Recent years have brought spikes in the frequency of strange weather patterns and severe storms, with many blaming the increase on human-caused climate change. If this "new normal," as it's being called, is here to stay, it will have profound implications on food production.
There are two basic ways that this threat to food production is being addressed. One is to develop new crops and agricultural methods tailored to withstand increased heat and water stresses. The other approach is to look to the past for solutions, at crops and techniques used in regions that have historically endured this kind of weather. A new book by agricultural ecologist Gary Paul Nabhan, Growing Food in a Hotter, Drier Land, is a comprehensive exploration of this latter approach.
Nabhan lives in the Sonoran desert along the Mexican border in southern Arizona, and his quest to understand the traditional farming systems of the world's driest places has taken him to the Sahara, Gobi, Taklamakan and other great deserts of the world. He has studied how inhabitants of these places grow food in thin desert soils, where long droughts are often punctuated by violent rains that can wash away topsoil and drown plants. His book presents numerous examples of farmers doing what seems impossible, and documents their primitive and effective techniques for blocking the hot wind, recovering fertile silt from storm runoff, shading dwellings, and capturing, storing and delivering rain water.
Crop diversity is central to Nabhan's concept of agricultural resiliency. Diversity offers options in case some crops fail, while agricultural polycultures—diverse plantings in the same area—can offer increased yields over the same crops grown separately.
One classic polyculture of the desert southwest, known as the "Three Sisters," consists of corn, squash and beans. It's possible there are other polycultures that could prove valuable as well. "Few seed catalogs explicitly tell us which heirloom varieties have been selected and adapted for inclusion in intercrops or polycultures. We must do our own on-farm description, selection and evaluation of annual seed crops to determine how we can put the pieces of the puzzle back together into a functioning polyculture," Nabhan writes.
It is his reverence for diversity, rather than any distrust of science, that makes Nabhan question the value of a modern agricultural science, which seems obsessed with polyculture's opposite: monoculture.
"We could evaluate adaptations and drought tolerance of 10,000 heirloom, open-pollinated seed varieties for the price of developing and patenting one new GM crop. I'll go with the former; it's a better strategy for climate adaptation than a $10 million investment in a single strain," Nabhan told me by phone.
Clearly, farmers in dry regions could have much to learn from this book, but what about those who rent, or live in urban areas, or who farm in regions that aren't dry, or don't have any interest in growing their own food? I asked Nabhan if his book has value outside of the parched fields of desert regions.
"In the last few years we've had drought disaster areas as far east as Illinois and Indiana," Nabhan told me. "The agro-ecological techniques I've gleaned from desert farmers around the world are now applicable to two-thirds of the continent."
The book also contains actionable information for the largest category of potential readers—those whose thumbs are no greener than the money they use to buy their food. Consumers have grown accustomed to thinking about how far from home their food was produced, and Nabhan deserves his share of credit for inspiring the locavore movement, thanks to his 2001 book Coming Home to Eat: The Pleasures and Politics of Local Foods. But while terms like "food miles" have worked their way into the foodie vernacular, the idea of "embedded water"i.e., the amount of water needed to produce somethingis less common.
"Compared to the water each of us drinks each day1 to 1.3 gallons—there is 3,250 times the amount of water embedded in the food we eat," Nabhan writes. For instance, there are 600 gallons of water embedded in a single feedlot-produced hamburger.
Longer, hotter summers will increase evaporation rates, while changing weather patterns will make that moisture's return to earth harder to predict, and potentially less frequent. Since food accounts for such a large share of the water we use, our eating habits have a huge impact on the planet's available water. While farmers in hotter, drier climates will need to adapt their cultivation practices, consumers can respond to this new normal by learning about the embedded water in the foods they buy, and purchasing accordingly.
Among the most water-thrifty crops, according to Nabhan's book, are beans, peas and cabbage. Melons are nearly as water-wise, despite their succulent flesh. Nabhan tells the story of a Mexican farmer who put three children through college by growing watermelons in the desert of northern Chihuahua. The farmer irrigated his melons with hauled water that he used to fill buried, porous, clay pots called ollas, which slowly release water to the melons' roots. A similar technique is used in the deserts of Central Asia and Northern Africa.
It isn't clear whether this irrigation method was imported to the Americas or evolved here independently. Human ingenuity is as universal as the conditions that inspire it. In the face of an unpredictable new normal, this ingenuity could be key to keeping us fed in our hotter, drier future. The examples in this book, beyond the specific information they convey, give reason to believe we can navigate the tricky conditions that appear to be coming our way.