Will the world be facing a severe food shortage within the next few decades? According to a number of scientific studies, the answer is quite likely yes, unless conservation measures can be taken to reverse the over-pumping of groundwater. Much of the world food supply is grown by using groundwater for irrigation. Worldwide, aquifer levels are dropping rapidly because far more water is being withdrawn from them than rain and snow can replace. The highest rates of groundwater loss occur in China, India, California’s Central Valley, and the southern high plains areas of Western Kansas and the Texas Panhandle.
A University of Texas study published in May, 2012, indicates that groundwater depletion in the high plains and in California’s Central Valley threaten to cripple agricultural production in two of America’s most important food producing regions. Between 2006 and 2009, farmers in the Central Valley pumped out enough groundwater to fill Lake Mead, or approximately 8 trillion gallons (approximately 25 billion cubic meters). This rate of withdrawal far exceeds nature’s recharge rate. As a consequence, the water level in the underlying Central Valley Aquifer System has dropped 400 feet (120 meters) since the first half of the 20th Century.
The high plains states of South Dakota, Colorado, Wyoming, Nebraska, Kansas, and Texas draw water from the huge Ogallala Aquifer. However, crop irrigation in the Texas Panhandle and Western Kansas, only 4% of the total high plains land area, accounts for one third of the aquifers water depletion. Since 1950, the level of the Ogallala has dropped 300 feet (90 meters). At the present rate of withdrawal, and with a low rate of replenishment due to local dry conditions, the southern high plains will not have enough water to support agriculture within 30 years.
The high plains and the Central Valley account for the much of the nation’s food supply, producing fruits, vegetables, and grains worth $57 billion annually.
Worldwide groundwater depletion rose 230% from 33 trillion gallons (126 billion cubic meters) a year In 1960, to 75 trillion gallons (283 billion cubic meters) a year in 2000. With global warming bringing longer and hotter drought periods, the natural recharge rate is expected to keep dropping, along with the water levels in the underground aquifers. 70% of groundwater withdrawal is used to irrigate crops. One simple way to conserve water is the use of drip irrigation instead of the flooding method presently used by many farmers. Unless such strict groundwater conservation methods are strictly adhered to by farmers everywhere, world food supply will decline while world population continues to expand, creating an inevitable food shortage crisis.