Monday, July 20, 2015

The Coming Water Crisis

A June 2015 NASA study found that 21 of the world’s 37 largest aquifers—in locations from India and China to the United States and France—have passed their sustainability tipping points, putting hundreds of millions at risk. Stunningly, more than half the rivers in China have disappeared since 1990. Asia’s Aral Sea and Africa’s Lake Chad—once the fourth- and sixth-largest lakes in the world, respectively—have all but dried up due to unremitting use for export-oriented crop irrigation.

In Brazil, almost 2 trillion gallons of water are extracted every year to produce sugarcane ethanol. Cutting down the Amazon rain forests has dramatically reduced the amount of rain in the hydrologic cycle. Healthy rain forests produce massive amounts of moisture that are carried on air currents called “flying rivers” and supply rain to São Paulo thousands of miles away. The destruction of the rain forests and groundwater mining for biofuels has created a killing drought in a country once considered the most water-rich in the world. Not surprisingly, large-scale cutoffs and water rationing are taking a toll on millions of poor Brazilians.

The story repeats itself in the North. According to the US Department of Agriculture, the Ogallala Aquifer is so overburdened that it “is going to run out…beyond reasonable argument.” The use of bore-well technology to draw precious groundwater for the production of water-intensive corn ethanol is a large part of this story. For decades, California has massively engineered its water systems through pipelines, canals, and aqueducts so that a small number of powerful farmers in places like the Central Valley can produce water-intensive crops for export. Over-extraction is also putting huge pressure on the Great Lakes, whose receding shorelines tell the story.
It is scary to think of the Great Lakes shrinking, but one would think that as much rain as that watershed has received this year that water levels would increase.  Overall, though, the stress put on the environment by 7 billion people is incredible.  The impacts in the Amazon watershed are terrifying.

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