The short answer to the question is “maybe”. The environments where wine grapes are grown are undergoing significant change as a result of anthropogenic global warming. Grape varieties suited to the new environments may be available to replace those now grown in a region, but not always. Continue reading for more.
Climates Good for Wine Grapes
Before we can know whether future climates will be amenable to growing wine grapes, we need to know where wine grapes flourish under climate regimes present during the beginning of the 21st century. Today, no matter what wine, you’ll find that the grape growing regions all lie between 30o and 50o latitude, in both the Northern and Southern Hemispheres. While there are many different grape varieties grown within these latitudes, the mean temperature during the growing season are critical: it generally cannot be less than 11oC (52oF) or more than 22oC (72oF). The graphic below shows wine producing regions of the world, with the optimal latitudes and temperatures (slightly different from the text here) annotated.
Within those temperature ranges, though, there are many types of climates, all of which bring their own risks of a suboptimal crop. In a broad sense, these climates fall into three categories:
- Mediterranean: cool, wet winters; warm to hot, dry summers; vines usually require irrigation to complete ripening process
- Biggest risks to crop: Drought
- Continental: cold winters; short warm to hot summers; summer precipitation typically sufficient to ripen grapes
- Biggest risks to crop:
- Risk of frost in spring
- Cooler than average or short growing season
- Biggest risks to crop:
- Maritime: cool winters, mild summers; precipitation tends to be evenly distributed throughout the year
- Biggest risks to crop: diseases from dampness during growing season
Winters must be cool enough for dormancy sufficient for the healthy growth of vines and development and ripening of good quality grapes. On average, grapevines require about 1390 to +2220 growing degree days (the sum of mean daily temperatures above 10°C (50°F)) in order to ripe properly, depending on the growing region and vine variety. Grapevines also need water in order to thrive. In some areas and climates, there is more than enough rain for the vines to survive (e.g. Burgundy in France), while in other regions, vines needs to be irrigated (e.g. California, Spain, Italy).
Here’s a partial list of the types of grapes and their optimal mean temperatures:
The flavor and alcohol content depend not only on the type of grape but how the growing season evolves. Generally, all else being equal, warmer/drier weather means more sugar for fermentation, fuller body, and higher alcohol content after fermentation. Cooler/wetter weather results in less sugar for fermentation, more tartness. and a generally lighter body.
Short-Term Global Warming Impacts
As we’d expect, global warming has started to change the climate in important grape growing regions, and some impacts are already being noticed. One change we’ve already begun to see, for example, is more and more extreme variability from season to season. This in turn results in more variability in the characteristics of any wine produced, in a manner explained above. In extremely anomalous years, grape quality will be too poor to be used for wine making at all. There are ways to mitigate some aspects of global warming induced year-to-year variability, such as leaving more vine foliage to shade the grapes or when frost threatens, using active (wind machines, sprinkler systems) and passive (delayed or double-pruning of buds) mitigation.
An indirect effect of increased extremes is the smoke produced by drought-enhanced wildfires. Soot lands on the grapes and the chemicals combine with those found naturally in the grape. The grapes are especially good at absorbing these chemicals and binding them to sugars found in them, starting a week after ripening starts. As the fermentation process converts sugar to alcohol, the chemicals from the smoke are freed to result in, as one expert described, “unpleasant aromas often described as disinfectant or burnt rubber and a taste like ‘licking an ashtray’”. Research is ongoing on how to deal with smoke-tainted grapes.
Less water available for irrigation also affects grape quality. We’re already seeing some of this in California, where earlier snowmelt from the Sierra Nevada and drier winters are resulting in water shortages. Vineyards will likely have less priority than vegetables, livestock or human beings. In Europe, there have always been restrictions on irrigation, so drought is harder to mitigate.
An indirect effect of increased extremes is the smoke produced by drought-enhanced wildfires. Soot lands on the grapes and the chemicals combine with those found naturally in the grape. The grapes are especially good at absorbing these chemicals and binding them to sugars found in them, starting a week after ripening starts. As the fermentation process converts sugar to alcohol, the chemicals from the smoke are freed to result in, as one expert described, “unpleasant aromas often described as disinfectant or burnt rubber and a taste like ‘licking an ashtray’”. Almost all grape-growing regions were impacted by wildfire smoke during the summer of 2021. Research is ongoing on how to salvage smoke-tainted grapes.
Long-Range Global Warming Impacts
The map below is a copy of where wine currently is produced over the globe. Areas with a Mediterranean climate dominate the map, with some additional areas in North America, South America, and Europe.
The next map shows current versus estimated areas favoring grape vineyards by 2050. Most of the lost area (red) is found in Europe, California, South Africa, South America, and Australia, where the current Mediterranean climate is expected to become hotter and drier over the next three decades.
Warming will open up some new areas (blue) over northern Europe into Russia, including southern England, and some areas of North America around the Great Lakes and the Pacific Northwest that currently have growing seasons too short for vine cultivation.
Mitigation Has Risks
According to the Huffington Post:
In recent years, wineries worldwide began hedging their bets against global warming and its fallout by moving to cooler zones, planting varieties that do better in heat and drought, and shading their grapes with more leaf canopy.
That seems logical, though the expected greater extremes would potentially have an ever greater impact on grape varieties being grown in a previously cooler place. It seems likely that such areas would have a higher risk for unseasonable rains (and mildew related diseases), growing seasons too short for ripening, and late frosts killing flower buds. In fact, in France and Germany, July 2021 might have been a preview. These areas were a disaster for growing wine grapes, with a late frost, hail, and “relentless rain”, and losses on the order of 2 billion Euros.
Adaptation to Global Warming in a Couple of Grape-Growing Areas
Oregon
The most popular Oregon grape, Pinot Noir, had accounted for 60% of wine production and 70% of wine sales in 2012. However, it may not survive global warming, as it is highly sensitive to small changes in temperature and precipitation. It’s expected by many vintners that Pinot Noir will be supplanted by grapes suited to warmer conditions and longer growing seasons, such as Syrah, Merlot, or Cabernet Sauvignon.
Bordeaux
Did you know that France has its own wine appellation body that controls where what grape varieties can be grown? They do …. and in Bordeaux, two organizations proposed the addition of six new grape varieties to their list in 2019, to slow the effects of climate change on wine growing. France’s appellation body, The National Institute of Origin and Quality (INAO), made it official this year, and announced by Professional Wine Council of (CIVB) in January. The six new grapes (four red and two white) will be limited in growing area initially to see how well they adapt to the area and limited in usage in wine blends.
australia
The Aussie taste for wine tends to cool-climate French varieties that don’t tolerate heat and drought. This has resulted in a stubborn refusal of vintners to grow grapes more suited to the hotter, drier conditions that are now extant in the southern parts of the country (e.g. Italian and Spanish wines). The problem is in convincing the Australian palate that wines from grapes they’ve never heard of can be just as enjoyable to drink. But changing over to new, unheard of grapes takes time and money.
It comes down to a race of changing tastes against changing climate. As one viticulturist, Kim Chalmers pointed out, "We have two choices. All move to Tassie (Tasmania) or try to adapt to a hotter, drier climate."
Concluding Remarks
Wine aficionados may or may not have something to worry about when it comes strictly to wine. At this point, it seems that the warmer, drier wine growing regions will become unable to consistently support even those varieties adapted to such climates. Expansion of wine growing to the north will be limited by greater seasonal climate extremes subjecting grapes to damage. However, at least through 2050, it’s likely that most if not all currently available wine grapes will be able to be cultivated, with at least some consistency.
In writing this, I’ve noticed that the subject area seems to be a bit, shall we say, trivial. While wine drinkers may not have to concern themselves with the availability of wine, there will be plenty else to worry about. But if wine will get some previously unconcerned people turned on to global warming mitigation and reversal, that’s a good thing!
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