The laws of thermodynamics, particularly the second law, explain the wastefulness of animal agriculture by highlighting the energy loss and low net primary productivity (NPE) when converting plant calories into animal calories, making it less efficient than consuming plant-based foods.
The laws of thermodynamics explain the wastefulness of animal agriculture through the concept of energy loss in biological systems. The second law of thermodynamics, which states that every energy transfer or transformation increases the entropy of the universe, is particularly illuminating. In animal agriculture, energy is transferred from crops to livestock, and in the process, much of it is lost as heat or used up by the animals' metabolic processes, resulting in a low net primary productivity (NPE). This low NPE means it's less energy-efficient to consume animal products than plant-based foods because more energy, from crops, is required to sustain the livestock. Therefore, it is more resource-intensive and economically costlier to produce animal-based calories compared to plant-based ones, leading to calls for a global shift towards non-meat and non-dairy diets to reduce energy wastage.
For instance, it takes approximately $0.01 to produce 1000 dietary calories of corn or soybeans, while it costs roughly $0.19 to produce the same caloric amount from beef, and about $0.16 for milk due to cattle's low NPE. Ecological pyramids visually represent this inefficiency, showing the significant loss of energy, biomass, and number of organisms as one moves up from producers to consumers in an ecosystem. Collectively, these principles present a compelling argument for reducing reliance on animal agriculture to improve the efficiency of our food systems.