By David L. Brown
As our readers know we have pointed out many problems facing the Earth and human civilization. There is always a common denominator, it seems, a thread that winds its way through all the dangers facing our planet. That is the imbalance between growing human numbers with “improving” lifestyles and the ability of the planet to support the ever-upward pressure of economies and societies based solely on growth.
A recent issue of Science magazine contains an article that highlights one particular example of this, the growing imbalance between the demand of California residents and farmers and uncertainties about the supply of fresh water.
As is so often the case when examining environmental impacts on human beings, the problem in California is not just that there are more people demanding more water—there is also less water, thanks perhaps to climate change. A serious drought has been plaguing the Golden State for the past three years. According to the Science article, titled “California’s Water Crisis: Worse to Come?” (March 27, 2009 issue; subscription required) in February, “Central Valley farmers were told that all water deliveries would be halted, and State Water Project managers said they would be forced to cut water deliveries to just 15% of normal.”
California is the nation’s No. 1 producer of many food crops, and yet the abundance depends in very large part on irrigation. The state has hundreds of miles of canals and waterways such as this:
This is a view of the Sacramento-San Joaquin River Delta, the hub of California’s fresh water system. This waterway is girdled by more than a thousand miles of levees. According to hydrologists, the levees are bound to fail at some point in the future, creating future problems that could be catastrophic.
Meanwhile, though, it’s drought that is the problem. For now, late winter snowfall brought mountain snowpack up to 90 percent of normal, relieving pressure on administrators to cut off irrigation water to farmers. For now, the bullet has been dodged. However, recent trends have been ominous, hinting at more years of drought and water shortages.
Discussing the future of the delta, Robert F. Service the author of the Science article writes:
Over the next few decades, a one-two punch of climate change and earthquakes is expected to change the delta dramatically. The delta contains some 1770 kilometers of levees holding back water from dozens of stadium-sized sunken “islands” inside which the land has subsided. By 2050, the chance of widespread levee failures is as high as 95%, due to runoff from the northern Sierras, which is predicted to be more concentrated in the late winter and early spring, and the increasing risk of earthquake, according to a report last summer by the Public Policy Institute of California (PPIC). If that occurs, salt water from the San Francisco Bay would rush in to fill the voids, dramatically increasing the salinity of water in the delta, possibly making it undrinkable. Adding sea-level rise to the equation–as climate models predict–brings the date of levee failures closer. “It will happen,” says Ellen Hanek, a PPIC economist in San Francisco.
This looming threat is merely a tiny sampling of a worldwide phenomenon that is threatening some of the regions where a large proportion of the world’s people live. The problem is that glaciers which feed rivers such as the Ganges in India, the Yellow and Yangtze in China, the Mekong in Vietnam and even the Po in Italy are melting. Snow alone does not feed the rivers a steady flow of water through the summer, and as global temperatures climb winter snow in the high mountains melts faster. The result is a growing tendency to disastrous flooding early in the season followed by drought just when crops need the water most.
Fresh water is just one of the many resources which are growing in short supply, and it is a crucial one to human existence. No form of agriculture has been devised that does not rely upon reliable and abundant sources of water. As the California example illustrates, even wealthy and advanced regions can be threatened when water scarcity spreads.