Growth: From Microorganisms to Megacities
By Vaclav Smil
664 pp., hardcover. The MIT Press – Sep. 2019. $39.95.
Vaclav Smil’s latest book explores growth in nature and society. It examines the rules and patterns of growth in four key domains, those of the living world; human energy consumption; human artifacts; and human populations, societies and economies. The author is a passionate advocate of quantitative analysis, and thus Growth is filled with numbers, graphs and mathematical notation. Yet it’s written to be easily understood by non-mathematicians, making brilliant but accessible use of statistics to illustrate salient features of growth in all its terrestrial forms (the book’s scope is limited to Earth). In short, Growth is a compelling read for statisticians and non-statisticians alike.
A favorite author of Microsoft cofounder Bill Gates and a Foreign Policy magazine Top 100 Global Thinker, Smil is known for his multidisciplinary approach, energy-related expertise and penchant for packing his many books with all manner of fascinating facts. Growth’s chapter on the biological realm supplies as fine a sampling of this latter propensity as can be found. Did you know that average dinosaur body volumes declined at the beginning of the final period of the Mesozoic era but then made a near-comeback to their previous highs by the time of the dinosaurs’ extinction? You will after reading this book—and if you’re as much of a nerd as I am, you’ll relish this and innumerable other scientific tidbits. You’ll also be awed by the 100-page bibliography and the fact that scarcely a sentence goes by without some bit of quantitative analysis or scholarly citation.
Prehistoric trivia aside, Smil’s chapter on the living world rightly focuses on those life forms most necessary to humanity’s survival and the functioning of the biosphere. These include, of course, modern-day trees and forests, microorganisms, agricultural crops and animals. We learn in fine detail about the rise of, among other things, multi-drug-resistant bacteria, toxic marine algal blooms visible from space, monoculture tree plantations and the litany of commercially desirable but freakish malformations in the bodies of industrial meat production animals. The book also highlights some worrying cases of declining growth rates (for example, of U.S. agricultural yields). Smil’s analysis turns to humans as well, charting our growth in stature and body mass over the course of our history as a species, as well as the typical growth rates of human brains, heights and weights over individual lifespans.
The shortest chapter consists of an impressively succinct history of humankind’s ever-greater reliance on extrasomatic energy sources, or those outside of what is produced by one’s own body. Smil engagingly recounts humans’ successive harnessing of fire, animate labor, falling water, wind, sunlight, fossil fuels and nuclear fission. He uses a series of charts to illustrate the growth of energy turbine capacities, power plant efficiencies, passenger vehicle power, solar cell conversion efficiencies, luminous efficacies, electricity use in manufacturing and many other revealing metrics. The common thread is that in most cases, growth rates have been increasing by less and less each year as we’ve moved ever deeper into a state of diminishing returns concerning our exploitation of extrasomatic energies.
The chapter on the growth of human-made objects and their performances reveals two main trends: growth curves still in their early stages of ascent, and growth curves that inflected long ago and are approaching their limit values. Internet traffic, global civilian aviation traffic and the total number of buildings taller than 200 meters are a few of the things that would appear to have plenty of growth ahead. Those whose growth began slowing long ago and has been leveling off include the average area of American houses, the maximum passenger capacity of commercial airplanes, U.S. adoption rates of numerous home electronics and appliances, the number of passengers on Japan’s trains and the total length of highways in China. For me, the most astounding fact in this chapter has to do with the sheer diversity of human artifacts. “[T]he universe of man-made objects and structures,” writes Smil, “is as rich, and in some cases even richer, than the variety contained within the biosphere.”
Human populations, societies and economies are, according to Smil, the world’s “most complex assemblies,” and so it’s fitting that they’re addressed in what is by far the book’s most substantial chapter at 145 pages. Yet for all the complexity involved in its analyses, this chapter consists largely of variations on a single theme: a period of sustained growth followed by a slow-down in the growth rate as some logistic curve or another nears its maximum. Graph after graph points to imminent limits to energy supplies, crop harvests, available cropland, economic growth and human life expectancy.
Though he acknowledges that our present society’s rates of consumption and environmental degradation can’t keep growing forever, Smil cautions against making specific forecasts on this front based on past trajectories. He explains that attempting to predict future growth or decline based on how closely past data conform to a particular curve is a recipe for error. He goes on to cite an obvious recent example of a mistaken forecast born of this common practice: the Hubbert curve for American crude oil extraction. Geoscientist Marion King Hubbert correctly predicted that U.S. crude oil output would peak around 1970, and his bell-shaped curve indicated that production would return to its 1940 level by 2015. This isn’t what happened, of course. Instead, thanks to the shale oil boom, American oil extraction began to reverse its post-1970 descent a little over a decade ago, eventually forming a bimodal distribution rather than the normal distribution that Hubbert originally put forward.
Few questions could be more consequential than that of the planet’s maximum sustainable human population size, also known as its carrying capacity. Many within the peak oil community have pegged this figure at less than two billion. Their reasoning is that this is how many humans existed before the advent of the fossil-fueled agricultural revolution that caused the global population to increase so drastically within our lifetimes. Smil would appear to be unconvinced by this argument, as he makes no mention of it and finds a number of considerably higher estimates to be credible. In the end, he concludes that, due to uncertainty over future technological breakthroughs and consumption patterns, “large uncertainties concerning the future national and global trajectories of population growth will remain” for the foreseeable future.
The matter of what comes after growth is dealt with in the book’s final chapter. In keeping with his nearly all-encompassing scope elsewhere, Smil takes an expansive look at this question, covering everything from the almost-instant death processes of microorganisms, to the market saturation points of key technologies, to the steady drop in the total number of U.S. and Soviet/Russian nuclear warheads in recent decades, to the declines of civilizations. However, he stops short of saying anything definite about the future of modern industrial civilization, and again he’s critical of some notable attempts by others to envision future scenarios. (For instance, he raises valid issues regarding the methodology behind the Club of Rome’s landmark 1972 report The Limits to Growth.)
Perhaps the most practical part of Growth is its chapter detailing the various types of growth. As Smil presents the basics of linear and exponential growth, confined growth patterns and collective outcomes of growth, he goes over some common mistakes people make when extrapolating from growth histories. One such error—that of projecting future growth or decline based on a past data set’s fit to one curve or another—has been covered already. Another frequent mistake stems from most people’s failure to recognize the temporary nature of exponential growth. It’s this latter blindness that causes people to fall for financial bubbles, or to naïvely assume that some new technology that’s currently advancing exponentially will continue to do so indefinitely, as opposed to settling into a phase of non-exponential growth the way that all technologies eventually do as they mature.
My one big criticism of Growth is that it cries out for an additional chapter, one focused on the growth of human ecological impacts. Granted, the countless ways in which humanity has long been degrading the biosphere, and the alarming escalation in the rate of this degradation that has taken place during the postwar years, do receive a fair amount of attention in the existing chapters. But when such attention is diffused throughout an entire book, it has to be searched for and doesn’t have nearly the impact it otherwise would. To my mind, this material should have been gathered into its own chapter and bulked up considerably. Smil certainly doesn’t want for original data or thoughts on the subject of humans’ impact on the biosphere; he’s devoted multiple previous books to it.
Smil lets us know early on that this book, like his other writings, steers clear of any “rigid prescriptions” for addressing humanity’s crisis. True to this initial caveat, Smil never ventures far into the realm of potential solutions, instead sticking to broad statements like the following: “I believe that a fundamental departure from the long-established pattern of maximizing growth and promoting material consumption cannot be delayed by another century and that before 2100 modern civilization will have to make major steps toward ensuring the long-term habitability of its biosphere.” Thus, if you’re looking for solutions, Growth isn’t the book for you. If, on the other hand, you want a general look at the topic of growth, only parts of which directly address modern industrial civilization’s prospects for continued growth—and then only in so much depth—this book delivers.
Teaser photo credit: By User Minesweeper on en.wikipedia – Minesweeper, CC BY-SA 3.0