http://www.energybulletin.net/node/48807Economics, as it has been taught for well over a century, is unecological. It overlooks or explains away long run natural constraints to economic growth. Nonetheless, the penetration of physics into economic thought has made the most fundamental condition of human existence unavoidable in debates about the future:
The terrestrial sphere is thermodynamically closed.
We may call the area in which we ride around the sun and fly with the solar system through the cosmos at breakneck speed the terrestrial sphere. It has a diameter of 20,000 miles. Its center is the center of the Earth. Meteors enter, space vehicles leave, hydrogen atoms escape, and dust becomes annihilated in nuclear explosions, but for all practical purposes, these events leave the weight and composition of matter fixed and unchanged in this imaginary bulb.
Modern thermodynamics distinguishes among three kinds of systems: open, closed, and isolated.
The open system exchanges both energy and matter with the exterior; the isolated does neither. Obviously, the terrestrial sphere falls between the two extremes; it is closed. It exchanges energy with the rest of the universe -- most of the intercepted solar radiation is extruded at night -- but not matter. Whatever we do with it -- incorporating it into our bodies, feeding it into economic processes, discarding bodies, throwing away or recycling substances over and over again -- our inventory of atoms remains virtually constant. The matter that we are, use and reuse, just rolls around “in the earth’s diurnal course with rocks, stones, and trees,” to quote William Wordsworth.
This undeniable fact remains disconnected from traditional economics.