Not A Drop To Drink: Our Shrinking Freshwater Supply
...but no more than seven days without fresh water. Freshwater is a renewable resource but it is finite. Considering the abundance of water on this planet, comprising 70 percent of the earth’s surface, a freshwater shortage runs counter to general expectations. Previously, I assumed water to be an unlimited resource, as this is a common perception in the United States; but freshwater comprises less than 3 percent of the earth’s water and only 13 percent of that freshwater is in liquid form, (most of it is locked up in ice caps and glaciers). Water use has increased about twice as fast as population growth over the past century. Globally, we already appropriate over half of the available excess runoff and over 1 billion people currently lack access to clean drinking water (Jackson, Carpenter, Dahm, McKnight, Naiman, Postel, & Running, 2001). Groundwater depletion, low or nonexistent river flows, and worsening pollution levels are among the more obvious indicators of water stress (Postel, 2000). The three main uses of freshwater are irrigation of cropland, industrial and commercial activities, and residential needs. On a global scale, environmental policy changes need to be made along with increases in water productivity, especially in these three areas of consumption, if freshwater reserves are to support future generations.
Freshwater is produced by the hydrologic system (the cycle of water as it moves through the environment): water evaporates, falls as rain or snow, passes through living organisms, and returns to the ocean to repeat the process). Groundwater aquifers are large subterranean areas of porous sand and gravel, which are saturated with freshwater. These aquifers are replenished by rainwater and runoff as they filter through soil layers. Groundwater aquifers naturally store about 99% of the earth’s liquid freshwater that is made accessible to...
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