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Vintners feel the heat 

What does a changing climate mean for SLO County's wine industry?

In wine there is truth, according to the ancient Bacchanalian philosophers. These days, though, it’s more of an inconvenient truth, as the rising temperatures associated with climate change are already having an effect on the world’s—and SLO County’s—premium wine grapes.

- CHANGING CLIMATE, CHANGING PRACTICES :  Viticulturists, including Jean-Pierre Wolff of Wolff Vineyards, are planting drought-resistant vines to cope with declining water resources due to global warming. -  - PHOTO BY STEVE E. MILLER
  • CHANGING CLIMATE, CHANGING PRACTICES : Viticulturists, including Jean-Pierre Wolff of Wolff Vineyards, are planting drought-resistant vines to cope with declining water resources due to global warming.
As “toasting” takes on a new meaning for the billion-dollar local wine industry, some vineyard growers in Paso Robles and Edna Valley are recognizing the challenges of global warming, and are taking steps today to try to cope with its future effects. But those who don’t adapt their vineyards as the climate changes are likely to be “history” within 20 years, according to Dr. Greg Jones, a climatologist at Southern Oregon University and a winemaker himself.

San Luis Obispo County’s warm growing area in eastern Paso Robles has “less elasticity,” in terms of adaptability to rising temperatures compared with other SLO regions, according to viticulturist Jean-Pierre Wolff, who owns Wolff Vineyards in Edna Valley. “They may ultimately end up growing cacti. Wine grapes don’t grow well in the desert,” Wolff said. “Twenty-five to 50 years from now, you’re going to have some areas that are no longer suitable for growing grapes. Or if they can still grow, they’ll be sub-quality. You won’t be producing a best-of-show $80 bottle of wine.”

Each wine-grape variety needs specific conditions to grow well, known as the climatic niche. High-quality wine grapes are produced in a narrow climatic niche, characterized by a lack of extreme heat and extreme cold. Warmer areas tend to grow grapes in high volumes rather than high quality, Jones noted, adding, “Ever had wine from Fresno? It probably cost three to five dollars a bottle, but it’s not high quality.”

Pinot Noir, for example, requires an average temperature during its growing season of between 57 degrees F—found in New Zealand and Tasmania—and 61 degrees F—found in San Luis Obispo and Santa Barbara counties.

If temperatures keep rising, even by a few degrees, that “puts you outside the climatic niche for Pinot Noir as we know it today,” said Jones in a phone interview from his Ashland office. He spoke about Pinot Noir and climate change at the American Society of Viticulturists conference in Portland, which ended on June 20.

“Climate change is big. It’s fuzzy. It’s hard to sink your teeth into. As a society, I think we have a real hard time understanding what it’s all about. I’ve always felt there’s a large amount of risk associated with climate change that people just don’t understand,” Jones noted.

“The public needs to understand—we’re not talking next year, we’re talking about something that’s going on now. The data speaks.”

click to enlarge THE NEXT GENERATION:  The Beckett family of Peachy Canyon Winery—including Jake, left, and Josh, right—is focusing on leaving healthy, sustainably farmed vineyards for future generations in a climate-changed world. - PHOTO BY STEVE E. MILLER
  • THE NEXT GENERATION: The Beckett family of Peachy Canyon Winery—including Jake, left, and Josh, right—is focusing on leaving healthy, sustainably farmed vineyards for future generations in a climate-changed world.
Fuzzy or not, it’s an issue that’s starting to come under the magnifying glass for the wine industry worldwide.

Two years ago, the First International Global Warming and Wine Conference in Spain was sparsely attended. Pancho Campo, of the Wine Academy of Spain, gave a welcoming speech that exhorted his colleagues to spread the word about global warming, adding, “It might not help sell wine today, but global warming will bite us all in the ass in 20-years’ time.”

His colleagues seem to be feeling the nibbling already. The second conference, the World Congress on Climate Change and Wine held in Barcelona in February this year, had five times the attendance, 350 participants from 40 countries. Al Gore joined the conference via video link.

As parts of California, Spain, and Portugal become too warm to grow premium wine grapes in the future, the “winners” will be Denmark, Sweden, Finland, and Ireland, which will soon be able to grow palatable wine, the conference was told.

Locally, wine-grape growers could adapt to warming temperatures by moving their vineyards higher in elevation, farther north in latitude, closer to the coast, or onto north- and east-facing slopes, according to Jones.

For Wolff’s Edna Valley vineyard, a change in grape varieties may be in the picture as the climate changes. Today, Wolff grows Pinot Noir and Chardonnay grapes, but future temperatures may necessitate varieties that are more tolerant of heat, such as Syrah, Viognier, and Cabernet Sauvignon, he said.

“If temperatures keep rising, it will be a challenge to produce well-balanced Pinot Noir and Chardonnay from my vineyard,” Wolff anticipates.

Already he’s seeing differences in his vineyard, based on more than 30 years’ worth of records of bud-break and harvest times. Today’s grapes have a much higher sugar content at harvest time in November than in the past, he said, emphasizing, “There’s a definite change, no question about it.”

The higher sugar content, resulting from higher temperatures, tends to make wine more alcoholic—“I call them fruit bombs,” Wolff says of the grapes.

In the past, he said, an “almost Port-like” alcohol content of 15 or 16 percent was “fine” with consumers, who wanted big, ripe flavors. Now there’s more of an issue of drinking in moderation, with consumers wanting wines with just 12 or 13 percent alcohol.

“Plus high-alcohol wines are very difficult to pair with food. Take a 16-percent-alcohol wine: Pairing that with trout or poultry would be very, very difficult, because the wine would overwhelm the food to your taste buds,” noted Wolff.

High-quality grapes require a combination of cool nights and long “hanging time” on the vines to develop sugars and maintain the acidity needed for the wine to have a good finish that is “not flabby,” he said. Otherwise winemakers need to add tartaric acid, “but you can’t beat Mother Nature for the taste.”

SLO County’s future wine industry may see a shift in the location of planted areas, with more vineyards in Cayucos and Cambria where it’s cooler, and fewer in eastern Paso Robles, Wolff said.

A looming concern for wine-grape growers is water availability, which is also governed by climate change. Grape vines need more water in warmer temperatures, which increase evapotranspiration. But climate change could reduce rainfall and groundwater recharge in SLO County, thereby decreasing water supplies.

Wolff is ready. He’s already planting new deep-rooted, drought-resistant rootstocks that tolerate the higher sodium levels that show up in soil as a consequence of drought. He’s also “drought-proofing” his irrigated vines, training them to need less and less water each year.

“When you plant a vineyard, you’re thinking a quarter of a century ahead,” said Wolff.

The Beckett family of Peachy Canyon Winery in west Paso Robles is doing just that, looking ahead to future generations.

“Climate change is huge for our family,” said Doug Beckett. “What are our grandchildren going to do? We all need to look at that generation.

“Are we going to leave dying vines, or maintain a sustainable program so we don’t run out of water resources? We have no intention of leaving a desert for our grandchildren. All of us need to look to the future and find ways to use less and less water.”

Vineyard manager and chief winemaker for Peachy Canyon Josh Beckett is applying sustainable growing techniques to the wine-grape operation, including using drought-tolerant rootstocks, reducing water and fertilizer consumption, reducing tractor and energy use, and adding large amounts of compost to the soil.

Josh and his brother Jake, the national sales director, are starting a new wine label dedicated to sustainable practices, conserving water and energy with an eye to climate change. Chronic Cellars’ tasting room on Nacimiento Lake Road is scheduled to open on June 27.

“We have to do things wisely. We have to acknowledge climate change, and be proactive about it,” Josh said.

“Start the process now to conserve the energy your plants have, so they’ll last a lot longer and still be around when the kids take over. Don’t over-manipulate and overload the vines, or you’ll lose quality on top of the added heat. The temperature is going up every year,” he noted.

Their new label—designed to appeal to a younger demographic—has been created with “100-percent awareness” about climate change, said Beckett.

The SLO County wine industry is seeing more of a “sustainable trend” in general, according to Stacie Jacob, executive director of the Paso Robles Wine Country Alliance.

“The key to handing down the vineyard is to make sure it’s in a healthy condition for the next generation to come. Lots of brands or vineyards have a long family history, and they’re asking, ‘What do we have to do to take care of our environment and have an economic benefit?’”

The county’s wine industry—which now has around 230 wineries—pumps $1.8 billion a year into the economy, according to a study last year by the Wine Country Alliance.

Some of the bigger Paso Robles wineries, including EOS, J. Lohr, and Meridian, are installing $5 million worth of solar panels that will pay for themselves in five years, Jacob said. Many wineries have switched to biodiesel. Turley Winery is even using draft horses in their vineyards, so the soil is less compacted and holds water better.

“In the grape business, we’re some of the original stewards of the land, and sustainability has become a way of life. I think the consumer really cares how the product was created, and whether it was done with care for the environment,” she added.

Now, local wineries are being asked to care for another aspect of the environment: the clean air. In a new program, partly related to climate change, larger wineries will be required to obtain a permit for the air pollutants emitted during wine fermentation.

Especially in porous oak barrels, fermenting wine produces ethanol, considered a “volatile organic compound” that reacts with sunlight to form ozone, which is the main constituent of smog.

The Paso Robles region sees regular violations of state and federal ozone standards, which should be a concern for the wine industry, according to SLO County’s Air Pollution Control Officer, Larry Allen.

Ozone in the air cuts down on vineyards’ yields by around 20 percent, according to a statewide study. Grapes are one of the most sensitive crops to ozone pollution.

“The reason is that ozone damages the leaf surfaces, and the plant can’t photosynthesize, take in the sunlight, store carbohydrates, and produce as big a crop of grapes,” Allen explained.

“Also, because of the reduced ability of grapevines to photosynthesize with ozone damage, there’s less carbon dioxide absorbed, so there’s more remaining in the air. Then there’s more climate change, more warm weather, more ozone produced, more plant damage, less yield. It’s an infinite destructive feedback loop that just keeps increasing. That’s the science behind it.”

The SLO County Air Pollution Control District wants wineries to pay “their fair share” for air quality management, estimated at around one-tenth of a cent per bottle for the biggest facilities, much less for the smaller ones. Wineries emit around ten percent of the ozone-pollution pie, Allen said.

“I think the wine industry overall is more conscientious about green techniques. My personal impression,” he added, “is that since they’re dealing with a discretionary use product—it’s not like wine is food you have to have—the industry is conscientious about their image and tries to operate in a green, sustainable fashion.”

Over at Wolff Vineyards in Edna Valley, viticulturist Wolff is predicting economic consequences due to climate change.

Because the cool-climate grape-growing areas would be limited, “You would have price pressure on the availability of grapes, which would ultimately be felt by the consumer,” said Wolff.

“Plus it’s got a big economic impact on the value of the land if it suddenly becomes a challenge to grow grapes on that land.”

Some former vineyards in the San Joaquin Valley are already switching to olive trees, which can handle higher temperatures and declining water availability.

Locally, the wine industry is going to need major changes to stay in business, Wolff warned, concluding, “I don’t want to be an alarmist, but now it’s not going to be farming the way it was done 25 years ago, and it won’t be today’s way of farming in 25 years.”

As Doug Beckett at Peachy Canyon noted, “I believe all of us have to be concerned with climate change.” ?

Is our climate really changing?
Climate change occurs gradually over a long period of time, and is difficult to track without years of data, according to Mark Batteny, farm adviser for the University of California Cooperative Extension. In SLO County, measurements of vineyard temperatures are just beginning to be collected.

“Without more data, climate change is a tough one to tackle,” Batteny noted.

But we do know that sugar content in local wine-grapes at harvest time has increased over the last 20 years, said Cal Poly viticulture professor Keith Patterson. At Wolff Vineyards in Edna Valley, for example, sugar content in the grapes of 30 years ago was 22 Brix at harvest time in November, while today 24 1/2 Brix is the norm.

Higher sugar due to warmer temperatures translates to higher alcohol content. In Napa Valley, average alcohol levels have risen from 12.5 percent to 14.8 percent between 1971 and 2001, according to a study by Dr. Greg Jones of Southern Oregon University. He attributes more than half of that difference to climate change.

Jones analyzed growing season temperatures in 27 of the best wine-producing areas in the world, and found that the average temperature warmed 1.3 degrees Celsius over the last 50 years. The greatest warming was in the western U.S., including California, with an increase of more than 2.5 degrees C.

Climate models show an increase in the frequency of extremely hot days, over 95 degrees F. Grapes can tolerate 14 superhot days in a season, but scientists say by the end of the century we can expect 50 to 60 superhot days, according to a study published in the Proceedings of the National Academy of Sciences.

As Jones concludes in his research paper, “While exact spatial changes in the magnitude and rate of climate change in the future are speculative at this point, what is absolutely clear from historical observations and modeling is that the climates of the future, both over the short and long term, will be different than those today.”


Contributor Kathy Johnston may be reached at



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