In Northern France, Warming Presses Fall Grape Harvest Into Summertime

For centuries, the "vendange," or annual grape harvest, has been treated as a near-religious ritual, with parish churches maintaining meticulous records in dusty, crumbling ledgers.

In France, wine growers are subject to the world's most rigid cultivation restrictions: Vintners can grow only varieties authorized for their region, harvests are tightly regulated and, until this year, no irrigation was allowed. Year after year, the climate is the single greatest variable in France's wine production, making its vineyards the perfect climate-change laboratory for scientists.

Ren? Mur?'s family has been growing grapes and producing wine in the hills surrounding the picturesque village of Rouffach since 1648. The family tree, with its 12 generations of wine growers -- Ren?'s children, V?ronique, 31, and Thomas, 27, are the newest Mur? vintners -- is tacked to a wall in his cellars, which produce 350,000 bottles of wine a year.

The wines are aged in 100-year-old oak barrels personalized by Mur?'s grandmother with the names of famous French women, including Marie Antoinette and Joan of Arc.

In 1932, his grandfather bought the 37.5-acre Domaine du Clos St Landelin, named for the abbey whose monks tilled the vineyards in the 8th century. Its sunny, southern exposure on the steep mountain flanks made it one of the choicest vineyards in the area, and it produced the Mur? family's finest wines.

Mur? and other French vintners have tasted global warming in their wines for the last three decades. They liked what they tasted. Their red pinot noirs were more aromatic, and their white Gewurztraminers were sweeter with fragrances of litchi and roses.

All over France, vintners abandoned their forefathers' practice of adding sugar to the wines to improve their flavors and alcohol content. The sun and warmer summers were doing the job for them. Through the 1980s and 1990s, French wines won higher and higher ratings from domestic and international wine critics.

But the climate warming has accelerated faster than vintners or French scientists anticipated. That has forced sugar levels, and consequently alcohol levels, higher in the wines. Some producers in Provence are adding acidic compounds to their wines to keep them from becoming too sweet and undrinkable.

Vintners in Alsace are now facing similar problems. The average temperature in Alsace, which is bordered by the Rhine River and Germany, has risen 3.5 degrees in the last 30 years -- a dramatic increase for sensitive grapevines, according to the French National Agronomy Institute.

"For 10 years, our problem has been to keep the acidity," Mur? said. "Wines need to be balanced to have fresh, crisp flavor."

Mur? has already started changing the way he cultivates his grapes, growing some vines closer to the ground with fewer leaves in the style of southern grape growers, giving his vines less exposure to the sun.

He wants to experiment with growing southern Syrah grapes in Alsace. The way Mur? sees it, if the southern climate is moving north, he should be prepared to grow grapes that can withstand the heat.