From Muscle and Water to Fossil Energy

For most of history people relied on renewable but limited sources of energy: their own muscles, animals, wood, wind and water. Industrialization shifted Britain toward coal, a vast store of ancient solar energy. Water wheels still powered many mills well into the 19th century, and horses remained vital for local transport, so the transition was gradual. But coal-fired steam engines could be placed anywhere, worked in any season, and were not limited by the size of rivers or forests.

By the mid-19th century, coal supplied the great majority of Britain's energy, and output per worker in industry rose sharply. Economic historians argue that this energy transition was the deepest change of the era, because it broke the ceiling on growth set by land. It also began the large-scale release of carbon dioxide from fossil fuels, a consequence no one understood at the time.