But Touzard went on to argue that Hannah's paper ignores the human element. "Growers and winemakers have lots of options. For instance: Within the same terroir [wine-growing region], there are highly diverse microclimates. In some places, there is more sunlight; in others, more shade. It is possible to mobilize the diversity," he said, suggesting that the growers have options to replant their vineyards nearby.
The temperature gradients in a hilly area, he said, offer one possibility. "Within 500 meters, you have a climate difference greater than that predicted by global warming."
The situation has not been helped by the French media, which, according to Touzard, misconstrued the PNAS paper's conclusions. One French television news program reported that a U.S. scientist predicted that by 2050, 70 percent of all European vineyards would be wiped out.
The more things change, the more Bordeaux wines improve?
Denis Dubourdieu, director of the Institute of Vineyard and Wine Science, professor of oenology at the University of Bordeaux, and himself a winemaker from a long line of Bordeaux-region vignerons, consults with vintners worldwide on the art of making classic wines. In Bordeaux, he said, a warming climate is making conditions better.
"Winemakers are using a lot less sugar now than they were even 10 years ago. Not one is complaining." In fact, he said, during his lifetime, especially in the past 20 years, vintages have done nothing but improve. "Vintages when I was a young man, like 1972 and 1973, were awful."
Since then, he added, there have been annual ups and downs, but since 2001, he said, "they've all been good. In 2003, when we had the highest temperature on record in France, the vintage was very good. Since 2005, they've all been exceptional."
Dubourdieu is quick to add that climate change is not trivial. "It's something we need to fight against, to be sure," he said, but he finds the tendency to make it seem like a catastrophe across the board troublesome.
Classic wines, he believes, don't lend themselves easily to moving. Merlot is a good example. "Merlot does fine in Bordeaux today, but in a warmer climate, it would not. It's not a Mediterranean variety." The grapevine, he points out, "started out in Mesopotamia. It has a genetic predisposition to warmer climates." Later varieties were adapted after much experimentation to local conditions, such as Bordeaux, which averages 31.5 inches of rain per year.
Classic vintages from China and Yellowstone?
In China, where wine growing is just getting a foothold, the scenario is entirely different. The areas most suited to viticulture include mountain forests that are home to the giant panda. Recently, the Chinese government yielded more control to local authorities in areas where interested investors have hosted European vintners and are keen to produce wine grapes.
Wildlife conservation organizations are attempting to counteract the impact on wildlife by paying local authorities "ecocompensation" fees. "They're paid to leave the habitat alone," explained Hannah, the author of the PNAS study. "The pandas can stay in the forest, and they can still profit."
In the western United States, there is growing pressure to convert land above Yellowstone National Park to vineyards. Supporters assert that the two activities -- vineyards and wildlife -- can coexist. They envision creating a complete tourist experience, a tourism-wildlife-and-wine package, similar to those in parts of South Africa.
But vineyards are "barriers to wildlife movement," Hannah countered. "Black bears and grizzlies need to move through their habitat in order to forage."