16 August 2012
LOSING OUR GROUNDWATER
Many years ago, I worked as a surveyor for the Tucson, AZ, water department. One of the men who trained me had lived in the region all his life. He had witnessed the skyrocketing growth of the city's population, the increased demand for potable water, and the subsequent drawdown of the aquifer underlying the metro area. Whether for mining, for agriculture, for landscape watering, or for direct human consumption, our water wells were removing water far faster than it could be replaced by the then-average 12 inches of rainfall per year (the amount of rainfall which defines of a desert). The result ~ over time the water table was falling (see illustration above, click to enlarge), and wells had to drill deeper and deeper to reach that precious resource.
This was forty years ago. Population growth has continued to outrun the ability of the water cycle to replenish subsurface water reserves. To make matters worse, the area now suffers from the effects of a sustained drought, with temperature records falling across the Southwest, the Midwest, and much of the rest of the nation.
The situation in Tucson is a microcosm of planet-wide aquifer depletion, according to Sophia Li in the NYTimes. In Stressed Aquifers Around the Globe, she stresses that the grim situation isn't merely a result of one or two years' overuse, but rather the unsustainable depletion of groundwater reserves over many years, especially in agricultural areas. As with so many other natural resources, we humans seem to act only for today, with little thought to long-term consequences until we must respond to an avoidable crisis which we ourselves created.
Groundwater supplies from India and Pakistan to China, Mexico, and the U.S. are under siege. How do we possibly justify building water-intensive golf courses and maintaining home lawns, in low-rainfall environments? How can we answer the stares of starving children when we continue inefficient agricultural practices which we know are sucking the earth dry? The day will come, sooner rather than later, when water use in distressed regions will be strictly monitored and rationed.
The root cause of the groundwater problem is the same root cause of so many other problems in society ~ human overpopulation (see graph below, click to enlarge). At 7 billion souls and counting, our numbers are ten times what the planet can sustainably support. Crunch the numbers ~ the maximum number of humans living on Earth should be 700 million, preferably fewer. The longer we avoid addressing our cancerous, irresponsible proliferation, the more suffering we inflict on ourselves and our fellow creatures. So insatiable is our appetite for land and for resources that we drive other species to extinction daily, destroy entire ecosystems weekly. These precious beings cannot be replaced. The cruel irony (and perhaps poetic justice) is that our own survival depends on theirs.