Climate and crops

Corning fig farmer Bob Steinacher of Maywood Farms usually begins harvesting his main crop of fruit in early- to mid-August. But this year, Steinacher was in his 170-acre orchard picking figs on July 6.

Other California farmers also have experienced record early harvests, thanks to exceptionally warm weather during the winter, spring and summer. Some say these changes offer farmers and scientists a glimpse of what could become the norm as climate change trends advance.

Early harvests are not necessarily a bad thing. However, they are significant because they are among the first visible symptoms of what may lead to a dramatic rearrangement of California’s agricultural geography and water-use policies. Decreased snowpack in the mountains will mean less late-summer stored water. As water supplies become increasingly stressed, agricultural industries will wither in places. Growing regions likely will shift northward, arid regions will become less productive and measures will be taken to regulate use of water.

In some cases, the global-warming phenomenon that is causing sea level rise and Asian heat waves actually may be creating benefits for local farmers. While winter chill hours are required by many temperate fruit trees—such as most stone fruits—in order to produce large, healthy crops, Ed George, a Winters peach farmer, says the absence of cold this year actually resulted in a better crop: The fruits were fewer, but bigger.

“It made it easier for me,” he said. “I was harvesting bigger fruit and less of them. If your crop is too big you get a bunch of marbles.”

Overall, however, the effects of warming on California’s most lucrative fruit crops are likely to be negative ones. After the balmy winter and spring of 2014, the state’s pistachio crop was thick with blanks—empty shells that result when erratic temperatures throw male and female trees out of sync during bloom time. Almonds may be in trouble, too.

Gurreet Brar, the UC extension farm adviser for nut crops in Fresno County, says the almond industry may be effected as winters and springs become warmer. Although almonds are heat-loving trees with a low requirement for chill hours, Brar says they pollinate less effectively during heat spells. He also says there is evidence that bees may be less effective as pollinators during warmer weather. Bees are essential for almond farmers, who pay to have millions of beehives shipped into the state from around the world during the winter bloom period.

The almond industry, in cooperation with the UC extension system, is conducting trials of about 30 new almond varieties that could be used to replace those that lose productivity under long-term warming trends. Some of these varieties show increased tolerance for high salinity levels in the soil.

“And about 10 of them are self-fruitful,” Brar said. That means they will self-pollinate, without the assistance of bees.

It may hardly be a coincidence that the state’s warmest years have come with its most severe drought, and water supply problems are likely to plague farmers in the future.

Roger Boulton, a professor of enology at UC Davis, says creating a water market in which all users pay a fair rate would be a first—and very big—step toward long-term water use sustainability, since it would incentivize intensive users—like growers of alfalfa and almonds—to improve their water use efficiency.

“Under the current system, smaller communities and cities pay a lot for water so that big growers in agriculture can get water very cheaply,” Boulton said. “If people who use lots of water had to pay more for it, they’d probably think harder about how to use less of it.”