The wines they are a-changin’

Today we discuss the nebulous, somewhat arcane subject of global warming. We’ve seen the graphs, we’ve heard about the ice caps and we know how Al Gore feels. Even if it is happening, will it really affect us anyway? After all, we still bundle up in winter and wear shorts in summer, just like the old days.

But what if an expert said you could actually taste the effects of climate change in your next glass of wine?

That possibility, say many climatologists and winemakers, shows the reality of this phenomenon. In some cases it tastes good, and in other cases it does not. Parts of Oregon and Washington, for example, once too cold for grapes to thrive, now produce world-renowned wines, due to a measurable temperature increase since the 1950s largely attributed to global climate change caused by carbon emissions. And according to U.S. Historical Climatology Network records, temperatures in Napa Valley’s vineyards climbed several degrees Fahrenheit in the last five decades, allowing for the propagation of some new varietals. However, by the same token, some winemakers and scientists worry that, should global temperatures continue to increase, cool-weather grapes will eventually be smothered by the heat, perhaps even forcing some winemakers out of work.

Foppiano Vineyards, located in Healdsburg in the Russian River Valley, was founded in 1896 and produces a line of bold red wines, including the cool-tempered pinot noir. Fifth-generation vineyard manager Paul Foppiano remains undaunted that a changing climate will affect his family’s business anytime soon, but he has noticed that springtime frost seems to have vanished in the past 30 years. While frost is not crucial to the health of highly-sensitive wine grapes, its disappearance does suggest a steady long-term warming trend.

“In 1970, we had 21 straight days of frost, but that sort of cold weather has subsided,” Foppiano said.

Dr. Greg Jones, professor of environmental studies and geography at Southern Oregon University and a globally recognized authority on climate change, agreed that Foppiano’s concerns about a long-term temperature increase are warranted. Jones’ records show that since the 1930s, the average temperature in Napa Valley has increased by 2.9 degrees Fahrenheit and minimum temperatures by 5.2 degrees Fahrenheit. And the frost-free period in the height of the growing season—generally April through October—now lasts about 90 days longer every year, clear evidence of temperature trending upward.

“What this means is that we are not living in the same climate that we were living in 50 years ago,” Jones said.

Average temperatures throughout California could rise by a staggering 4.7 to 10.5 degrees Fahrenheit in the next century, according to Louise Jackson, professor of environmental plant sciences at UC Davis.

Many researchers agree that climate change will greatly affect California’s agriculture. Higher temperatures could push commodities like kale and other winter greens off the market in coastal regions or harm lettuce by promoting the spread of tipburn disorder, which damages leaf quality. Stone fruits, which require winter frost to produce robust crops, may suffer. Early melting of summer snowpack at high elevations will raise logistical issues of how to maintain water supplies for the state’s farmers.

And farmers will be forced to adapt or go broke, said Richard Howitt, professor of agricultural and resource economics at UC Davis.

In Oregon’s Willamette Valley, winemakers are already innovating, according to Harry Peterson-Nedry of Chehalem Wines near Newburg, Ore. The Willamette Valley is famed for its pinot noir, often described as elegant, supple, graceful, light and crisp, but rising temperatures in the past decade have offset the balance of these esteemed pinots. The 2003 and 2006 vintages were particularly affected by hot weather, Peterson-Nedry said. The wines were ripe, fleshy and high in alcohol—all bad for pinot. Willamette’s winemakers have responded en masse by changing their growing techniques. People who used to grow grapes at 600 feet are now planting at 1,000 feet, he said, adding that every year since 1997 has been measurably balmier than the long-term average, but never cooler.

“The chances of that happening purely by chance to 11 vintages in a row are about 0.1 percent,” he said. “It means something’s up.”

Some of the world’s cooler wine regions could prove particularly susceptible to global warming, said Adam Richardson, winemaker with international distributor Underdog Wine Merchants.

“Bordeaux, Burgundy, coastal California and Tasmania have a large buffer of security because they’re cooler already, but they also have a more finely attuned balance between their really good vintages and their average vintages,” Richardson said. “A little adjustment in these areas, and the wines could become less characteristic more often.”

Professor Jones pointed to a telling change in winemaking practices in the Burgundy region of France. Winemakers in cooler areas regularly add unfermented grape juice to wine vats to boost the body, fruitiness and alcohol content of the finished product. In warmer years, when grapes ripen fully of their own accord, juice additions are not required. Winemakers essentially ceased this practice around 1990.

But Bill Regan, winemaker at Foppiano Vineyard’s, said that higher alcohol levels represent a winemaker’s response to consumer demand for bigger wines rather than a response to global warming. Allowing more hang time before harvest leads to more sugar and, subsequently, more alcohol.

Other winemakers, such as Stu Smith of Smith-Madrone Winery in Napa County, don’t sweat climate change. Smith has tended grapes and made wine for 37 years and said his vines are as happy as ever. While he, too, has felt the warmer springs reported by other winemakers, he’s not yet convinced that the overall climate is warming. In fact, he said, even though there’s been no springtime frost in Napa Valley to speak of since 1974, the 1980s was one of the warmest decades he can recall; the 1990s were on the cool side and the summer of 2007 among the chilliest he’s experienced.

“Looking at my records, I’d say we’re cooling down,” he said.

But the discussion will almost certainly heat up, and even if a Sonoma pinot noir never loses that crisp cherry-limestone body, there could eventually come a time when carbon emissions, shrinking ice caps and traffic-jammed SUVs linger on the finish.