It sounds like a vintner's nightmare: Sharp shifts in temperature help trigger potent off-season rains that bloat grapes with unwanted moisture. Then an overpowering heat wave withers vines and shrivels grapes. Desperate winemakers advance the harvest by as much as a month to save what they can. This is no vineyard horror film; it's a description of some of the 2003 Cabernet Sauvignon and merlot harvests in parts of southern and western France.
And boy, was it good. In a decade that keeps breaking records for heat, we're already sipping climate-changed wines. Hot years like 2000 and 2006 produced some stellar, rich, full-bodied and mature Bordeaux, but the 2003 heat-wave harvest was the best in memory—at least until the hot harvest of 2005. Global-warming cru is more flavorful, fruitier, less acidic and higher in alcohol content than the average-temperature stuff, a near-perfect fit for today's wine drinkers. And these hot wines tend to come mature, so even a big Bordeaux no longer needs to ripen in the cellar for a decade.
For the wine industry, the biggest advantage of global warming is that it's expanding the world's prime grape-growing areas. Hotter, dryer weather means that even volatile wine regions like Burgundy—with great soil but often terrible weather—are flourishing more consistently. Growers in the Mosel Valley, who in the 1980s had to add sugar and water to their wine to counter its acidity, now produce low-acid wines with plenty of alcohol. Respectable pinot noirs, long a staple in California, are regularly harvested in Oregon and even Washington state now.
And if forecasts are correct, the coming decades could bring even greater gains. Scientists estimate that every increase in temperature of one degree Celsius drives wine regions north by 180 to 200 kilometers. The Champagne region is France's traditional good-wine limit in the north, while northern Germany long grew grapes that only a local could love. Now even northern Rieslings are winning fans, winemakers are harvesting in parts of the U.K. and some see potential in developing Belgian vineyards. "If the climate crosses a certain threshold," says winemaking consultant Michel Rolland, "we could see the inconceivable become foreseeable."
Visionaries anticipate Alsatian and German winemakers shifting away from cold-weather Rieslings, pinot gris and pinot noirs toward Mediterranean whites and sunnier merlots. By the latter half of the century, areas in southern Britain may have weather similar to France's Champagne region today. A glass of Sparkling Kent may sound absurd today, but who's to say it will in 50 years?
To thrive in the long run, winemakers will have to be nimble, innovative and, above all, flexible. Portugal and Spain could see temperatures increase by as much as five degrees, potentially driving high-quality wine from the Iberian Peninsula altogether. A recent Italian analysis suggested that rising heat could ruin fine Tuscan wines. And by the year 2100, Normandy and Brittany may enjoy weather found in southern France today. But, says Rolland, "nature never changes from one day to the next, so this usually allows us to adapt."
No wonder so many traditional winemakers are feeling so upbeat. "For us in the north, it is 90 percent great and 10 percent problematic," says wine-industry marketing consultant David Skalli of Skalli & Rein in Paris. "For wine, it will be a party." A very hot one.