Sunday, March 20, 2011

Weathering climate change with Napa Valley’s grapegrowers

Rebecca Huval has a packed-with-content article in the Napa Valley Register: Grapes drooped off the vine last summer like sacks of raisins. Rows and rows of fruit shriveled as Will Drayton, a viticulturist at Treasury Wine Estates, examined them with dread. Low in sugar and high in acid, this type of grape, he said, “makes terrible wine.”

…To adapt to global warming, Treasury and others who grow Napa Valley wine grapes have recently tweaked their growing techniques. The trend isn’t new — vineyards have been shifting toward “green” for decades. Change has been spurred on by anti-herbicide activism, Napa River restoration and worldwide sustainability movements. In Napa, sustainable farming “is not just strictly an environmental thing,” Drayton said. “It makes healthier grapes.”

...Over decades, this more holistic acceptance of wildlife has led to an overall attitude change still at play. Vineyard managers invited insects back by cultivating cover crop, built birdhouses and erected solar panels.

…In the Napa Valley, climate reports have shown nighttime temperatures shifting more than daytime highs. Overall, the nights have become slightly warmer by less than one degree over 60 years, according to the climate report commissioned by the Napa Valley Vintners. The same geography that’s ideal for many wine grapes and keeps the temperature moderate might turn Napa into an anomaly of global warming.

…“We have been very fortunate because of the marine influence and the dampening effect it has,” said Jim Verhey, director of Napa Valley Grapegrowers, “but what’s really happened is weather has gotten more extreme.” Extreme highs — up to 114 degrees — shriveled many grapes in Napa Valley last summer. Will Drayton declared the majority of a vineyard block unfit for wine. It produced one ton of grapes per acre instead of the 3.5 tons it normally makes…

A vineyard in Napa Valley, California, shot by Mila Zinkova, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

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