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Science Philosophy & Social Aspects

How the World Really Works

The Science Behind How We Got Here and Where We're Going

by (author) Vaclav Smil

Penguin Publishing Group
Initial publish date
May 2022
Philosophy & Social Aspects, Science & Technology Policy, General
  • Hardback

    Publish Date
    May 2022
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“A new masterpiece from one of my favorite authors… [How The World Really Works] is a compelling and highly readable book that leaves readers with the fundamental grounding needed to help solve the world’s toughest challenges.”Bill Gates
“Provocative but perceptive . . . You can agree or disagree with Smil—accept or doubt his ‘just the facts’ posture—but you probably shouldn’t ignore him.”—The Washington Post
An essential analysis of the modern science and technology that makes our twenty-first century lives possible—a scientist's investigation into what science really does, and does not, accomplish.

We have never had so much information at our fingertips and yet most of us don’t know how the world really works. This book explains seven of the most fundamental realities governing our survival and prosperity. From energy and food production, through our material world and its globalization, to risks, our environment and its future, How the World Really Works offers a much-needed reality check—because before we can tackle problems effectively, we must understand the facts.

In this ambitious and thought-provoking book we see, for example, that globalization isn’t inevitable—the foolishness of allowing 70 per cent of the world’s rubber gloves to be made in just one factory became glaringly obvious in 2020—and that our societies have been steadily increasing their dependence on fossil fuels, such that any promises of decarbonization by 2050 are a fairy tale. For example, each greenhouse-grown supermarket-bought tomato has the equivalent of five tablespoons of diesel embedded in its production, and we have no way of producing steel, cement or plastics at required scales without huge carbon emissions.

Ultimately, Smil answers the most profound question of our age: are we irrevocably doomed or is a brighter utopia ahead? Compelling, data-rich and revisionist, this wonderfully broad, interdisciplinary guide finds faults with both extremes. Looking at the world through this quantitative lens reveals hidden truths that change the way we see our past, present and uncertain future.

About the author

Vaclav Smil is Distinguished Professor Emeritus at the University of Manitoba. He is the author of forty books, including Power Density: A Key to Understanding Energy Sources and Uses and Made in the USA: The Rise and Retreat of American Manufacturing, both published by the MIT Press. In 2010 he was named by Foreign Policy as one of the Top 100 Global Thinkers. In 2013 Bill Gates wrote on his website that “there is no author whose books I look forward to more than Vaclav Smil.”

Vaclav Smil's profile page

Excerpt: How the World Really Works: The Science Behind How We Got Here and Where We're Going (by (author) Vaclav Smil)

1. Understanding Energy


Fuels and Electricity


Consider a benign science fiction scenario: not travel to distant planets in search of life, but the Earth and its inhabitants as targets of remote monitoring by an exceedingly sapient civilization that sends its probes to nearby galaxies. Why do they do this? Just for the satisfaction of systematic understanding, and perhaps also to avoid dangerous surprises should the third planet orbiting around an unremarkable star in a spiral galaxy become a threat, or perhaps in case they should require a second home. Hence this planet keeps periodic tabs on Earth.


Let us imagine that a probe approaches our planet once every 100 years and that it is programmed to make a second pass (a closer inspection) only when it detects a previously unobserved kind of energy conversion-the changing of energy from one form to another-or a new physical manifestation dependent on it. In fundamental physical terms, any process-be it rain, a volcanic eruption, plant growth, animal predation, or the growth of human sapience-can be defined as a sequence of energy conversions, and for a few hundred million years after the Earth's formation the probes would see only the same varied, but ultimately monotonous, displays of volcanic eruptions, earthquakes and atmospheric storms.


Fundamental shifts


The first microorganisms emerge nearly 4 billion years ago but passing probes do not register them, as these life forms are rare and remain hidden, associated with alkaline hydrothermal vents at the ocean's floor. The first occasion for a closer look arises as early as 3.5 billion years ago, when a passing probe records the first simple, single-celled photosynthetic microbes in shallow seas: they absorb near-infrared radiation-that which is just beyond the visible spectrum-and do not produce oxygen. Hundreds of millions of years then elapse with no signs of change before cyanobacteria begin to use the energy of the visible incoming solar radiation to convert CO2 and water into new organic compounds and release oxygen.


This is a radical shift that will create Earth's oxygenated atmosphere, yet a long time elapses before new, more complex aquatic organisms are seen 1.2 billion years ago, when the probes document the rise and diffusion of brilliantly colored red algae (due to the photosynthetic pigment phycoerythrin) and of much larger, brown algae. Green algae arrive nearly half a billion years later, and because of the new proliferation of marine plants the probes get better sensors to monitor the sea floor. This pays off, as more than 600 million years ago the probes make another epochal discovery: the existence of the first organisms made of differentiated cells. These flattish, soft, bottom-dwelling creatures (known as Ediacaran fauna after their Australian domicile) are the first simple animals requiring oxygen for their metabolism and, unlike algae that are merely tossed by waves and currents, they are mobile.


And then the probes begin to document what are, comparatively speaking, rapid changes: instead of passing over lifeless continents and waiting hundreds of millions of years before logging another epochal shift, they begin to record the rising, cresting, and subsiding waves of the emergence, diffusion, and extinction of a huge variety of species. This period starts with the Cambrian explosion of small marine bottom-dwellers (541 million years ago, dominated first by trilobites) through the arrival of the first fishes, amphibians, land plants, and four-legged (and hence exceptionally mobile) animals. Periodic extinctions reduce, or sometimes almost eliminate, this variety, and even just 6 million years ago the probes do not find any organism dominating the planet. Not long afterwards, the probes nearly miss the significance of a mechanical shift with enormous energetic implications: many four-legged animals briefly stand or awkwardly walk on two legs, and more than 4 million years ago this form of locomotion becomes the norm for small ape-like creatures that begin spending more time on land than in trees.


Now the intervals between reporting something noteworthy to their home base shrink from hundreds of millions to mere hundreds of thousands of years. Eventually the descendants of these early bipeds (we classify them as hominins, belonging to the genus Homo, along the long line of our ancestors) do something that puts them on an accelerated path to planetary dominance. Several hundred thousand years ago, the probes detect the first extrasomatic use of energy-external to one's body; that is, any energy conversion besides digesting food-when some of these upright walkers master fire and begin to use it deliberately for cooking, comfort, and safety. This controlled combustion converts the chemical energy of plants into thermal energy and light, enabling the hominins to eat previously hard-to-digest foods, warming them through the cold nights, and keeping away dangerous animals.These are the first steps toward deliberately shaping and controlling the environment on an unprecedented scale.


This trend intensifies with the next notable change, the adoption of crop cultivation. About 10 millennia ago, the probes record the first patches of deliberately cultivated plants as a small share of the Earth's total photosynthesis becomes controlled and manipulated by humans who domesticate-select, plant, tend, and harvest-crops for their (delayed) benefit. The first domestication of animals soon follows. Before that happens, human muscles are the only prime movers-that is, converters of chemical (food) energy to the kinetic (mechanical) energy of labor. Domestication of working animals, starting with cattle some 9,000 years ago, supplies the first extrasomatic energy other than that of human muscles-they are used for field work, for lifting water from wells, for pulling or carrying loads, and for providing personal transportation. And much later come the first inanimate prime movers: sails, more than five millennia ago; waterwheels, more than two millennia ago; and windmills, more than a thousand years ago.


Afterwards, the probes don't have much to observe, following the arrival of another period of (relative) slowdown: century after century, there is just repetition, stagnation, or the slow growth and diffusion of these long-established conversions. In the Americas and in Australia (lacking any draft animals and any simple mechanical prime movers), all work before the arrival of Europeans is done by human muscles. In some of the Old World's preindustrial regions, harnessed animals, wind and running or falling water energize significant shares of grain milling, oil pressing, grinding, and forging, and draft animals become indispensable for heavy field work (plowing above all, as harvesting is still done manually), transporting goods, and waging wars.


But at this point, even in societies with domesticated animals and mechanical prime movers, much of the work is still done by people. My estimate, using necessarily approximate past totals of working animals and people and assuming typical daily work rates based on modern measurements of physical exertion, is that-be it at the beginning of the second millennium of the Common Era or 500 years later (in 1500, at the beginning of the early modern era)-more than 90 percent of all useful mechanical energy was provided by animate power, roughly split between people and animals, while all thermal energy came from the combustion of plant fuels (mostly wood and charcoal, but also straw and dried dung).


And then in 1600 the alien probe will spring into action, and spot something unprecedented. Rather than relying solely on wood, an island society is increasingly burning coal, a fuel produced by photosynthesis tens or hundreds of millions of years ago and fossilized by heat and pressure during its long underground storage. The best reconstructions show that coal as a heat source in England surpasses the use of biomass fuels around 1620 (perhaps even earlier); by 1650 the burning of fossil carbon supplies two-thirds of all heat; and the share reaches 75 percent by 1700. England has an exceptionally early start: all the coalfields that make the UK the world's leading 19th-century economy are already producing coal before 1640. And then, at the very beginning of the 18th century, some English mines begin to rely on steam engines, the first inanimate prime movers powered by the combustion of fossil fuel.


These early engines are so inefficient that they can be deployed only in mines where the fuel supply is readily available and does not require any transportation.But for generations the UK remains the most interesting nation to the alien probe because it is an exceptional early adopter. Even by 1800, the combined coal extraction in a few European countries and the United States is a small fraction of British production.


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.


Even by 1850, rising coal extraction in Europe and North America supplies no more than 7 percent of all fuel energy, nearly half of all useful kinetic energy comes from draft animals, about 40 percent from human muscles, and just 15 percent from the three inanimate prime movers: waterwheels, windmills, and the slowly spreading steam engines.The world of 1850 is much more akin to the world of 1700 or even of 1600 than that of the year 2000.


But by 1900 the global share of both fossil and renewable fuels and of prime movers shifts considerably as modern energy sources (coal and some crude oil) provide half of all primary energy, and traditional fuels (wood, charcoal, straw) the other half. Water turbines in hydro stations generate the first primary electricity during the 1880s; later comes geothermal electricity, and after the Second World War nuclear, solar, and wind electricity (the new renewables). But by 2020 more than half of the world's electricity will still be generated by the combustion of fossil fuels, mainly coal and natural gas.


By 1900, inanimate prime movers supply about half of all mechanical energy: coal-fired steam engines make the greatest contribution, followed by better-designed waterwheels and new water turbines (first introduced during the 1830s), windmills and brand-new steam turbines (since the late 1880s), and internal combustion engines (gasoline-fueled, also first introduced in the 1880s).


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. Animate prime movers hold only a 5 percent share of mechanical energy, as human exertions and the work of draft animals are almost completely displaced by machines fueled by liquids or by electric motors.


During the past two centuries, the alien probes will have witnessed a rapid global substitution of primary energy sources, accompanied by the expansion and diversification of fossil energy supply, and the no less rapid introduction, adoption, and growth in capacity of new inanimate prime movers-first coal-fired steam engines, then internal combustion engines (piston and turbines). 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.


Modern energy uses


What difference has this mobilization of extrasomatic energies made? Global primary energy supply usually refers to total (gross) production, but it is more revealing to look at energy that is actually available for conversion into useful forms. To do this, we need to subtract pre-consumption losses (during coal sorting and cleaning, crude oil refining, and natural gas processing), non-energy use (mainly as feedstocks for chemical industries, and also as lubricating oils for machines ranging from pumps to aircraft turbines and as paving materials), and losses during electricity transmission. With these adjustments-and rounding heavily to avoid impressions of unwarranted accuracy-my calculations show a 60-fold increase in the use of fossil fuels during the 19th century, a 16-fold gain during the 20th century, and about a 1,500-fold increase over the past 220 years.


This increasing dependence on fossil fuels is the most important factor in explaining the advances of modern civilization-and also our underlying concerns about the vulnerability of their supply and the environmental impacts of their combustion. In reality, the energy gain was substantially higher than the 1,500-fold I just mentioned, because we must take into account the concurrent increase in average conversion efficiencies. In 1800, coal combustion in stoves and boilers to produce heat and hot water was no more than 25-30 percent efficient, and only 2 percent of coal consumed by steam engines was converted into useful work, resulting in an overall conversion efficiency of no higher than 15 percent. A century later, better stoves, boilers, and engines raised the overall efficiency to nearly 20 percent, and by the year 2000 the mean conversion rate was about 50 percent. Consequently, the 20th century saw a nearly 40-fold gain in useful energy; since 1800 the gain was about 3,500-fold.


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.


Moreover, within a lifetime of people born just after the Second World War the rate had more than tripled, from about 10 to 34 GJ/capita between 1950 and 2020. 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.

Editorial Reviews

“A new masterpiece from one of my favorite authors… [How The World Really Works] is a compelling and highly readable book that leaves readers with the fundamental grounding needed to help solve the world’s toughest challenges.”Bill Gates

“You can agree or disagree with Smil—accept or doubt his ‘just the facts’ posture—but you probably shouldn’t ignore him. . . In Smil’s provocative but perceptive view, unrealistic notions about carbon reduction are partly, and ironically, attributable to the very productivity that societies achieved by substituting machine work, powered by fossil fuels, for draft animals and human laborers.”—The Washington Post

"[It is] reassuring to read an author so impervious to rhetorical fashion and so eager to champion uncertainty. . . Smil’s book is at its essence a plea for agnosticism, and, believe it or not, humility — the rarest earth metal of all. His most valuable declarations concern the impossibility of acting with perfect foresight. Living with uncertainty, after all, “remains the essence of the human condition.” Even under the most optimistic scenario, the future will not resemble the past. "—The New York Times
"How the World Really Works represents the highly readable distillation of this lifetime of scholarship… Mr. Smil looks over the horizon of the future with humility and calmness, foreseeing 'a mixture of progress and setbacks, of seemingly insurmountable difficulties and near-miraculous advances.'”Wall Street Journal

“The renowned energy scientist … aims to [recenter] materials rather than electronic flows of data as the bedrock of modern life — largely through examining what he calls the four pillars of modern civilization: cement, steel, plastics and ammonia.” The New York Times Magazine

"A scientific panorama of our well-being and how it can be sustained in our current tumultuous times and beyond. [Smil] aims to combat the widespread “comprehension deficit” about basic scientific facts, and he seeks to “explain some of the most fundamental ruling realities governing our survival and our prosperity.” That aim is marvelously achieved…[this is] an exceptionally lucid, evenhanded study of the scientific basis of our current and future lives.”Kirkus, STARRED review

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