Sunday, November 30, 2014

The Declining Availability of Fresh Water

The natural fresh water cycle (the cycling of water from oceans to the atmosphere, becoming precipitation in the form of rain and snow) is the source of the fresh water in the Earth's lakes, streams, and underground aquifers. The water cycle is timeless and largely unaffected by man, except for the probable influence of global warming. But the supply of clean fresh water available to humans (where humans choose to locate) is slowly but surely declining.

Many western U.S. cities rely primarily on water derived from the winter snowpack in nearby mountain ranges. The cities are growing and demand for water is up. To make matters worse, the winter snowpack has been declining in recent years. Some of the snowpack's decline may be due to global warming, but it may also be partly due to normal decades-long cyclic fluctuations in the water cycle. Centuries-old glaciers have been receding; some have disappeared entirely. If the current 30-year trend continues, Montana's Glacier National Park in may not have a single glacier by 2030. This does not bode well for Western lakes and streams.

Some human populations rely heavily on ancient underground aquifers for water to irrigate thirsty crops. China, India, and the U.S. plains States all rely heavily on aquifers that are not being replenished at the rates at which they are being used. Wells in some areas are going dry, leading to a loss of agricultural productivity.

Pollution of freshwater is a constant concern. Industries that use a lot of water or that run the risk of polluting rivers and streams, such as mining for coal, copper, and gold, face increasing government regulation or outright opposition from environmental groups. The world's largest gold mining company, Barrick Gold, shut down a major investment in a massive mine in Chile due in part to costs related to the risk of polluting nearby rivers and streams.

These are not problems that are going to go away quickly. Humans will have to adapt. We'll need to reduce water use in our homes, recycle water wherever possible, locate our human populations nearer to abundant supplies of fresh water, develop agricultural crops that require less water, irrigate crops more efficiently, and improve industrial techniques that require water. Some of these actions are already being taken. As they must, if we are to prosper in the long run.

No comments: