Widening the Frame Until It Hurts
Every scale of history is a choice about what can count as a cause. Big History (David Christian) sets the frame at 13.8 billion years — Big Bang to the present, one continuous story with human civilization as a late thin band — and asks about increasing complexity, energy flows, and thresholds. Environmental history sets a narrower but equally destabilizing frame: it makes climate, soil, disease, and animals into actors rather than scenery.
The payoff is that some questions are simply unanswerable at the conventional scale. Why did Eurasian societies conquer American ones rather than the reverse? Confine yourself to politics and you get answers about institutions and character. Widen the frame and something colder appears: the continental axis. Eurasia runs east–west, so domesticated crops and animals spread along a shared latitude and climate band; the Americas and Africa run north–south, so every diffusion crosses climate zones and mostly fails. From that follow dense populations, herd animals, and — decisively — epidemic disease. Smallpox, measles, and influenza came from millennia of living beside livestock. In the Americas, disease killed on a scale that dwarfs every battle: estimates of 50–90% mortality within a century and a half, with the majority dying ahead of the conquerors' arrival, often before they had seen a European.
| Factor | Consequence |
|---|---|
| East–west continental axis | Crops and animals diffuse along one climate band |
| Large domesticable herd animals | Traction, protein, manure — and zoonotic disease |
| Long exposure to livestock disease | Endemic immunity in Eurasia; none in the Americas |
| Contact | Demographic catastrophe preceding conquest |
Climate as Actor, Not Backdrop
Ice cores, tree rings, pollen cores, and speleothems have given climate a chronology precise enough to correlate with events. The Little Ice Age (roughly 1300–1850) coincides with the seventeenth-century general crisis — harvest failure, revolt, and state collapse across Eurasia in the same decades. The 1815 eruption of Tambora produced the "year without a summer" in 1816: crop failure in New England and Europe, famine, migration, and — for good measure — a wet Swiss holiday that produced Frankenstein. And the Black Death (1347–51) killed perhaps a third to a half of Europe, then reorganized it: labour scarcity strengthened the surviving peasants' bargaining power and helped break serfdom in the west.
The Discipline's Objection, and the Answer
The charge is determinism: if geography and germs explain everything, human agency dissolves and — worse — outcomes acquire an air of inevitability that quietly excuses what people actually did. The objection has real force. Diamond's Guns, Germs, and Steel is widely admired and widely criticized on exactly this ground: the framework explains the broad continental pattern well and the specific decisions badly, and it can slide into reading conquest as something that happened rather than something that was done.
The answer is the Braudelian one, and it is a speed error to ignore it in either direction. Environmental factors set the field of possibility; humans play on the field. The axis of a continent does not decide who is enslaved; it decides who arrives carrying which pathogens. Disease made the conquest of the Americas demographically possible; it did not make the encomienda, the mines, or the slave trade — those were decisions, made by people with names, who had alternatives.
The honest formulation: widening the frame is not a way of relieving anyone of responsibility. It is a way of seeing which causes were operating at which speed, so that agency can be located precisely rather than assumed everywhere or dissolved entirely. That is why environmental history sits so naturally beside Braudel — both are asking the same question, which is at what scale does this cause operate, and both refuse the two easy answers.