Grape breeder in Viticulture and Enology at the University of California-Davis Andy Walker walks through UC Davis's test vineyard. Climate change could dramatically affect the microclimates that have made California wine country so successful. science.kqed.orgBy Lauren Sommer from QUEST Northern California
4 September 2012 You’ve probably heard of the wines that made Napa and Sonoma famous, like Cabernet Sauvignon or Chardonnay. But what about Negroamaro or Nero d’Avola? They’re wine grapes that are well-adapted to hotter climates – the kind of conditions that California may be facing as the climate continues to warm. But for wineries that have staked their reputations on certain wines, adapting to climate change could be a tough sell. Talk to any wine lover in California and they’ll tell you how lucky they are to live in such rich wine-producing region. Take the recent meeting of the San Francisco Wine Lovers Group at Toast wine bar in Oakland, where the favorites are California Pinot Noir, Russian River Zinfandel, and Napa Cabernet. In fact, the type of grape – or varietal – is how most of us think about wine. “That’s the big problem,” says Andy Walker, a grape breeder in Viticulture and Enology at the University of California-Davis. “We’ve spent the last 100 years emphasizing varieties and we’ve really marketed those names very effectively.” Walker is strolling through UC Davis’s test vineyard, where hundreds of different wine grapes from around the world are grown. The vast majority are unknown to consumers, because most wineries focus on only a handful of grapes. “Chardonnay, cabernet, merlot, pinot noir – those would make up probably a large percentage,” he says. Those are all French varieties, mostly suited for cool climates. California is warm by comparison and thanks to climate change, it’s expected to get a lot warmer. Extreme heat can be the enemy of good wine. “It destroys acidity primarily and it changes color and aromatics,” says Walker. According to a recent study from Stanford University, about two degrees of warming could reduce California’s premium wine-growing land by 30 to 50 percent. That could happen as soon as 2040. Water supply is also expected to be an issue. “I think the interesting thing for me as a breeder is to take advantage of this and say, OK, here’s a chance now to change thought and let’s actually readapt varieties to California,” he says. But in many circles, grape breeding is a dirty term, according to Walker. “Viticulture is the most backward form of horticulture that exists. We use these varieties that haven’t been changed for decades, for millennia in some cases. And it really doesn’t make any sense.” […]

The Heat is On For California Wines