Energy And Civilization
How energy shaped civilization
Description
Vaclav Smil is not a household name, but the people who build the world read him. Bill Gates has said he waits for a new Smil book the way some of us wait for a new season of a favorite show. What Smil does, across dozens of dense books, is refuse the tidy story. In "Energy and Civilization," published in 2017 as a much-expanded version of a book he first wrote in the nineties, he takes a single quantity — energy, measured in joules and watts — and runs it through the entire span of human history, from a forager digging up tubers to a jet crossing the Atlantic.
The bet is deceptively simple. Everything a society does — feeding itself, moving goods, building cities, waging war, writing symphonies — requires converting energy from one form to another. A muscle burning sugar, a fire burning wood, a turbine burning gas: all the same underlying transaction. So if you track how much energy a civilization can command, and how efficiently it converts it, you have a thread that runs through the whole story, cutting underneath politics, culture, and the great-man biographies we usually reach for.
Smil follows that thread without flattering it. He resists the idea that history marched neatly upward, and he is just as skeptical of the promise that clean energy will arrive on schedule to save us. What he offers instead is a measured, data-soaked account of how we got this powerful — and how strange, in the long view, our present appetite really is.
The question we’re asking : What happens to the story of human progress when you retell it entirely in terms of energy — where it comes from, and how much we can command?What we’ll see : How societies climbed from muscle to machines, why the source mattered more than the effort, and what that climb quietly committed us to.
Table of contents
01Chapter 1 — The muscle economy and its ceiling
For almost all of human existence, the only engine available was the body. A working human, Smil notes, sustains an output of roughly 70 to 100 watts over a day — about the draw of an old lightbulb. That is the entire power supply of a forager, and later of a farmer. Everything a society built, it built at that rate, multiplied by however many bodies it could feed. This is the constraint that shaped everything downstream: with muscle as your only source, ambition is capped by how many people you can keep alive, and how much surplus food they can grow beyond their own hunger.
The first great move was farming, and Smil is careful not to romanticize it. Settled agriculture did not make life easier; often it made it harder, with longer hours and worse diets than foraging offered. What it did was raise the energy return on land — more edible calories per hectare — which meant more people per square mile, which meant, eventually, cities, priests, soldiers, and everyone else who does not grow their own food. The pharaohs and the cathedral builders were, in energy terms, running on the same sunlight-into-grain conversion, just organized on a larger scale.
02Chapter 2 — Coal, steam, and the great acceleration
What removed the ceiling was buried sunshine. Coal is the compressed remains of ancient forests, a store of solar energy laid down over tens of millions of years, and burning it meant a society was no longer living on its annual energy budget but drawing down a vast inheritance. Smil is precise about why this mattered: coal carries far more energy per kilogram than dry wood, and there was, for practical purposes, an enormous amount of it. A civilization that learned to dig it up had, for the first time, escaped the tyranny of this year's harvest.
The turning point was learning to turn heat into motion. Early steam engines, the Newcomen design of the early 1700s and then James Watt's far more efficient version later that century, were built first to pump water out of coal mines — energy used to get more energy. Smil treats the steam engine not as a lightning-bolt invention but as a slow, grinding improvement in efficiency, engineers squeezing more useful work out of each lump of coal over decade after decade. The early machines were absurdly wasteful. That they got better is the whole point.
03Chapter 3 — Density is the whole story
If there is a single idea Smil wants readers to carry away, it is energy density — how much power you can pack into a given weight, volume, or patch of ground. It sounds like a technical footnote. He treats it as the hinge on which the whole history turns, because density is what determines what a fuel can actually do. Wood is bulky and weak; coal is denser; oil is denser still and, crucially, liquid. Each step up in density unlocked machines and speeds that the previous fuel simply could not sustain.
This is why he is unsentimental about the great transitions. A society did not switch from wood to coal because coal was cleaner or nicer — the smoke of industrial cities was famously vile — but because coal packed more energy into less space and let people do things wood never could. The transition was driven by physics and economics working together, not by preference. Smil's respect for the numbers keeps him from mistaking what people wanted for what the energy allowed.
04Chapter 4 — A civilization no one designed to be this hungry
Step back from the sequence of fuels and Smil's larger claim comes into focus: energy is the universal currency of everything a society does, and the amount it can command sets the outer wall of what is possible. This reframes a lot of history. The wealth of the modern world, the food that feeds eight billion people, the mobility we treat as ordinary — none of it is primarily a triumph of ideas or institutions, though those matter. It is, at bottom, the result of learning to burn an inheritance of ancient sunlight at a spectacular rate.
That reframing is not celebratory. Smil documents the scale we have reached with something closer to unease. Modern agriculture, which he has studied for decades, is essentially a way of turning fossil fuel into food — natural gas into nitrogen fertilizer, diesel into tractors and transport. We eat oil, in a real sense. A civilization that feeds itself this way is extraordinarily productive and extraordinarily dependent, and it did not arrive at that dependence through any deliberate plan. It accumulated, transition by transition, each step rational on its own terms.
05Conclusion
Smil's history ends where it has to: with us, commanding more power per person than any pharaoh or emperor could have imagined, and only beginning to reckon with what that costs. The thread he pulls — from a body burning a hundred watts to a planet burning ancient carbon by the gigatonne — turns the familiar story of progress into something stranger and heavier. Progress, on this reading, is largely the story of getting our hands on denser and denser sources of energy, and rebuilding everything around each new one before we quite understood what we were committing to.