North Coast grape growers say they take climate change seriously, but they remain optimistic about finding ways to produce premium crops should temperatures rise as much as a new study suggests.

The study, the latest in a decade of such research, predicts parts of the Rocky Mountain region could become suitable for growing wine grapes by 2050, even as large swaths of California vineyards decline in productivity.

But growers in Sonoma and Napa counties maintain that the region's proximity to the Pacific Ocean, the work of grapevine researchers and the adaptability of farmers will help prevent the demise of Wine Country.

"Do I think in the next three or four decades that grapes will disappear in Sonoma County?" Sonoma County Wine Grape Commission President Nick Frey asked Thursday. "No, I don't."

Jon Ruel, president of the Napa Valley Grape Growers, said studies often don't account for the natural ability of farmers and wine producers to adjust their techniques to match climate change.

"We are concerned, but we are dealing with it," said Ruel, chief operating officer for Trefethen Family Vineyards. "There are a lot of ways that we as smart farmers are setting up to adapt."

And, he added, "none of us are moving to Oregon anytime soon."

The study is at least the fourth since 2004 to warn of the harm that climate change could cause on world wine production. Past studies have suggested that Sonoma and Napa could become as sweltering as Tijuana, Mexico, by the end of this century, and that the suitable vineyard lands in the Napa Valley could be cut in half by 2040.

The latest research, published this week in the Proceedings of the National Academy of Sciences, concludes that land currently suitable for grapes in the world's major wine-producing regions could be reduced by 20 to 70 percent by 2050.

The study uses wine grapes as a test case for the theory that climate change might open some regions to new crops even as current farmlands experience declines in productivity. In that regard, the authors raise concerns that the planting of vineyards in new regions could reduce wildlands and tap into limited freshwater supplies.

The research has led to news stories postulating such forthcoming vintages as "Danish Cabernet" and "Yellowstone Pinot Noir," as well as those raising questions about whether future vineyards might affect the Rocky Mountain ecosystems of timber wolves and elk.

Patrick Roehrdanz, one of the study's authors, said researchers concluded that both Napa and Sonoma counties would experience a decline in vineyard suitability, but "it doesn't mean you can't grow grapes there."

"Absolutely people will continue to grow grapes in Napa and Sonoma valleys, it just will need some adaptation," Roehrdanz said.

Rex Stults, government relations director for Napa Valley Vintners, called for perspective about the study and climate change.

If broad regions of Europe, Australia and the Americas are eliminated as productive farming areas, Stults said, "then we have much greater challenges than where the next great cabernet is coming from."

In 2011, researchers at Scripps Institution of Oceanography at UC San Diego, working on behalf of the Napa vintners, published a report looking at climate change and the Napa Valley. The researchers concluded that the valley had warmed slightly over recent decades, but not to the extent suggested by previous studies based on broader statewide data.

Growers noted that summer heat from the Central Valley has long pulled cooler air and morning cloud cover over Wine Country. Some suggested that even if inland vineyards suffer from rising temperatures, the effect may be more muted in Napa and Sonoma.

"The general climate is going to be slower to change the closer you are to the ocean," said Pete Opatz, vice president and senior viticulturist for Silverado Premium Properties.

Opatz noted that developments in new rootstock and clones has led to varietals that ripen as much as three weeks earlier than older vines. The same sort of research could help develop vines whose fruit takes more time to ripen in hotter temperatures.

Already researchers in the past decade have helped greatly improve the quality of grapes grown in the hotter climate of the Central Valley.

Lise Asimont, director of grower relations for Francis Ford Coppola Winery, said growers and winemakers already are adapting. In the past five years, her staff has noted and adjusted for what they believe are climate-related impacts on the flavor profile and characteristics of grapes purchased from a wide region of coastal California.

"There is no such thing as an average, normal year anymore," Asimont said. "It keeps you on your toes because something's happening."

Staff Writer Cathy Bussewitz contributed to this story. You can reach Staff Writer Robert Digitale at 521-5285 or robert. digitale@pressdemocrat.com. You can reach Staff Writer Sean Scully at 521-5313 and sean.scully@pressdemocrat.com.