Evil Almonds? California's Drought Villain Is a Climate Change Hero
More than half a million acres of California farmland will be left bare this year, a vast expanse of arid dirt that is both a symbol and a symptom of the four-year-long drought, considered to be the worst in 1,200 years.
Not the almond farms, though. Water will continue to flow to most of the state’s 1-million-plus acres of No. 1 cash crop (not counting marijuana). With at least 25 years of potential production in each tree, farmers can't afford to simply shut down an almond orchard without millions of dollars of their investment and future revenue drying up right along with the trees. So they are going after every available source—groundwater, chiefly—to keep the taps on.
It appears to be a gross abuse of resources: Why should water go to keeping thirsty, hedge-fund-backed, foreign-bound nuts alive while other farmers are unable to grow the more water-efficient crops that feed the nation? But that’s an oversimplification on a number of levels—the “don’t blame almonds” essay is becoming a genre unto itself—including subterranean ones. While those 500,000-some acres of fallow land are losing soil fertility and releasing stored carbon, California’s maligned almonds, as well as other perennial fruit and nut crops, are sucking up CO2 and keeping it in the soil. According to one carbon life cycle analysis of the industry, with proper management and a credit system, the state’s almond industry could sequester more carbon than it emits. Do we need to reimagine the infamous nut a climate change savior?
So, Why Should You Care? Agriculture plays a complex role in climate and climate modeling. If the world’s cropland is farmed with little regard for carbon production, the 14 percent of overall emissions that agriculture accounts for could help push humanity toward the climate catastrophe of a two-degree-Celsius rise in global average temperature. Conversely, careful management of farmland could turn agriculture into part of the solution. Instead of pumping out greenhouse gases, farms need to be planned and managed in such a manner that they capture and sequester carbon in both plants and the soil. One of the key ways of achieving that goal is to transition away from annual row crops and toward perennials—like almonds.
Not only can such long-lived crops capture carbon from the atmosphere, but once they are ensconced it in the soil, it stops being a liability and becomes an asset. Increased levels of soil carbon “would translate into better plant nutrient content, increased water retention capacity and better structure, eventually leading to higher yields and greater resilience,” according to a 2008 paper on food security and climate change published by the U.N. Food and Agriculture Organization. With 74 percent of agricultural greenhouse gas emissions originating in developing countries, carbon capture and carbon farming—planting quick-growing, nonedible crops as dedicated carbon sinks—are seen as a means of greening the economic growth of emerging economies and, potentially, as a new revenue stream for rural farmers, who might someday sell carbon offsets to polluters in developed nations.
Such a cap-and-trade system exists in California, and while currently the only official offset programs apply to rice growers and farmers who use anaerobic digesters to generate energy from what is often dairy waste, a number of studies have looked at the possibility of integrating almonds—the largest permanent crop acreage in the state—in the system.
Selling offsets on California’s market is nothing more than an idea at this point; a public information officer with the state Air Resources Board told me that carbon offset programs here "must meet the most stringent requirements in the world for verification and acceptance into our program,” and focus primarily on methane. But the life-cycle studies help set a benchmark for the emissions almonds produce and what they’re capable of capturing.
A 2012 analysis from the Sustainable Agriculture Research and Education Program at the University of California, Davis (and commissioned by the California Almond Board, an industry trade group), found that annual greenhouse gas emissions are 2,370 kilograms of CO2 per acre during each of the 25 years during which an orchard is productive. Nearly a third of that—and more than half of annual energy use—is tied up in fertilizers. Switching to organic production, which does not rely on petrochemical fertilizers, would cut emissions by a third and energy use in half. According to the study, irrigation, pollination, and harvesting account for the majority of the “other management” category, which represents 61 percent of total emissions.
Spread out across 1 million acres, that’s more than 2 million metric tons of CO2 a year, the equivalent of the annual emissions of 500,000 cars, according to the EPA’s emissions calculator. In other words: part of the problem.
But orchards don’t just produce nuts—they produce hulls and shells and prunings and other biomass that, if burned as a renewable fuel source to produce electricity, could bring down the overall emissions significantly. With a credit system, according to the UC Davis study, the carbon offsets could amount to 38 percent more than the total emissions, including those from chemical fertilizers, produced by almond farms.
Biomass electricity causes pollution, too, and facilities aren’t always conveniently available for growers looking to sell their waste materials. Instead, they could be chipped or otherwise processed and returned to the orchard, where a percentage of the carbon would be taken up in the soil. The Davis study found that maximum sequestration credits would amount to 82 percent of overall emissions (although achieving that number would be impossible, as it's based on all of the carbon in clippings and the like being captured in the soil).
Even without the incentive of carbon credits, almonds and other perennial crops are already storing CO2 —and a significant amount of it. A 2006 study published by the Ecological Society of America found that between 1980 and 2000, California farms captured 14.5 million metric tons. Sequestration was highest in land that was switched from annuals to perennial, with orchards capturing more carbon than vineyards. Conversely, carbon storage was lowest in farmland used to grown annuals other than rice. The overall carbon capture, according to the study, was equivalent to 0.7 percent of California’s total fuel emissions over those two decades. The researchers wrote that if the industry adopted “conservation tillage, changed management of almond and walnut prunings, and used all of its orchard and vineyard waste wood in the biomass power plants in the state, California's agriculture could offset up to 1.6% of the fossil fuel emissions in the state.”
Other studies have shown that in addition to drastically cutting ag emissions by eliminating chemical fertilizers, organic farming increases the amount of carbon stored in soils. No-till farming and planting cover crops between rows can similarly increase the rate of sequestration. (According to a survey conducted by the California Almond Board, 89 percent of orchards use no-till and other orchard floor management practices to limit how much the soil is broken up and turned.)
And a study published in the journal California Agriculture in 2013 sought to set a baseline for carbon storage for a variety of perennial crops—grapes, almonds, and walnuts—grown under different circumstances. Soil analysis conducted by researchers from UC Davis and Colorado State University found that the most carbon was being stored at each of the three depths measured in a block of organic walnuts. The organically grown almonds held little carbon, but the orchard was quite young, and its age was likely a contributing factor to the low level of sequestration. The well-established walnut orchard likely held the largest amount of carbon owing to the “large amount of waste walnut shells, orchard prunings, manures and composts that have been added to the soil over the years,” according to the researchers. The same blocks of trees also showed the highest level of soil moisture: Another upside of high levels of carbon is that it helps dirt to hold water, and mulching with shells and clippings helps to reduce evaporation as well.
Overall, the study estimated that California vineyards—which commonly use no-till, cover crops, and dry farming, all of which increase carbon capture—were holding the largest amount of carbon. The researchers estimated that farmland planted in wine grapes stores nearly 25 million metric tons of carbon at 1 meter deep—nearly five times as much as held in similar soil in almond and walnut orchards.
In many parts of the state where almonds are grown and farming rules the economy, there are families who, like Steinbeck’s Joads, can trace their history in California back to the dust bowl. That epic drought is remembered for the red clouds that blew across the Plains. But the more quiet and longer-lasting tragedy in Oklahoma was the loss of soil fertility that blew away with all of the dust. Even when the rains came back, the soil couldn’t be farmed.
So while almonds and other orchard crops may be sucking up a lot of water, their quenched roots are helping California farmers—and all of us—to hold on to the future.