In some parts of the Midwest, homeowners are turning on their taps and getting nothing but air as the water tables have so precipitously dropped. More intense droughts and heat waves are likely as the Earth’s temperature rises.
With regard to agricultural water use, Lester Brown has long been talking about the need for a major push to raise the level of water productivity. Two decades ago, he said that a shortage of water was the most underreported threat to civilization.
Here is some of what he writes on the subject (from Chapter 2 of World on the Edge)
The global water deficit is a product of the tripling of water demand over the last half-century coupled with the worldwide spread of powerful diesel and electrically driven pumps. Only since the advent of these pumps have farmers had the pumping capacity to pull water out of aquifers faster than it is replaced by precipitation.
As the world demand for food has soared, millions of farmers have drilled irrigation wells to expand their harvests. In the absence of government controls, far too many wells have been drilled. As a result, water tables are falling and wells are going dry in some 20 countries, including China, India, and the United States—the three countries that together produce half the world’s grain.
The overpumping of aquifers for irrigation temporarily inflates food production, creating a food production bubble, one that bursts when the aquifer is depleted. Since 40 percent of the world grain harvest comes from irrigated land, the potential shrinkage of the supply of irrigation water is of great concern. Among the big three grain producers, roughly a fifth of the U.S. grain harvest comes from irrigated land. For India, the figure is three fifths and for China, roughly four fifths. … More
