Lester R. Brown
Chapter 3. Emerging Water Shortages: A Food Bubble Economy
As noted earlier, overpumping is a way of satisfying growing food demand that virtually guarantees a future drop in food production when aquifers are depleted. Many countries are in essence creating a “food bubble economy”—one in which food production is artificially inflated by the unsustainable mining of groundwater.
The effects of overdrafting were not obvious when farmers began pumping on a large scale a few decades ago. The great attraction of pumping groundwater in contrast to large-scale surface water systems is that farmers can apply the water to crops precisely when it is needed, thereby maximizing water use efficiency. Groundwater is also available during the dry season, enabling many farmers in mild climatic regions to double crop.
To illustrate, yields of foodgrains in the Punjab on land irrigated from wells was 5.5 tons per hectare, while yields on land irrigated from canals averaged 3.2 tons per hectare. Similar data for the southern state of Andhra Pradesh also showed a strong advantage in pumped irrigation, with foodgrain yields averaging 5.7 tons per hectare compared with 3.4 tons on land irrigated with canal water. 73
In the United States, 37 percent of all irrigation water comes from underground; the other 63 percent comes from surface sources. Yet three of the top grain-producing states—Texas, Kansas, and Nebraska—each get 70–90 percent of their irrigation water from the Ogallala aquifer, which is essentially a fossil aquifer with little recharge. The high productivity of groundwater-based irrigation means that the food production losses will be disproportionately large when the groundwater runs out. 74
At what point does water scarcity translate into food scarcity? In which countries will the irrigation water losses from aquifer depletion translate into a drop in grain production? David Seckler and his colleagues at the International Water Management Institute, the world’s premier water research group, summarized this issue well: “Many of the most populous countries of the world—China, India, Pakistan, Mexico, and nearly all the countries of the Middle East and North Africa—have literally been having a free ride over the past two or three decades by depleting their groundwater resources. The penalty for mismanagement of this valuable resource is now coming due and it is no exaggeration to say that the results could be catastrophic for these countries and, given their importance, for the world as a whole.” 75
Since expanding irrigation helped triple the world grain harvest from 1950 to 2000, it comes as no surprise that water losses can shrink harvests. With water for irrigation, many countries are in a classic overshoot-and-decline mode. If countries that are overpumping do not move quickly to reduce water use and stabilize water tables, then an eventual drop in food production is almost inevitable. 76
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