Pressure to find new sources of energy would eventually conjure up the mega-innovations that we describe today as the fossil-fuels revolution. These gave humans access to flows of energy much greater than those provided by farming—the energy locked up in fossil fuels, energy that had accumulated not over a few decades but since the Carboniferous period, more than 360 million years earlier. In seams of coal, oil, and gas lay several hundred million years’ worth of buried sunlight in solid, liquid, and gaseous forms.
