Inside a climate-controlled laboratory at the Duarte Nursery outside Modesto, California, 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 2 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.
If you’re already a pistachio fan, you can offer a perverse thanks to climate change: Pistachio trees require somewhere between one-third and one-half as much water as almond trees. Unlike almond trees, pistachio trees don’t die during extended droughts. Their metabolism merely slows and when water returns, they start producing nuts again. And they can produce nuts for 80 years or longer, almost four times the life span of an average almond tree. Pistachios can also handle, as Duarte’s team discovered, levels of salt that have already killed many an almond tree.