Climate change to radically alter vineyard map?

Napa Valley, Calif. -- Climate change may have wine makers over a barrel.

A new study suggests it may drastically affect some of the world's great wine-producing regions.

The study, from Stanford University, says vineyards in California could shrink by 50 percent over the next 30 years. California wine is currently a $16.5 billion industry.

Other famous regions could be affected, as well.

As CBS News Correspondent John Blackstone points out, the vineyards of California's sunny Napa Valley are known for their top-quality cabernets and chardonnays. Which may explain why the people who make wine there, such as Michael Honig, of Honig Vineyards and Winery, aren't known for their modesty.

"We're perceived as the best, and rightfully so," Honig says. "We make some of the best wines in the world."

Others say the great wines come from Europe. Wine writer Tim Atkin points to "places like Burgundy, Bordeaux, Champagne, and Piermonte in Italy and Rioja in Spain."

But climate change may be shifting that landscape, Atkin says, noting, "We could find that certain wine regions in France and Spain and Italy that historically have produced wines are going to be effectively desert."

There are now even award-winning Vineyards in England, never before known as a wine region.

Says Atkin, "You may find the entire world of wine -- in Europe, anyway -- shifting northwards."

In America, says Blackstone, temperatures in the Napa Valley could rise by 2 degrees in the next 30 years, according to the new study, by Stanford's Noah Diffenbaugh, an assistant professor of environmental earth science. "This can be" he says, "very damaging to the delicate balances that are so important for making the best wines."

Diffenbaugh calculates 50 per cent of Napa vineyards may no longer be suitable for producing the very best wines.

His study of global warming has had a chilly reception among Napa's growers.

"It sounds good on paper," says Honig. "I don't think its reality, though."

Because, Honig says, Napa is already preparing for climate change.

He says Napa growers aren't "at all" global warming deniers. "We know the world's changing," he says.

Honig's vineyard and many others in the valley are now powered by solar energy, cutting their greenhouse gas footprint.

Growers are also developing ways to plant and prune their vines to deal with days that may heat up fast.

"We've really opened up the cool morning side, so we can get some doppled sunlight in here, some freckled light,' Honig said as he and Blackstone walked through a field. "On the afternoon side, we've kept it nice and shaded, so the fruit doesn't get burned.

Grower Andy Beckstoffer, of Beckstoffer Vineyards, figures NAPA wines are so valuable, wineries here will find answers to global warming. "We can afford the technology," he says. "We can afford to do anything we need to do ... to get these things right, because we have the money."

Stanford's Diffenbaugh says, "People are tremendously creative and ingenious in dealing with different environments."

He says that, while hotter weather presents a challenge to growers in NAPA, they can start now working on ways to adapt.

Beckstoffer says he's confident he'll be able to keep growing exactly what he grows now.

In fact, he thinks climate change could even make his grapes better, if the nights aren't so cold. "This global warming," he says,"it's getting warmer at night, which might mean that we get more flavor development. So, there is a chance for a silver lining here."

Napa's wine makers, it seems," Blackstone observes, "never like to see a glass as half-empty, but rather, as half-full. Even the prospect of global warming can't destroy their sunny optimism."