Winemaking and Climate Change:
How Vineyards are Adapting Ancient Practices to New Climate Challenges

by Carlos João Parreira

Making wine may be a romanticized idea, but it is a precise science regarding a highly sensitive crop. Unlike spirits, beer, or other food crops, each year a winemaker’s harvest has a markedly different profile, reflecting the weather conditions of a particular season (Downey et al., 2006). Despite having spent millennia refining methods to specific microclimates and grape varieties, subtle changes in weather each year have a significant impact on flavor and, by extension, economic value.

With human actions affecting global climate and weather patterns becoming more extreme, the risk of a lost or unacceptable crop has exponentially increased. As an industry of economic and cultural importance, governments are motivated to help it adapt and thrive in these new conditions. The question is: how?

Discussion of Findings

To put it simply, if a single grape variety is planted in a few different locations, even if harvested at the same time, using the same methods, by the same person, it would produce different quality wines. Wine grapes are so sensitive to the world around them that the French required a whole new word to describe it - terroir. Soil properties, subsoil properties, daytime and nighttime temperature fluctuations, exposure to sunlight, rain levels, water quality, and harshness of wind are only some of the conditions that influence a wine’s terroir and perception of worth. They are also some of the clearest consequences of man-made climate change (van Leeuwen, 2022).

Although the wine industry had been fundamentally unchanged for hundreds of years and proudly tied to tradition, when faced with globalization and competition at the end of the last century, wine producers turned to technology and data for the analysis of unpredictable conditions and their impact on quality. Wine producers have been documenting longer growing seasons, which cause grapes to mature further on the vine, with warmer temperatures increasing ripening pace and measures of sugar and alcohol content. In many ways, these were welcomed changes as overall quality of wine increased, and the harvest process was optimized to locations and taste preferences (Almaraz, 2015).

However, these changes have not plateaued but continued to progress. A watershed 2005 study analyzed the growing-season temperature variations in the 27 regions best regarded in the world for wine production from 1950-1999. They were all found to have increased an average of 1.26 degrees Celsius (2.3°F), primarily affecting the northern hemisphere. Temperatures in four of these regions had climbed to an average of over 1.5 degrees Celsius (2.7°F) at the time of the study. The Northern Rhône Valley in France, long considered to have the terraced soil and cool weather conditions to grow the world’s best Syrah grapes for highly valued Côte Rôtie and Hermitage wines, had increased its average by 4 degrees Celsius (7.2°F) (Jones et al.).

These drastic deviations have significant consequences for growers, particularly small family estates. A 2-degree Celsius (3.6°F) increase can alter a region to the point where grape varieties grown for centuries can no longer thrive. Growers must then spend years experimenting with untried varieties suited for hotter weather, with different flavor profiles than consumers are expecting from the region, likely affecting quality and sales (Morales-Castilla et al., 2020; Galbreath, 2011). Even if the experimentation is successful, many industry authorities remain strict about what is an accepted grape variety for a particular area, rejecting their inclusion in the demarcations that the market requires (Yeginsu, 2021).

For regions already growing hot-weather grapes, such an increase will exceed the maximum temperature that any grape can endure (Morales-Castilla et al., 2020). A study published by the University of Oslo in 2020 predicts that areas facing a 4-degree Celsius (7.2°F) increase in average temperature should expect an 85% decrease in production area. In other words, it would be impossible to grow wine (Lei Win, 2020).

However, areas with appropriate soil characteristics but previously unsuitable climate, such as the United Kingdom, Belgium, and Sweden, have also warmed, attracting those seeking better conditions. Southeastern England has similar chalky soil to the Champagne region in France, and although traditionally too cold for wine, local temperatures have increased faster than the global average. These improved conditions have led to the production of new English sparkling wines, some of which have received better scores at international competitions than Champagnes. This has prompted Champagne companies such as Taittinger and Vranjen-Pommery Monopole to invest in English vineyards or plant new ones in the region, which will take years to develop before entering the high-end wine market (Kantchev, 2013).

Despite changing climate conditions, English sparkling wine would not be able to call itself Champagne, a regulated classification exclusive to the French region with centuries of heritage and market power. This added risk of losing protected status and certifications has led many wine estates to consider moving countries as a last resort, pressuring them to explore different avenues (Gaidos, 2014).

In Spain, the Torres family, which has been producing wine in Cataluña since the 16th century, is looking to the past to safeguard its future. Originally, the estate had attempted to recover ancestral grape varieties eradicated in the late 19th century by Phylloxera infestations, an insect native to North America that decimated most of the vineyards in Europe (The British Medical Association, 1875). However, six of the ancient varieties have been found to be highly adaptable to the high temperatures and drought that are becoming more prevalent, and their reintroduction is currently being researched (Familia Torres, 2020).

The estate is also looking to higher altitudes for new growing grounds, planting in the nearby Pyrénées mountain range at altitudes as high as 4,000 feet, which would have been unthinkable twenty-five years ago. Although temperatures are not significantly cooler during the daytime, the mountains have lower nighttime temperatures and shorter heatwaves. These more pronounced daily temperature drops cause the grape to ripen at a more beneficial pace than what has been possible at lower altitudes (Asimov, 2019b).

Untraditional vineyard placement seems to be an approach within the control of even small-scale growers. In the northern hemisphere, sunny south-facing hillside planting has been the norm for centuries, while the opposite is true in the southern hemisphere. With rising temperatures and sun damage being a priority, some vineyards in the northern hemisphere have begun to add north-facing plantings where they receive less direct sun (Hannah et al., 2013). These may seem like small decisions, but unlike other crops, grapevines take years to produce fruit, with yet another few years required for the quality to rise to the level needed for winemaking. For a fickle market, this gamble could prove costly.

Rather than relocating their vineyards, some estates in northern Portugal are taking a gamble on new processes and interpretations of traditional grape varieties. The Douro region is known for its robust red wines, particularly the fortified Port wines that are famous worldwide. However, some winemakers are now turning to previously undesirable locations that are better suited for lighter wines. The response from domestic consumers has been lukewarm due to local expectations of the region, but foreign interest continues to rise, possibly proving that new introductions from established regions could be commercially viable internationally (Asimov, 2019a).

Another way of adapting an existing estate is being explored in southern France, with the specific goal of delaying the ripening process of traditional grape varieties. Warming temperatures have caused the ripening to occur two to three weeks earlier than it did fifty years ago, significantly altering the final product. To combat this, an experimental farm near Montpellier is planting trees.

Agroforestry, the scientifically proven philosophy that intentionally integrating trees with crops is mutually beneficial, has been around for centuries, but it is recently receiving more attention for its benefits surrounding climate change (USDA, 2019). It has been found that growing trees and other woody perennials in combination with crops and fruits creates a system of increased cooling and moisture level, as it sequesters more atmospheric carbon than crops alone (Hoffner, 2020).

The experimental Montpellier farm is part of the French government’s wine-focused agroforestry exploration, conducted by its National Research Institute for Agriculture, Food and Environment (INRAE). Using a technique called ‘alley cropping,’ the INRAE planted rows of pines, cypress, pear trees, and service trees, all several meters apart, interspersed with traditional trellised rows of local grape varieties Sauvignon gris, Merlot, and Grenasch (Grimaldi et al., 2017).

During this ongoing study, ripening is being shown to slow down with the shade and wind protection that the trees provide, with their natural evapotranspiration processes moving water from the land’s surface to the atmosphere, making it more readily available (USGS et al., 2018; Hoffner, 2020). During its 2019 study period, the region was hit by 44 degrees Celsius (111°F) in the shade, with many vineyards reporting significant damage to the leaves and grapes, while the vineyards protected by ‘alley cropping’ suffered no damage.

Beyond heat extremes, researchers are also finding benefits during late frosts. Infrared radiation from tree canopies has been found to cause a slight elevation of temperature, creating protective microclimates that resist frost, while vineyards not in the study lost entire crops (Favor & Udawatta, 2021). The trees have also generally made ecosystems richer, with beneficial insects attacking vine pests and mites, lower instances of mildew, and higher levels of acidity and tannin contributing to healthier, higher-quality wine (Hoffner, 2020).

While these planting techniques would fundamentally change the winemaking process, some vineyards are choosing technology to increase the efficiency of ever-dwindling resources. In a 2011 analysis of the responses by global businesses to climate change, Jeremy Galbreath explored the methods of one of the largest wine producers in the world, Foster’s, as it adapted to falling rainfall and more frequent droughts in Australia.

By examining Plant Cell Density (PCD) imagery of the vines, Foster’s is identifying the ratio of infrared to red reflectance as an alert mechanism of plant stress. This allows for more targeted increases in care, reducing wasteful broad attempts. Foster's has also implemented specialized watering drip lines to divert water from longer-rooted varieties to those with shallower, thirstier roots, enabling more precise targeting of resources. The focus on conservation as a means of defense has also introduced automatic soil-moisture monitors that only trigger watering when needed, instead of scheduled watering, irrigation at night to reduce evaporation, and more sustainable sources of water, including stormwater capture and recycled water (Galbreath, 2011).

CONCLUSION

As with many other industries, there is little agreement on the definite steps that any one vineyard must take to be best suited for the changing climate. Nevertheless, there is agreement on the challenges faced and a surprisingly open mind on possible solutions. I had expected tradition to be the largest roadblock to innovation, but centuries of history have instead shown that to survive, one must adapt.

At the start of this journey, the goal had been to create a resource for vintners. However, with the significant challenges facing us all, we should instead learn from their efforts. Winemakers are the canaries in the coal-mine, with their livelihoods much more sensitive to changes in our atmosphere. The range of proposed solutions is vast, some unexpected and some obvious, some successful, and some less so. Nevertheless, all winemakers are entering the fight with open eyes.

We should follow their lead.

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