When water conservation fails

Water, we are repeatedly told, will be “next oil.” In the United States, climate projections predict increasing drought frequency throughout most of the country. Around the world, political and even military conflicts due to water scarcity are multiplying. Water is a limited and essential resource, and we are becoming more sensitive to the need to use it wisely.

So it probably seems like good news that the U.S. Interior and Agriculture Departments have pledged almost $50 million in new public investment to improve water efficiency in domestic agriculture. This money will build on the hundreds of millions of dollars that were allocated by federal and state agencies in the past two decades to subsidize the adoption of waterefficient technology and practices in farming.

But there is one problem: The assumption that such spending automatically leads to reduced water use is not grounded in theory or evidence. In fact, improving efficiency may fail to deliver large water savings and even, paradoxically, increase use.

Agriculture is the major consumer of water in the United States— responsible for 80 percent of consumptive use nationwide and 90 percent in some Western states. This consumption takes place against a backdrop of growing water scarcity problems: droughts in the West, “water wars” in the Southeast, and depletion of aquifers nationwide. Promoting efficiency is perceived as a winwin for farmers and environment.

Here’s the problem: Human behavior is complex. Cutting-edge techniques to increase water efficiency are designed and tested by agricultural scientists and engineers. This research usually focuses on the performance of new technologies and practices, with human behavior held constant. When human behavior enters into the mix, the results may look quite different.

In the press release on the new investments, an Interior Department official said “there are technologies and management strategies available that conserve water while maintaining yield and production standards.” That’s true. Yet the link between improved efficiency and reductions in water use hinges on the conjecture that farmers will stick to those last six words: keep everything else about their yields and production constant — just use less water.

But like all businesses that innovate, farmers might change their operations to take advantage of the innovation, and these changes may also affect