TABLE 3 THE PER CAPITA BIOSPHERE FOR 6E9 PEOPLE of the recycled oxygen and 0.7% of the carbon, oxygen and hydrogen photosynthesized by vegetation. There are many other users on Earth of the C-O-H. Organisms of the food chains on which human beings depend consume much of the C-O-H. Before long humans will compose 0.02% (4 E + 8 tons) of all living matter in the biosphere. Cellulose, predominantly tropical trees, composed most of the biospheric mass, therefore humans are a dominant fraction of the non-cellulose mass. Spaceship Earth is a concept that should be considered accurate and relevant to efforts of the various space programs of the world. Evaporation of ocean water (4.3 E + 13 tons/year; 10% falls on land) is the largest matter cycle of the biosphere. However, at most only 2,500 tons/person-year (4% of maximum possible) will eventually be available from precipitation. U.S. usage rates are shown in Table 3 (5,B). Ancient ground waters are being mined much faster than they can be naturally replaced. Antarctic ice accumulates at faster rates than human water utilization. Iceberg gathering and towing has been studied (18). Management of large fractions of the waters of the Earth for human purposes would be a monumental, endless challenge. Perhaps local artificial recycling, as must be done in a space facility (column C), will be a less disruptive path for mankind to follow. Energy will be required. Not only is mankind making for all of us an artificial or “man-made” world, but mankind is systematically using the highest available grades of matter (liquid fuels, economic trace elements, etc.) to do so. This is not a problem if energy is readily accessible. However, the carbon energy resources are being used up at a rate at least one million times faster than they were originally produced by nature. Even the enormous world carbon reserves can be depleted by an aggressive and energy hungry world. A 6 E+9 people world using 10 tons of coal per year per person could deplete coal in less than 150 years, or less than half of the time since the world struggled into the industrial age (19-21). This brings us to a central problem and challenge of both Earth and space industry. We use our skills, energy, and matter to
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