibIc. The projected 5% annual increase in energy consumption, however, will, by the end of the century change this ratio by a factor of 10 or more. Also, we must remember that heat waste in some concentrated local areas is considerably greater than the world average. From this fact, we can see that heating effect due to fuel combustion might be unevenly distributed over the earth. We modified Budyko’s marco model [IS] for atmospheric temperature change so that we could simulate the changes in the earth’s temperature distribution due to unevenly distributed fuel consumption. To do this we divided the earth into sectors according to latitude and assumed evenly distributed heat waste within each sector. We also assumed that energy consumption will continue to increase at present rates. The advanced nations almost all lie within 30” and 70” north latitude. It is there that 80% of the total energy consumption takes place. The developing nations which use the other 20% lie from 30” north to 40” south latitude. The details of our mod:] are explained in Appendix 4; here we present only the final results plotted in Fig. IO. Taking the average atmospheric temperature of 197C as zero, we see that by the year 2000. there would be only a negligible Increase in temperature. By 2030, however, the wcrld average temperature increase is O.lS”C with the advanced-nation sector increasing by 0S”C. By 2068. the average has tripled, and the advanced na?ion sector of the earth has warmed up far more than 1°C. Our model simulates atmospheric changes which would be caused by the radiation of

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292

f :

9oe.

2 60'.

I I

I I I

I

0.5*c

I

-+--

2000

2030

1

2060

FIG. 10. Tempemture increase caused by wasted thermal energy. (Advanced nations are situated between 30” and 70’ north latiltude.)

heat from the earth’s surfxe as well as by the diffusion of this heat laterally over the surface of the earth. The model assumes cloud coverage and the total albedo of the earth to be constant. Consequently, because cf these simplifications, it would be a mistake to conclude immediately that our model predicts the temperature changes which will actually occur. But these results do help us to see in a quantitive way that if we continue to increase our energy consumption at present rates until the middle of the 2!st century, we will be able to affect seriously the world climate, and this effect will be much greater in some parts of the world, A world-wide cooperative research effort is needed to learn more precisely what this effect will be.

Restrictions on Ehergy Consumption At present, ‘we still do not have enough knowledge to study the overall effect on the atmospheric tefmperature of SQ many interlinking factors: increased concentration of carbon dioxide gas, increasing discharge of wasted heat, increasing discharge of dust into the atmosphere, and changes in the earth’s albedo. We can already see, however, that the human race, by its cumulative .activity, does have the possibility of significantly changing the earth’s climate during ,the Crst half of the 211stcentury. Just lookiilg at the changes on the climate that might be brought about by growing cqergi consumption is enough to m,ake us realizle that we must restrain our energy consumption or we will run into trouble much sooner $l:hanwe expect. To delay this effect as long as possible, the human race must begin a ‘cooperative poliicy of self-restraint in the use of energy, and as is evident from Fig. 6, this obligation falls primarily on the advanced nations. In Sec. 1.1 we stated that metallic resources are rather abundant, but the statement rested on the assumption that we could use energy almost. without limit to recover them. We see now that this assumption cannot be realized, and so as a result, our access to metallic resoul’ces is, as a Imatter of fact, greatly reduced by energy restrictions.

GLOBAL CONSTRAINTS

AND A NEW VISION FOR DEVELOPMENT

I

293

TABLE Al

Cumulated tonnage for copper deposit m 1969 Grad 2 I%) __ ____I_____

(million tons) _

0.8 0.9

309 224

1.0 1.3 1.5 3.4 4.0

214 159 99 51 21

USBM Commodity mary Sheet-2,197O. Source:

Data Sum-

Appendix I. Relationship between Tonnage an Grade in Copper Deposits Lasky’s equation of the relationship between tonnage and grade in c2rtain mineIal deposits is H =K, -KZ log& where H is the grade of mineral deposit, IZ is the cumulated reserve abo\b* the grade of H % andKl and K2 are constants to be determined for each deposit. The cumulated tonnage and grade relations for the actual world copper deposit is shown in Table Al. The plot for this table is shown in Fig. A 1. From this figure, it is seen

Grade

FIG. Al.

of

copper

YOICHI KAYA AND YUTAKA SUZUKI

294

that Lasky’s equation is fitted to the acuual data relatively well between the grade of 0.8% and 4%. Our interest is to estimate the quantity of copper reserve for the i:rade lower than 0.8%. In this paper the estimation is carried out using Fig. Al because of the difficulties in getting the data of copper reserve under 0.8% grade. The straight line in Fig. Al is connected through the t-j,~intsof 4% and 0.8%. From this line, the constants in the Lasky’s equation are determineu as fol!ows: H :=25.7 - 2.93 log C From this, the estimated total reserlre of copper above 0.4% grade is 430 million tons. This amount is roughly 40% more than the total copper I ?serve above 0.8% grade. Appendix B. Energy Consumption Estimation for Production of Crude Steel and Aluminum PRODUCTION

We consider the production of crude steel and aluminum on a world basis. We can show that both crude steel and aluminum production have increased in proportion to gross domestic product (GDP) per capita (shown in Fig. Bl). Supposing that thess trends continue, we can estimate production until the year of 2000. The average growth rate of GDP per capita in the last seven years is 3.6%. Using this value, the production per capita of crude steel and aluminum are estimated. Multiplying these by population, calculated by using a 2% average growth rate, the total production of each material is given in Tables Bl and B2. ENERGY CONSUMP’FIONFOR CRUDE STEEL The energy consumption for producing a ton of crude steel is 6.6 X lo6 kcal, which is c&ulated by using the total energy consumption of the steel industry and crude steel

stee I

GOP

EIC. 81. Source: V.N.

--

’ The

Statistical Year Book, 1971.

Institute of Energy Economics; hergy

Matrix, 1972.

per

coplto

GLOBAL CONSTRAINTS

AND A NEW VISION FOR DEVELOPMENT-i

TABLE

295

Bi

Crude Steel Production Estimation (million tons)

Es1iraa ted by authors

1970

1975

1980

2000

592

780

1030

3100

production of Japan in 1970 [5]. Using this value, the energy consumption for the production of crude steel in 2000 is estimated as 2.0 X 1016 kcal (2.9 X 10’ tons coal equivalent2). ENERGY CONSUMPTION

FOR ALUMINIJM

The

energy consumptio~n for producing a ton of aluminum is 4.5 X lo7 kcal,3 where for producing a ton of a.uminum, electric power consumption is 1.6 X lo4 kwh and alumina consumption is 1.95 ions, and, for producing a ton of alumina, electric power consumption is 269 kwh snd heavy oil is 248 liters.4 Using this value, energy consumption for the production of aluminum is 3.7 X lo5 kcal (5.2 X lOa tons coal equivalent). If we use the value estimated by Rev del’AIuminium (see Table B2), the energy consumption becomes roughly 7 X lo* tons coal equivalent. Appendix C. Estimatinn of CO2 Concentration Increase in the Atmosphere The contents of carbon in coal, crude oil, and nalural gas are 70-80, 82-87, and 65-80%, respectively. ’ For the sake of simplicity the average content of carbon in these

TABLE

B2

Aluminum Production Estimation (million tons)

Estimated by Authors Demand Estimated by USBM Demand Estimated by Rev del’Alminium

’ ’ * ’

1970

197s

1980

2000

9.59

14.6

21.3

81.3

45-9s

99.8

coal: lkg = 7000 kcal. 1 kwh + 2450 kcal (primary energy quivalent). heavy oil 1 liter = 9900 kcal. Japan Light Metal Association; Light Metal Statistics in Japan, 1971. B.J. Skinner, Earth Resources, Prentice-Hall, 1969.

YOlCHl KAYA AND YUTAKA SUZUKI

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fossil fuels is assumed to be 80 percent here. Therefore, if a fossil fuel of E kg is burnt, CO2 of E X 0.80 X (12 t 32:/12 kg is produced. The mass of the entire atmosphere is 5.14 X 10” Ags and the total mass of CO1 in it is 2.44 X 10” kg at present. Iihalf of the amount of COa produced by the combustion of fossil fuels remains in the atmosphere, its concentration by mass is calculated as (EX 0.80X *x 12

0.s t 2.44 x lOI )/5.14 x 1o18.

Using the estimated energy consumption in the year 2000 and 2030 shown in Table 1, COz concentrations alre calculated as given in Table 2, where the values are expressed on the volume percentage basis. Appendix D. Marco Climate Model Consider the heat balance of the earth-atmosphere system. This system is considered to be divided into 10” latitude belts. V:e incoming energy to this system is solar radiation energy Q, (l_ors) and the human was: :J Lhermal energy is W, in kcal,‘cm’/year, where crS is the aibedo and Q, is the solar radiation incoming to the outer boundary of the atmosphere in the considered latitude belt. The values of QS and cw,are shown in Table Dl. The outgoing energy I, in kcal/cm*/year from the earth-atmosphere system to outer space is given as function of cloudiness pt and the temperature PC at the level of the earth’s surface as’ lS = 168 t 1.687’- (36 + 1.2T)n.

@.O

For the mean annual condition, the equatic.n ok the heat balance of the earth-atmosphere .system has the following form:

where Rs expresses the gain or loss of heat as a result of the atmosphere and hydrosphere circulation, including heat redistribution of phase water transformations. It is known that R, is proportional to the quantities T - T,,, that is’ 0.3)

TABLE D-l. Qs rnd Q~. O”10”

1O”--20”

QS

320

311

us

0.32 --.

---

0.32 _-_ ~_. ____-_

20°-30”

30”-4o”

40”-50”

5o”-600

60”-70”

70”-80”

294

269

234

202

167

145

0.32

0.32

0.32

0.32

0.50

0.62

-’ M. 1. Eu~igbo, The rf‘fcct of solar radiation 61 I a19 (1969).

variations

on the climate of the earth, Tellus 21(5),

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297

where TP is the earth’s mean temperature and y is equal to 2.82 kcal/cm2/year. Eqs. (D.l), (D.2). and (D.3) we obtain the temperature T as T_QSil

-a,)+y-

The earth’s temperature

From

WS+36n+yTp-168 .

1.2n + 1.68

(D-4)

Tp is also calculated from Eqs. (D.l -D.3) by using the condition

R,=O as W,t36n-168

=QW(l-c+)t

T P

1.68

- 1.2n

-7

VW

where QW, av and Ww are planetary values of solar radiation, albedo and wasted thermal energy, respectively. Necessary data to compute T and Ts,are as follows: From present climate conditions it is known that Qsp = 250 and oq = 0.?3. Cloudiness n is equal to 0.5. Ww is 0.01 kcz3/cm2/year in the year 1870 and this value is assumed to increase by 5% eve?.; year. “rhe .., value of W, is determined as follows. in the region between 30”N and 70”N, 80% of the world energy is consumed and the remaining 20% is consumed in the region betwelen 40”s and 30”N. ?‘he areas of the two regions are 18 and 57% of the earth’s total surface area, respectively. Accordingly, in the year 1978, W, in the former region is given by 0.01 X 0.8OjO.18 = 0.0437 kcal/cm2/year and W,in the latter region is given by 0.01 X 0.20/0.57 = 0.0035 kcal/cm2/year These two values are assumed to increase by 5 percent every year.

References 1. 2. 3. 4. 5.

D. Meadows et al., The Limits to Growt?, Universe Books, 1972 B. J. Skinner, Earth Resources, Prentice Hall, 1969. S. G. Lasky, Engineering and Mining J. 151(,1), 81-85 (1950). K. J. B. Booth,ClM Trans. LXXJV (1971). U.N, Statistical Yearbook 1971 1 Statistical Office of the United Nations Department of Economic and Sotial Affairs, 1972. 6. World Conference Survey on Energy Resources. 1968. 7. U.N. Economic and Social Council, Note,; of the Committee on Natural Resources, 1973. 8. M. K. Hubbert, Sci. Amer. 225(3), 60- 87 (197; ). 9. H. R. Warman, Petroleum Rev., 3 (1971). 1.0. Oiland GasJ., 12 (1972). 11. Oiland Gas J., 12 (1970). 12. ENEA-IAEA, Uranium Resources, Prou”uction and Demand, 1970. 13. Report of FORATOM. Oct., 1972. 14. Matthews et al., Man’s fmpact on the Ciima:c, MIT Press, 197 1. Received February I, 19 74