Volatile weather affecting Modesto-area crops

MODESTO -- Duarte Nursery of Hughson is at the front line of dramatic changes under way in California's immense agriculture industry.

The family-run nursery, founded in 1976, is one of the largest in the United States, and there's a good chance the berries, nuts and citrus fruits eaten across the West began their journey to market as seedlings in Duarte's 30 acres of greenhouses, labs and breeding stations.

The nursery's owners have built a thriving business using state-of-the-art techniques to develop varieties adapted to the particular conditions and pests California farmers face.

These days, according to John Duarte, president of the nursery, that means breeding for elevated levels of heat and salt, which researchers say are symptoms of climate change, even if Duarte doesn't necessarily see it that way.

"Whether it's carbon built up in the atmosphere or just friggin' bad luck," he said, "the conditions are straining us."

The cause of Duarte's woes might be in dispute among farmers in California's $31 billion agriculture industry. But the symptoms are clear. From the vast fields of fruits and nuts in the Central Valley to the wineries of Napa and Sonoma, the increasingly volatile weather is altering the fundamental conditions for growing food, California's largest industry.

Farmers are in many ways at the front line of climate change. They conjure food from soil, sunlight and water, which are profoundly affected, scientists say, by climate change. Stresses have emerged across the state as water supplies have tightened. Rain is coming at unexpected times. Winters aren't getting cold enough. And salt from the rising ocean is making its way into Central Valley water.

Climate change already has cost farmers money. In the valley, some growers are paying more for seeds designed to withstand the new extremes.

At the nurseries and colleges in what Duarte calls "the SiliconValley of agricultural innovation," these changing conditions have forced botanists to look for varieties of almond, pepper, citrus, cherry and other crops resistant to drought and salt.

Other interests also are bracing for dramatic change. The crop insurance industry is calculating potential billion-dollar losses from extreme weather conditions, as well as the floods and fires that occur in their wake. Climate change could join the ranks of earthquake and hurricane insurance as a special — and expensive — problem for insurers.

Over the past 20 years, there has been more than $500 million in crop losses from heat waves, floods and ill-timed rainstorms in the agricultural counties of San Joaquin, Merced, Kings, Kern, Napa and Sonoma, according to a study last year by Stanford University researchers.

"Compared to 20 or 30 years ago, farmers are recognizing a lot more risk factors in climate events," said Jeff Yasui, director of the U.S. Department of Agriculture's Risk Management Agency office in California, which handles crop insurance in the state.

Water could be biggest issue

Climate and agriculture scientists predicted much of this. Charles Kolstad, an environmental economist at the University of California at Santa Barbara, said California agriculture is being hit with a trifecta of converging forces prompted by climate change: longer seasons of extreme heat, shorter cold seasons and dwindling water supplies.

Roger Duncan, director of the UC Cooperative Extension in Stanislaus County, said he does not expect major effects on its fruit and nut crops from rising temperatures or a reduction in the winter "chill hours" that prepare the trees for the blooms that yield the crops.

Almonds and grapes, he noted, originated in places with hot, dry summers and could withstand increased valley temperatures. Some fruit and nut varieties have been bred to need less chilling, he said.

The water supply is another matter. Many irrigation districts rely mainly on the Sierra Nevada snowpack to get their farmers through the warm, dry stretch from April to October. Climate change could mean less snow and more rain, and at times when the reservoirs cannot capture much of it.

"If they're predicting a significantly reduced snowpack, the available water would be the biggest issue," Duncan said.

Climate scientists believe the Earth's average temperature will rise at least 2 degrees in the next four decades — their most conservative estimate. Along the way, the yields of citrus crops in the San Joaquin Valley are expected to drop about 18 percent, grapes about 6 percent, and cherries and other orchard crops about 9 percent.

Those crops, accustomed to the cooler edges of California's climate, are showing declining yields already, according to the USDA's National Agricultural Statistics Service. That could mean higher prices for consumers as the supply shrinks. This summer's record drought in the Midwest also prompted the USDA to predict a rise in prices driven by devastated yields for corn and soybeans, the primary food for chicken and cattle in the valley and nationwide.

Dairy cows also could suffer. The valley is a huge milk producer in part because cows do well in the mild winters and in summers that only occasionally get too hot. Climate change could bring more extreme heat waves, such as the one in 2006 that killed more than 3,000 cows in Stanislaus County alone.

Much of the southern valley, spreading along Interstate 5, is a patchwork of fallow fields, according to Gayle Holman with the Westlands Water District near Fresno. Thousands of acres that once grew onions, tomatoes, melons and other crops have been set aside by farmers who no longer can obtain, or afford, water — a scarcity, scientists say, that is significantly because of the dramatic shifts in the timing of rainfall in the state.

A sequence of trapdoors

As with just about everything having to do with climate change, the consequences unfold like a sequence of trapdoors. First, there's the temperature, a jagged progression over the past decade of unusual highs and lows occurring at times of the year that can debilitate growing crops.

Then there's water. California's water sources are caught in a pincer: More water is needed at a time when less water is being delivered into the canals carrying it from the north to the agricultural regions in the south.

A precipitous drop in snowfall has led to declining water runoff in the San Joaquin and Sacramento rivers in the spring and summer months, when it's central to irrigation in the valley. Over the past century, the state Department of Water Resources has measured a steady 10 percent decline in runoff from April to July. In recent years, however, that rate has accelerated to as much as 20 percent.

Farmers in the valley generally blame the drop-off in water on the 2007 state Supreme Court decision affirming the need for water to preserve Pacific smelt and other endangered species.

A study by the Public Policy Institute of California, however, concludes that the roughly 300,000 acre-feet of water diverted to comply with the Endangered Species Act constitutes no more than 20 percent of the reduced water flow to the valley.

Rather, the overall pool of water is shrinking.

"The water that used to exist is now coming earlier in the year," said Francis Chung, chief of the Modeling Support Branch for the Department of Water Resources. "So there's less water to distribute (to the valley) during the summer."

Another growing problem has been rising sea levels associated with climate change. San Francisco Bay, according to a recent National Academies of Sciences assessment, is projected to rise by as much as 18 inches, and potentially triple that by the end of the century. Those inches translate into waves of salt sources lapping into the delta.

Less water channeled into the delta from the Sierra means less available freshwater to dilute the onrush of salt, which has been pushing steadily eastward.

A study by UC Davis estimates that if salinity continues to rise at the current rate, by 2030, the financial costs to the valley could be huge: as much as $1 billion to $1.5 billion a year in decreased agricultural activity, amounting to some 27,000 to 53,000 jobs lost.

Not enough chill hours for cherries

For a look into the future, look at the state's cherry crop, grown primarily in San Joaquin and also in Stanislaus and other counties.

In April, the cherries were blooming in the Colombini family orchard near Lodi, their blossoms a signal that the harvest would be coming in six weeks.

But there was trouble lurking under those delicate blossoms. Jeff Colombini, director of the family company, Lodi Farming, pointed to the erratic blooms on his trees — a blossom here and there but many stunted, half-grown blossoms. That is a sign, he said, of the "stresses that come with not enough chill hours" in November and December.

For a perfect California cherry, the trees need 1,200 to 1,400 hours of "chill time." But Joseph Grant, a UC Cooperative Extension farm adviser based in Stockton, said that lately, cherry growers have been seeing more like 1,000 to 1,100 hours per season.

Another factor may be the fog: Early results from a study at UC Berkeley's College of Natural Resources suggest that a lack of the usual fog hours also might be contributing to overheating of cherry buds.

The overall cherry crop recovered late in the season, but the effect of the shortened chill, according to Grant, is declining quality of California cherries. They're shrinking in size, and the extended ripening time means the cherries are not as firm.

Last year, California cherry growers received a record $22.5 million in crop insurance payouts, sending crop insurers into the red. For every $1 paid into the system for cherry policies that year, $1.60 was paid to farmers. The USDA paid almost $8 million to subsidize the losses.

"What's happening," Grant said, "is that the climate here around Stockton is looking more and more like the climate down in Bakersfield."

Bee staff writer John Holland contributed to this report.

This story was produced by the nonprofit Center for Investigative Reporting, the country's largest investigative reporting team, in collaboration with KQED public radio. For more, visit www.cironline.org. Valley crops are startingto experiencethe effects of increasingly volatile weather'Compared to 20 or 30 years ago, farmers are recognizing a lot more risk factors in climate events' — Jeff Yasui, U.S. Department of Agriculture