The 18th century writer Adam Smith provided a workable metaphor for the way society utilizes resources. In his book "The Wealth of Nations," he argued that even as individuals strive, through personal industry, to maximize their advantage in life, they inadvertently contribute---as if under the influence of a "hidden hand"---to an aggregate disposition of wealth. Well, if Smith were a physicist and alive in the 21st century he might be tempted to compare people or nations to molecules and to replace the phrase "hidden hand" with "thermodynamic process."
Victor Yakovenko, a scientist at the Joint Quantum Institute (1), studies the parallels between nations and molecules. The distribution of energies among molecules in a gas and the distribution of per-capita energy consumption among nations both obey an exponential law. That is, the likelihood of having a certain energy value is proportional to e^(-E/kT), where T is the temperature and k is a proportionality factor called Boltzmann's constant. ("Temperature" here is taken to be the average national per-capita energy consumption in the world.)
Studies of world energy consumption often feature plots of energy consumption or population over time. Yakovenko and his colleagues prefer to draw out the underlying exponential distribution of national energy use by plotting the fraction of world population versus per-capita consumption.
The JQI researchers draw on data from the U.S. Energy Information Administration (EIA). It covers the period from 1980 to 2010 and includes numbers from more than 200 countries; see figure 1. Their results are published in the Journal "Entropy" (2). A few years ago Yakovenko made a similar study of national per-capita income distributions (3).
Actually, the consumption data can be graphed in another way, one that illustrates the distributive nature of energy use. In a "Lorenz p
|Contact: Phillip F. Schewe|
Joint Quantum Institute