Climate change seems as though it will only affect those communites most vulnerable to it, but damages may hit closer to home for many than they might expect. If climate change continues as is and reaches two degrees warming, wine production and quality will be severely affected, as temperature and climate are the primary determinant for effective vine development and for proper flavor emergence in wines (Koufos et al., 2014; Cook and Wolkovich, 2016; Ashenfelter and Storchmann, 2016; Wang et al., 2020; IPCC, 2022). This will affect the most affluent members of our society the most, as opposed to most climate change impacts which typically affect already marginalized communities.
Temperature shifts have varying effects based on region, but typically result in:
decreased grape quality due to advanced harvest dates;
higher sugar content;
reduced shoot and berry size;
(Ashenfelter and Storchmann, 2016; Bai et al., 2022; IPCC, 2022).
Therefore, climate change is poised to drastically decrease total output of high-quality wine, and the overall quality of that wine, particularly in key areas such as Italy, France, Argentina, China, and the focus of this case study: Napa County, California (Shultz and Jones, 2010; Mosedale et al., 2016; IPCC, 2022).
These key areas are also likely to change to new locations under the conditions described below as suitability will change based on region. In other words, there will be ‘winners’ and ‘losers’ of these changes. Winemakers closer to the poles will benefit, at least for the moment, as warmer climates will grant them new options for grape varieties (Ashenfelter and Storchmann, 2016; IPCC 2022).
However, with the majority of winemakers being already in warmer, more ideal climates, temperature shifts will devastate wine quality in the most important wine making regions of the world, including California.
Key impacts of Climate Change will involve:
- Increased drought changing harvest dates and reducing shoot growth and berry size (Cook and Wolkovich, 2016; IPCC, 2022);
- Spread of insect pests, increasing in number, generations per year, winter survival, survivable area, more invasive species, and more plant diseases (Skendžić et al., 2021; Gutierrez and Ponti, 2022);
- Increased wildfire occurrence, resulting in burning of crops and tasting rooms as well as smoke taint and worsened destination image (Bauman, Yuan and Williams, 2019; Kropp and De Andrade, 2022);
- And as a product of each of the previous issues, massive economic losses in California’s wine industry, particularly in the Napa region (Ashenfelter and Storchmann, 2016; Fourth National Climate Assessment (FNCA), 2018; Bauman, Yuan and Williams, 2019; Downey Brand, LLP, 2021; Gbejewoh, 2021; Yasui et al., 2021; IPCC 2022).
One key hazard for grape growing is change in drought conditions. Seasonal drought was originally a key factor in successful grape growing, but only when it consistently occurred in the later parts of summers and followed a wet season. This allowed vines to have time to mature and then for them to be forced into focusing on grape growth due to decreased moisture availability (Cook and Wolkovich, 2016). Now, these late season droughts are irrelevant to grape growers as droughts begin much earlier and force vines into fruit production with much smaller buds, which results in fewer and less mature grapes (IPCC, 2022). Net water requirements of agriculture are also projected to increase over the next century, putting even more stress on the region (Funes et al., 2020).
Grapes, largely grown in coastal areas such as Napa on the north coast of California, are not affected as much by droughts as other regions might be, but due to their labor intensity and higher gross revenue per acre, even small losses due to drought have large economic impacts (Medellín-Azuara et al., 2022).
Changing frost patterns seem to increase yield, however with the slow but steady spread of these insects, it gives them time to begin feeding earlier in the Spring, and to possibly produce additional insect generations during the growing season (Skendžić et al., 2021). This also means increased overwintering survival, increase in insect-transmitted plant diseases, and increased occurrences of invasive species.
Another hazard is the emergence and expansion of insect pests, which are also more pronounced in coastal areas (Skendžić et al., 2021). Several insects including the Pink Bollworm and the Olive fly previously existing in only southern California and Arizona have now expanded north into California's wine country, hindering many other forms of agriculture in the area in addition to vineyards. The impacts and expansions of these insects have exceeded the projections of a 2006 study, meaning they may continue to exceed current projections, which have mid-century, around 2055, as the key date when insect populations become unmanageable for the wine industry (Gutierrez et al., 2006; Kerr et al., 2018; Skendžić et al., 2021; Gutierrez and Ponti, 2022).
Wildfires in the Napa Valley area, the primary area of wine production in California, have already begun to damage crops and community alike. Community-wise, studies have found wine tourism, one of the largest economic contributors to the area, has taken big hits- wildfires have caused extensive concern for the industry, including fear of the fires as well as worry about the industry (Bauman, Yuan and Williams, 2019). The destination image has worsened significantly, which has huge negative economic implications (Lai and Li, 2016). Crops and tasting rooms are burnt down directly at times, but more impactful is the indirect effect of smoke exposure (Kropp and De Andrade, 2022). This typically leads to smoke taint, a burnt aftertaste in wine, which often affects much more widespread areas than are affected by direct fires. When mild, smoke taint makes wine quality worse. When extreme, it makes grapes not harvestable or wine unsellable. In 2020, this resulted in $601 million of Californian wine grapes going unharvested (Downey Brand, LLP, 2021), and another $227 million being paid in crop insurance (Yasui et al., 2021).
The effect of these fires is more extreme in the Napa region, which poses an even greater economic threat. Napa only accounts for 4% of California's wine exports, but accounts for 78% of its revenue, meaning the wine coming from there is on average far and away the highest quality that is produced in CA (Kropp and De Andrade, 2022). Therefore, wildfire damage to this region means damages to the highest valued wine in the state. These fires are also a key part of holding back insect pests, but when they become too extreme, they go from being beneficial to being extremely detrimental (FNCA 2018).
California wine seemingly benefits from climate change in many ways currently. Frost decrease in both days of the year it is present and of land on which it appears has resulted in similar or increased yields for wine grapes. However, this benefit will not last if climate change continues, but rather will be reversed (Gbejewoh, 2021). These projections of increased production have already been found to be inconsistent or untrue in other crops. Almonds, the second most produced specialty crop in CA behind grapes (Kerr et al., 2018), had been projected to increase in their production by and after 2018, but because of the droughts offsetting the more favorable growing temperatures, production has instead greatly decreased (Reisman, 2019).
Adaptation options exist, but even when available, costs of adaptation in the short run will be extreme and the costs will likely be recurring as the climate continues to change in new or in more extreme ways (Ashenfelter and Storchmann, 2016; Gbejewoh, 2021). The highest quality wines are produced via the finding of microclimatic niches that function exceptionally well for winemaking within less favorable macroclimatic conditions (Mosedale et al., 2016). The locations of these niches may move, or even disappear. Moving is an ineffective strategy due to varying vulnerabilities to change in potential new regions (Gbejewoh, 2021). Wine is also particularly ill equipped to adapt to this as it has very limited cultivar options. There are over 3000 grape cultivars, but 12 of those make up nearly 90% of total planting areas (Bai et al., 2022). Otherwise simply finding the correct cultivar to fit each microclimatic niche would be an easy and effective solution.
ABOUT THE AUTHOR
Timothy Boyce, originally from Silver Spring, Maryland, graduated from St. Lawrence University in 2025 with a Bachelors Degree in Environmental Studies. He competed in cross country and track and field for the university, and continues to pursue athletic goals post-collegiately. He worked on his parents vineyard in Mount Airy, MD throughout his childhood. He is very interested in computer science and in social justice movements in his free time.
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