Energy availability and energy sources as determinants of societal development in a long-term perspective

The dominant energy sources used by human societies and the transitions from one energy source to another have fundamental implications for societal development. A future energy transition is pending but it remains unclear what its socioeconomic corollaries will be. The history of the dominant energy sources used by human societies and their implications for societal development are traced in this review. “Passive solar energy utilization” in the hunting and gathering mode requires mobility of societies following the biomass that is their sole energy input. Fertility is constrained both by the available nutrition and by the need to migrate: population density is low. The agrarian mode relies on “active solar energy utilization”. Solar energy is harnessed through cultivated crops providing energy to humans. This mode requires a sedentary way of life and allows for much higher population density; progress in raising yields is achieved by additional labor-inputs and drives population growth. The industrial mode relies largely on fossil energy carriers supplying human societies with an amount of energy never accessible before, and with new materials. It relieves human societies of their dependence on land, fosters urban growth, and decreases fertility. At the same time, the industrial mode is based on a dominant energy source that will not be available indefinitely and that is associated with severe impacts on the environment. A future energy transition seems unavoidable and historical evidence suggests that it will be associated with fundamental socioeconomic change.