Growth: From Microorganisms to Megacities

by Vaclav Smil

All that is just sloppy data gathering, and an uninformed rush to make an impression, but more important is an indefensible categorical error made by comparing a complex system based on a new and extensive infrastructure with an entertaining software.

And this is one of the most consequential undesirable consequences of this information flood: time spent per adult user per day with digital media doubled between 2008 and 2015 to 5.5 hours (eMarketer 2017), creating new life forms of screen zombies.

Inevitably, their growth, and for higher organisms also their cognitive and behavioral advances, are fundamentally limited by the biosphere’s physical conditions and (wide as it may seem by comparing its extremes) by the restricted range of metabolic possibilities. Studies

As always in my writings, I stay away from any rigid prescriptions—but I hope that the book’s careful reading conveys the key conclusion: before it is too late, we should embark in earnest on the most fundamental existential (and also truly revolutionary) task facing modern civilization, that of making any future growth compatible with the long-term preservation of the only biosphere we have.

Consequently, in terms of actual average individual betterment, the recent 2% growth has been quite superior to the former, 2.5 times higher, rate. This is simple algebra, but it is repeatedly ignored by all those bewailing the “low” post-2000 growth of the US or European Union (EU) economies.

most of the advances have been concentrated in relatively brief growth spurts separated by long periods of no growth or marginal gains.

Reliable historical reconstructions for societies with adequate statistical services go back only 150–200 years.

personal computers have seen a millionfold growth of memory/mass ratio since 1981!

As a result, new houses built in 2015 are about 2.6 times larger than was the 1950 average, but for many of them the mass of materials required to build them is four times as large.

Second, exponential growth, natural or anthropogenic, is always only a temporary phenomenon, to be terminated due to a variety of physical, environmental, economic, technical, or social constraints.

it can be so misleading to use exponential growth for longer-term forecasting.

Taking temporarily high rates of annual exponential growth as indicators of future long-term developments is a fundamental mistake—but also an enduring habit that is especially favored by uncritical promoters of new devices, designs, or practices: they take early-stage growth rates, often impressively exponential, and use them to forecast an imminent dominance of emerging phenomena.

Overlapping logistic growth of unit ratings of steam engines, water turbines, and steam turbines produces a temporary hyperbolic growth trend with nearly seven-order-magnitude gain in 300 years.

the accelerating growth has been achieved by the relay phenomenon as the overlapping logistic (self-limiting) curves produce an impressively ascending envelope.

The instantaneous growth rate of the logistic function (its derivative with respect to time) is normally distributed, peaking at the curve’s inflection point

Most instances of power-law distributions do not even have strong statistical support, and any purely empirical fitting—while interesting, perhaps even remarkable—does not justify unsubstantiated suggestions of universality.

“the mechanistic insights are almost always too limited for the identification of power-law behavior to be scientifically useful.”

Perhaps the most remarkable attribute of natural growth is how much diversity is contained within the inevitable commonality dictated by fundamental genetic makeup, metabolic processes, and limits imposed by combinations of environmental factors.

Their degradative enzymes can eventually dismantle any kind of organic matter, and the two groups of microorganisms act in both synergistic and antagonistic ways.

But even the span between 20 minutes for average generation time of common gut and soil bacteria and 1,000 years of generation time for barophilic extremophiles amounts to the difference of seven orders of magnitude, and it is not improbable that the difference may be up to ten orders of magnitude for as yet undocumented extremophilic microbes.

The US output of chicken meat has risen more than 20-fold since 1950, from 1.1 to 23.3 Mt in 2015, and the worldwide growth has been even more impressive, from less than 4 Mt in 1950 to just over 100 Mt in 2015 (FAO 2018). But this growth has subjected modern broilers to a great deal of stress, even to outright suffering.

Enough to go vegetarian

This crowding is also a perfect illustration of how maximization of profit drives growth even as that growth is not optimal. Studies have shown that broilers convert feed more efficiently, grow heavier, and have lower mortality when given more space (Thaxton et al. 2006), but as Fairchild (2005) noted broiler farmers cannot afford low densities because they would not achieve a satisfactory return.

This, in sum, is the growth of modern broilers: abbreviated lives with malformed bodies in dark crowded places that preclude normal activity of what are, after all, social birds, forced to live on a layer of excrement that damages feet and burns skin. Of course, this unprecedented growth causing a great deal of suffering has its ultimate commercial reward, inexpensive lean meat.

These adjustments show that in mass terms (kg of feed/kg of edible meat and associated fat), the recent American feeding efficiency ratios have averaged about 25 for beef (but it must be remembered that most of it is phytomass indigestible by nonruminants), nine for pork and more than three for chicken, implying respective energy conversion efficiencies of less than 4%, nearly 10% and 15%, and protein conversion efficiencies of 4%, 10% and 30%, while about 25 MJ of feed energy are needed to produce a gram of beef protein and the rates are about10 MJ/g for pork and 2.5 MJ/g for chicken (Smil 2013c).

Unlike in nonhuman primates that have nearly half of their gut mass in the colon and 14–29% in the small intestine, the reverse is true in humans, with the small intestine accounting for nearly 60% and the colon for 17–25%.

But a new study of total energy expenditure in humans and large primates—using the doubly labelled (with isotopes of hydrogen and oxygen) water method (Lifson and McClintock 1966; Speakman 1997)—shows that the key to our high encephalization has been metabolic acceleration.

High encephalization is thus supported by hypermetabolic existence.

The growth of those children who received inadequate nutrition was depressed to such an extraordinary degree that even by ages 14 or 15 their height was less than the fifth percentile of modern height standards—but the adult heights of American slaves were comparable to those of the contemporary European nobility, only 1.25 cm shorter than the Union Army soldiers, and less than 5 cm below the modern height standard.

The subsequent history of civilization can be seen as a quest for ever higher reliance on extrasomatic energies (Smil 2017a).

The maximum share of the wind’s kinetic energy that can be harnessed by a turbine is 16/27 (59%) of the total flow, a limit known for more than 90 years (Betz 1926).

This important development illustrates a key lesson applicable to many other growth phenomena: the best and the latest may not be the best in specific circumstances. Relatively low-capacity, inefficient, and outdated steam engines were the best choice to win the delivery war.

Rather than staying small and serving decentralized enterprises, massive diesel engines became one of the principal enablers of unprecedented industrial centralization, mainly because they reduced transportation costs, previously decisive determinants of industrial location, to such an extent that an efficient mass-scale producer located on any continent could serve the new, truly global, market.

This means that between 1982 and 2017 capacities of the largest solar park grew by three orders of magnitude (1,500 times to be exact), with recent rapid increases made possible by the declining costs of PV panels.

Electric drive was a key factor in the near-doubling of US manufacturing productivity during the first 30 years of the 20th century, as well as in another doubling that was accomplished by the late 1960s (Schurr 1984).

The World Steel Association recognizes about 3,500 grades of steel, that is more than all described species of rodents, the largest mammalian order.

In terms of macroscopic components, complex machines are easily as “species-rich” as complex ecosystems: the average Toyota car has 30,000 parts, Boeing 737 (the smallest plane of the 700 series) has about 400,000 parts (excluding wiring, bolts, and rivets), the new Boeing 787 has 2.3 million, and Boeing 747–8 has 6 million parts (Boeing 2013).

There is a 100 million-fold difference in the mass of mammals between the smallest (Etruscan shrew 1.3–2.5 g) and the largest (blue whale, 180 t), but there is an even larger mass difference between the lightest flying object (miniature photo drone at 5 g) and fully loaded Airbus 380 (560 t).

basic artifact capabilities achieved primarily by ingenious design and only secondarily by deploying more powerful prime movers.

Sixteen of the top 20 cities with most skyscrapers are now in Asia, with nine in China, and Moscow (17th) the only European city in the group.

Rapid growth of urban housing continued during the first decade of the 21st century, when China’s cities added twice the total of houses in the UK and Spain and roughly the equivalent of Japan’s total housing stock (EIU 2011).

In one of greatest technical stagnations of history, these realities remained unchanged for more than a millennium.

Roads : technical stagnation

Even during the first half of the 18th century, it was cheaper to ship goods from overseas than to transport domestic inland products to ports, and in such a rainy country as England roads were often impassable and justly described as barbarous, execrable, abominable, and infernal (Savage 1959).

As I showed in chapter 2, there have been some significant long-term changes in human size but higher statures and heavier bodies have not resulted in any appreciable increase in human capacities to transport loads.

Women’s improvements were significantly higher for shorter distances as well as for the marathon. The gain for a world record 100 m sprint was 8.1% for men and 22.9% for women, with the respective increases of 9.7% and 25.7% for 400 m, 12.4% and 10.3% for 1,500 m, 15.1% and 8.5% for 10 km, and 21.5% and 38.6% for the marathon.

a speed plateau dictated by the economics of commercial operation has been thus in place ever since the beginning of the jetliner era.

A new attempt to revive supersonic commercial flight is underway: Boom Technology of Colorado is developing a 2.2 M plane for 45–55 passengers, promising actual service certification by 2023 (Boom Technology 2017).

Passenger capacity and the cruising speed of airplanes display clear sigmoidal (saturation) curves. Improvements in operating efficiency of jetliners (energy required per pkm or per seat) show linear improvements with the shift from early turbojets to the latest turbofans. And the growth of worldwide air traffic (in pkm) has seen exponential growth averaging 5.4%/year between 1970 and 2016, with a significantly slower rate (3.7%) expected between 2016 and 2035. Most people still want to fly more, but, inevitably, another S-curve is forming.

competitive substitution waves

one looking at key properties of vacuum and solid-state devices and showing that high rates of performance growth (roughly doubling every two years) characterized successive vacuum devices before they became associated with the increasing capacities of microprocessors, whose growth has conformed to Moore’s law. Simply put, vacuum electronics had seen gains anticipated by Moore’s law for decades before that growth rule was formulated by Gordon Moore in 1965.