Supplemental energy puts humans in charge

Energy is a subject that is greatly misunderstood. Its role in our lives is truly amazing. We humans are able to live and move because of the energy that we get from food. We count this energy in calories.

Green plants are also energy dependent. In photosynthesis, plants use energy from the sun to convert carbon dioxide and water into the glucose that they need to grow.

Ecosystems are energy dependent as well. The ecologist Howard T. Odum in Environment, Power, and Society explains that ecosystems self-organize in a way that maximizes the useful energy obtained by the group of plants and animals.

Economies created by humans are in some respects very similar to ecosystems. They, too, self-organize and seem to be energy dependent. The big difference is that over one million years ago, pre-humans learned to control fire. As a result, they were able to burn biomass and indirectly add the energy this provided to the food energy that they otherwise had available. The energy from burning biomass was an early form of supplemental energy. How important was this change?

How Humans Gained Dominion Over Other Animals

James C. Scott, in Against the Grain, explains that being able to burn biomass was sufficient to turn around who was in charge: pre-humans or large animals. In one cave in South Africa, he indicates that a lower layer of remains found in the cave did not show any carbon deposits, and hence were created before pre-humans occupying the cave gained control of fire. In this layer, skeletons of big cats were found, along with scattered gnawed bones of pre-humans.

In a higher layer, carbon deposits were found. In this layer, pre-humans were clearly in charge. Their skeletons were much more intact, and the bones of big cats were scattered about and showed signs of gnawing. Who was in charge had changed.

There is other evidence of human domination becoming possible with the controlled use of fire. Studies show a dramatic drop in numbers of large mammals not long after settlement by humans in several areas outside Africa. (Jeremy Lent, The Patterning Instinct, based on P. S. Martin’s “Prehistoric overkill: A global model” in Quaternary Extinctions: A Prehistoric Revolution.) Continue reading