The Rise and Fall of the Carbon Civilization

January 21, 2011 • Climate Change & Mitigation, Daily Email Recap

Thanks to Andrew Ferguson for this book review of Rise and Fall of the Carbon Civilization by two Australian PhDs, Patrick Moriarty and Damon Honner. The review will appear in the April OPT Journal.

by Patrick Moriarty and Damon Honnery, a review essay by Andrew Ferguson

Abstract. This is an exceptionally informative book, well structured and well written. Without being too long it covers all the relevant ground thoroughly. It is somewhat over optimistic in its suggestions for resolving the problems, but outlines them brilliantly; and the subject matter is so well presented that readers can make their own decision about what is going to be politically possible in the likely circumstances. Using their data, my interpretation results in the conclusion that for the longer term the global aim needs to be to reduce population to about 2 billion.

The title of the book is well chosen, but the subtitle, “Resolving global environmental and resource problems,” owes more to hope than to reality. At least that is the conclusion that my analysis will lead to.
Despite its short length, 200 pages, the book comprehensively surveys most of the important issues, including global climate change, vital material resources, degree of uncertainty about forecasting the future, renewable energy, nuclear energy, improving efficiencies, carbon sequestration, geo-engineering, and the need for a new economy. That list approximates to the chapter headings. Based on a wealth of background reading, every subject is impressively covered. The writing is excellent. It makes no compromises with the science, yet matters are presented with such clarity that it is easy for anyone with a grounding in science to follow. I will pick out a few places where this concern for the layman falls short, but such lapses are very much the exception. With regard to the subtitle, let us first observe that the authors are less optimistic than the subtitle words might suggest. On page 2 they say:

We are struck by the extraordinary technological optimism shown in discussions on new sources of energy, and on climate mitigation proposals such as carbon sequestration and geoengineering. Indeed, a great deal of this book is devoted to a detailed examination of these ideas and their likely consequences. Much of this optimism has been the result of the undoubted successes – and high public profile, given the widespread ownership of its products – of the new Information Technology (IT). For IT, forecasts have often not kept pace with the progress actually made. Yet IT projections are exceptional – most technology forecasts for other areas severely under-estimate the difficulties and time needed to bring them to market. As we shall see in Chapter 4, this optimism is shared by both most experts as well as the general public.

The excessive optimism to which they draw attention pervades not only the popular media (e.g. New Scientist and Scientific American) but extends to academia, so it is good to see the authors – both doctors of science – showing realism. They take account of most aspects of the world’s problems and the scale of those problems, including something often underplayed or ignored, namely the inevitable drive of the poor for better lifestyles. On page 12, after pointing out that the world is already in overshoot, they make this point:

We have this scale of overshoot even though a small fraction of the global population presently enjoys high standards of material consumption. Any further growth in global population, or any movement towards OECD income levels – which themselves are themselves expected to continue rising – by the great majority of the world population presently living in low-income countries, will place even greater stresses on Earth’s resources and pollution absorption capacity.

On page 20, in a superb chapter on climate change, we encounter the first example of a point at which the authors are perhaps not sufficiently helpful to laymen. They mention that Roger Pielke, in a paper A broader view of the role of humans in the climate system, “argued that a more accurate way of quantifying climate change is to look at how the Earth’s energy balance is changing as a result of the global imbalance between insolation and outgoing thermal radiation.” Taking data from another paper, based on Pielke’s idea, the authors then tabulate the energy flows over the last half century into (a) the ocean, (b) melting glacial systems, (c) land surface and (d) the lower atmosphere. By far the biggest figure is 200,000 EJ (1 exajoule = 1018 joules) into the oceans. They go on to mention that a mere 200 EJ is sufficient energy to raise all of the water in Lake Eyrie (in the North American Great Lakes system) from 0ºC to 100ºC. However, most laymen don’t have any idea of how that would relate to the huge volume of water in the oceans. Something on these lines would surely be helpful: “The extent of the mixed layer in the oceans is normally taken as 75 metres. The mooted 200,000 EJ would be sufficient to raise the temperature of that by 1.7ºC;[ii] yet the measured rise in temperature between the decade 1950-59 to the decade 2000-09 was 0.53ºC.[iii] This suggests that a good proportion of the heat is carried down below the mixed layer. The mixed layer is only one fiftieth of the total ocean volume. Thus a complete interpretation of the 200,000 EJ figure is fraught with difficulty, but the above calculation gives an insight into the potential for an increase in temperature, and indicates that there are longer-term problems which cannot be assessed even by five decades of measurements of temperature rise.”

A more serious lapse in addressing the needs of laymen occurs on page 81 in the chapter on renewable energy, where it is stated:

The real question is: how much biomass energy of any type can the world sustain? The answer to this question has varied greatly. As discussed above, a figure of 1,174 EJ has been cited, but values as high as this seem most unlikely, given that the total terrestrial NPP [Net Primary Production] is only 1,900 EJ. More recently, a Dutch study included water and land-use availability constraints, and gave a minimum global estimate of 65 EJ, with an upper limit of around 300 EJ. A US study put the sustainable potential of biomass even lower, at only 27 EJ; higher levels would either threaten food supplies or worsen global climate change.

What are laymen to make of that range, between 1,174 and 27 EJ? I suggest that scientists attempting to address the general public should recognize that there are always some crackpot scientific papers; laymen deserve to be shown a back-of-envelope calculation to see which papers might fall in that category. In this case, a rough calculation is easy. Globally there are about 1,500 million hectares (Mha) of cropland 3,300 Mha of pasture and grassland and 4,200 Mha of forest and woodlands. Forest is being lost at an alarming rate, and part of the reason is to turn it into cropland or grazing land, and partly to satisfy the demand for timber. Thus there would seem little hope of finding any new lands suitable for growing biomass. Let us nevertheless choose a high figure for what might possibly be achieved by assuming that somehow 1,000 Mha can be found to grow biomass for energy purposes. This won’t be the best land, which will likely go to cropland, thus it would be optimistic to assume a yield of 4 t/ha/y (average forest yield is estimated at 3 t/ha/y). The energy density of wood is 18 GJ (1 gigajoule = 109 joules) per tonne. Thus the total energy made available per year would be (1000 x 106) x 4 x (18 x 109) = 72 EJ. This immediately shows that anything above 72 EJ is crackpot
Another crackpot figure, that the authors do not give guidance on, is population size. Regarding it, they say, on page 3:

A good example of technological optimism is provided by Jesse Ausubel. In a recent interview article entitled ‘Ingenuity wins every time’, Ausubel argued that the world can support 20 billion people, almost three times its year 2010 population.

Clearly Jesse Ausubel is as crackpot as Professor of Marketing Julian Simon, whom many academics took the bother to refute (although this did not seem to much abate the popularity of his fantasies expressed in various books). The authors don’t bother to do this with Ausubel but later, on page 52, they return to the point about inequity mentioned earlier, with these words:

The trouble is that most of the world’s population aspire to the material living standards of the OECD – all would like to be ‘OECD-equivalent people’. At this level of affluence the world may only be able to sustainably support a far lower population level than today. According the Optimum Population Trust in the UK, this figure is between 2.7 and 5.1 billion.

But they don’t comment further on that estimate, published on the Optimum Population Trust (OPT) website. Maybe the reader will wonder if the OPT estimate is as misleading as that of Ausubel (but in the opposite direction). Yet very simple calculations can show that to support people in a modest lifestyle and not exceed a safe level of carbon emissions, the lower figures are in the ball-park, indeed probably high.[iv] Calculations related to renewable energy are more complicated, but that is something we will return to later.

Doubtless the authors have quoted the website figures correctly, but to be more precise, OPT has been making these calculations every two years based on the Living Planet Reports (LPR) 2000, 2002, 2004, 2006, and 2008, and our favoured presentation is for a lifestyle that is West European but with energy use reduced to 40% of 2001 usage. On this basis, we estimate the sustainable population falls in the range of 3.0-3.6 billion. However, as we have always stressed, this does not include the limit set while we are relying on fossil fuel, for which the carbon dioxide calculation gives a limit of 2.2 billion.4 Two points should be made about our figures: (a) although we use LPR data, we do so on the basis of a careful assessment that the land normally allocated to carbon absorption is equal in area to the land needed for renewable energy generation; (b) we claim only that these figures are ball-park figures -a billion less or more would not be surprising. The data, including that on renewable energy, is simply not accurate enough to do more than get in the ball-park.

In the wind energy section of the renewable energy chapter, on page 86, the authors say:
Denmark, the country with the highest wind penetration, has experienced almost no growth since 2000.
The authors are here surveying the extent of growth in the installation of wind turbines, but neither here nor later do they point out a vital fact about Denmark’s experience. The amount of electricity from wind turbines that the Danes produce amounts to about 25% of their total electricity demand, yet the amount of electricity from wind turbines they manage to use directly is only about 8.5%. The rest they have to persuade Norway to take, which Norway can do by lowering the output from their hydro turbines. This problem with using the output of the wind turbines directly is partly due to poor internal transmission lines from the west coast of Denmark (where the wind turbines are mainly placed) to the more populated east side. However, the fact that the Danes have not bothered to build adequate internal transmission to ameliorate the problem introduced by the wind turbines producing electricity at inconvenient times gives an indication of the difficulty of integrating the uncontrollable output of wind turbines.

In the chapter on Engineering for Greater Energy Efficiency it reads, on page 136:
Robert Ayres and his co-workers have pointed out that the system efficiency of power stations was often higher in the US in the early years of the 20th century than it is today. Then, utility companies used small power plants located in urban areas close to their consumers. Electrical conversion efficiencies were very low by modern standards, but because they sold heat as well, they could achieve combined efficiencies of over 50%. Much of the progress in technical efficiency has been at the expense of efficiency at a larger scale.

The quotation of 50% appears to be an example of a common fallacy about Combined Heating and Power (CHP), namely that there is a straight comparison to be made between the combined efficiency of the heat output and electricity output of a CHP plant with the efficiency of producing electricity. There is some gain but not always great and CHP has some disadvantages. This is what David Mackay[v] says in an acute review of CHP (p. 149).

The ideal CHP systems are slightly superior to the “new standard way of doing things” (getting electricity from gas and heat from condensing boilers). But we must bear in mind that this slight superiority comes with some drawbacks – a CHP system delivers heat only to the places it is connected to, whereas condensing boilers can be planted anywhere with a gas main; and compared to the standard way of doing things, CHP systems are not so flexible in the mix of electricity and heat they deliver; a CHP system will work best only when delivering a particular mix; this inflexibility leads to inefficiency at times when, for example, excess heat is produced in a typical house, much of the electricity demand comes in relatively brief spikes, bearing little relation to heating demand.

But strictures on the analysis are minor. The book is very sound in nearly all its details. When it comes to taking an overview, as is done in Chapter 10, The New Economy, then there is room for differing views. What I shall do is make my own calculation using their figures except where noted, as this will provide the best basis for further comments.

Making best use of the energy supply that should be available in 2050

The controllable electric supply will consist of:
20 EJ from hydro (currently 12 EJ. This is their optimistic estimate for 2050).
10 EJ from geothermal (and other minor sources other than wind and solar).
50 EJ from biomass.
72 EJ from fossil fuel for power stations (I choose this as part of the 124 EJ which they estimate that could be made available while keeping within a safe limit of carbon emissions). The rest of the 124 EJ is allocated for transport as explained below.
152 EJ total thus far. We will assume that this is all controllable although this is not strictly true in the case of hydro, which may not be available at times of drought.
65 EJ supplement from wind and solar. Because of its uncontrollable nature wind and solar are unlikely to be able to constitute more than 30% of an electrical grid (Denmark’s trouble at 8.5% is not the only indicator of problems with too much uncontrollable input), thus the supplement available from uncontrollables is 3/7 x 152 = 65 EJ (i.e. 65 / (152 + 65) = 30%). This type of estimate does not exist in the author’s text, but as will be seen our overall results are similar.
217 EJ total electricity thus far.
52 EJ fossil fuel for transport. Current global usage for transport is 77 EJ, of which 35 EJ is for private vehicles. A drastic reduction of the latter to 10 EJ would thus give 52 EJ for transport. This deduction in turn determined the 72 EJ shown above as being available for producing electricity.
49 EJ from nuclear. Currently 20 EJ. A very convincing case is made for why it is unlikely that more than 49 EJ/y could be produced by 2050 (or increase much thereafter without dire problems).
318 EJ Grand total of all energy available in 2050, electric and non-electric.

This is actually a slightly higher result than the authors give, as on page 182 they say, “Although the figures we have calculated are only indicative, we think a total of about 300 EJ of primary energy could be available to supply our energy needs while limiting global temperature rise to 2ºC.
At 2 kW/p (63 GJ/y), 318 EJ allows a population of 5.0 billion.[vi] On a couple of occasions the authors quote the view that life remains tolerable at 1 kW per person (e.g. 24 kWh/day/p), but they also mention a paper with another view, Distribution of energy consumption and the 2000 W/capita target. Moreover Vaclav Smil, the doyen of renewable energy experts, has made an estimate of a need for 2 kW per person to maintain a good education and health care. Some instructive statistics, to put these figures into perspective, are that the average power consumption for the USA was about 3.7 kW per person until the 1890s when electricity and widespread rail traffic increased consumption.[vii] Even 3.7 kW/p is a bit fanciful when one considers that in the USA power consumption is now about 11 kW/p and in West Europe about 5 kW/p. It is idle to imagine that, when energy is scarce, it will be shared out equally between the whole world. Those with the economic strength to do so will preserve at least a modicum of comfort for themselves before leaving the rest to be shared out between the others. So even an average of 2 kW/p would be somewhat skimpy for the poor, but nevertheless, let us take 2 kW/p as an average, and conclude that if developed countries can manage such reductions as are needed to enable an average 2 kW/p (the current world average is about 2.4 kW/p), a population of 5.0 billion could be supported in 2050 without further damaging the ecosystem. Of course population won’t actually reduce by then to 5 billion, and this figure is mainly just a measure of overshoot.

But 2050 is only 40 years away, and we should be looking ahead further than that. It is arguable as to when fossil fuels will be totally exhausted (exhausted in terms of practical extraction that is) but some put it at about the end of this century. Whether or not it is longer than the end of the century, to safeguard the future we should redo the above calculation without assuming any fossil fuel input. As the authors show, there are not great prospects for much increasing the estimates for energy from renewable sources, or nuclear energy, and repeating the calculation without fossil fuel arrives at a grand total of 163 EJ, which, at 2 kW/p, gives a population that can be supported in moderate comfort of 2.6 billion. And there is an element of optimism in even that. While fossil fuel is available it can be used for transport. Without the fossil fuel, liquid fuels will either (a) have to be produced from biomass, which will require energy both for growing the feedstock and for supplying energy for growing, harvesting and conversion which amount of input energy is currently about the same as is in the ethanol produced; or (b) if not from biomass, then from converting electricity to hydrogen by electrolysis (about 70% efficient), and compressing it for storage (more loss), or perhaps converting the hydrogen to methane (which would have many advantages, one being that it has an energy density about 3.5 times that of hydrogen), but conversion to methane would incur further losses. Note too that if the purpose is to store the hydrogen to produce electricity later, then reconversion by turbine may be in the order of 50% efficient (if it can be made to equal modern gas plant), making the overall efficiency only 35%. Fuel cells are often mentioned for reconversion, but it is optimistic to think that fuels cells will be cheap enough to use for the purpose.


The book is excellent in looking at all the details of energy sources, and shows realism in what is likely to be politically possible, except that in regard to the latter, it surely goes too far in suggesting 1 kW/p as something which might be accepted voluntarily, and perhaps it is partly for that reason it fails to point out the sort of population levels that we should be striving for in order to reduce the extent of the die off which seems likely to occur if we run out of fossil fuels before significantly reducing population size.
Let us finish by asking which of the five inconvenient truths avoided by Al Gore (climate change was the only one he did not avoid) are also avoided by the our authors. I’m glad to say that they meet them all head on with the exception of number four:

The fourth inconvenient truth arises from the fact that it is bound to be a slow process to reduce the per capita emissions of the developed nations. Thus the action that would most rapidly ensure that there was some mitigation in burgeoning use of fossil fuels would be to prevent the populations of the developed nations growing by net immigration (as is happening in the USA and to a lesser extent in the European Union).

This is a very instructive book, outstanding in many ways, and it is in sharp contrast to many popular articles and books based on starry-eyed optimism about what technology is likely to deliver.


[i]. Rise and Fall of the Carbon Civilisationby Patrick Moriarty and Damon Honnery. Springer. 2011. Hardcover (ISBN: 978-1-84996-482-1, Oct. 11, 2010) US$116; GBP90; Aus$216 incl. postage from,
[ii]. The volume of the mixed layer, extending 75 m down, is 2.7 x 1016 m3,= 2.7 x 1022 cc, or ml (data from John Harte’s The Spherical Cow).
200,00 x 1018 J = 200,000 x 1018 / 4.186 = 4.78 x 1022 calories.
So increase in temperature = 4.78 x 1022 / 2.7 x 1022 = 1.77ºC.
Mixed layer is 1/50 of the total ocean volume (data from John Harte’s The Spherical Cow), so increase in temperature for the whole ocean were it to be evenly mixed would be 1.77 / 50 = 0.035ºC.
[iv]. Since the international conference in 1992, climatologists have been warning that the world needs to get down to annual emissions of about 9,000 Mt of carbon dioxide per year. Actually when the world was emitting that amount, the atmospheric concentration was increasing, but as the atmospheric concentration has now reached 390 ppm, 9,000 Mt/y holds out some promise for reducing the concentration. As mentioned later in the main text, 2 kW per person is probably about the minimum acceptable average for a lifestyle of minimum opulence, and this would be associated with about 4 tonnes of carbon dioxide release per year. Thus the limit to population on emission grounds while we are reliant mainly on fossil fuels is around 9,000 million / 4 = 2,200 million people.
[v]. MacKay, D.J.C. 2008. Sustainable Energy – without the hot air. UIT Cambridge. ISBN 978-0-9544529-3-3 Available free online from
[vi]. The 5.0 billion calculation is simply 318 EJ / 63 GJ, i.e. 318 x 1018 / 63 x 109 = 5 billion.
[vii]. Page 20 of Hayden, H. C. 2004. The Solar Fraud: Why Solar Energy Won’t Run the World (2nd edition). Vales Lake Publishing LLC. P.O. Box 7595, Pueblo West, CO 81007-0595. 280 pp.

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