Hear About Climate History Through the Grapevine

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The delicate pinot noir grape must be harvested at just the right moment to achieve the correct water percentage, acidity and other characteristics in the fruit, if a vintner wishes to create the wine that master sommelier Madeline Triffon called "sex in a glass."

The date of that perfectly timed pinot noir harvest in Burgundy, France, over the past seven centuries has been correlated with sea surface temperatures and climate in Western Europe, in a study published in the journal Climate Research.

Yves Tourre, of Columbia University's Lamont Doherty Earth Observatory in Palisades, N.Y., and the French meteorological service, Meteo-France, in Toulouse, used records started by monks in the 14th century to study 16 vineyards planted with picky pinot noir vines.

Pinot noir's sensitivity led French regional authorities to decree the official "ban des vendanges," or date when harvesting may begin, until official regulation ended in 2007. Hence pinot noir has a recorded harvest history like no other grape.

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During the past 700 years, the grape harvest start date fluctuated in sync with winter temperature records from Paris. And both were influenced by natural cycles in the flow of the Atlantic Ocean, such as the Atlantic multi-decadal oscillation.

Winter temperatures are important to the next summer's grape production, which runs from April to September. Higher temperatures in the ocean result in warmer winter weather and a better grape harvest.

Over the centuries, Burgundy showed little evidence of long-term increases or decreases in winter temperatures, until 1998, Tourre said in a recent presentation to the American Geophysical Union, according to Inside Science News Service.

But since then “winters have become milder,” he added.

Other research has suggested that climate change could shrivel the harvests of vintners.

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This research could give French grape farmers another forecasting tool.

"You can have people in Burgundy looking at the sea surface temperature to add another variable to determine the harvest," Tourre said.

Tourre put his observations to the test this spring. He correctly predicted that the harvest would be early. It began Aug. 20, though it usually starts in September.

Tourre suggests investing in 2011 pinot noir. Weather conditions made this an excellent year for Burgundy. In another decade or so, a 2011 pinot noir may be a delicious reward for listening to a scientist.

IMAGES:

Pinot noir in Burgundy, France. (Credit: PRA, Wikimedia Commons).

Bunch of pinot noir grapes in Volnay, Burgundy, in early August, when the grapes have begun to get their color. (Credit: Olivier Vanpé, Wikimedia Commons).