Erratic weather systems, shifting harvest dates, and rising temperatures have forced winemakers to adopt new practices. 

By Vicki Denig
July 30, 2019
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For winemakers worldwide, global warming has brought a new set of challenges to viticultural practices, especially for growers cultivating fruit in cooler climate regions. Cultivating new grape varieties, shifting harvest dates, and modifying vinification techniques in the cellar are just a few adaptations that winemakers across the Northern Hemisphere have had to make.

Due to the exceptional need for high acid fruit, Champagne continues to be one of the regions most affected by global warming. Avize-based (Côte des Blancs) grower Etienne Calsac notes that shifting harvest dates is one of the most obvious impacts of global warming.

“When I first left viticultural school, the average harvest date was around September 23,” he says. “Now ten years later, the average harvest date is around September 9.” Additionally, Calsac says that three of his last nine harvests started in August. Similar things are happening in Austria. In Styria, Manuel Ploder of Weingut Ploder-Rosenberg says that the region is beginning to lose its four-season cycle, as winter months become warmer and spring seasons pass more quickly. As rising winter temperatures lead to less snow, water levels in soil have also begun to decrease.

Alois Lageder, a biodynamic winemaker in Alto Adige, says that temperature extremes are occurring faster, particularly between dry-wet periods. During certain years, temperature extremes have caused winemakers to lose up to 80% of their crops, due to intense overnight lows that bring deadly frosts. Warm winters cause grapes to shoot earlier, and because of rising daytime temperatures, preserving natural acidity and low pH levels in grapes becomes more challenging.

“Cool climate regions are typically characterized by the length of their season,” says Francis Hutt, winemaker at Phantom Creek Estate in Canada’s Okanagan Valley. “As the seasons lengthen, we have new considerations. Early budburst puts us in danger of spring frost, longer autumns can mean longer hang times.” Hutt notes that above all, the most detrimental effect of climate change is the uncertainty of erratic weather systems, which can wreak havoc on a vineyard.

Changing biodiversity also threatens his vines. Ploder has added a significant amount of fruit trees and cover crops in the vineyards to provide necessary shade and encourage the regrowth of biodiversity. Hutt echoes the need for meticulous cover cropping, particularly to limit water loss from evaporation.

“Soil temperature and moisture are big considerations for us,” he says. “With the lengthening of the season and corresponding hangtimes, we can retain more leaves in the canopy, shading the bunches that will reach maturity without the need of being blasted all day with UV-B as a result of excessive leaf plucking.” Hutt believes that this ultimately leads to more balanced flavors in final wines.

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Already seeing the effects of climate change a decade ago, Calsac decided to plant a new parcel of ancient grapes (Pinot Blanc, Petit Meslier, and Arbane) to accommodate rising temperatures.

“These grape varieties were abandoned by our ancestors because they often produced small quantities, low maturity, and too much acidity,” he says. “I find that with global warming, these varieties now play an interesting role and the results of the finished wines are very interesting, more adapted to the climate now.” Ploder is also cultivating “new” fungi resistant varieties, including Souvignier Gris and Bronner.

In Italy, Lageder has begun to seek out higher altitude growing sites to continue his quest for maintaining freshness in his final wines. “We can [grow at] higher altitudes where it is cooler, but we have to be careful not to bring monocultures to higher elevations where we still have a natural landscape,” he says. Cultivating varieties with loose clusters and thick skins help fruit become less susceptible to disease in extreme and fluctuating weather conditions.

When it comes to cellar activity, most winemakers claim that not much has changed. Ploder continues to spontaneously ferment his fruit, both for primary and malolactic fermentations, though he now harvests his grapes during cooler hours of the day, particularly during the early morning. Calsac continues to vinify his Champagne with a minimalist mentality, explaining that nowadays, the wines are simply less acidic and richer than in the past.

Lageder has found an interesting solution in vinification, which involves “playing” with the components of the process. He uses using skin contact, stem inclusion, and careful extraction to create perceived acidity and tension in final wines, despite an overall lower TA (total acidity) than in past vintages.

At the end of the day, most winemakers are realistic but not overly paranoid about climate change.

“I think Champagne wines will keep their identity,” says Calsac, explaining that a sense of established place and the “know-how” of the region will continue to keep Champagne on the world’s radar. Lageder notes that while Alto Adige is currently known as a white wine region, perhaps the future will lead them to become a red wine dominant zone.

Hutt has found that in British Columbia, climate change is causing many more wineries to adopt sustainable practices.

“Wineries are more woke now than ever before,” he says. “I can see that momentum only getting stronger.” He points out that most wine produced in British Columbia stays within the region. “The carbon saved from not shipping wine all over the place is huge, not to mention all those winemakers and marketers globe-trotting in jumbo jets to sell their wares.”

In fact, global warming has opened a discussion amongst vignerons and consumers alike. “The best thing about climate change is the rising awareness of it and a general acceptance amongst people that change is needed,” Hutt says. “Companies are taking a closer look at the way they operate.”

In the vineyard, Calsac also points out the positive side to rising temperatures, which brings faster phenolic ripeness to a region that longtime struggled with fruit maturation. “A ‘hot’ vintage does not necessarily mean ripe,” he explains. “We are continuing to discover and learn from experience with these early harvests.”

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