We Americans love to have ourselves a big old time. It's not just our waistlines that have exploded outward since the post-WWII era. Our houses have grown larger, as have the appliances within them, the vehicles in their driveways, the income inequalities between ourselves and our neighbors, and the challenges we face on a rapidly warming planet. In his new book, Size: How It Explains the World, Dr. Vaclav Smil, Distinguished Professor Emeritus at the University of Manitoba, takes readers on a multidiscipline tour of the social quirks, economic intricacies, and biological peculiarities that result from our function following our form.
From SIZE by Vaclav Smil. Copyright 2023 by Vaclav Smil. Reprinted courtesy of William Morrow, an imprint of HarperCollins Publishers.
Modernity’s Infatuation With Larger Sizes
A single human lifetime will have witnessed many obvious examples of this trend in sizes. Motor vehicles are the planet’s most numerous heavy mobile objects. The world now has nearly 1.5 billion of them, and they have been getting larger: today’s bestselling pickup trucks and SUVs are easily twice or even three times heavier than Volkswagen’s Käfer, Fiat’s Topolino, or Citroën’s deux chevaux — family cars whose sales dominated the European market in the early 1950s.
Sizes of homes, refrigerators, and TVs have followed the same trend, not only because of technical advances but because the post–Second World War sizes of national GDPs, so beloved by the growth-enamored economists, have grown by historically unprecedented rates, making these items more affordable. Even when expressed in constant (inflation-adjusted) monies, US GDP has increased 10-fold since 1945; and, despite the postwar baby boom, the per capita rate has quadrupled. This affluence-driven growth can be illustrated by many other examples, ranging from the heights of the highest skyscrapers to the capacity of the largest airplanes or the multistoried cruise ships, and from the size of universities to the size of sports stadiums. Is this all just an expected, inevitable replication of the general evolutionary trend toward larger size?
We know that life began small (at the microbial level as archaea and bacteria that emerged nearly 4 billion years ago), and that, eventually, evolution took a decisive turn toward larger sizes with the diversification of animals during the Cambrian period, which began more than half a billion years ago. Large size (increased body mass) offers such obvious competitive advantages as increased defense against predators (compare a meerkat with a wildebeest) and access to a wider range of digestible biomass, outweighing the equally obvious disadvantages of lower numbers of offspring, longer gestation periods (longer time to reach maturity), and higher food and water needs. Large animals also live (some exceptions aside — some parrots make it past 50 years!) longer than smaller ones (compare a mouse with a cat, a dog with a chimpanzee). But at its extreme the relationship is not closely mass-bound: elephants and blue whales do not top the list; Greenland sharks (more than 250 years), bowhead whales (200 years), and Galapagos tortoises (more than 100 years) do.
The evolution of life is, indeed, the story of increasing size — from solely single-celled microbes to large reptiles and modern African megafauna (elephants, rhinos, giraffes). The maximum body length of organisms now spans the range of eight orders of magnitude, from 200 nanometers (Mycoplasma genitalium) to 31 meters (the blue whale, Balaenoptera musculus), and the extremes of biovolume for these two species range from 8 × 10^12 cubic millimeters to 1.9 × 10^11 cubic millimeters, a difference of about 22 orders of magnitude.
The evolutionary increase in size is obvious when comparing the oldest unicellular organisms, archaea and bacteria, with later, larger, protozoans and metazoans. But average biovolumes of most extinct and living multicellular animals have not followed a similar path toward larger body sizes. The average sizes of mollusks and echinoderms (starfish, urchins, sea cucumbers) do not show any clear evolutionary trend, but marine fish and mammals have grown in size. The size of dinosaurs increased, but then diminished as the animals approached extinction. The average sizes of arthropods have shown no clear growth trend for half a billion years, but the average size of mammals has increased by about three orders of magnitude during the past 150 million years.
Analyses of living mammalian species show that subsequent generations tend to be larger than their parents, but a single growth step is inevitably fairly limited. In any case, the emergence of some very large organisms has done nothing to diminish the ubiquity and importance of microbes: the biosphere is a highly symbiotic system based on the abundance and variety of microbial biomass, and it could not operate and endure without its foundation of microorganisms. In view of this fundamental biospheric reality (big relying on small), is the anthropogenic tendency toward objects and design of larger sizes an aberration? Is it just a temporary departure from a long-term stagnation of growth that existed in premodern times as far as both economies and technical capabilities were concerned, or perhaps only a mistaken impression created by the disproportionate attention we pay nowadays to the pursuit and possession of large-size objects, from TV screens to skyscrapers?
The genesis of this trend is unmistakable: size enlargements have been made possible by the unprecedented deployment of energies, and by the truly gargantuan mobilization of materials. For millennia, our constraints — energies limited to human and animal muscles; wood, clay, stone, and a few metals as the only choices for tools and construction — circumscribed our quest for larger-designed sizes: they determined what we could build, how we could travel, how much food we could harvest and store, and the size of individual and collective riches we could amass. All of that changed, rather rapidly and concurrently, during the second half of the 19th century.
At the century’s beginning, the world had very low population growth. It was still energized by biomass and muscles, supplemented by flowing water turning small wheels and wind-powering mills as well as relatively small ships. The world of 1800 was closer to the world of 1500 than it was to the mundane realities of 1900. By 1900, half of the world’s fuel production came from coal and oil, electricity generation was rapidly expanding, and new prime movers—steam engines, internal combustion engines, steam and water turbines, and electric motors—were creating new industries and transportation capabilities. And this new energy abundance was also deployed to raise crop yields (through fertilizers and the mechanization of field tasks), to produce old materials more affordably, and to introduce new metals and synthetics that made it possible to make lighter or more durable objects and structures.
This great transformation only intensified during the 20th century, when it had to meet the demands of a rapidly increasing population. Despite the two world wars and the Great Depression, the world’s population had never grown as rapidly as it did between 1900 and 1970. Larger sizes of everything, from settlements to consumer products, were needed both to meet the growing demand for housing, food, and manufactured products and to keep the costs affordable. This quest for larger size—larger coal mines or hydro stations able to supply distant megacities with inexpensive electricity; highly automated factories producing for billions of consumers; container vessels powered by the world’s largest diesel engines and carrying thousands of steel boxes between continents—has almost invariably coincided with lower unit costs, making refrigerators, cars, and mobile phones widely affordable. But it has required higher capital costs and often unprecedented design, construction, and management efforts.
Too many notable size records have been repeatedly broken since the beginning of the 20th century, and the following handful of increases (all quantified by 1900–2020 multiples, calculated from the best available information) indicate the extent of these gains. Capacity of the largest hydroelectricity-generating station is now more than 600 times larger than it was in 1900. The volume of blast furnaces — the structures needed to produce cast iron, modern civilization’s most important metal — has grown 10 times, to 5,000 cubic meters. The height of skyscrapers using steel skeletons has grown almost exactly nine times, to the Burj Khalifa’s 828 meters. Population of the largest city has seen an 11-fold increase, to Greater Tokyo’s 37 million people. The size of the world’s largest economy (using the total in constant monies): still that of the US, now nearly 32 times larger.
But nothing has seen a size rise comparable to the amount of information we have amassed since 1900. In 1897, when the Library of Congress moved to its new headquarters in the Thomas Jefferson Building, it was the world’s largest depository of information and held about 840,000 volumes, the equivalent of perhaps no more than 1 terabyte if stored electronically. By 2009 the library had about 32 million books and printed items, but those represented only about a quarter of all physical collections, which include manuscripts, prints, photographs, maps, globes, moving images, sound recordings, and sheet music, and many assumptions must be made to translate these holdings into electronic storage equivalents: in 1997 Michael Lesk estimated the total size of the Library’s holdings at “perhaps about 3 petabytes,” and hence at least a 3,000-fold increase in a century.
Moreover, for many new products and designs it is impossible to calculate the 20th-century increases because they only became commercialized after 1900, and subsequently grew one, two, or even three orders of magnitude. The most consequential examples in this category include passenger air-travel (Dutch KLM, the first commercial airline, was established in 1919); the preparation of a wide variety of plastics (with most of today’s dominant compounds introduced during the 1930s); and, of course, advances in electronics that made modern computing, telecommunications, and process controls possible (the first vacuum-tube computers used during the Second World War; the first microprocessors in 1971). While these advances have been creating very large numbers of new, small companies, increasing shares of global economic activity have been coming from ever-larger enterprises. This trend toward larger operating sizes has affected not only traditional industrial production (be it of machinery, chemicals, or foods) and new ways of automated product assembly (microchips or mobile phones), but also transportation and a wide range of services, from banks to consulting companies.
This corporate aggrandization is measurable from the number and the value of mergers, acquisitions, alliances, and takeovers. There was a rise from fewer than 3,000 mergers — worth in total about $350 billion — in 1985 to a peak of more than 47,000 mergers worth nearly $5 trillion in 2007, and each of the four pre-COVID years had transactions worth more than $3 trillion. Car production remains fairly diversified, with the top five (in 2021 by revenue: Volkswagen, Toyota, Daimler, Ford, General Motors) accounting for just over a third of the global market share, compared to about 80 percent for the top five mobile phone makers (Apple, Samsung, Xiaomi, Huawei, Oppo) and more than 90 percent for the Boeing–Airbus commercial jetliner duopoly.
But another size-enlarging trend has been much in evidence: increases in size that have nothing to do with satisfying the needs of growing populations, but instead serve as markers of status and conspicuous consumption. Sizes of American houses and vehicles provide two obvious, and accurately documented, examples of this trend, and while imitating the growth of housing has been difficult in many countries (including Japan and Belgium) for spatial and historical reasons, the rise of improbably sized vehicles has been a global trend.
A Ford Model T — the first mass-produced car, introduced in 1908 and made until 1927 — is the obvious baseline for size comparisons. The 1908 Model T was a weakly powered (15 kilowatts), small (3.4 meters), and light (540 kilograms) vehicle, but some Americans born in the mid-1920s lived long enough to see the arrival of improbably sized and misleadingly named sports utility vehicles that have become global favorites. The Chevrolet Suburban (265 kilowatts, 2,500 kilograms, 5.7 meters) wins on length, but Rolls Royce offers a 441-kilowatt Cullinan and the Lexus LX 570 weighs 2,670 kilograms.
These size gains boosted the vehicle-to-passenger weight ratio (assuming a 70-kilogram adult driver) from 7.7 for the Model T to just over 38 for the Lexus LX and to nearly as much for the Yukon GMC. For comparison, the ratio is about 18 for my Honda Civic — and, looking at a few transportation alternatives, it is just over 6 for a Boeing 787, no more than 5 for a modern intercity bus, and a mere 0.1 for a light 7-kilogram bicycle. Remarkably, this increase in vehicle size took place during the decades of heightened concern about the environmental impact of driving (a typical SUV emits about 25 percent more greenhouse gases than the average sedan).
This American preference for larger vehicles soon became another global norm, with SUVs gaining in size and expanding their market share in Europe and Asia. There is no rational defence of these extravaganzas: larger vehicles were not necessitated either by concerns for safety (scores of small- and mid-size cars get top marks for safety from the Insurance Institute for Highway Safety) or by the need to cater to larger households (the average size of a US family has been declining).
And yet another countertrend involving the shrinking size of American families has been the increasing size of American houses. Houses in Levittown, the first post–Second World War large-scale residential suburban development in New York, were just short of 70 square meters; the national mean reached 100 in 1950, topped 200 in 1998, and by 2015 it was a bit above 250 square meters, slightly more than twice the size of Japan’s average single-family house. American house size has grown 2.5 times in a single lifetime; average house mass (with air conditioning, more bathrooms, heavier finishing materials) has roughly tripled; and the average per capita habitable area has almost quadrupled. And then there are the US custom-built houses whose average area has now reached almost 500 square meters.
As expected, larger houses have larger refrigerators and larger TV screens. Right after the Second World War, the average volume of US fridges was just 8 cubic feet; in 2020 the bestselling models made by GE, Maytag, Samsung, and Whirlpool had volumes of 22–25 cubic feet. Television screens started as smallish rectangles with rounded edges; their dimensions were limited by the size and mass of the cathode-ray tube (CRT). The largest CRT display (Sony PVM-4300 in 1991) had a 43-inch diagonal display but it weighed 200 kilograms. In contrast, today’s popular 50-inch LED TV models weigh no more than 25 kilograms. But across the globe, the diagonals grew from the post–Second World War standard of 30 centimeters to nearly 60 centimeters by 1998 and to 125 centimeters by 2021, which means that the typical area of TV screens grew more than 15-fold.
Undoubtedly, many larger sizes make life easier, more comfortable, and more enjoyable, but these rewards have their own limits. And there is no evidence for concluding that oversize houses, gargantuan SUVS, and commercial-size fridges have made their owners happier: surveys of US adults asked to rate their happiness or satisfaction in life actually show either no major shifts or long-term declines since the middle of the 20th century. There are obvious physical limits to all of these excesses, and in the fourth chapter I will examine some important long-term growth trends to show that the sizes of many designs have been approaching their inevitable maxima as S-shaped (sigmoid) curves are reaching the final stages of their course.
This new, nearly universal, worship of larger sizes is even more remarkable given the abundance of notable instances when larger sizes are counterproductive. Here are two truly existential examples. Excessive childhood weight is highly consequential because the burden of early onset obesity is not easily shed later in life. And on the question of height, armies have always had height limits for their recruits; a below-average size was often a gift, as it prevented a small man (or a very tall one!) getting drafted and killed in pointless conflicts.
Large countries pose their own problems. If their territory encompasses a variety of environments, they are more likely to be able to feed themselves and have at least one kind of major mineral deposit, though more often several. This is as true of Russia (the world’s largest nation) as it is of the USA, Brazil, China, and India. But nearly all large nations tend to have larger economic disparities than smaller, more homogeneous countries do, and tend to be riven by regional, religious, and ethnic differences. Examples include the NorthSouth divide in the US; Canada’s perennial Quebec separatism; Russia’s problems with militant Islam (the Chechen war, curiously forgotten, was one of the most brutal post–Second World War conflicts); India’s regional, religious, and caste divisions. Of course, there are counterexamples of serious disparities and discord among small-size nations — Belgium, Cyprus, Sri Lanka — but those inner conflicts matter much less for the world at large than any weakening or unraveling of the largest nations.
But the last 150 years have not only witnessed a period of historically unprecedented growth of sizes, but also the time when we have finally come to understand the real size of the world, and the universe, we inhabit. This quest has proceeded at both ends of the size spectrum, and by the end of the 20th century we had, finally, a fairly satisfactory understanding of the smallest (at the atomic and genomic levels) and the largest (size of the universe) scale. How did we get there?