Climate change isn’t some abstract concept in the wine world. It alters every facet of winegrowing and production. It has a direct effect on what’s in, or not in, our glasses.
In South Africa’s Agulhas Wine Triangle, winemakers harvest unorthodox grapes to withstand cooler temperatures. Meanwhile, as temperatures fluctuate, some producers in British Columbia no longer make Icewines. And in central Mexico, vineyard managers repurpose hail shields to shade their fields from solar radiation.
There’s no single solution for vineyards to respond to climate change. Many analysts embrace very granular climate data, which targets specific regions, wineries and even parcels of vineyards. Sources range from on-the-ground weather stations to satellites positioned more than 400 miles above Earth.
An interesting caveat persists, however. Winemakers have to balance such science and innovative analytics with such realities as budgets, staffing and the most valuable resource of all, time. In the face of rapid climate change, how they calibrate these concerns is a distinctly modern challenge.
From the Ground Up
Temperature and precipitation are among the most important measurements climate-conscious winemakers can make, according to James McMahon, CEO of The Climate Service. McMahon and his team build models that offer predictions on climate change in the years to come, which rely on local weather stations as well as decades of precipitation and temperature records.
The focus of one Climate Service study was days in Napa above 86°F. In the 1980s, the average was 13 days per year.
McMahon’s model predicts that, if conditions remain constant, that number would increase to 65 days per year by the 2040s.
“We watch the forecast models and it seems that unfortunately, most forecasts are pointing toward more aggressive/rapid temperature increases… Historically, they were more focused on the optimistic/conservative models,” says Aron Weinkauf, winemaker/vineyard manager at Spottswoode Estate Vineyard & Winery in St. Helena, in California’s Napa Valley.
St. Helena is home to a weather station that tracks data historically through factors like rainfall, humidity, wind and temperature. An Italian company, Saturnalia, studied the data against figures collected by its own satellite. It found that the area’s climate is changing in diverse ways, and in very localized patterns.
According to Saturnalia’s findings, minimum temperatures are rising around St. Helena. As the heat accumulates, it accelerates budburst in the summer. During winter, drought risk is high.
“We have already been working on rootstock trials,” says Weinkauf. “We have planted a block where we will be trialing new varietals for our area, and we are looking to invest in areas outside our existing area to avoid having all our proverbial eggs in one basket.”
Joseph Brinkley, director of organic and biodynamic vineyards at Bonterra in Hopland, California, has also changed how he farms.
“We recognize that climate change is having an impact on the California wine industry due to shifting microclimates, changes in precipitation patterns and more frequent extreme weather events,” says Brinkley. “In the face of these challenges, we seek to improve resiliency in our vineyard operations through our approach to farming.”
Bonterra also uses regenerative processes that align with its commitment to biodynamic practices, like cover cropping and using compost and grazing sheep. Provisional studies indicate that this type of farming may store more carbon underground than conventional practices.
From the Top
Saturnalia also studied data from the weather station at Mérignac, France, located near the Bordeaux airport. Precipitation records date to 1901, and temperature data extends to 1924.
Saturnalia merged these historic measurements with satellite data to explore vine vigor and water deficits over the last four vintages. It found 1975 to be a turning point for Bordeaux. That year, temperatures suddenly rose, as extreme weather and unstable conditions accelerated in tandem.
Extreme weather patterns, like frequent heavy rainfall, impact the quantity and caliber of harvests. Fluctuating temperatures also leave late-ripening fruits vulnerable to early frosts.
These results speak specifically to Bordeaux, but the methods apply to vineyards worldwide. Growers that understand climate instability and use data monitoring can better adapt their practices to rapidly changing conditions.
Such rises in temperature are not limited to California or France. In Canada’s Okanagan Valley, winemaker Dave Paterson at Tantalus Vineyards has stopped Icewine production, despite its popularity and significant profit margin.
“We are getting warmer,” says Paterson. “We’re seeing that Icewine temperatures are a lot later, and they aren’t lasting as long.”
Canadian law requires Icewine to be produced from grapes naturally frozen on the vine. Grapes must be picked while the temperature is minus-8° Celsius (17.6° Fahrenheit) or lower, then immediately pressed.
Tantalus winemakers noticed that the Riesling grapes on vines in January or February, that were used to make Icewine, are now one of the only food sources available for local wildlife. Rather than have their crop further diminished by hungry animals, Paterson now picks the grapes sooner and uses them for other purposes.
“By the time we get to legal temps, it’s not worth it,” says Paterson.
At Familia Torres in Spain, winemakers see similar volatility. The winery monitors temperature and vine maturation data over the last 50 years from different points in its vineyards. Its data shows that Torres harvests start an average of 10 days earlier than it did 20 years ago. Also, the region’s average temperature has increased 1.2º Celsius (34.16° Fahrenheit) over the last 50 years.
BLB Vignobles monitors temperature and precipitation to assess water conditions year over year in Combaillaux, just northwest of Montpellier in France. From 1955–74, the climate in that area “fit” the water needs of the local Carignan grapes. However, from 1995–2014, while water needs stayed the same, farmers had a serious water deficit.
“We understand climate change with just a glimpse at how the chart curve changes over the years,” says Morgane Le Breton of Vignobles. “Every year we face a new challenge.”
Can There Be Too Much Data?
The biggest concern for winemaker Lluis Raventos Llopart of Finca Sala Vivé by Freixenet México is solar radiation, which evaporates moisture off his vines.
“If they don’t sweat properly, the vines will shut down under intense heat,” he says.
Despite scores of scientific measurements at his fingertips, which includes data Saturnalia collected from the weather station in nearby Parras, in central Mexico, Raventos Llopart found the best way to monitor the impact of solar radiation is a simple bucket of water.
Raventos Llopart and his team leave a bucket full of water in the vineyard and measure its evaporation over time. They use the results to best determine levels of irrigation.
It’s an analog instrument in a very sophisticated toolkit, and it demonstrates the need for a “human factor” in climate analysis.
Lucas Pope, vineyard manager at Halter Ranch Vineyard in Paso Robles, California, points to the handwritten notebooks many farmers have kept for centuries. They may be illegible to anyone except the author, but they record factors like rainfall and significant weather events.
“Being relatively new to farming and not having a family history to lean on and learn from, my snapshot of what is going on with the earth’s climate has been a roller coaster the past 15 years,” says Pope. “Warm years, dry years, cool springs, harsh winters, early and late frost have all hampered grape growers’ efforts to produce the best possible crop with what nature gives us.”
Still, Pope warns against data collection for its own sake.
“If there is no time to spend dissecting the information that is being thrown at you all the time, is it doing you any good?” he asks. “Growers are being asked to do more work with less labor and resources, so selecting what to monitor and the quality of the data are ever more important.”
For those on the front lines of climate change, a cutting-edge toolkit is only valuable if you know how to use it.
Last Updated: May 5, 2023