How the World Really Works: A Scientist’s Guide to Our Past, Present and Future

by Vaclav Smil

the 19th century, through to the very latest assessments of global challenges...

I tend to think about modern scientists as either the drillers of ever-deeper holes (now the dominant route to fame) or scanners of wide horizons (now a much-diminished group).

Drilling the deepest possible hole and being an unsurpassed master of a tiny sliver of the sky visible from its bottom has never appealed to me.

I have always preferred to scan as far and as wide as my limited capabilities...

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 attent...

and specific properties and processes (power density, energy transitions).

And it also does, yet again, what I have been steadfastly doing for decades: it strongly advocates for moving away from extreme views.

I hope that my rational, matter-of-fact approach will help readers to understand how the world really works, and what our chances are of seeing it offer better prospects to the coming generations.

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 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.

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.

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.

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.

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 thei...

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 transpo...

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.

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 ...

share reaches 75 percent ...

England has an exceptionally early start: all the coalfields that make the UK the world’s leading 19th-century economy are al...

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 manu...

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 spread...

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

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 trad...

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 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.

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.

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.

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.

Tracing the trajectory of useful energy deployment is so revealing because energy is not just another component in the complex structures of the biosphere, human societies, and