Mark Schapiro, BAY NATURE
Inside a climate-controlled laboratory at the Duarte Nursery outside Modesto, an experiment is taking place that could help determine what food we will eat for decades to come. Rows of steel racks contain numerous tiny almond, apple, walnut, pomegranate, pecan, avocado, fig, and pistachio trees in small translucent plastic cylinders. The saplings, planted in a high-nutrient agar mix that accelerates growth, are no more than two inches high and a few weeks old. Each is being subjected to versions of the stresses experienced just outside these walls in fields across the Central Valley: declining levels of water, escalating levels of salt. The big overarching, if unmentionable, force driving these experiments is climate change, which is beginning to roil the Central Valley.
Duarte, one of the largest commercial nurseries in the world, specializes in tree nuts and fruits, which have boomed across the valley in recent decades. Founded four decades ago, the nursery grew rapidly as water piped into the valley from the Sierras gave birth to the most bounteous center for agriculture in North America. The nursery now sprawls over 200 acres in the town of Hughson, just outside Modesto. Things began to change about a decade ago, according to John Duarte, the nursery’s president.
When I first met Duarte back in 2012, he resisted calling the shifts he was seeing climate change: “Whether it’s carbon built up in the atmosphere or just friggin’ bad luck,” he said then, “the conditions are straining us.” Today, he still avoids the climate change label. (“You should meet my daughter; I think she agrees with you on the climate business,” he told me recently.) But even seven years ago, Duarte was on the forefront of researching tree varieties suited to a hotter, drier, saltier future.
Trees present a particular challenge: Conditions shift, but the trees can’t move. A fruit or nut tree planted today may, depending on the species, be ill-suited to climatic conditions by the time it begins bearing fruit in five or ten years. So the question Duarte is trying to answer, the one bedeviling farmers across the valley, is, what to plant today that can thrive and bear fruit over the next quarter century or more?
“Everyone,” Duarte said, “is thinking about the impacts of warm winters and not enough water.” Valley temperatures are predicted to rise between 3.5 and 6 degrees Fahrenheit by 2100, while periods of extreme heat are expected to lengthen. Even now, it’s often not cold enough in winter to permit trees’ metabolism to slow down, a process critical to the spring flowering that produces fruits and nuts later in the season. Irrigation water is becoming saltier, too. Desperate farmers drilling ever-deeper wells are pumping up saltier water. And a new state law, the Sustainable Groundwater Management Act, will likely serve as a catalyst of change. Starting in 2020, it will regulate how much water farmers can withdraw from the Central Valley aquifer. The law promises to shake up the methods and business of valley agriculture.
The lessons learned here, or not learned, have implications for agricultural regions elsewhere, from the American Midwest to North Africa, southern Europe and southwest China. These breadbaskets are already experiencing similar extremes of heat, drought, and flood, and new pests and diseases.
Climate change is revealing the vulnerabilities of an industrial agriculture system that relies on predictability. And it’s shining a light on alternative growing practices that are potentially more resilient to these environmental shifts.
“When I drive to the Central Valley, I get goose bumps; I feel the urgency,” says Amélie Gaudin, an agronomist at UC Davis who works with many Central Valley growers on improving soil quality. “I see an agriculture that is basically hydroponics. It’s like a person being fed/kept alive by an IV.”