Napa wine industry warned of future climate threat

Local growers confident of ability to adapt
2013-05-04T23:00:00Z 2013-05-06T17:31:44Z Napa wine industry warned of future climate threatHOWARD YUNE Napa Valley Register
May 04, 2013 11:00 pm  • 

Might climate change help push Napa Valley wines off the store shelves of the future, and put bottles from Idaho, Canada or even China in their place?

A study published last month in the journal Proceedings of the National Academy of Sciences forecasts temperature increases triggering the loss of two-thirds or more of the Napa Valley’s current grape output by 2050, with similar losses projected in France and other prime winemaking regions.

The same trends of increasing average temperatures, the report’s authors predicted, also could enable a major northward shift in winemaking into the Pacific Northwest, central China and other regions once too cold for vineyards.

But would rising temperatures affect all grapegrowing havens equally? Some California researchers and growers are unsure how quickly rising global temperatures will affect the Napa Valley, pointing to a balance of inland and coastal weather elements that have produced a uniquely friendly environment for the vine.

For the climate change projection published last month, a team of nine researchers used 17 different climate models to gauge the effects of global warming on nine major winemaking regions, including California, the Bordeaux and Rhône regions of France, Chile and Australia.

One scenario assumed a rise in average temperature of 4.5 degrees Fahrenheit, while a second assumed average warming of 8.5 F. In either case, the academy’s model predicted sharp production losses in traditional wine regions, as rising temperature forces growers to irrigate more frequently to ward off heat damage, move vines to higher and cooler elevations, or pull out of unprofitable areas altogether.

California’s territory suitable for wine grapes is predicted to shrink by about 70 percent by midcentury, with an even steeper 85 percent loss forecast for France, Italy and the rest of Mediterranean Europe.

“What the report says is that using current grape varieties and current techniques, those areas would become not very good for producing wine,” said Lee Hannah, the report’s lead author and a senior research fellow for Conservation International.

“Vineyard (owners) are quite aware of the importance of climate and what they can do to adapt,” he said last month by telephone from his offices at the University of California, Santa Barbara. “That doesn’t mean Napa will be out of the wine business in 2050, but it does mean they’ll have to produce it differently — and it will almost certainly be more expensive.”

The same climactic changes that would disrupt grapegrowing conditions in Napa and Bordeaux, meanwhile, stand to open up or expand winemaking regions farther up the Northern Hemisphere — including British Columbia, Idaho and lands surrounding Yellowstone National Park.

However, such expansions also open the way for new conflicts between winemaking and wildlife. Many of the North American regions identified as suitable grapegrowing land in the future — including Idaho, Washington state and British Columbia — lie in areas coveted by conservationists for a Yellowstone-to-Yukon corridor that would shelter gray wolves, grizzly bears and migrating big game.

In China, the central hill country expected to become suitable vineyard land by midcentury also is the last major haven for the country’s endangered giant pandas.

Grapegrowers and scientists closer to Napa, however, painted a more complex picture, one driven by coastal air currents and by numerous differences in soil and elevation.

A 2011 study commissioned by the Napa Valley Vintners concluded that most climactic models may have inflated the rate of temperature change in Napa County by relying mostly on decades-old monitoring stations in Napa and St. Helena, close to the reflective surfaces of urban areas.

“At Napa State Hospital, the weather station is next to a paved road, an irrigated lawn and an air conditioner unit,” said Rex Stults, the Vintners’ director of government relations. “In St. Helena, the station is atop the local fire house. I can’t think of another place where a weather station should not be.”

While the older weather stations have measured a 4- to 5-degree rise in average temperatures over 60 years, information gathered from private weather stations and farmers’ logbooks during that time suggests only a 1- to 2-degree increase in the county’s rural districts, according to Daniel Cayan, a Scripps Institution of Oceanography climate researcher who led the Vintners study. Furthermore, the increases were concentrated in the overnight hours, with daytime peaks staying nearly flat since the 1950s, he said last week.

Napa County’s apparently steady daytime temperatures are a product of layers of cooler marine air from the Pacific Ocean and San Francisco Bay, which Cayan said actually may intensify as streaks of hot weather become more frequent in the Central Valley.

“The nature of (the shift) from one season to next is still under some question, but there have been years in the last 20 where we’ve seen a pattern of very warm air in the interior, while coastal regions influenced by the marine environment have not been excessively warm,” he said of the theory. “Whether or not that is a symptom of this mechanism is still under question.”

Even more important than the possibility of higher temperatures is their timing, argued Christopher Howell, winemaker for Cain Vineyard & Winery in St. Helena. While the effect of warmer winters would be light, an increase in peak temperatures at the beginning and end of the grape season — around the times of bud break and harvest — would affect both the length of the growing season and the sugar and acid levels that determine the wine’s character.

“We agree the low temperatures in winter and spring are not as low as before, but the high temperatures are not obviously getting hotter,” Howell said last week. “Averages are going up but highs aren’t, and those have more to do with how the wine will taste than the lows.”

Another grower saw more of a risk even in a relatively modest creeping-up of local temperatures, but not mainly from the heat itself.

“A 1- or 2-degree average temperature increase changes the kind of pests that can thrive” in Napa vineyards, said Jim Verhey, a Napa grapegrowing consultant who spent 25 years with Silverado Grapegrowers. If warming trends affect the county’s winter climate, pests that normally are destroyed in hard freezes — such as European grapevine moths, mildews and red blotch virus — can survive to the next growing season and threaten vineyards later, he said.

An important wild card for today’s winemaking powerhouses could be the beverage’s future in China, home to the world’s largest population and second-largest economy, said Hannah, leader of the Proceedings of the National Academy of Sciences’ climate-change report. As long as the nation’s incomes rise and continue building its citizens’ taste for luxuries, he suggested, winemakers may find it worthwhile to invest in increased irrigation and other steps to sustain their vineyards even in a hotter and more hostile climate.

“What happens to demand in China has a huge bearing on this,” he said. “The upper class is already bidding up wine prices at auction, and the prices of vineyards here and in Europe. If that trickles down to the middle class and you have that explosion in demand for wine, then it’s possible that all sorts of expensive ways to deal with climate change could become affordable.”

Indeed, the report’s authors suggested that changes in watering and planting practices may keep vineyards productive longer than climactic models suggest. More efficient, precise misting, and new ways of trellising and orienting vines, can keep water demands in check and growing costs in hand, the authors wrote.

“Change is happening, but I think it’s well within our range of adaptability,” said Toby Halkovich, who directs viticulture for Cakebread Cellars’ 510 acres in the county and the Anderson Valley. “If hot summers become more frequent, we can use the tools we’ve already developed.”

Since joining the Rutherford-based winery 17 years ago, the spread in water use between the coolest and warmest growing seasons has been about 10 percent, according to Halkovich, who said that misting, leaf canopy management and adjustments to the irrigation pattern have so far sufficed to deal with the hottest conditions.

On his 21 acres in the Oak Knoll district north of Napa, Verhey has spent the past seven years remaking his vineyards with the future in mind — as well as larger harvests today.

A “modified lyre” trellis system lets light onto the vine tops but also provides more shade over the fruit, while Verhey’s overhauled irrigation system includes fewer but longer waterings to encourage deeper root penetration, enabling the plants to stay healthier in the dry summers. As a result, he said, his annual water consumption has dropped to about 10-12 gallons per vine even as the yield has risen from 4-5 tons an acre to 7-8 tons.

“It’s like savings; you can’t just wake up one day when you’re 55 and say to yourself, ‘I gotta save for my retirement so I’d better start now!’ By then, it’s too late,” he said.

“Am I solving the problem today? No. Am I working toward it? Yes.”

Copyright 2015 Napa Valley Register. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

(23) Comments

  1. glenroy
    Report Abuse
    glenroy - May 05, 2013 4:49 am
    From manmade global warming, to global warming to climate change….that’s what happens when liberalism comes up with a consensus that never was.
    The fact is last week NASA all but confirmed warming and cooling cycles are within norms and have been for decades, or there never was a threat because there never was unusual warming.….but moderating resources is always wise farming.
    They need to come up with a new scam.
  2. foss valley
    Report Abuse
    foss valley - May 05, 2013 9:32 am
    Hog wash
  3. Old Towner
    Report Abuse
    Old Towner - May 05, 2013 9:37 am
    A warning to readers here--Glenroy and I are about 180 degrees apart on this. And as usual, I will be asking Glenroy to cite his sources, so--here goes, Glenroy--what NASA study might you be referring to?
  4. gettingreal
    Report Abuse
    gettingreal - May 05, 2013 11:12 am
    The real goal of the climate scare is to take money from the makers and give it to the takers. Do a little research. Even the EPA admits that the new regulations coming down the pike will potentially bankrupt this countries businesses. I'm all for protecting the environment, but when you overdo it green becomes the new red and the capitalism that created this country dies..
  5. Old Towner
    Report Abuse
    Old Towner - May 05, 2013 11:17 am
    So, glenroy, which study was this so we can all read it?
  6. naparealestate
    Report Abuse
    naparealestate - May 05, 2013 7:20 pm
    Every grapegrower I've ever met, regardless of political orientation, is keeping track of historic weather data and making decisions accordingly. And it does seem even the most politically conservative grapegrowers acknowledge rising global temperatures are having a real impact on the micro-climate in their own vineyards.
  7. eyeremembertim
    Report Abuse
    eyeremembertim - May 05, 2013 8:17 pm
    Nice coverage of what is often a controversial topic. Climate warms significantly and life in downtown Napa becomes problematic with sea level rise and certainly what grapes we grow takes a back seat. As a Davis graduate and industry veteran I trust the evolution of ag practices ( I have seen quite a bit of change there in the last 30 years) and a good old fashioned can do entrepreneur response should all the hype be true. There is a lot on the table here in Napa. I am sure there would be winners and losers. If were catastrophic, it would not be the first time here in Napa. In my family one side was dairy and the other grew prunes. I feel blessed.
  8. shantz
    Report Abuse
    shantz - May 05, 2013 8:21 pm
    Bottom line is: wine making is not sustainable. It can't be the economic engine that drives us into this next century. Scientists have been warning us about global warming for decades. Business leaders and politicians didn't pay attention. And, now we are suffering the consequences of our inaction.
  9. eyeremembertim
    Report Abuse
    eyeremembertim - May 05, 2013 8:43 pm
    By the way I am sympathetic with the comments of both glenroy and gettingreal. Big government often frightens me too. It is why I try to stay informed. But who knows, sometimes we're glad they're there. Vigilance, self reliance.... get to know your neighbors in a positive way. It might be the best we have.
  10. glenroy
    Report Abuse
    glenroy - May 06, 2013 6:48 am
    Are you incaptable of research OT?

    The study which was released in the last couple weeks confirmed there has been NO WARMING out of historical norms..

    Put a little effort into it instead of jingo...
  11. shantz
    Report Abuse
    shantz - May 06, 2013 8:11 am
    That's good to know. Global warming is not a conservative or progressive issue. It's something we all need to come together on.
  12. Old Towner
    Report Abuse
    Old Towner - May 06, 2013 8:24 am
    So, heeding glenroy's advice, I went to the NASA website and the only things I found clearly were not what glenroy had in mind--a recent report on Arctic sea ice (shrinking) and extreme thunderstorms (increasing). So I have no clue what the "last week NASA confirmed" report is--and I don't think glenroy does either, until he shows us otherwise.
  13. glenroy
    Report Abuse
    glenroy - May 06, 2013 9:07 am
    Temps are meaningless without context...take the drought yearslate 70s early 80s the finest wine ever produced … temps were higher and irrigation was restricted. Vineyards as currently management are not sustainable unless do as Verhey is doing….as for global warming, manmade or otherwise, is nothing but another Ponzi to accomplish what liberalism cannot do on a level playing field, to our detriment…small businesses and wage earners…because liberalism uses government agencies for their political, and much worse, their exclusive financial benefit. Liberalism has essentially ruined blue state economies, if it were not for red state energy growth on private property our nation would still in the latest Progressive Depression and may return...
    BTW…crops, forests, plants of every type benefit by an increase of manmade is a matter of fact but it never enters the liberal jingo or pubic debate....perhaps that would explain why life existed when carbon was 500% higher?
  14. gymnosperm
    Report Abuse
    gymnosperm - May 06, 2013 9:25 am
    Hello? There has been NO lower atmospheric warming this millennium within the measurement uncertainty. Get a clue, then write.
  15. Old Towner
    Report Abuse
    Old Towner - May 06, 2013 11:39 am
    Atmospheric physics dictates that if the lower atmosphere warms from increasing concentrations of greenhouse gases, the stratosphere will cool--so which part of the atmosphere is this about--and does gymnosperm have his or her own satellites, or is this someone else's work that we could look up if gymnosperm shared the source? So, gymnosperm, obey your own rule--get a clue, then write.
  16. Rob McMillan Silicon Valley Bank
    Report Abuse
    Rob McMillan Silicon Valley Bank - May 06, 2013 3:30 pm
    I've read the study referenced in this article and the Napa AVA isn't referenced in the study whatsoever. This is a repetition of bad coverage that used the Napa Valley brand to generate a buzz in the media. This situation was covered in my blog ( ) and the sources cited and included within.
  17. Rob McMillan Silicon Valley Bank
    Report Abuse
    Rob McMillan Silicon Valley Bank - May 06, 2013 3:34 pm
    Sorry - Here is the correct link to the blog discussed below.
  18. napablogger
    Report Abuse
    napablogger - May 06, 2013 5:31 pm
    Rob, thanks for this.
  19. publiusa
    Report Abuse
    publiusa - May 07, 2013 6:15 am
    Fermentation of Napa Valley grapes sends thousands of tons of CO2 into the atmosphere. Based on that the wineries are contributing to their own demise.
  20. glenroy
    Report Abuse
    glenroy - May 09, 2013 7:34 am
    So that's what made it cooler today than 16 years ago...LOL...

    Based on NASA's earth/atmospheric data there hasn't been any change outside norms which is measured over 1,000 year periods...some of it data and rest best guesses.... there no link between greenhouse gases PPM or climate change...zilch... The data proves one thing... climate always changes but they can find no link to man..yet.

    But the scam artist don't use norms, they edit data and still use the same program that cannot replicate known weather patterns...that's should be obvious to a marginal follower of this research dollar ponzi. It's called junk in and junk out...

    Just about everything on earth creates greenhouse gas and all man's portion is measured in parts per million plant life on this rock can consume that easily.

    The data proves the myth is a myth.

    Defending a false premise is a game for fools and scammers…these days one in the same with the left.
  21. glenroy
    Report Abuse
    glenroy - May 09, 2013 8:27 am
    This is an old school text book study of what is WRONG with government, what our Founders feared beyond all other fears.
    NASA, like every other government agency in the new wave liberal era, tows the far left-socialist line that government knows all because government must know best and they use government agencies to pound that message home. For those weak on history that’s what all dictators from Castro to Mao and Hitler to Lenin said…birds of a feather top down socialists.
    Anyway here’s link to our reality today…another useless NASA prediction, they made Mendoza look more like a .500 in a slump hitter (their internal data indicates normal weather patterns) 'Explained as extreme weather patterns'…that’s the game the facts and truth is what they say it is. Think about that….before you vote liberal nex time.
  22. ValleySwag
    Report Abuse
    ValleySwag - June 04, 2013 3:47 pm
    What you just said contradicts NASA. They have an entire website dedicated to climate change -

    Hopefully you're not a vintner because that kind of thinking is dangerous for the valley.
    Report Abuse
    VINETOSHELF - May 30, 2014 6:21 am
    I think the best thing that can happen is Napa loses some market share to make way for more eco friendly suppliers from countries like France & New Zealand that are putting the brakes on fancy CO2 heavy glass bottles. Napa is a huge contributor of greenhouse gases with the exception of brands like Black Box and BOTA (among others). The simple fact that they don't even take reusing of wine bottles seriously is an issue they'll need to explain to their grandkids. Let people buy wine, not environmentally toxic bottles. Shame on CA.
Add Comment
You must Login to comment.

Click here to get an account it's free and quick