Growth From Microorganisms to Megacities

Growth as a process is ubiquitous. It is the hallmark of every living organism. It motivates much of what we as humans do, as often unspoken as it is outspoken. It is the narrative lens through which we examine societies and civilizations past and present. And it is the altar at which economists worship. You would think that nobody in their right mind would write a book that tries to encompass all of the above. Leave it to a deep thinker such as Vaclav Smil to prove you wrong.

Smil has written about 40 books – some of which are on my shelf and many more on my wishlist – but I admit with some trepidation that this is my introduction to his work. He has built a research career around energy: how we generate it, how we use it, and how it shapes our civilization. So why a book about growth? Because, as he points out, growth requires the conversion of energy.

The first chapter introduces the reader to patterns and outcomes of growth without going into the mathematical nitty-gritty. Patterns include linear, exponential, hyperbolic, and (importantly) sigmoid or logistic growth; outcomes include normal and power-law distributions (e.g. Pareto and Zipf). The remainder of the book systematically discusses growth in living organisms, energy converters (i.e. power generators and secondary devices that use electricity), man-made artefacts (e.g. tools, buildings, infrastructure, vehicles, and electronics), and complex systems (populations, cities, empires, economies, and civilizations).

Before discussing artefacts and complex systems, Smil first gives an in-depth treatment of energy converters as "the history of civilization can be seen as a quest for ever higher reliance on extrasomatic energies". In particular, civilizations have come to rely on ever power-denser fuels, from wood to coal to oil to nuclear. This is easily the most technical chapter of the book, rich in engineering details on the growth in both capacities and efficiencies of the machines we use to generate energy.

Biologists reading this book might feel a bit short-changed by the chapter on growth in nature. Though Smil covers growth in micro-organisms, trees, animals, and humans, much of what he discusses comes from intensely studied applied fields such as forestry, agriculture, and animal farming. There is less information about wild animals, animal populations, or ecosystems. And allometry – how shapes and proportions change with size – is only briefly mentioned when he discusses metabolic theory and expresses his scepticism of its universal applicability as promoted by e.g. Geoffrey West in his book Scale. For more on this topic see e.g. On Growth and Form, Animal Body Size, and The Design of Mammals.

Short-changed or not, this chapter serves two important ends. First, to show the many similarities between growth in living and non-living systems. Second, to highlight that few people (especially economists) understand growth and think that anything other than organisms can grow indefinitely. These similarities are not mere curiosities and many systems show logistic growth patterns that result in a characteristic S-shaped curve when plotted. This is as true of the spread of viruses and animal or human body size as it is of the growth over time of the size of building cranes or the maximum velocities of different modes of transportation.

But logistic growth is not universal and Smil warns of indiscriminate use of such curves to forecast growth. Bigger is not always better (engineers try to minimise the length of tunnels and bridges). Sometimes growth shows no particular trend and periods of stasis are followed by sudden jumps (the size of cathedrals) while civilizations can rise and fall and rise again. Or growth can be limited by other factors such as cost (the height of skyscrapers). Some of the processes graphed here are caught in an early phase of logistic growth (the volume of internet traffic), while others show the decline that can follow afterwards (the size of the US railroad network). Reconstructing historical growth of cities, empires, and civilizations is particularly tricky. Data is patchy and proxies imperfect.

I found the section on economic growth particularly revealing. Smil highlights the problems with the commonly used measure of Gross Domestic Product (GDP) and provides an eye-opening quantification of the energy and material flows underpinning our economies. Economists tend to either take these for granted or ignore them, but, as Smil has written elsewhere, we are still living in the iron age. The widespread techno-optimism that has come with Moore’s law and the astounding advances in computing power is misplaced and he is critical of dematerialization advocates, pointing out that, in absolute terms, we are only using more of everything.

Growth is a whopper of a book and Smil knows it: twice he refers to the "persevering reader”. Early on he warns that his systematic quantification is "unavoidably repetitive” and parts of the book are indeed somewhat dull. There is no grand theory being pushed here. But that is the whole point of the book: "grand predictions turn out to be, repeatedly, wrong”, he notes in his preface. What really characterises Smil’s attitude is caution, nuance, and scepticism. And nowhere does this show more than in his final chapter, where he ponders what comes after growth.

Smil has, in his own words, a "respect for complex and unruly realities”. He calls the idea of an imminent circular economy misleading ("modern economies are based on massive linear flows”), highlights the fallacy of thinking that economic growth can be decoupled from energy and material inputs ("[it] contradicts physical laws”), and considers sustainable development "one of the most misused descriptors of desirable human actions”. But he does not side with prophets of doom either, labelling peak oil advocates "a new catastrophist cult”.

On balance though, it is clear what camp Smil falls in, quoting from Emmott’s book 10 Billion that "we urgently need to consume less. A lot less”. To arrive at this conclusion "there is no need to be a catastrophist”. The way Smil sees it "Good life within planetary boundaries is possible [...] but not without fundamentally restructured provisioning systems”. And, as he points out in his conclusion to the book, we have to accept the "impossibility of infinite growth on a finite planet”.

Growth is a book that, well, grows on you. Yes, reading it is a substantial investment of time, but Smil’s meticulous and cross-disciplinary approach provides many insightful ideas – of which I have mentioned only a few – that lead to a well-reasoned conclusion. And as my personal introduction to his writing, it has convinced me that I urgently need to read more of his books.