Death and taxes are commonly cited as the two constants we can rely upon in life, but there is a third: change. Living organisms are engineered to adapt to change. It’s in our genes. And when our genes adapt over long periods of time, we evolve. Grapevines, too, thrive in a diverse range of environments. And when adverse conditions develop, Mother Nature’s programming instructs them to adjust.
But what happens when the rate of change outstrips our ability to adapt? According to the Intergovernmental Panel on Climate Change (IPCC), the planet’s mean annual temperature will increase at least 2°F (manageable) to as much as 11.5°F (catastrophic) over the next century. Can the world’s vaunted vineyards, and the growers who tend them, keep pace?
Both Old World and New World wine regions are already struggling with this, though in very different ways. In the increasingly warm Burgundy and Mosel Valley (both governed by rigorous rules that have been codified over centuries), strict adherence to the grape varieties, production methods and styles that define their identities and command their prices may grow increasingly difficult. And while the New World has fewer rules, California’s widespread heat and drought could dramatically alter its vinous and economic landscape.
Burgundy: Ripening with Repercussions
On June 6, 2012, plumes of yellow and grey thunderheads gathered above the vineyards of Corton-Charlemagne. Working within the folds of his vines, Blair Pethel of Domaine Dublère peered up and recognized imminent danger. Ten minutes later, hail exploded from the sky as though Zeus, in an angry, mercurial mood, had decided to punish the wayward mortals below. Blair recounts that, in a panic, he “hightailed for the car…it was hailing hard enough to damage vehicles and the temperature plunged from 82° to 55°F.”
The tempest, followed by a swift two inches of rain, eroded soils and thrashed Burgundy’s legendary — and expensive — vineyards, especially those in Beaune, Pommard and Volnay. Two more storms would ravage the region that summer, and the trend would repeat itself in 2013 and 2014. Villages invested in hail-mitigating cannons to seed clouds with silver iodide, but to indeterminable effect. With crop loss ranging from 20 to 90 percent, depending on the domaine, prices rose higher in a market already challenged by supply-and-demand economics. Pethel, for one, has lost the equivalent of one and a half years’ production since 2010.
With climate change discourse focused on “extreme weather” and adjectives like “freak” ascribed to the speed and scope of the storms, drawing a connection between the two is tempting. Benjamin Bois, a senior lecturer in climate and viticulture at Université de Bourgogne thinks it’s too short a period to prove a causal relationship. “At this point, three years represents bad luck, not a trend,” he says.
Bois recognizes a link between planetary warming and changes in Burgundy’s vegetative cycle, though. Since the second half of the 20th century, the growing seasons are, on average, 1.4°C (2.5°F) warmer, and harvest starts around two weeks earlier. Built from this data, his formula shows that each degree increase in temperature pushes the harvest ahead by ten days.
Warmer weather during the winter has also had an insidious effect. Losing the benefit of disease-killing hard freezes increases fungal pressures and demands more frequent spraying in the vineyard. Cold-averse pests look to lease new homes amongst warmer Burgundian vines. (According to Bois, a leafhopper carrying the incurable vine-killing flavescence dorée disease, recently arrived, inciting panic.)
However, Bois says, as shortsighted as it may seem, many vignerons presently have positive feelings toward the warming effect. “With higher temperatures, grape ripening has been enhanced,” he says.
How long before the current ripening window tips beyond the optimal, fundamentally altering terroir, is unknown, but climate science warns it is inevitable. For Burgundy, culture and strict regulation under the appellation system—for example, a special dispensation is required to experiment with hail nets, which are disallowed under AOC rules—may prove the biggest initial impediment to adaptation. As Domaine Dublère’s Pethel puts it, “France is incredibly reactionary…we’re going to need the Atlantic lapping at the vineyards before any real changes can occur.”
Mosel: Riesling Paradigm Shift
The elemental qualities of Mosel riesling stem, of course, from its place of origin. Vertiginous slate slopes edge to the meandering river below, while warm summer days ebb into brisk nights, combining to create the unique growing environment of this famed region, first planted with the noble grape in the 16th century. The final manifestation of the wine delivers delicate, pure expressions of floral and mineral aromatics, balancing high-acidity with low-alcohol and, often, the cushion of residual sugar.
But if the grape’s growing conditions change to the effect of altering the wine’s stylistic framework, can it still be “Mosel riesling”?
In the latter 20th century, before climate change kicked into second gear, each decade delivered Mosel a handful of vintages marked by unreliable weather and uneven ripening. Since 2000, there has been only one. While it might seem like a positive development in the short term, the trend toward even, consistent growing seasons has produced riper fruit and a richer wine that, if pushed too far, will no longer resemble the region’s iconic style, typified by tension and ethereal lightness.
Prof. Dr. Hans R. Schultz, president of Geisenheim University, a horticulture and viticulture school in Rheingau, acknowledged growers profit from current conditions, but face a looming problem. “These light and elegant wines will be a challenge to preserve under the climatic changes we are undergoing,” he says. “We’ve already seen higher alcohols and a concerning drop in acidity.”
Similar to Burgundy, Mosel riesling’s ripening period has become warmer, but also wetter, inviting previously unseen pests, new diseases and increased frequency of rot from humid conditions. Do the positives outweigh the challenges, as some in Burgundy suggest?
According to Schultz, end-of-century forecasts by regional climate models leave Germany squarely within a temperature framework that “we can mitigate and adapt to,” he says. “Even if there is a 3°C change in 70 years, there will be a change in style, but not necessarily a loss of riesling vineyards. The margins are much tighter for regions already at the warmer end.” Regions like California.
California: Heating Up, Drying Out
Scraping at the arid earth, Sashi Moorman crumbles a handful of marine shale rock for an impromptu show-and-tell. Farmed organically, the unique soil composition and cooling ocean breezes of Santa Barbara, California, contribute to the ethereal, racy expressions of pinot noir grown in his Domaine de La Côte vineyards. But the vines, planted in the late aughts, require irrigation—albeit, as Moorman frames it, with “as light a touch as possible.”
America’s leading wine producing state has entered its fourth year of drought. Last November, the U.S. Geological Survey released a worrisome visualization tool depicting steadily declining reservoir levels. Whether or not climate change has triggered the current rainless conditions (Stanford scientists argue yes, the National Oceanic and Atmospheric Administration argues no), there’s little disagreement that it has exacerbated them. The state has suffered record-high temperatures contributing to evaporation and record-low snowpack, and, according to the IPCC, “It is very likely that hot extremes [and] heat waves…will continue to become more frequent. “
“What we have seen in the last couple of years is alarming,” Moorman says. “While the most immediate concern is the lack of rain to replenish reservoirs and aquifers, winter rains also remove salt from soils, which builds up with the use of irrigation due to the high mineral content of well water. High levels of salt…damage vineyards and affect the pH of the wines in an adverse way.”
Warmer weather also zaps grapes of their mouthwatering acidity (producing flabby wine), accelerates vegetative cycles (which negatively impacts quality and yields) and prompts vines to shut down photosynthesis (potentially altering or ruining flavors). Some of Moorman’s colleagues even believe the increasing levels of CO2 in the atmosphere are “contributing to a greater efficiency of photosynthesis in the grapevines, and therefore leading to higher levels of alcohol in the wine.” The comprehensive effect will make elegant, nuanced wines, like Moorman’s pinots, more difficult and expensive to produce—or even impossible—to produce.
Research published in the Environmental Research Letters by leading American climate and viticulture researchers Noah S. Diffenbaugh and Gregory Jones predicts prime wine growing land in California will shrink by 50 percent in 30 years.
When I asked Moorman what he thought could be done to mitigate some of the changes, he didn’t offer much hope. “We must learn to adapt…but adapting vineyards to warming and cooling trends takes many years.”
Warming predictions suggest that, in some instances, it may already be too late. Vineyards that succeed in adapting to new conditions may do so at the cost of what drew them acclaim in the first place. They may be able to survive, but wines they once produced may not.