The Romans made wine throughout England, almost up to the Scottish borders. With a deterioration in climate vine growing subsequently dwindled, even on southern English soils that were almost identical to those of Champagne. During the twentieth century only a few hardy eccentrics dared make wine in such marginal conditions, but with renewed climatic warming, this is changing. We chose one from the increasing range of English sparkling wines now available. Made with the classic Champagne grape varieties, it was a revelation: fresh, vibrant, with a fine mousse and a hint of warm bread in the finish. We wished we could have afforded to buy a few more.
We started this book by peering into the ancient past; as we near its end, our focus shifts to the future. Looking back, we can see that the climatic history of the world has been notoriously unstable. At one time, the entire planet Earth was a frozen snowball; at another, dinosaurs lived in Antarctica. Asteroid impacts, variations in the planet’s orbit around the sun, large-scale volcanism, and changes in the composition of the atmosphere are only a few of the influences that have interacted to produce enormous fluctuations in climates and environments around the globe. Going forward, conditions are unlikely to remain static for the wine industry, whatever the specific reasons for change at any particular time. We have glanced at the impact of modern technology on the quality of the wines we drink; now, as significant climate change in the near term looms as an increasingly alarming possibility, it is natural to ask how technology might help mitigate its effects on the vineyards and their products. One obvious candidate is genetic engineering.
Any human intervention that involves genetics—whether altering genes, directing particular kinds of interbreeding, or moving genes from one genome to another—is considered genetic engineering. By this broad criterion, humans have genetically engineered grapes for millennia, an activity that has played a large part in creating the broad spectrum of wines available. But traditional methods of genetic engineering are both imprecise and time-consuming. They can also be frustrating, especially when the desired product does not result from a cross. Modern gene engineering techniques, however, can alleviate both the wait and the frustration. As we saw, a genetic studbook for all the vines used in the production of wine has been constructed, using the genome sequences of thousands of rootstocks and grape varieties. Not only is this studbook important for tracking and identifying the different varieties of grapes involved in winemaking; it can also potentially be used to identify which crosses will yield desired qualities.
The grapevine genome has over twenty thousand genes. Some of these are essential to the vine’s existence at the cellular level. Other genes are important to traits of the grape and vine, such as seed production and grape color, that make the wine tasty or in some way unique. To date, few of the genetic markers in the vine studbook have been connected to genes for specific functions. Rather, they have been identified simply because they vary among different grape varieties. But once a gene has been discovered that is involved in a specific wine characteristic, it is a simple task to determine which of the studbook markers is in close proximity—what geneticists call linked—to that gene. If, for instance, a genetic marker is shown to be linked to more efficient sugar production, or to a particularly attractive grape color, the vineyard manager can scan the studbook for varieties of grapes that have that trait coded in their genomes and make the appropriate crosses. The availability of the studbook allows the grape grower to become a more efficient matchmaker. As it is refined, its potential for modifying grape lineages will be enhanced. Thus, although grape growers two centuries from now will be doing the same basic job as their predecessors did thousands of years ago, they will have a much better grasp of how genetic crosses can enhance particular grape traits useful to wine production.
The molecular, or genomic, version of genetic engineering involves moving desired genes from one genome to another. Some of the more famous cases of agricultural molecular engineering include genetically modified corn that resists insect infestation and grows faster. This kind of intervention is controversial, but it is potentially valuable in two areas of plant and animal husbandry: the prevention of disease and the enhancement of traits that increase yield or quality. For grapevines, genetic engineering might be used to enhance traits relating to the palatability, purity, or alcohol content of the wine. Genetic engineering can also be used to ensure that vines and grapes are resistant to infections from insects like phylloxera, or bad fungi such as bunch rot. Indeed, as of 2005 there were already about thirty genetically engineered grape varieties in existence. The production of genomically modified grape varieties has slowed a bit in the past few years, but available varieties include forms engineered to enhance resistance to viral, bacterial, and fungal infections such as Agrobacterium, Botrytis, Clostridium, nepovirus (nematode-transmitted viruses), and beet yellow virus. In 2002, researchers at the University of Illinois in Champaign-Urbana, focusing on how grapes succumb terribly to the herbicide known as 2,4-D, transferred into a grape genome a gene from a soil bacterium (Ralstonia eutrophus) that degrades the chemical. Specifically, it was inserted into the Chancellor grape, yielding a grape strain known as “improved Chancellor.”
Researchers at Cornell University have field-tested Californian vines into which they incorporated genes from the soil fungus Trichoderma harzianum in the hope of producing vines resistant to botrytis and powdery mildew, while Australian scientists have inserted a gene that prevents fruit browning into grapevine genomes. Such browning usually occurs as a result of the accumulation of a protein called polyphenol oxidase (PPO), which makes simple changes to the phenolic molecules known as quinones that are found in fruits, and that clump to make the browning pigment. Molecular biologists have figured out a way to turn down the production of PPO in the Sultana grape by inserting foreign DNA into its genome. Although many such attempts at genetic engineering in plants seem to be working, it remains to be seen whether genetic modification will become generally accepted as a way to produce wine grapes. Uncertainty exists because attitudes toward genetically modified plants and animals (GMOs) seem to vary by continent. People in European Union countries are wary of GMO food products, while Australians and Americans are more receptive to them. (It is interesting to contrast this with the overwhelming acceptance in Europe of the notion of evolution, while more than 50 percent of Americans reject it.) But attitudes do change. A decade ago, Australians were dead set against GMOs; now over half of those surveyed accept them. Still, current attitudes help explain why the United States and Australia are leading the way in GMO grapevines.
In 1999, a time when the genetic engineering of humans was being broadly discussed, the Princeton geneticist Lee Silver proffered an intriguing possibility. In his Remaking Eden, Silver suggested that unchecked genetic engineering in humans would lead to two species of humans: the gene-rich and the gene-poor. He based his Brave New World view on the understanding that only the rich would be able to take advantage of the new technology, while poor people, especially in developing countries, would not—leading to a scary Wellsian future divided between Elois and Morlocks. Although the issue with grapes is based not on wealth or availability but on opinion as to appropriateness, it is still in theory possible to envision a future dichotomy in wine production between the gene-contaminated New World and the gene-pure Old World. The wine trade has become so thoroughly globalized, however, that it is hard in practice to imagine such changes along continental lines. Future developments will clearly depend on the resilience of cultural attitudes in the face of powerful commercial imperatives.
In our discussion of terroir, we saw how certain places seem to be, or to have been, regarded as particularly adapted for producing great wine. But we noted the importance of local climate in determining the perfect terroir; and the evidence indicates that climates are changing worldwide. The time scale on which the change is happening, its causes, and whether we are observing an oscillation or a long-term trend are contentious political issues. But climates are changing, and the vine-growing conditions at any one spot on the planet are changing right along with them.
We see evidence of this in unexpected places. The rocks that crop out in France’s Champagne region and England’s South Downs, on either side of the English Channel, are geologically almost identical, as are the soils formed from them. Topographically the two regions are not unalike either, and geographically the difference in latitude is not much more than one degree. Yet traditionally one area produces wines that are prized the world over, while in the other sheep graze peacefully on the grassy meadows as their shepherds swill beer in the local pub.
View across England’s South Downs, near the town of Lewes. The slopes in the middle ground, beyond the grazing sheep, may well one day be planted with vines. (Composite after a photograph by Will Harcourt-Smith)
Some twenty years ago, a French friend rather gleefully gave Ian a book titled Les Vins de l’impossible, which took the reader on a tour of the bizarre and unlikely places in which eccentric people somehow contrived to grow wine grapes. Among them, England took pride of place; and in 1990, when the book was published, very little wine was produced there—or even could be. Virtually everywhere, it was just too cloudy and rainy. Sunlight was inadequate, and the ripening period was too short. Even then, though, change was afoot. In the years between 1961 and 2006, the mean annual temperature in southern England increased by about 2° Celsius. That may not sound like much, but it is highly significant in terms of climate, being equivalent to a southern shift in latitude of over 300 kilometers. Largely as a result of this warming (although also facilitated by adjustments in the law), a boutique wine industry is now booming in southern England. The most successful sector of this industry produces sparkling wines. By some reckonings, the best of these sparklers are entirely comparable to their counterparts made across the Channel; occasionally an English wine will beat an illustrious marque of Champagne in a blind competition.
For now, though, the viticulturists of Champagne are not exactly unhappy. They inhabit the most northerly major winemaking region in France, at a marginal latitude for grape growing. Indeed, the tradition of making sparkling wine in Champagne probably developed because the still wines made there were a little too acidic for most palates. Since the warming trend set in conditions have improved for the Champenois, too, and the frequency of outstanding years marked for vintage (single-year) production has increased. Nonetheless, there are reasons for concern in the longer term. The two main grape varieties grown in Champagne are the Pinot Noir and the Chardonnay. These are both cool-country grapes, but they have different temperature tolerances. When the fruit is setting, Pinot Noir grows best in a narrow range of 14° to 16°C, while Chardonnay is more forgiving, doing well in temperatures up to around 18°. Currently, temperatures in Champagne remain well within the favorable range for both grapes, and immediate further warming might increase the amount of land appropriate for cultivating vines; but excessive temperature rise could at some point force a diminution of the amount of Pinot Noir grown and eventually a change in the style of the wine produced in this classic wine region.
One way in which wine producers can compensate for climatic warming is by growing their vines at higher, cooler elevations. But this is not a solution available everywhere, and especially not in the gently undulating Médoc, some four and a half degrees of latitude (nearly 500 kilometers) to the south of Champagne. By some reckonings the Bordelais region as a whole is already close to the temperature maxima for the grape varieties traditionally grown there, and one alarming estimate is that the next quarter-century or so may see temperatures increase by as much as a whopping 7°C inland and 5° along the coast. Even a much more modest increase would take traditional white grapes such as the Sémillon and Sauvignon Blanc well out of their comfort zones, and eventually compel the planting of other varieties. It would probably also affect the viability of the currently grown red varietals and, at the least, have a huge effect on the style of the wines produced. At higher temperatures, and with more intense sunshine, grapes ripen more quickly; they also produce greater quantities of sugars at the expense of acids and other compounds that contribute to the structure of the wine.
Experiments in Australia have revealed that, by varying their pruning practices, growers may be able to manipulate ripening times to limit imbalances in the composition of the fruit, or to ensure that the varietals grown in a particular locality do not create logistical problems by ripening all at once. But there is a limit to the effectiveness of such interventions, and changing climates will have a significant impact on the production of wines in traditional regions. This is of special concern in areas like Bordeaux, where reputations depend on producing wines of a particular style. Wine drinkers the world over expect their clarets to have a strong tannic structure and relatively restrained fruit flavors; nobody knows how the market would react if growers in the Bordelais started to produce lush, fruit-forward wines in the style of California’s hot Central Valley. The proprietors of highly reputed châteaux that cater to a clientele with specific expectations need to think about this, and many have begun to do so.
The situation in Bordeaux and elsewhere in France is complicated, however, not only by Mother Nature but also because of the country’s Appellation d’Origine Contrôlée laws. These rigorously specify which varietals may be grown where, and how they may be blended. A winemaker in the Bordelais who switched varietals to accommodate to a changing environment would automatically forfeit the right to a Bordeaux designation or to any of the even more highly prized sub-denominations such as Pauillac or Saint-Estèphe. When a wine is declassified, it sells at a lower price, a reality that acts as a disincentive to vignerons to respond to climate change by growing more appropriate varietals.
The United States has its own systems of designations for winemaking areas, but since the market is organized principally by the dominant varietal, winemakers have greater flexibility in the grapes they use. Nonetheless, climate change is affecting wine production in the New World as much as in the Old. In 2006, Michael White of Utah State University and colleagues modeled future climates across the North American continent and concluded that the surface area suitable for the production of premium wines in the mainland United States could potentially decline by as much as 81 percent by the end of the century. They suggested that wine production in traditional areas would increasingly shift toward warmer-climate and lower-quality varietals, and that in many regions viticulture would be eliminated altogether because of lengthening periods of excessive heat. They also predicted that, within this century, the production of fine wines in the United States would become restricted to certain limited areas of the West Coast and the Northeast, most of which are currently handicapped by excessive rainfall.
But high temperatures and possibly associated episodes of drought and wildfire are not all that winemakers worldwide have to cope with. Along with warming comes increasing climatic instability, and if there is anything a farmer hates—and vine-growers are above all farmers—it is unpredictability. Further, vines are fussy about the conditions in which they grow, and are susceptible to disease. If conditions are unfavorable during the flowering period early in the growing season, for example, poor setting of the fruit can lead to low yields. This is not invariably bad, because as the season progresses the vines may put more effort into less fruit and produce a concentrated product. But if low fruit set is followed by anything other than ideal conditions, the results can be dire. Similarly, if it is too hot and damp during the growing season, fungal diseases may take hold, while if there is too little warmth and light as the berries develop, they may not reach the point of ripeness at which sugar levels start to increase and unpleasant organic acids decrease. In contrast, if it is too hot and moist as the grapes grow, sugar ripeness may occur before the grapes achieve phenolic ripeness, which means that the tannins and phenols in the resulting wines will remain hard and rough.
Climatic warming also increases the probability of extreme weather events, whether expressed paradoxically as winter freezing, as springtime hail, or as summer droughts. After several favorable years, the growing season of 2012 was miserable in Europe, even as record-high temperatures plagued the United States. Very dry conditions in southern Europe and extreme cold in the north played havoc with wine production. In France, production dropped by 20 percent overall, and the quality of the wines that were made varied. In Champagne, despite a string of recent successes, productivity declined by 40 percent.
Climatic modeling is a notoriously tricky process, and not all predictions agree on what lies ahead. But some trends seem to be evident, even though many vine scientists remain convinced that they will find ways of compensating for change through technological innovation. Though the time scale is hazy, in the longer term California wineries will have to consider moving their vineyards to higher elevations (although in well-established areas the best upland sites are already taken), and shifting their plantings away from cooler-clime varieties such as Riesling, Pinot Noir, and Chardonnay to those that flourish in hotter conditions, such as Nebbiolo, Zinfandel, and Carignane.
Vigorous experimentation both with the vines themselves and with the methods used to grow them may prolong the dominance of established areas, and genetic engineering techniques could also help. But even so, some think that within a few decades the area of the Napa Valley suited to fine-wine production will have declined by as much as 50 percent. At the same time, some of the cooler parts of Oregon (notably the Willamette Valley) and Washington State (Walla Walla, east of the Cascades, where some fine Cabernet Sauvignons are already made, and even the unlikely area around Puget Sound near Seattle, where vines would barely grow a mere half-century ago) will have moved to the fore in West Coast wine production. Even the Okanagan Valley of Canada’s British Columbia may go from being a marginal to a prominent producer. In the eastern United States, the Finger Lakes, the lower Hudson Valley, and Long Island are all poised to move up in reputation as climates warm.
Worldwide, a similar shift from traditionally famous wine-producing areas to currently obscure regions is also predicted. Tasmania and parts of the South Island of New Zealand are expected to assume greater importance in Australasian fine wine production, while in Europe we have seen that southern England is projected to become more significant (if vineyards can compete with other forms of land use). In hot dry regions like Portugal and southern Spain, wine production has already begun the move to higher elevations. Altogether we are in a period of extraordinary flux, in which wine producers are going to have to be nimble if they wish to cope with potential major changes that will include an increased frequency of disasters such as wildfire and flooding.
Does this mean that we consumers will need to learn to enjoy wines of different styles, made from different grapes, from the ones we are used to? If present climatic trends continue, in the long term the answer is almost certainly a qualified yes. But nobody knows how far away the long term might be, and we cannot predict what human ingenuity might devise to mitigate the situation. A best guess might be that wine producers, who have an enormous incentive to stay where they are, will use every means at their disposal to provide a stable product for wine consumers, who tend to know what they like (or at least think they do). But adaptation to a changing climate will involve a lot of work. Gregory Jones, a climatologist at the University of Oregon who has estimated that in the Northern Hemisphere the broad geographical swaths of territory suitable for winemaking will move northward by between 275 and 550 kilometers over the next hundred years, has pointed the way ahead: “It will be those . . . that are the most aware, that experiment with both methods and technology—in plant breeding and genetics, in the field, and in processing—that will have the greatest latitude of adaptation.”
So just as the march of technology has begun to offer winemakers an infinity of possibilities, it seems that viticulturists will find themselves in much the same position as the Red Queen in Through the Looking Glass, whose subjects had to run as fast as they could to stay in the same place. And before long, it seems, many winegrowers will similarly find themselves obliged to change their vineyard and production procedures in order to keep their wines looking and tasting the same. Oenophiles, by and large a pretty conservative group in their vinous tastes and expectations, will be hoping they succeed.
