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

by Vaclav Smil

In 1872, a century after the appearance of the last volume of the Encyclopédie, any collection of knowledge had to resort to the superficial treatment of a rapidly expanding range of topics, and, one and a half centuries later, it is impossible to sum up our understanding even within narrowly circumscribed specialties: such terms as “physics” or “biology” are fairly meaningless labels, and experts in particle physics would find it very hard to understand even the first page of a new research paper in viral immunology. Obviously, this atomization of knowledge has not made any public decision-making easier. Highly specialized branches of modern science have become so arcane that many people employed in them are forced to train until their early or mid-thirties in order to join the new priesthood.

Still, such continuing uncertainties and disputes do not excuse the extent to which most people misunderstand the fundamental workings of the modern world. After all, appreciating how wheat is grown (chapter 2) or steel is made (chapter 3) or realizing that globalization is neither new nor inevitable (chapter 4) are not the same as asking that somebody comprehend femtochemistry (the study of chemical reactions at timescales of 10-15 seconds, Ahmed Zewail, Nobel Prize in 1999) or polymerase chain reactions (the rapid copying of DNA, Kary Mullis, Nobel Prize in 1993). Why then do most people in modern societies have such a superficial knowledge about how the world really works?

Urbanization and mechanization have been two important reasons for this comprehension deficit. Since the year 2007, more than half of humanity has lived in cities (more than 80 percent in all affluent countries), and unlike in the industrializing cities of the 19th and early 20th centuries, jobs in modern urban areas are largely in services. Most modern urbanites are thus disconnected not only from the ways we produce our food but also from the ways we build our machines and devices, and the growing mechanization of all productive activity means that only a very small share of the global population now engages in delivering civilization’s energy and the materials that comprise our modern world.

None of the people reading this book will relocate to Mars; all of us will continue to eat staple grain crops grown in soil on large expanses of agricultural land, rather than in the skyscrapers imagined by the proponents of so-called urban agriculture; none of us will live in a dematerialized world that has no use for such irreplaceable natural services as evaporating water or pollinating plants. But delivering these existential necessities will be an increasingly challenging task, because a large share of humanity lives in conditions that the affluent minority left behind generations ago, and because the growing demand for energy and materials has been stressing the biosphere so much and so fast that we have imperiled its capability to keep its flows and stores within the boundaries compatible with its long-term functioning.

The first chapter of this book shows how our high-energy societies have been steadily increasing their dependence on fossil fuels in general and on electricity, the most flexible form of energy, in particular. Appreciation of these realities serves as a much-needed corrective to the now-common claims (based on a poor understanding of complex realities) that we can decarbonize the global energy supply in a hurry, and that it will take only two or three decades before we rely solely on renewable energy conversions.

The second chapter of this book is about the most basic survival necessity: producing our food. Its focus is on explaining how much of what we rely on to survive, from wheat to tomatoes to shrimp, has one thing in common: it requires substantial, direct and indirect, fossil fuel inputs. Awareness of this fundamental dependence on fossil fuels leads to a realistic understanding of our continued need for fossil carbon: it is relatively easy to generate electricity by wind turbines or solar cells rather than by burning coal or natural gas—but it would be much more difficult to run all field machinery without liquid fossil fuels and to produce all fertilizers and other agrochemicals without natural gas and oil. In short, for decades it will be impossible to adequately feed the planet without using fossil fuels as sources of energy and raw materials.

The relative decline of material needs per unit of many finished products has been one of the defining trends of modern industrial developments. But in absolute terms, material demands have been rising even in the world’s most affluent societies, and they remain far below any conceivable saturation levels in low-income countries where the ownership of well-built apartments, kitchen appliances, and air conditioning (to say nothing about cars) remains a dream for billions of people.

The sixth chapter will look first at how unfolding environmental changes might affect our three existential necessities: oxygen, water, and food.

Moreover, we have been aware of the actual degree of warming associated with the doubling of atmospheric CO2 for more than a century, and we were warned about the unprecedented (and unrepeatable) nature of this planetary experiment more than half a century ago (uninterrupted, accurate measurements of CO2 began in 1958). But we have chosen to ignore these explanations, warnings and recorded facts.

Add to this all other environmental worries, and you must conclude that the key existential question—can humanity realize its aspirations within the safe boundaries of our biosphere?—has no easy answers. But it is imperative that we understand the facts of the matter. Only then can we tackle the problem effectively.

My main area of interest throughout my life has been energy studies, because a satisfactory grasp of that vast field requires you to combine an understanding of physics, chemistry, biology, geology, and engineering with an attention to history and to social, economic, and political factors.

Inevitably, this book—the product of my life’s work, and written for the layperson—is a continuation of my long-lasting quest to understand the basic realities of the biosphere, history, and the world we have created.

By 1800 a passing probe will record that, across the planet, plant fuels still supply more than 98 percent of all heat and light used by the dominant bipeds, and that human and animal muscles still provide more than 90 percent of all mechanical energy needed in farming, construction, and manufacturing.

In the UK, where James Watt introduced an improved steam engine during the 1770s, the Boulton & Watt company begin to build engines whose average power is equal to that of 25 strong horses, but by 1800 they have sold less than 500 of these machines, merely denting the total power provided by harnessed horses and hard-working laborers.[14]

The world of 1850 is much more akin to the world of 1700 or even of 1600 than that of the year 2000.

By 1950, fossil fuels supply nearly three-quarters of primary energy (still dominated by coal), and inanimate prime movers—now with gasoline- and diesel-fueled internal combustion engines in the lead—provide more than 80 percent of all mechanical energy. And by the year 2000 only poor people in low-income countries depend on biomass fuels, with wood and straw providing only about 12 percent of the world’s primary energy.

The most recent visit would see a truly global society built and defined by mass-scale, stationary, and mobile conversions of fossil carbon, deployed everywhere but in some of the planet’s uninhabited regions.

To get an even clearer picture of the magnitude of these changes, we should express these rates in per capita terms. The global population rose from 1 billion in 1800 to 1.6 billion in 1900 and 6.1 billion in the year 2000, and hence the supply of useful energy rose (all values in gigajoules per capita) from 0.05 in 1800 to 2.7 in 1900 and to about 28 in the year 2000. China’s post-2000 rise on the world stage was the main reason for a further increase in the global rate to about 34 GJ/capita by 2020. An average inhabitant of the Earth nowadays has at their disposal nearly 700 times more useful energy than their ancestors had at the beginning of the 19th century.

Translating the last rate into more readily imaginable equivalents, it is as if an average Earthling has every year at their personal disposal about 800 kilograms (0.8 tons, or nearly six barrels) of crude oil, or about 1.5 tons of good bituminous coal. And when put in terms of physical labor, it is as if 60 adults would be working non-stop, day and night, for each average person; and for the inhabitants of affluent countries this equivalent of steadily laboring adults would be, depending on the specific country, mostly between 200 and 240. On average, humans now have unprecedented amounts of energy at their disposal.

An abundance of useful energy underlies and explains all the gains—from better eating to mass-scale travel; from mechanization of production and transport to instant personal electronic communication—that have become norms rather than exceptions in all affluent countries.

Between 1950 and 2020 the United States roughly doubled the per capita useful energy provided by fossil fuels and primary electricity (to about 150 gigajoules); in Japan the rate had more than quintupled (to nearly 80 GJ/capita), and China saw an astounding, more than 120-fold, increase (to nearly 50 GJ/capita).[18]

Modern history can be seen as an unusually rapid sequence of transitions to new energy sources, and the modern world is the cumulative result of their conversions.

And, more recently, physicist Robert Ayres has repeatedly stressed in his writings the central notion of energy in all economies: “the economic system is essentially a system for extracting, processing and transforming energy as resources into energy embodied in products and services.”[23]

As Ayres noted, economics does not only lack any systematic awareness of energy’s importance for the physical process of production, but it assumes “that energy doesn’t matter (much) because the cost share of energy in the economy is so small that it can be ignored . . . as if output could be produced by labor and capital alone—or as if energy is merely a form of man-made capital that can be produced (as opposed to extracted) by labor and capital.”[25]

Understanding how the world really works cannot be done without at least a modicum of energy literacy.

The first law of thermodynamics states that no energy is ever lost during conversions: be that chemical to chemical when digesting food; chemical to mechanical when moving muscles; chemical to thermal when burning natural gas; thermal to mechanical when rotating a turbine; mechanical to electrical in a generator; or electrical to electromagnetic as light illuminates the page you are reading. However, all energy conversions eventually result in dissipated low-temperature heat: no energy has been lost, but its utility, its ability to perform useful work, is gone (the second law of thermodynamics).[31]

In the next chapter, when I detail the massive energy subsidies going into modern food production, we will encounter the truly existential reality of different energy qualities. Producing chicken requires energies whose total is several times higher than the energy content of the edible meat. Although we can calculate the subsidy ratio in terms of energy quantities (joules in/joules out)—there is, obviously, a fundamental difference between inputs and outputs: we cannot digest diesel oil or electricity, while lean chicken meat is an almost perfectly digestible foodstuff containing high-quality protein, an indispensable macronutrient that cannot be replaced by an equal amount of energy from lipids or carbohydrates.

Another common mistake is to confuse energy with power, and this is done even more frequently. It betrays an ignorance of basic physics, and one that, regrettably, is not limited to lay usage. Energy is a scalar, which in physics is a quantity described only by its magnitude; volume, mass, density, time, and speed are other ubiquitous scalars. Power measures energy per unit of time and hence it is a rate (in physics, a rate measures change, commonly per time). Establishments that generate electricity are commonly called power plants—but power is simply the rate of energy production or energy use. Power equals energy divided by time: in scientific units, it is watts = joules/seconds. Energy equals power multiplied by time: joules = watts × seconds. If you light a small votive candle in a Roman church, it might burn for 15 hours, converting the chemical energy of wax to heat (thermal energy) and light (electromagnetic energy) with an average power of nearly 40 watts.[34]

Analogically, an adult man’s basal metabolic rate (the energy required at complete rest to run the body’s essential functions) is about 80 watts, or 80 joules per second; lying prone all day a 70-kilogram man would still need about 7 megajoules (80 × 24 × 3,600) of food energy, or about 1,650 kilocalories, to maintain his body temperature, energize his beating heart, and run myriad enzymatic reactions.[35]

Here is a density ladder (all rates in gigajoules per ton): air-dried wood, 16; bituminous coal (depending on quality), 24–30; kerosene and diesel fuels, about 46. In volume terms (all rates in gigajoules per cubic meter), energy densities are only about 10 for wood, 26 for good coal, 38 for kerosene. Natural gas (methane) contains only 35 MJ/m3—or less than 1/1,000 of kerosene’s density.[36]

And hydrocarbons have yet another indispensable non-fuel use: as feedstocks for many different chemical syntheses (dominated by ethane, propane, and butane from natural gas liquids) producing a variety of synthetic fibers, resins, adhesives, dyes, paints and coatings, detergents, and pesticides, all vital in myriad ways to our modern world.[40]

Given these advantages and benefits, it was predictable—indeed unavoidable—that our dependence on crude oil would grow once the product became more affordable and once it could be reliably delivered on a global scale.

Commercial crude oil extraction began during the 1850s in Russia, Canada, and the US. The wells, drilled using the ancient percussion method involving the raising and dropping of a heavy cutting bit, were shallow, their daily productivities were low, and kerosene for lamps (which displaced whale oil and candles) was the main product of the simple refining of crude oil.[41]

Diffusion of these new prime movers was slow, and the US and Canada were the only two countries with high rates of car ownership prior to the Second World War.

Not surprisingly, demand was coming from all sectors. In real terms, crude oil was so cheap that there were no incentives to use it efficiently: American houses in regions with a cold climate, increasingly heated by oil furnaces, were built with single-glazed windows and without adequate wall insulation; the average efficiency of American cars actually declined between 1933 and 1973; and energy-intensive industries continued to operate by using inefficient processes.[44]

In 1950 the US still produced about 53 percent of the world’s oil; by 1970, although still the largest producer, its share fell to less than 23 percent—and it was clear that the country would need increased imports—while the Organization of the Petroleum Exporting Countries (OPEC) produced 48 percent.

April 1972 the Texas Railroad Commission lifted its limits on the state’s output and hence surrendered its control of the price that it had held since the 1930s. In 1971, Algeria and Libya began to nationalize their oil production, and Iraq followed in 1972, the same year that Kuwait, Qatar, and Saudi Arabia began their gradual takeover of their oilfields—which until that point had been in the hands of foreign corporations. Then in April 1973, the US ended its limits on the import of crude oil east of the Rocky Mountains. Suddenly, it was a sellers’ market, and on October 1 1973 OPEC raised its posted price by 16 percent to $3.01/barrel, followed by an additional 17 percent rise by six Arab Gulf states and, after the Israeli victory over Egypt in Sinai in October 1973, it embargoed all oil exports to the US.

From 1950 to 1973 the Western European economic product had nearly tripled, and the US GDP had more than doubled in that single generation. Between 1973 and 1975 the global economic growth rate dropped by about 90 percent, and as soon as the economies affected by higher oil prices began to adjust to these new realities—above all by impressive improvements in industrial energy efficiency—the fall of the Iranian monarchy and the takeover of Iran by a fundamentalist theocracy led to a second wave of oil price rises, from about $13 in 1978 to $34 in 1981, and to another 90 percent decline in the global rate of economic growth between 1979 and 1982.[47]

Two generations later, only those who lived through those years of price and supply turmoil (or those, increasingly few, who studied their impact) appreciate how traumatic these two waves of price rises were. Consequences of the resulting economic reversals are still felt four decades later, because once demand for oil began to increase, many oil-saving measures remained in place and some—notably the transitions to more efficient industrial uses—kept on intensifying.[48]

In large, populous nations, the complete reliance on these renewables would require what we are still missing: either mass-scale, long-term (days to weeks) electricity storage that would back up intermittent electricity generation, or extensive grids of high-voltage lines to transmit electricity across time zones and from sunny and windy regions to major urban and industrial concentrations. Could these new renewables produce enough electricity to replace not only today’s generation fueled by coal and natural gas, but also all the energy now supplied by liquid fuels to vehicles, ships, and planes by way of a complete electrification of transport? And could they really do so, as some plans now promise, in a matter of just two or three decades?

In contrast, electricity is intangible and we can’t get an intuitive sense of it in the same way as we do with fuels. But its effects can be seen in static electricity, sparks, lightning; small currents can be felt, and currents above 100 milliamperes may be deadly. Common definitions of electricity are not instinctively accessible, they require a prior knowledge of other functional terms such as “electrons,” “flow,” “charge,” and “current.”

Electricity can be thought of as a ubiquitous and ultimate black box system: although many people have a fairly good understanding of what goes in (combustion of fossil fuel in a large thermal plant; falling water in a hydro station; solar radiation absorbed by a photovoltaic cell; the splitting of uranium in a reactor) and everybody benefits from what comes out (light, heat, motion), only a minority fully understand what goes on inside the generating plants, transformers, transmission lines, and final-use devices.

Commercial electricity generation began in 1882, with three firsts. Two of them were the pioneering coal-fired generating stations designed by Thomas Edison (Holborn Viaduct in London began operating in January 1882; Pearl Street station in New York in September 1882), and the third was the first hydroelectric station (on the Fox River in Appleton, Wisconsin, also generating since September 1882).[62]

The concurrent expansion of hydroelectric capacity accelerated during the 1930s, with large state-funded projects in the USA and the USSR, and reached new highs after the Second World War, culminating in the construction of record-size projects in Brazil (Itaipu, completed in 2007, 14 gigawatts) and China (Three Gorges, completed in 2012, 22.5 gigawatts).[64] Meanwhile, nuclear fission began to generate commercial electricity in 1956 at Britain’s Calder Hall, saw its greatest expansion during the 1980s, peaked in 2006, and has since declined slightly to about 10 percent of global electricity generation.[65] Hydro generation accounted for nearly 16 percent in 2020; wind and solar added almost 7 percent; and the rest (about two-thirds) came from large central stations fueled mostly by coal and natural gas.

If the COVID-19 pandemic brought disruption, anguish, and unavoidable deaths, those effects would be minor compared to having just a few days of a severely reduced electricity supply in any densely populated region, and if prolonged for weeks nationwide it would be a catastrophic event with unprecedented consequences.[70]

Ideally, the decarbonization of the global energy supply should proceed fast enough to limit average global warming to no more than 1.5°C (at worst 2°C). That, according to most climate models, would mean reducing net global CO2 emissions to zero by 2050 and keeping them negative for the remainder of the century.

Given the fact that annual CO2 emissions from fossil fuel combustion surpassed 37 billion tons in 2019, the net-zero goal by 2050 will call for an energy transition unprecedented in both pace and scale. A closer look at its key components reveals the magnitude of the challenges.

We need very large (multi-gigawatt-hour) storage for big cities and megacities, but so far the only viable option to serve them is pumped hydro storage (PHS): it uses cheaper nighttime electricity to pump water from a low-lying reservoir to high-lying storage, and its discharge provides instantly available generation.[76]

In contrast, modern nuclear reactors, if properly built and carefully run, offer safe, long-lasting, and highly reliable ways of electricity generation; as already noted, they are able to operate more than 90 percent of the time, and their lifespan can exceed 40 years.

But this may not last: even the European Union now recognizes that it could not come close to its extraordinarily ambitious decarbonization target without nuclear reactors. Its 2050 net-zero emissions scenarios set aside the decades-long stagnation and neglect of the nuclear industry, and envisage up to 20 percent of all energy consumption coming from nuclear fission.[78]