Cabernet Sauvignon grapes make America’s favorite wine, and they are the lifeblood of Napa Valley, our country’s most famous wine region. Cabernet accounts for 65 percent of the grapevines grown in Napa, where last year the crop reached a record $1 billion in gross value.

Frustrated by the lack of industry-wide action, some are taking matters into their own hands by planting experimental vineyards — and, in some cases, acknowledging that the future of Napa Valley may not lie solely with Cabernet.

“I hear some wineries saying, ‘We’re going to have to start thinking about different grape varieties in 30 years,’” says Dan Petroski, winemaker at Larkmead Vineyards in Calistoga. His incredulous response: “You’re going to start thinking about it in 30 years?”

Like virtually all Napa wineries, Larkmead is a Cabernet house: The variety represents 73 percent of its estate vineyards, and its exquisite bottles sell for up to $350. Since Petroski started working for the winery in 2006, he has watched warmer temperatures shift the annual Cabernet harvest almost four weeks earlier. In the short term, that’s resulted in delicious wines, and the Larkmead team has been able to mitigate the effects of the heat with technologies like shade cloths, which currently blanket 90 percent of its vines.  […]