Elsewhere, forward-thinking farmers have replaced flood irrigation with micro-sprinkler systems, laser leveled their fields, and installed soil-moisture monitors to better time irrigation. In California, says the Pacific Institute, such improvements could potentially conserve roughly five million acre-feet of water a year, enough to meet the household needs of 37 million people. Unfortunately, most farmers lack the incentive to install efficient but expensive irrigation systems: Government subsidies keep farm water cheap. But experts agree that more realistic water pricing and improved water management will significantly cut agricultural water use. One way or another, the developed world will get the water it needs, if not the water it wants. We can find new supplies—by desalinating water, recycling water, capturing and filtering storm water from paved surfaces, and redistributing water rights among agriculture, industry, and cities. Cheaply and quickly we can slash demand—with conservation and efficiency measures, with higher rates for water wasters, and with better management policies.
What about the rest of the world? In places lacerated by poverty, the problem is often a lack of infrastructure—wells, pipes, pollution controls, and systems for disinfecting water. Though politically challenging to execute, the solutions are fairly straightforward: investment in appropriately scaled technology, better governance, community involvement, proper water pricing, and training water users to maintain their systems. In regions facing scarcity because of overpumped aquifers, better management and efficiency will stretch the last drops. Farmers in southern India, for example, save fuel in addition to water when they switch from flood to drip irrigation; other communities landscape their hillsides to retain rainwater and replenish aquifers.
Still, the time is coming when some farmers—the largest water users and the lowest ratepayers—may find themselves rethinking what, or if, they should plant in the first place. In the parched Murray-Darling Basin of Australia, farmers are already packing up and moving out.
It is hardly the first time that water scarcity has created environmental refugees. A thousand years ago, less than 120 miles from modern-day Santa Fe, the inhabitants of Chaco Canyon built rock-lined ditches, headgates, and dams to manage runoff from their enormous watershed. Then, starting around A.D. 1130, a prolonged drought set in. Water scarcity may not have been the only cause, but within a few decades, Chaco Canyon had been abandoned. We hardly need reminding that nature can be unforgiving: We learn to live within her increasingly unpredictable means, we move elsewhere, or we perish.