How the World Really Works: The Science Behind How We Got Here and Where We're Going

by Vaclav Smil

When expressed in terms of carcass weight, annual meat supply in many high-income countries has averaged close to, or even in excess of, 100 kilograms per capita—but the best nutritional advice is that we do not have to eat more than an adult’s body mass equivalent in meat per year to obtain an adequate amount of high-quality protein.[73]

Meat consumption in Japan, the country with the world’s highest longevity, has recently been below 30 kilograms per year; and a much less appreciated fact is that similarly low consumption rates have become fairly common in France, traditionally a nation of high meat intake. By 2013, nearly 40 percent of adult French were petits consommateurs, eating meat only in small amounts adding up to less than 39 kg/year, while the heavy meat consumers, averaging about 80 kg/year, made up less than 30 percent of French adults.[74]

Moreover, there are billions of people in Asia and Africa whose meat consumption remains minimal and whose health would benefit from more meaty diets.

Given that we are expecting at least 2 billion more people by 2050, and that more than twice as many people in the low-income countries of Asia and Africa should see further gains—both in quantity and quality—in their food supply, there is no near-term prospect for substantially reducing the global dependence on synthetic nitrogenous fertilizers.

These advances are, at present, a very long way off. They will depend on inexpensive renewable electricity generation backed up by adequate large-scale storage, a combination that is yet to be commercialized (and an alternative to large pumped hydro storage is yet to be invented; for more see chapter 3).

Fifty years later, this existential dependence is still insufficiently appreciated—but the readers of this book now understand that our food is partly made not just of oil, but also of coal that was used to produce the coke required for smelting the iron needed for field, transportation, and food processing machinery; of natural gas that serves as both feedstock and fuel for the synthesis of nitrogenous fertilizers; and of the electricity generated by the combustion of fossil fuels that is indispensable for crop processing, taking care of animals, and food and feed storage and preparation.

All these critical interventions have demanded substantial—and rising—inputs of fossil fuels; and even if we try to change the global food system as fast as is realistically conceivable, we will be eating transformed fossil fuels, be it as loaves of bread or as fishes, for decades to come.

Where it matters, ranking is impossible—or, at least, inadvisable. The heart is not more important than the brain; vitamin C is no less indispensable for human health than vitamin D. Food and energy supply, the two existential necessities covered in the preceding chapters, would be impossible without mass-scale mobilization of many man-made materials—metals, alloys, non-metallic and synthetic compounds—and the same is true about all our buildings and infrastructures and about all modes of transportation and communication. Of course, you would not know this if you were to judge the importance of these materials by the attention they get (or rather do not get), not only from mass media “news” but also from supposedly much more exalted economic analyses or forecasts of notable developments.

First things first. We could have an accomplished and reasonably affluent civilization that provides plenty of food, material comforts, and access to education and health care, without any semiconductors, microchips, or personal computers: we had one until, respectively, the mid-1950s (first commercial applications of transistors), the early 1970s (Intel’s first microprocessors), and the early 1980s (first larger-scale ownership of PCs).[1]

Silicon (Si) made into thin wafers (the basic substrate of microchips) is the signature material of the electronic age, but billions of people could live prosperously without it; it is not an existential constraint on modern civilization. Producing large, high-purity (99.999999999 percent pure) silicon crystals that are cut into wafers is a complex, multi-step, and highly energy-intensive process: it costs two orders of magnitude more primary energy than making aluminum from bauxite, and three orders of magnitude more than smelting iron and making steel.[2]

Of course, annual consumption of a material is not the best indicator of its indispensability, but in this case the verdict is clear: as useful and as transformative as post-1950 electronic advances have been, they do not constitute the indispensable material foundations of modern civilization. And while there can be no indisputable ordering of our material needs based on claims of their importance, I can offer a defensible ranking that considers their indispensability, ubiquity, and the demand size. Four materials rank highest on this combined scale, and they form what I have called the four pillars of modern civilization: cement, steel, plastics, and ammonia.[4]

In 2019, the world consumed about 4.5 billion tons of cement, 1.8 billion tons of steel, 370 million tons of plastics, and 150 million tons of ammonia, and they are not readily replaceable by other materials—certainly not in the near future or on a global scale.[5]

Similarly, even if we were able to produce identical masses of construction lumber or quarried stone, they could not equal the strength, versatility, and durability of reinforced concrete. We would be able to build pyramids and cathedrals but not elegant long spans of arched bridges, giant hydroelectric dams, multilane roads, or long airport runways. And steel has become so ubiquitous that its irreplaceable deployment determines our ability to extract energies, produce food, and shelter populations, as well as ensuring the extent and quality of all essential infrastructures: no metal could, even remotely, become its substitute.

Iron ore smelting in blast furnaces requires coke made from coal (and also natural gas); energy for cement production comes mostly from coal dust, petroleum coke, and heavy fuel oil. The vast majority of simple molecules that are bonded in long chains or branches to make plastics are derived from crude oils and natural gases. And in the modern synthesis of ammonia, natural gas is both the source of hydrogen and processing energy. As a result, global production of these four indispensable materials claims about 17 percent of the world’s primary energy supply, and 25 percent of all CO2 emissions originating in the combustion of fossil fuels—and currently there are no commercially available and readily deployable mass-scale alternatives to displace these established processes.[7]

The synthesis of ammonia from its elements belongs to the opposite class of discoveries—those with a clearly defined goal pursued by some of the best-qualified scientists and eventually reached by a persevering researcher. The need for this breakthrough was obvious. Between 1850 and 1900 the total population of the industrializing countries of Europe and North America grew from 300 million to 500 million, and rapid urbanization helped to drive a dietary transition from a barely adequate grain-dominated supply to generally higher food energy intakes containing more animal products and sugar.[11]

The challenge was to ensure that humanity could secure enough nitrogen to sustain its expanding numbers. The need was explained in 1898 in the clearest possible manner by William Crookes, chemist and physicist, to the British Association for the Advancement of Science, in his presidential address dedicated to the so-called wheat problem. He warned that “all civilized nations stand in deadly peril of not having enough to eat,” but he saw the way out: science coming to the rescue, tapping the practically unlimited mass of nitrogen in the atmosphere (present as the unreactive molecule N2) and converting it into compounds assimilable by plants.

It was a no smaller challenge to scale up Haber’s experimental success to a commercial enterprise. Under the leadership of Carl Bosch, an expert in chemical as well as metallurgical engineering who joined BASF in 1899, success was achieved in just four years. The world’s first ammonia synthesis plant began to operate at Oppau in September 1913, and the term “Haber-Bosch process” has endured ever since.[17]

I hasten to add that the 50 percent of humanity dependent on ammonia is not an immutable approximation. Given prevailing diets and farming practices, synthetic nitrogen feeds half of humanity—or, everything else being equal, half of the world’s population could not be sustained without synthetic nitrogenous fertilizers.

But Africa, the continent with the fastest-growing population, remains deprived of the nutrient and is a substantial food importer. Any hope for its greater food self-sufficiency rests on the increased use of nitrogen: after all, the continent’s recent usage of ammonia has been less than a third of the European mean.[33]

The best (and long-sought) solution to boost nitrogen supply would be to endow non-leguminous plants with nitrogen-fixing capabilities, a promise genetic engineering is yet to deliver on, while a less radical option—inoculating seeds with a nitrogen-fixing bacterium—is a recent innovation whose eventual commercial extent is still unclear.

Some thermoplastics combine low specific gravity (light weight) with fairly high hardness (durability). Durable aluminum weighs only a third as much as carbon steel, but PVC density is less than 20 percent and PP less than 12 percent compared to steel; and while the ultimate tensile strength of structural steel is 400 megapascals, that of polystyrene is, at 100 megapascals, twice that of wood or glass and only 10 percent less than that of aluminum.[36]

Thermoplastic polymers have found widespread uses in car interiors and exteriors (PP bumpers, PVC dashboards and car parts, polycarbonate headlight lenses); light high-temperature or flame-retardant thermoplastics (polycarbonate, PVC/acrylic blends) dominate the interiors of modern aircraft; and carbon-fiber reinforced plastics (composite materials) are now used for building aircraft airframes.[37]

During the interwar years came the first large-scale syntheses of PVC, which was discovered as early as 1838 but never used outside a laboratory, and DuPont in the US, Imperial Chemical Industries (ICI) in the UK, and IG Farben in Germany funded (very successfully) research dedicated to the discovery of new plastic materials.[39]

Nylon has been produced since 1938 (toothbrush bristles and stockings were the first commercial products; it now goes into products ranging from fishing nets to parachutes) and—as already noted—so has Teflon, a ubiquitous non-stick coating. The affordable production of styrene also began during the 1930s, and the material is now mostly used as polystyrene, or PS, in packing materials and disposable cups and plates.

Polyethylene terephthalate (PET)—since the 1970s the scourge of the planet in the form of discarded drink bottles—was patented in 1941 and mass-produced since the early 1950s (the infernal PET bottle was patented in 1973).[40] The best-known post–Second World War additions include polycarbonates (for optical lenses, windows, rigid covers), polyimide (for medical tubing), liquid crystal polymers (above all for electronics), and such famous DuPont trademarks as Tyvek® (1955), Lycra® (1959), and Kevlar® (1971).[41] By the end of the 20th century, 50 different kinds of plastics were on the global market, and this new diversity—together with rising demand for the most commonly used compounds (PE, PP, PVC, and PET)—led to exponential growth in demand.

The best way to appreciate the ubiquity of plastic materials in our daily lives is to note how many times a day our hands touch, our eyes see, our bodies rest on, and our feet tread on a plastic: you might be astonished at the frequency of such encounters! As I am typing this: the keys of my Dell laptop and a wireless mouse under my right palm are made of acrylonitrile butadiene styrene, I sit on a swivel chair upholstered in a polyester fabric, and its nylon wheels rest on a polycarbonate carpet protection mat that covers a polyester carpet . . .

But plastics have found their most indispensable roles in health care in general and in the hospital treatment of infectious diseases in particular. Modern life now begins (in maternity wards) and ends (in intensive care units) surrounded by plastic items.[43]

And those people who had no prior understanding of plastics’ role in modern health care got their lesson thanks to COVID-19. The pandemic has taught us this in often drastic ways, as doctors and nurses in North America and Europe ran out of personal protective equipment (PPE)—disposable gloves, masks, shields, hats, gowns, and booties—and as governments outbid each other in order to airlift limited (and highly overpriced) supplies from China, to which the Western producers of PPE, obsessed with cutting costs, had relocated most of their production lines, creating dangerous yet entirely avoidable supply shortages.[44]

Steels (the plural is more accurate as there are more than 3,500 varieties) are alloys dominated by iron (Fe).[47]

Modern steels are made from cast iron by reducing its high carbon content to 0.08–2.1 percent by weight. Steel’s physical properties handily beat those of the hardest stones, as well as those of the other two most common metals. Granite has a similar compressive strength (capacity to withstand loads that shorten the material) but its tensile strength is an order of magnitude lower: granite columns bear their load as well as steel, but steel beams can bear loads 15–30 times higher.[50] Steel’s typical tensile strength is about seven times that of aluminum and nearly four times that of copper; its hardness is, respectively, four and eight times higher; and it is heat resistant—aluminum melts at 660°C, copper at 1,085°C, steel only at 1,425°C.

Alloy steels include varying shares of one or more elements (most commonly manganese, nickel, silicon, and chromium, but also aluminum, molybdenum, titanium, and vanadium), added in order to improve their physical properties (hardness, strength, ductility). Stainless steel (10–20 percent chromium) was made for the first time only in 1912 for kitchenware, and is now widely used for surgical instruments, engines, machine parts, and in construction.[52]

Tool steels have a tensile strength 2–4 times higher than the best construction steels, and they are used for cutting steel and other metals for dies (for stamping or extrusion of other metals or plastics), as well as for manual cutting and hammering. And all steels (except for some stainless varieties) are magnetic and hence suitable for making electric machinery.

City streets are lined by regularly spaced lighting poles made from hot-dip galvanized and powder-coated steel for rust resistance; rolled steel makes roadside traffic signs and structures for overhead signage; and corrugated steel is used for crash barriers. Steel towers support thick steel wires to lift downhill skiers by the millions and to carry visitors in cable cars to tall peaks. Radio and TV towers (guyed masts) broke many height records for man-made structures, and modern landscapes contain seemingly endless repetitions of high-voltage electricity transmission towers. Two recent, prominent additions are dizzyingly tall guyed towers (to carry mobile telephone signals) and groups of large wind turbine towers, both onshore and offshore; and the most massive steel assemblies in the ocean are huge oil and gas production platforms.[57]

Although modern high-speed trains (aluminum bodies, plastic interiors) are only about 15 percent steel (wheels, axles, bearings, and motors), their operation requires dedicated tracks using heavier-than-normal steel rails.[61]

But the greatest revolution in postwar shipping has been the deployment of container ships (for more detail, see chapter 4). They transport cargo in steel crates of standardized dimensions.[62] These steel boxes are about 2.5 meters high and wide (length varies) and are stacked inside the hulls and high above the deck. Chances are that everything you wear was carried to its final point of sale in a steel container that started its journey in a factory in Asia.

Crude oil refineries are essentially forests of steel, with tall distillation columns, catalytic crackers, extensive piping, and storage vessels. Finally, I must note how steel saves lives in hospitals (from centrifuges and diagnostic machines to stainless-steel scalpels, surgical hooks, and retractors), and how it also kills: armies and fleets with their vast arrays of weapons are nothing but enormous repositories of steel dedicated to destruction.[64]

Can we secure the required massive supply of steel and how consequential is the metal’s global production? Do we have adequate supplies of iron ore to keep making steel for many generations to come? Can we produce enough of it in order to build modern infrastructures and raise the standards of living in low-income countries, where average per capita steel consumption is even lower than it was in the affluent economies a century ago? Is steelmaking environmentally friendly or is it exceptionally damaging? Can we produce the metal without using any fossil fuels?

Today’s BOFs are large, pear-shaped vessels with an open top used to charge up to 300 tons of hot iron, which gets blasted with oxygen blown in from both top and bottom. The reaction reduces the metal’s carbon content (to as little as 0.04 percent) in about 30 minutes. The combination of a blast furnace and a basic oxygen furnace is the basis of modern integrated steelmaking. Final steps include the transfer of hot steel to continuous casting machines to produce steel slabs, billets (square or rectangular shapes), and strips that are eventually converted into final steel products.

Ironmaking is highly energy-intensive, with about 75 percent of the total demand claimed by blast furnaces. Today’s best practices have a combined demand of just 17–20 gigajoules per ton of finished product; less efficient operations require 25–30 GJ/t.[76]

The total energy requirement of global steel production in 2019 was about 34 exajoules, or about 6 percent of the world’s primary energy supply.

The World Steel Association puts the average global rate at 500 kilograms of carbon per ton, with recent primary steelmaking emitting about 900 megatons of carbon a year, or 7–9 percent of direct emissions from the global combustion of fossil fuels.[78] But steel is not the only major material responsible for a significant share of CO2 emissions: cement is much less energy-intensive, but because its global output is nearly three times that of steel, its production is responsible for a very similar share (about 8 percent) of emitted carbon.

Since 2007, most of humanity has lived in cities made possible by concrete. Of course, there are plenty of other materials in urban buildings: skyscrapers have steel skeletons covered by glass or metal; detached houses in North American suburbs are made of wood (studs, plywood, particle board) and gypsum drywall (and are often sheathed in brick or stone); and engineered lumber is now used to build apartments many stories high.[82]

But skyscrapers and tall apartment buildings stand on concrete piles, concrete goes not only into foundations and basements but also into many walls and ceilings, and it is ubiquitous in all urban infrastructures—from buried engineering networks (large pipes, cable channels, sewers, subway foundations, tunnels) to aboveground transportation infrastructure (sidewalks, roads, bridges, shipping piers, airport runways). Modern cities—from São Paulo and Hong Kong (with their multistoried apartment towers) to Los Angeles and Beijing (with their extensive networks of freeways)—are embodiments of concrete.

But the preparation of modern cement was patented only in 1824 by Joseph Aspdin, an English bricklayer. His hydraulic mortar was made by firing limestone and clay at high temperatures: lime, silica, and alumina present in these materials are vitrified or transformed into a glass-like substance, whose grinding produced Portland cement.[84]

Aspdin chose that name (still widely used today) because once hardened, and after reacting with water, the glassy clinker had a color similar to limestone from the Isle of Portland in the English Channel.

During the 1860s and 1870s, the first reinforcing patents were filed by François Coignet and Joseph Monier in France (Monier, a gardener, began to use iron mesh to reinforce his planters), but the real breakthrough came in 1884 with Ernest Ransome’s reinforcing steel bars.[86]

The earliest designs of modern cement rotary kilns, where the minerals are vitrified at temperatures of up to 1,500°C, appeared during the 1890s and made it possible to use affordable concrete in large projects. The sixteen-story Ingalls Building in Cincinnati became the world’s first reinforced concrete skyscraper in 1903.[87]

Just three years later, Thomas Edison became convinced that concrete should replace wood in the building of American detached houses, and began to design and cast in place concrete homes in New Jersey; in 1911 he tried to revive the failed project by also offering cheap concrete furniture, including entire bedroom se...

Early concrete designs were also favored by architects Auguste Perret in France (elegant apartments and the Théâtre des Champs-Élysées) and Frank Lloyd Wright in the US. Wright’s most famous interwar concrete designs were Tokyo’s Imperial Hotel, finished just before the 1923 earthquake leveled the city and damaged the new structure, and Fallingwater in Pennsylvania, completed in 1939. The Guggenheim Museum in New York was his last famous concrete design, completed in 1959.[90]

The first major pre-stressed design, Eugène Freyssinet’s Plougastel Bridge near Brest, was finished in 1930.[91] With its bold, white, sail-like design, Jørn Utzon’s Sydney Opera House (built between 1959 and 1973) is perhaps the world’s most famous pre-stressed concrete strucuture.[92]