Is Agriculture Nimble Enough for the Climate Crisis?

Yields from Fruit and Nut Trees are Down, but Old Varieties and Gene Banks Offer Hope

The farmer holds rice in hand. | Credit: Infocuspix

Jon Foley, director of the Institute for the Environment at the University of Minnesota, claims that agriculture is the world’s biggest environmental problem ​— ​utilizing 40 percent of land and 70 percent of fresh water, and being responsible for 35-45 percent of greenhouse gas emissions. The challenge of reducing these impacts is only going to grow with the projected addition of another 2-3 billion people in the next 30 years. Big changes are required, which will be made even bigger by unprecedented climate extremes that threaten the yield of many crops.

California grows over a third of the country’s vegetables and two-thirds of its fruits and nuts. Alarmingly, many of the perennial crops ​— ​pistachios, walnuts, cherries, peaches, apricots, plums, and wine grapes ​— ​are producing less and experiencing existential threats from previously unseen extremes in heat, rain, and drought. For example, pistachio orchards are out of sync: A lot of the male trees are no longer producing pollen when the female trees need it.

Summers are getting hotter, but the bigger threat is from warmer winters. Scientists recorded that chilling hours in California dropped by 30 percent between 1950 and 2000, and they predict that the decrease will reach 80 percent by 2100. In the San Joaquin Valley, wintertime lows have risen four times faster than summertime highs. The Valley’s Tule fogs, crucial for cool winters, are dissipating. Farmers have always had weather uncertainty, but wild temperature swings are creating even more uncertainty.

All around the world, farmers are trying to cope and outsmart climate fluctuations. In China’s Fujian region, growers of wheat and corn have switched to apples; in India, farmers are shifting from rice to millet, an ancient grain that thrives in parched, infertile soils. Growers in Costa Rica are changing from temperature-sensitive coffee to oranges. 

For some of these tree crops, scientists are seeking out old varieties from the Middle East that evolved for warmer winters. Agriculture hasn’t changed much over centuries; consequently, making the radical changes required for permanent crops to adapt takes research, patience, guts, and money. Scientists are also crossing genes to breed trees that need fewer chilly days. All this takes time, however. Twenty years is fast to breed, test, grow, and harvest a new variety of nut or fruit tree. Changed weather patterns are also accompanied by new and more prevalent pests and diseases.

Most of our food comes from row crops, but much of the food that makes life delightful comes from trees. Imagine no chocolate, juicy peaches, wine, or coffee. Row crops also face climate challenges, but since they are on short cycles, it is possible to try something and know quickly whether it works or not.

Many local beekeepers feared the northward migration of aggressive, Africanized bees as temperatures increased. But we found that the mixing of genes between new arrivals and locals made our hives more robust and less prone to disease. Maybe orchards will similarly benefit from gene mixing. 

Dennis Allen is chair of Allen Construction, an employee-owned company committed to building and operating sustainably. He also serves as chair of the Dean’s Council at the Bren School of Environmental Science & Management at UCSB and as a boardmember of the Community Environmental Council.


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