Ecoscience: Pollution Problems With World Groundwater Supplies

One of the most crucial "public service" functions of Earth's ecosystems is the provision of the fresh groundwater needed for agriculture, industrial processes, drinking, and other domestic uses.

| November/December 1982

The Ecoscience column focuses on pollution problems with world groundwater supplies and the hazards posed by acid rains. 

Paul Ehrlich (Bing Professor of Population Studies and Professor of Biological Sciences, Stanford University) and Anne Ehrlich (Senior Research Associate, Department of Biological Sciences, Stanford) are familiar names to ecologists and environmentalists everywhere. But while most folks are aware of the Ehrlichs' popular writing in the areas of ecology and overpopulation (most of us—for instance—have read Paul's book The Population Bomb) . . . few people have any idea of how deeply the Ehrlichs are involved in ecological research (the type that tends to be published only in technical journals and college texts). That's why we're pleased to present this regular semi-technical column by these well-known authors/ecologists/educators.  


One of the most crucial "public service" functions of Earth's ecosystems (in the eyes of humanity, at any rate) is the provision of the fresh water needed for agriculture, industrial processes, drinking, and other domestic uses . . . and the amount of the precious liquid that these systems circulate is truly colossal! Something on the order of 27,000 cubic miles of fresh water fall on our planet's land surface annually, and about 15,000 of them are subject to direct evaporation or are returned to the atmosphere through the action of plants. The other 12,000 cubic miles flow over and through the land to the ocean, and the cycle is completed by the winds that carry 12,000 cubic miles of moisture, evaporated from the oceans, back to the land.

The freshwater flow to the oceans amounts to over 2.5 million gallons for every man, woman, and child in the human population. And as large as the flows of fresh water are, the stocks are immensely greater. One estimate suggests that the volume of groundwater—that is, the water in saturated soil or rock formations that supplies springs and wells—may be about 50 times the annual surface flow. (In the United States, this would amount to a volume about four times that of the Great Lakes.)


How, then, can there possibly be any difficulty in supplying all the water needs of humanity? Why do we continually hear warnings of shortages? And why does the United Nations strive to call world attention to the problem of providing people with enough pure water?

Well, the answer to such questions has several parts. First, the freshwater supplies are not distributed evenly over the continents . . . nor are human needs. Indeed, in the United States we seem—perversely—to be creating more and more "need" in areas already short of water.

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