Global Warming Endangers California Wine Industry
MELISSA BLOCK, Host:
Another climate story now. This one is from this planet and a pretty nice part of it, at that. In California's wine growing region, winemakers are worried about global warming. A recent study published in the Proceedings of the National Academy of Sciences says that by the end of this century, climate change may mean that California's premium wine industry could all but disappear.
Deirdre Kennedy has the story.
DEIRDRE KENNEDY: In a 45-acre vineyard north of Santa Barbara, Jeff Frey snaps off a tiny pinot noir grape and crunches it up in his mouth.
JEFF FREY: They're becoming sweet. They're still tart, but they're tasting very good.
KENNEDY: Frey oversees the grapes for a winery called Au Bon Climat, French for to the good climate. It's the climate that gives these wine grapes their high value. In a good year, this vineyard can produce about a half million dollars worth of premium pinot noir. Rows and rows of vines stretch across a beautiful hillside in the Santa Maria Valley. The valley opens out to the sea, drawing in the cool coastal fog.
FREY: Very seldom do we get above 85 degrees and at night, it always cools down below 45, 50 when the fog comes in. We have a warm spring and, you know, very mild temperatures. Let's put it that way. Not extremes.
KENNEDY: Those consistently favorable temperatures mean the grapes can hang on the vine longer, accumulating more flavor without burning under the hot sun. But some climatologists say the idyllic weather that supports this vineyard and those in other premium wine producing areas could change dramatically in the coming decades.
In a study that looks at some of the gloomiest climate model predictions, scientists at Purdue University, Utah State and Southern Oregon University see massive losses for the premium wine industry. One of the study's authors, Dr. Noah Diffenbaugh.
NOAH DIFFENBAUGH: We project potentially an 81 percent reduction in total premium wine production.
KENNEDY: That's because, Diffenbaugh says, global warming means more super hot days. He says to escape that heat, premium wine growers will have to move their vineyards to higher elevations.
California makes up about 92 percent of the entire U.S. wine industry. And in California, more than 90 of the profit is in premium wines.
It's not the first time wine grapes have fallen victim to climate change. About 1000 years ago, during what's known as the Medieval War Period, farmers grew wine grapes in southern England. Those vineyards later died out during a cooler period climatologists call the Little Ice Age. But Diffenbaugh says despite the names, climate fluctuations back then were much less than they are now.
DIFFENBAUGH: So what you're talking about for those time periods is maybe 50 percent of the temperature change of what we've already seen over the late 20th century. So we're really talking about small fluctuations even relative to what we've seen in the last 25 to 50 years.
KENNEDY: There's little dispute that the planet is heating up. The question is, how fast? Some scientists use a more conservative climate model to predict rising temperatures. One scientist who disagrees with Diffenbaugh's take on the issue is Dr. John Christy of the University of Alabama.
JOHN CHRISTY: The models tend to warm up the planet more than what we see in the actual data, so I think the models are over-projecting what changes might occur.
KENNEDY: The models also aren't detailed enough to predict what might happen in any particular coastal valley, like the one where Jeff Frey's grapes grow. Frey certainly doesn't feel the end of the earth is coming.
FREY: Being a farmer, especially a grape grower, we're very adaptive to situations and I believe the grape growers in California will, if it gets that severe, move into areas that haven't been farmed before. With our technology, we will overcome a lot of this for a lot of time to come.
KENNEDY: After all, this is California, where we have already managed to grow birch trees, rose bushes and golf courses in the dry, hot desert.
For NPR News, I'm Deirdre Kennedy.
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