Studies have shown that climate change will have a fundamental impact on weather patterns causing extreme temperature fluctuations and increasing the risk of droughts or floods. Given wine grapes’ sensitivity to weather conditions this will have a severe impact on the wine industry globally. Increasing summer temperatures can cause sugar levels in grapes to rise too quickly forcing growers to pick sooner or manipulate them at a sacrifice of tannin quality. Warmer temperatures increase the likelihood of pest epidemics, calling for expensive and potentially quality reducing chemical responses. Shrinking glaciers, melting snow and erratic, unpredictable rainfall cause water supply security and price concerns for this irrigation intensive industry.
The impact, however, is not homogenous across regions. Californian vineyards are especially affected by rising temperatures and growing days over 35 degrees Celsius. Suitable vineyard area of premium wine production in the US (mostly located in California) could decrease by as much as 81% by the year of 2100 . Many people argue that wine is a luxury good and therefore less of a concern, however, the wine industry has a 57.6bn impact on the Californian economy and is one of its largest employers . Tax laws further complicate the problem of rising temperatures as high sugar content leads to wine with higher alcohol content, which falls into a higher sales tax bracket. Many vineyards in California are family run with limited financial resources to adapt to the challenges posed by climate change.
One example of a typical Californian family vineyard is the Van Ruiten Family Vineyard in the Lodi Area of California’s Central Valley. 78% of vineyards in this region fall into the Winkler Index (a heat summation method used to classify the climate of wine growing regions) Class 4 and 22% into Class 5 , putting this area at an immediate risk of small temperature shifts having detrimental effects on wine production. The Van Ruitens produce a wide range of wines including Sauvignon Blanc, Chardonnay, Pinot Noir and Cabernet Shiraz. In response to the challenges posed by climate change the vineyard has taken a number of measures to reduce its carbon footprint by moving towards more Sustainable Farming Practices and eco-friendly farming techniques. They erected nesting boxes for owls throughout their vineyards allowing the owls to help keep the rodent population down without the use of poisons in the soil. The family also avoids the use of machinery in the harvest and 100% of the grapes are handpicked.
There are further steps the vineyard may consider to adapt its Operating Model. The wine growing process can be broadly summarised by plantation, soil management, canopy management and harvest.
Figure 1 Source: self-drawn
In the Planting Phase the vineyard may consider mitigating the risk by changing its product mix (i.e. the grape variety). An Australian study found that temperature effects on tannin and PH levels were variety specific . Cabernet Franc and Chardonnay experienced the greatest shifts in both, whilst Shiraz showed little change in either measurement. The vineyard could produce less of their current variety and replace it with more resistant grapes. They may consider moving their vineyard to slightly more protected areas by relocating within the same region or considering a new location. Due to the high costs associated with a move this would be a more long-term solution of last resort.
Canopy management refers to the management of the shoots, leaves and fruits of the grapevine and has a considerable impact on yield and quality of produce. It involves pruning, “training” (positioning) the shoots and cutting leaves to allow air and light to flow to achieve optimal photosynthesis and ripening. To protect from heat exposure, shading systems could be introduced. The vineyard could partner with technology companies to look at geoengineering their grapes in an ecological and sustainable way.
Soil management is another important aspect of growing wine. Adequate irrigation is essential throughout the ripening process. To avoid dependence on water availability during a drought, the Van Ruitens may consider introducing self-managed water storage system.
The harvesting period is typically adjusted to the ripening process of the grapes. Bearing in mind changes in climate when evaluating the harvest dates would ensure that the sugar level in the grapes and therefore lower alcohol content of the wine does not increase substantially. This would be advantageous from a tax perspective as mentioned above.
Especially for family vineyards environmental effects that reduce the yield or quality of their production are critical. They typically do not have the financial means to introduce high tech solutions. A community approach, in which small vineyards partner with other vineyards from the region to lobby the government for adequate support and to represent their interests could be a good way to strengthen their voice.
 “Global Changes in Local Places: Climate Change and the Future of the Wine Industry in Sonoma and Napa, California” by K.N. Cahill, PhD Dissertation, Stanford University
 The SOMM (Sommelier) Journal, October / November 2015 edition, page 124
 “The impact of climate change on the global wine industry: Challenges & Solutions” by Michelle Renée Mozell and Liz Thachn Sonoma State University, Science Direct
 “The Future Impact of Climate Change on the California Wine Industry and Actions the State of California Should Take to Address It” by Jonathan Gatto et al., International Policy Studies Program, Stanford University
“Effects of elevated temperature in grapevine. II juice pH, titratable acidity and wine sensory attributes” by Sadras et al., Feb 2013