Energy

The scale, once measured, is staggering. Humanity now consumes energy at a rate on the order of eighteen terawatts — a figure that has climbed roughly twenty-five-fold since the mid-nineteenth century, far outpacing population growth. Behind the abstraction is a lived reality: an American or a Canadian commands, through machines and fuels, the equivalent of dozens of tireless servants working around the clock, a standard of comfort no monarch could have imagined two centuries ago.

And the overwhelming share of it still comes out of the ground. Fossil fuels — coal, oil, natural gas — supply something like four-fifths of the world's primary energy, a proportion that has barely budged in decades despite enormous investment in alternatives. Smil traces why. Coal is dense, storable, and cheap; oil is denser still and pours conveniently into a tank; natural gas burns cleaner than both. These fuels won not by conspiracy but by physics: they pack a great deal of energy into a small, portable, controllable package.

Here Smil turns to history, because he is convinced the past is the best available guide to how fast the future can move. Wood and charcoal powered human societies for millennia. Coal began its rise in earnest in eighteenth-century Britain, yet it did not overtake biomass as the world's leading fuel until around 1900 — well over a century after the first steam engines. Oil, discovered commercially in the 1850s, needed until roughly the 1960s to become the single largest global source. Each transition unfolded across generations, not decades.

The reason is not that people were slow to see the advantages. It is infrastructure. A new prime mover demands mines, pipelines, refineries, tankers, distribution networks, engines built to burn it, and workers trained to run all of it — an entire physical and social apparatus that takes decades and vast capital to erect. You cannot conjure a global fuel system; you have to build it, brick by brick and pipe by pipe, while the old one keeps the lights on.

Step back, and Smil's larger argument comes into focus: energy is the master resource, the thing everything else is bought with, and its transformations are governed by physics and infrastructure rather than by how badly we want them. This is why he treats renewables with a sympathy that stops short of enthusiasm. He is not against solar and wind — he expects them to grow enormously — but he insists on stating what they must overcome before we can lean on them.

The first hurdle is density again. Sunlight and wind are diffuse; harvesting meaningful power from them requires spreading collectors across large areas, whereas a coal plant or a gas turbine concentrates output on a small footprint. The second is intermittency: the sun sets and the wind drops, but demand does not, which means a renewable grid needs either vast storage or fossil-fired backup — and the storage to smooth a modern economy across cloudy windless weeks does not yet exist at anything like the required scale.

Smil ends where he began: with the ledger. The world runs on an enormous, growing flow of energy, still four-fifths of it drawn from fuels laid down over hundreds of millions of years, and the systems that deliver it were built over more than a century of steady accumulation. Any honest account of the future has to start from that inventory rather than from a hope. He is not telling us the transition is impossible; he is telling us it is a construction project of civilizational scale, subject to the same slow physics that governed every transition before it.