Cape Town, South Africa, a city of 450,000 in a metropolitan area of 3.7 million, is experiencing a catastrophic drought. Capetonians have been dreading the arrival of July 9, or “Day Zero”— when taps in private homes will be switched off and residents will have to go to collection points for rationed allotments of water.
Some version of Day Zero could one day come to parts of California, where water woes continue to bedevil government officials and citizens. From 2011 to 2015, the state experienced the driest four-year period in recorded history (though geologic evidence indicates there have been worse droughts in the past). A robust rainy season in 2017 replenished many reservoirs, but the winter of 2018 has been dry. As of February 1, the snowpack, which provides much of the state’s water during the dry season, was only 21 percent of its normal size. The 2011–2015 drought led Governor Jerry Brown to mandate a 25 percent reduction in water use, but mandating it doesn’t mean that it will happen. Mandated reductions that require homeowners to spend money and time irrigating with non-potable water and replacing old toilets are unlikely to meet their targets, given the low nominal cost of water.
A number of remedies have been suggested, one of which is to allow markets, rather than politics, to allocate water. At a recent conference at Stanford University’s Hoover Institution, scholars focused on the importance of market signals in getting people to change their behavior in the face of climate uncertainty. Economist Gary Libecap noted that when prices signal the real value of water, they encourage “agricultural users to switch to water-saving irrigation technologies or to water-saving crops.” (Agriculture accounts for 80 percent of California’s water consumption.) The same is true for urban users, who pay much more per unit of water than agricultural users.
In the absence of water markets, prices don’t reflect the full cost of using this precious resource, resulting in inefficient use. The best example: organic farming. Organic agriculture produces lower yields than traditional agriculture and uses disproportionately more inputs—especially low-cost, high-value water. Lower yields in organic farming mean less output per unit of water used.
Plant pathologist Steve Savage analyzed data from the U.S. Department of Agriculture’s 2014 Organic Survey, which measures productivity from most of the nation’s certified organic farms, and compared them with those at conventional farms, crop-by-crop and state-by-state. His findings are extraordinary: of the 68 crops surveyed, organic farms showed a “yield gap”—poorer performance—in 59. Many of the shortfalls were large: organic strawberries yielded 61 percent less than conventional farms; fresh tomatoes, 61 percent less; tangerines, 58 percent less; cotton, 45 percent less; rice, 39 percent less; peanuts, 37 percent less. “To have raised all U.S. crops as organic in 2014 would have required farming of 109 million more acres of land,” Savage concludes. “That is an area equivalent to all the parkland and wildland areas in the lower 48 states, or 1.8 times as much as all the urban land in the nation.”
One reason that inefficient organic agriculture uses more water is that it excludes the cultivation of crop varieties crafted with molecular genetic-modification techniques—so-called GMOs—that can be made to withstand droughts and to be irrigable with brackish water. For example, more than a decade ago, Egyptian researchers showed that transferring a single gene from barley to wheat allows the wheat to grow with far less irrigation than conventional wheat; it can survive on meager rainfall alone. Similar genetic modification has created drought-tolerant corn varieties, and more such crops are in the works.
Genetically engineered crops also conserve water by allowing cultivation in salty soils. Fully one-third of irrigated land worldwide, including much of California, is unsuitable for growing crops; every year, nearly 500,000 acres of irrigated land are lost for cultivation due to salt accumulation. Scientists have enhanced the salt tolerance in crops as diverse as tomatoes and canola, and made them irrigable with brackish water, thus conserving fresh water for other uses. Another innovation: by making no-till cultivation possible, the genetic engineering of crops for herbicide tolerance helps trap soil moisture (and also releases less CO2 into the atmosphere). Under drought conditions, this can mean the difference between a harvest and a crop failure.
The best solution to California’s water problems would be to encourage water markets and end water subsidies for farmers. A second-best approach is to tax the most egregious examples of waste—and organic products are at the top of the inefficiency list. Placing a tax on already outrageously priced, water-wasting organic products would lessen the demand for them and alleviate some of the pressure on California’s uncertain water supplies. And such a tax would be progressive, falling disproportionately on wealthy consumers. In short, reducing California’s organic agricultural production in favor of more efficient, modern techniques would deliver “more crop for the drop.”