Climate change might sour California’s wine grapes

Many Californians are familiar with fish-friendly wines, produced in vineyards that minimize the environmental impact on salmon and steelhead habitat.

But in the future, American consumers may also be seeking out wolf-friendly rieslings and grizzly-friendly cabernets, and we may see imported panda-friendly wines from China. That’s because agricultural regions important to food and wine production today are expected to shift northward as climate change takes its toll on the planet, according to a study recently conducted in part with UC Davis scientists.

The report, which studied only wine crops, concluded that those regions in parts of France, Chile, Australia and California that are esteemed for their wines today may eventually become unsuitable for growing quality grapes and that by the year 2050, currently uncultivated wild regions of Canada, China and Siberia could be prime wine zones. And other crops may be affected, too.

“Certainly, agriculture will see a general move northward, and the Yellowstone [National Park] area is one with a lot of room for expansion,” said Robert Hijmans, a UC Davis professor of Environmental Science and Policy and co-author of the report. “Those northerly areas are currently at the fringes of quality grape-growing areas.”

The report, published recently in the journal Proceedings of the National Academy of Sciences, warns that populations of large mammals, like grizzly bears, gray wolves and giant pandas, could suffer if winemakers move into these animals’ respective habitats without using conservation-minded caution.

“The reason we still have grizzlies in Montana and Canada is that it’s mostly too cold there for agriculture, but that will change, and these places will soon be suitable for growing wine,” said the study’s lead author Lee Hannah, a UC Santa Barbara-based climate specialist with Conservation International. Hannah points out that the presence of national parks, like Yellowstone, Glacier and Banff, and other protected areas is not on its own enough to preserve large mammals. These creatures may be migratory and depend largely on corridors between the parks. These open areas are the lands into which farmers, including winemakers, may be planting their own roots in 30 years.

In California, Hannah says, increased wildlife conflicts with species such as black bears could result if winemakers push upslope out of the hot valleys to utilize cooler growing regions. Redwood trees in unprotected parts of Mendocino County may also lose ground if farmers decide they want the land.

But future water shortages are the hottest topic in the Central Valley. Louise Jackson, a professor and extension specialist with UC Davis’ Department of Land, Air and Water Resources, says the Sierra Nevada snowpack will probably shrink by between 60 and 90 percent from today’s average volume. Farmlands downstream could go dry.

“But this isn’t a disaster,” she says. “We just need to plan for it.”

Jackson says farmers must diversify their crops, planting new varieties and seeing which ones show signs of resistance to greater heat or drier conditions—an evaluation process that can take many years.

Cherries and other stone fruits that depend on periods of cold temperatures during their bloom periods could prove especially vulnerable to warming climate trends, she says.

Hijmans, meanwhile, speculates that since rice does very well in warm tropical regions, the Sacramento Valley’s rice industry could benefit from climate change.

“But that’s only if we still have enough water,” he said.

Jackson agrees with her colleagues’ study—that wild areas in Canada, Idaho and Montana will probably become important agricultural regions. But she says California’s unique mountain and valley topography may mean that local farmers will have no choice but to adapt.

“It’s not like we can just move everything due north several degrees,” says Jackson. “We have a unique climate here. We have the Delta breeze, so it’s actually hotter if you go north to Redding.”

Plant experts with UC Davis and the U.S. Department of Agriculture are already thinking about bolstering food crops now grown in the state with genetic resistance to diseases and extreme environmental conditions. To do this, breeders will likely turn to the Wolfskill Experimental Orchards in Winters, home to thousands of varieties of tree fruits, including walnuts, stone fruits, persimmons, figs and grapes. The site, operated jointly by UC Davis and the U.S. Department of Agriculture, serves as a genetic library for preserving rare cultivars, while providing plant breeders with the material they need to create new varieties and hybrids—possibly with natural resistance to increased moisture, dryness and heat.

USDA plant geneticist Malli Aradhya, who has collected scores of new plant varieties for the Wolfskill orchard on expeditions to Azerbaijan and Georgia, says climate change is almost certain to affect California’s growing regions, though no one is quite sure how.

“People are saying that natural ecosystems are already being shifted around, especially in marginal climates like those in Mediterranean regions,” Aradhya said. In such regions, he says—including California—“the changes caused by climate change will be amplified.”

In the Clarksburg wine appellation, located 15 to 30 miles due south of downtown Sacramento, John Beckman, president of the Clarksburg Wine Company, anticipates the most dramatic local effect of climate change to be sea-level rise. He notes that most low-lying Delta regions are protected by high levees, and so he isn’t concerned about floods in his vineyards—but Beckman is worried about the Peripheral Canal.

“It’s a man-made threat, but if we build it and increase the volume of water we’re diverting from the Sacramento River, that will exacerbate the saltwater encroaching into the Delta from sea-level rise,” Beckman said.

Having a saltwater Delta, from which some farmers directly draw their water, “will not be good for agriculture,” he said.

Wine is hardly the only crop that will be affected by changing climate—but Hannah’s study used wine as the lens through which to view the world’s agriculture industries because “wine is very plugged into climate,” he explained. Many grape growers—especially those in Europe—do not use irrigation but, instead, dry-farm. This means slight changes in precipitation and temperatures can be clearly and immediately seen in the behavior of the vines.

“Wine is a great bellwether for other crops,” he said. With data from temperature-forecasting models indicating that wine regions will shift poleward in coming decades, it’s a good bet, Hannah said, that “other crops will be moving, too.”