Wine growers in California are facing a massive challenge: keeping their vines alive without water.
Bennett has been growing wine on Navarro Vineyards with his wife Deborah Cahn since they bought and converted the 110-acre former sheep ranch in Anderson Valley in the mid-1970s. Their children, Aaron and Sarah Cahn Bennett, work on the vineyard too.
"It’s one of those old fashioned family affairs," Bennet tells Newsweek.
Bennett has 200,000 grapevines, and each of them requires about 6 gallons of water per week. The vineyard’s ponds hold about 70 acre-feet, or about 23 million gallons of rainwater. That is their only source of water. The ponds are at 10 percent capacity now, and it is impossible to pump out the last few gallons.
“Conceivably we could have zero production,” Bennet says. “It could be a disaster.” Very heavy rain in late spring is the only hope to keep their vines growing and avoid a huge financial setback.
Wine growers across the state are choosing to forego some or even all of their grape production this season by clipping the new buds before they have a chance to develop. Grape yield this season will almost certainly be way down.
“Less shoots means less leaves, which means less water used by the vines,” Larry Williams, a professor of viticulture at the University of California Davis, who specializes in effects of water stress on vineyard performance, told Newsweek. “So instead of trying to produce a crop, they are making decisions just to keep the vines alive without applied water for next year.”
Wine growers have long been aware of the effects climate change is having on their industry. Notes about changing growing patterns and regional suitability of certain grape varieties have been features of wine guides for years.
“What we’re seeing is big changes under way already, that will get much bigger in the future,” Lee Hannah, a senior scientist at Conservation International, told Newsweek. He is an author on a recent study that projects massive geographic shifts in wine growing regions due to climate change by 2050.
According to Hannah, in the next ten years, it will get harder and harder for interiorly-located vineyards in California to thrive. That does not bode well for the hot, dry Central Valley, where three-quarters of all California’s wine (and the biggest raisin industry in the world) is produced.
“What we know is that the coastal areas in California will retain pretty good conditions for wine growing, while the interior will get hotter and drier, which is a pattern we’re seeing throughout the world with climate change models. The coastal areas hang on and the interior goes,” Hannah says. "These are the sort of droughts we expect to see more of."
Other experts echoed that sentiment. “If you have a drought condition and no water, you have multiple problems stacking on top of each other,” says Ray Isle, the executive wine editor at Food & Wine magazine.
Vineyards use water for two things: keeping vines hydrated, and preventing frost.
The combination of recent warm weather and little rainfall -- just 9 inches in the past year for Navarro Vineyards, compared with an average annual 45 inches -- could be a lethal combination for Bennett’s vines.
The vines are still dormant for the winter now. But warmer winters like this one can cause new shoots to sprout on the vines too early, making them more susceptible to crop-killing frost. Overhead sprinkler systems are often used to keep frost from settling in on the vines, by shielding them in a layer of ice. Without water, vineyards are left to figure out other means of frost prevention. This year, Bennett will try using giant overhead fans to mix warmer upper air with the cold air around the vines.
Even if the new shoots and fruit manage to keep growing to harvest, such parched conditions will likely hurt two years’ worth of grapes, Bennett says. The stress on the vines will dramatically reduce this year’s yield, and the crop in 2015 will likely be less than normal as well, because the vines have been weakened.
“Basically, they need a foot of rain between now and May just to get back to conditions they had during the drought of 1977,” Isle says.
Some water stress and a lower grape yield can sometimes produce a higher-quality wine, Isle says. But this has its limits: If prolonged, zero water can only cause severe damage.
It’s hard to know how wine produced from drought-stricken grapes will taste, but Bennett says his nearly 40 years of wine growing experience has taught him that every little environmental factor gets expressed in the flavor of the final product.
“We had a forest fire in July of 2008. It turns out the grape vines absorbed the smoke, and you could taste it in the red wines from that year,” Bennett says. “It came out in the stems, the seeds, the skins.”
For now, Bennett is watching soil moisture closely and conserving what little water he has left.
"Farmers have to be optimistic," he says, laughing.
Correction: An earlier version of this article gave the wrong name for a professor of viticulture at U.C. Davis. His name is Larry Williams.