I was waiting in line to speak to a wine shop owner in San Francisco when I struck up a conversation with a winemaker visiting from Italy. She and I started talking about the Cascadia fault in Oregon and the potential of much of the vineyard land sliding into the Pacific Ocean when the ‘big one’ hits.
The notion of planting a vineyard in such a potentially ill-fated locale is a foreign one to most vintners in Europe, where long-established, multigenerational vineyard-holdings are the norm. She couldn’t believe that anyone would take such a risk given that it takes years if not decades to establish and ‘unlock’ the potential of any given vineyard. Her point is a good one, but I couldn’t help but mention Mount Vesuvius as an example of past and perhaps future inconvenience in her own country.
Catastrophic events aside, there is perhaps a bigger looming threat to vineyards around the world in the form of man-made climate change. While rising temperatures may not devastate vineyards immediately, the prospect of altering the accepted styles of wines made in traditional regions is a very real one.
Our changing climate has become a political football—an issue we argue over because we don’t seem to want to face the economic implications of overhauling our infrastructure, corporate responsibilities, or sacrifices to the lifestyles we’ve become accustomed to. Despite the fact that winemakers’ political leanings run the same gamut as the general public, in almost two decades I’ve found almost zero opposition in the wine industry to the notion that our planet is steadily warming.
For those of us that work the land, it is an undeniable reality. Major wine research institutes throughout the world have tracked average harvest dates, must weights (the amount of sugar in the grapes), pH, and acidity of harvested grapes over the last decades. They’ve come to the conclusion that grapes are ripening earlier. Some of this certainly has to do with improvement in vineyard management techniques, but the weather and climatic data alone is enough to show obvious warming trends.
It is generally accepted that even a one- or two-degree shift in seasonal temperature norms is enough to dramatically change the character of a wine grown in any given vineyard, and even the suitability of a particular grape variety to a particular region. For example, growers are anticipating that it may become too hot to grow merlot in Bordeaux in the coming century. Warming is especially problematic in some European regions, where planting traditional or even indigenous grape varieties is required by law.
When grapes ripen faster, they build up more sugars, which yield higher alcohol wines. The problem is that consumer taste has been shifting towards a lower-alcohol wine over the past decade or so (so-called session wines). Many of us winegrowers now look to harvest grapes that are physiologically ripe, but with lower sugar accumulation—high-flavor, low-alcohol—which is why merely picking early is not always enough. What is the winegrower to do?
Fortunately, there are many techniques available to combat climate change at almost every stage of planning. Some of these things can be changed year to year, while other more permanent strategies require much more foresight.
For many grape varieties, there are dozens of clones that ripen at different times throughout autumn, sometimes weeks apart, and bring varying flavor profiles to the eventual wine. There are also myriad vine rootstocks, which can either help delay or advance ripening. Making the correct clone/rootstock decision at planting can have a major impact on the suitability of a grape to a particular site.
The difficulty is that vineyards need to be productive for long periods of time and forty years or more is not an uncommon lifespan. Even if a vineyard is planted with the long term goal of weathering climate change, the odd colder-than-average vintage here and there could result in grapes that fail to reach the minimum ripeness required to make anything but a thin, acidic wine.
A vineyard’s density can also be tinkered with at the planting stage, adjusting plant and row spacing to help control the vigor of the vines. The more plants in a vineyard, the more competition for nutrients and water in the soil, thus influencing a grape’s development. There are hundreds of cover crops—grasses, flowers, herbs and legumes—that can compete for resources, add plant-suitable forms of nitrogen and organic matter to the soil, and bring structure to the soil at different root-depths. Decisions about what cover crop to plant and when to till it will have a huge effect on ripening and nutrient uptake.
One of the easiest ways winemakers battle climate change is with yield. Allowing more grapes to hang on the vine will delay the ripening of the fruit, although it is imperative that the vines have enough water and nutrients to account for the heavier crop. Yield can be controlled by measures taken at many different stages throughout the year (at pruning, bud break, shoot thinning, and employing selective harvest passes), making yield adjustments one of the most useful tools for a winemaker to craft a desired style of wine each and every year based on the weather of the vintage.
Plant management effects yield, too. Different trellising systems can increase or decrease the number and length of fruiting canes and with that, the number of buds and finally new shoots that will bear fruit. One can also manipulate the potential photosynthesis in a vineyard by controlling the canopy. Lowering the height—and with that the surface area of leaves—of the canopy or pulling leaves at the right time will deplete the vine of the organs that produce sugar in the grapes and can help to keep alcohol down.
Climate change is also changing the location of new vineyards. Vintners throughout the world are now searching for land at higher elevations and also in side valleys or even north-facing slopes in an attempt to slow down ripening. In fact, in Germany there is a movement to reclaim and replant some of the vineyard land that was previously deemed too cold to produce premium wines. There is also some talk of allowing grapes to be grown in more northern regions of the country where wine production was unheard of even 10 or 20 years ago. This issue is complicated by the fact that the EU is actively trying to restrict new planting in an attempt to protect its market by keeping demand for the wines high.
Where I was trained, in the Pfalz region of Germany, the number of grape varieties allowed for production is on the rise. In the ‘60s and ‘70s, many new vine-crossings were developed and planted in an attempt to increase must weights and alcohol in the finished wine. Now these earlier-ripening grapes are being abandoned and we are seeing grape varieties planted for production that were once thought of as impossible to grow. There is now merlot, nebbiolo, syrah, grenache, and even cabernet sauvignon planted alongside the traditional riesling, silvaner, and spätburgunder (pinot noir) with excellent results.
In Oregon, we are seeing an influx of California producers coming north to escape the drought and high temperatures of parts of their state in an attempt to make lighter, more elegant wines. It’s heartbreaking to think that Napa Valley, the region that put American wine on the map, could become unsuitable for grape growing in the future.
Though we can experiment with new grapes and new regions, battling climate change will still require foresight and adaptive management of our plants and land. What remains unclear is how traditional regions like Burgundy will fare. They have made their name by mainly producing just two grape varieties, pinot noir and chardonnay, on vineyards that have been proven over centuries of winemaking to produce the world’s finest wine.
That Burgundy, the traditional mecca of these grapes may someday be more suited to the later-ripening syrah is pretty difficult to swallow—especially given how large a role the romantic histories of these villages plays in our enjoyment of the wines. When dealing with something so emotionally-charged as wine, it is sad to think that the window may be closing on the beautiful marriage of terroir and culture that is pinot noir and its spiritual homeland. Somehow “Vosne-Romanee la Tache Syrah” doesn’t have the same ring to it.