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

by Vaclav Smil

Why then do most people in modern societies have such a superficial knowledge about how the world really works? The complexities of the modern world are an obvious explanation: people are constantly interacting with black boxes, whose relatively simple outputs require little or no comprehension of what is taking place inside the box. This is as true of such ubiquitous devices as mobile phones and laptops

America now has only about 3 million men and women (farm owners and hired labor) directly engaged in producing food—people who actually plow the fields, sow the seeds, apply fertilizer, eradicate weeds, harvest the crops (picking fruit and vegetables is the most labor-intensive part of the process), and take care of the animals. That is less than 1 percent of the country’s population,

China is the world’s largest producer of steel—smelting,

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.[16]

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.

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.

Energy conversions are the very basis of life and evolution. 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.

Simply put, energy is the only truly universal currency, and nothing (from galactic rotations to ephemeral insect lives) can take place without its transformations.[24]

Google’s Ngram Viewer, a tool that allows you to see the popularity of terms that appeared in printed sources between 1500 and 2019,

This led to what is still the most common definition of energy: “the capacity for doing work”—a definition valid only when the term “work” means not only some invested labor but, as one of the leading physicists of the era put it, a generalized physical “act of producing a change of configuration in a system in opposition to a force which resists that change.”[29] But that, too, is still too Newtonian to be intuitive.

It is important to realize that in physics today, we have no knowledge of what energy is. We do not have a picture that energy comes in little blobs of a definite amount. It is not that way. However, there are formulas for calculating some numerical quantity, and when we add it all together it gives . . . always the same number. It is an abstract thing in that it does not tell us the mechanism or the reasons for the various formulas.[30]

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]

All forms of energy can be measured in the same units—joule is the scientific unit; calories are often used in nutritional studies.

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).

Most recently, a poor understanding of energy has the proponents of a new green world naively calling for a near-instant shift from abominable, polluting, and finite fossil fuels to superior, green and ever-renewable solar electricity. But liquid hydrocarbons refined from crude oil (gasoline, aviation kerosene, diesel fuel, residual heavy oil) have the highest energy densities of all commonly available fuels, and hence they are eminently suitable for energizing all modes of transportation.

The shift from coal to crude oil took generations to accomplish. 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]

Solid or liquid fuels (chemical energy) are tangible (a tree trunk, a lump of coal, a canister of gasoline), and their burning—be it in forest fires, in Paleolithic caves, in locomotives to produce steam, or in motor vehicles—releases heat (thermal energy). Falling and running waters are ubiquitous displays of gravitational and kinetic energy that are fairly easily converted to useful kinetic (mechanical) energy by building simple wooden waterwheels—and all it takes to convert wind’s kinetic energy into mechanical energy for grinding grain or pressing oil seeds is a windmill and wooden gears to transfer the motion to millstones.

generating electricity for mass-scale commercial use is a costly and complicated undertaking. Its distribution from where it is generated to the places and regions of its largest use—to cities, industries, and electrified forms of rapid transportation—is equally complicated: it requires transformers and extensive grids of high-voltage transmission lines and, after further transformation, distribution by low-voltage overhead or underground wires to billions of consumers.

electricity still supplies only a relatively small share of final global energy consumption, just 18 percent.

Notice the key qualifying adjective: the target is not total decarbonization but “net zero” or carbon neutrality. This definition allows for continued emissions to be compensated by (as yet non-existent!) large-scale removal of CO2 from the atmosphere and its permanent storage underground, or by such temporary measures as the mass-scale planting of trees.[71]

Annual global demand for fossil carbon is now just above 10 billion tons a year—a mass nearly five times more than the recent annual harvest of all staple grains feeding humanity, and more than twice the total mass of water drunk annually by the world’s nearly 8 billion inhabitants—and it should be obvious that displacing and replacing such a mass is not something best handled by government targets for years ending in zero or five. Both the high relative share and the scale of our dependence on fossil carbon make any rapid substitutions impossible: this is not a biased personal impression stemming from a poor understanding of the global energy system – but a realistic conclusion based on engineering and economic realities.

What we need is to pursue a steady reduction of our dependence on the energies that made the modern world. We still do not know most of the particulars of this coming transition, but one thing remains certain: it will not be (it cannot be) a sudden abandonment of fossil carbon, nor even its rapid demise—but rather its gradual decline.[85]

The history of the concept of energy is covered in revealing detail in J. Coopersmith, Energy: The Subtle Concept (Oxford: Oxford University Press, 2015). BACK TO NOTE REFERENCE 26

There is no shortage of introductory books on thermodynamics, but this one still stands out: K. Sherwin, Introduction to Thermodynamics (Dordrecht: Springer Netherlands, 1993). BACK TO NOTE REFERENCE 31