When Tom Gamble’s grandfather arrived in Napa Valley, California, in 1916, wine grapes did not seem like the best crop for a new farmer—lawmakers were discussing Prohibition at the time. So Gamble’s grandfather planted olives, tomatoes, pears, walnuts, and hay crops, and he raised livestock. It wasn’t until the 1980s that the Gamble family got into the region’s most well-known crop, and now Gamble is the owner of the 175-acre Gamble Family Vineyard, a sizable operation amid some of the valley’s most prestigious terroir.
As a third-generation farmer, Gamble knows that adjusting to the weather has always been part of agriculture. When he was a kid, the Napa River was dry, and he often rode his dirt bike in the riverbed. “We would never do that today,” he said—the Napa Valley has made a concerted effort to restore the aquifers and protect the watershed through legislation and sustainability initiatives.
But the weather has gotten worse. Because of the human-caused climate crisis, Gamble and other winemakers are battling extreme heat, unseasonable cold, torrential rain, and drought, not to mention wildfires. Sustainability initiatives are no longer sufficient: according to a 2020 paper published in the Proceedings of the National Academy of Sciences, long-established vineyards in Napa and other wine regions around the world will need to migrate or adapt to the changing climate in order to survive. In a scenario where the earth warms by 2 degrees Celsius (3.6 degrees Fahrenheit)—a scenario that is looking likely—the findings estimate that 56 percent of worldwide wine grapes would be wiped out. Losses may be unavoidable in countries that are already hot, such as Italy, Spain, and Australia. Meanwhile, historically cooler wine-growing regions, like Germany, New Zealand, and the Pacific Northwest, could become suitable for warmer varieties like mourvèdre and grenache, while pinot noir, a delicate, thin-skinned grape that grows best in a cool climate, could expand northward into new viticulture regions. Oenophiles who’ve come to love certain varietals and vintages are going to have to buckle up for change and uncertainty.
Napa Valley first achieved worldwide fame in 1976 at a prestigious French wine competition called the Judgement of Paris. Two wines from the region, a Chateau Montelena chardonnay and a Stag’s Leap Wine Cellars cabernet sauvignon, won the event’s top honors. This surprise win skyrocketed the wine industry in Napa.
Today there are more than 44,000 acres of vineyards in the Napa Valley, and over 50 percent of that acreage is dedicated to cabernet sauvignon, a small grape with thick skin that has a naturally low yield but makes complex, full-bodied wines with supple tannins and aromas of black fruit and leather. While it is grown in a variety of climates, the premium cabernets are from regions like Napa Valley and Bordeaux, France, where the fruit stays on the vine longer, allowing the grape and tannins to fully develop.
According to the 2018 Napa Vintage Report, between 1895 and 2018, California warmed an average of 2.3 degrees Fahrenheit during the wine-growing season. Last year the state endured its hottest summer on record. Rising temperatures are forcing grapes to ripen too quickly on the vine, lowering their acidity and increasing their sugar, which makes for wines that taste flat and are less dynamic in the glass. A grape that ripens later also stays on the vine longer, which means it’s at a higher risk of wildfire-induced smoke taint that can penetrate the grape’s skin and give the wine a smell and flavor of an ashtray or a campfire.
In the face of these challenges, many winegrowers in Napa Valley are slowly starting to make changes and experiment in the vineyard. This year, Gamble will begin replanting vines lower to the ground on weather-resistant native rootstock and adjusting the vines’ row orientation to protect grapes from the hot midday sun. He is also experimenting with varieties like syrah and zinfandel, which are more suitable to a warmer climate, rather than the popular Napa cab.
Situated at the northern end of the valley, Larkmead Vineyards is a historic wine estate established in 1895. While the winery makes cabernet and Bordeaux-style blends, it established its reputation with merlot—a varietal known for its lush and velvety texture, with notes of red fruits and dark chocolate. But it’s getting harder to grow. With warming temperatures, the heat-sensitive, thin-skinned grape overripens and the acidity drops, resulting in a wine that tastes flabby and lacks depth and complexity.
Last year in its three-acre research block, Larkmead planted one white variety (chenin blanc) and eight reds, including tempranillo, touriga nacional, and syrah—varieties that have historically done well in other hot viticulture areas like Italy, Spain, and Australia. They are typically more fruit forward and juicy, but Larkmead is mostly hoping to find out which grapes might blend well with cabernet. “Cab is not going away,” says Avery Heelan, the head winemaker at Larkmead. “But it is getting hotter and hotter here every day, and we need to adapt.”
It takes five years for a vineyard to hit a fully mature yield, so Heelan, Gamble, and others won’t see results any time soon. And replanting simply for temperature will not solve everything. “Later ripening does not mean it is heat tolerant or uses water well,” says Beth Forrestel, an assistant professor and a plant biologist in the department of viticulture and enology at the University of California at Davis. “And it doesn’t mean it makes good wine.”
Forrestel is working on updating the Winkler Index, a study that growers use to match suitable wine-grape varieties with different regions in California. The new study is analyzing 24 varieties—including Spanish, Portuguese, southern Italian, and Greek wines—for their response to heat extremes and drought, and assessing their tannins and aromas, elements which are critical to wine quality. It’s a long-term project, but Forrestel says she already has favorite varieties, although she won’t share which just yet. (She says she’ll have some useful data to share in the next year or two.)
But it’s not just vineyards that need to make changes. For all the challenges in growing wine grapes, consumers also need to adjust. And Tom Gamble thinks younger generations will be more willing to try new wines. Each generation has a better palate than the last, he says: “They are so experimental.” According to the 2020 State of the Wine Industry report, consumers are now interested in a wide variety of alcoholic beverages, including spirits, craft beer, foreign wine, and spiked seltzers, instead of the premium domestic wine that previous generations gravitated toward.
In a few years, you might be tasting a touriga nacional or tempranillo from Napa Valley, a mourvèdre from Washington State, or a pinot noir from Canada. The wine might be something you have never heard of—but the world hadn’t heard of Napa cab, either, in the 1970s, when the first wines from that region were showed at the Judgement of Paris.
“We have pushed the limits, and we are swinging back to nuance,” Gamble said. “Now we are thinking about how we can make wine that is not only more indicative of the terroir in Napa writ large, but all of the microclimates. These aren’t going to be your parents’ wines.”