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Would Hotter Summers Hurt Wine Quality?

Stanford scientists take a stab at what could happen by 2040
Photo by: David Yellen

Posted: Jul 13, 2011 9:57am ET

It's a standing joke, though a somewhat nervous one, among winegrowers when the subject of global climate change comes up. "Well, I guess they'll be growing Cabernet in Burgundy," someone is sure to remark, "because it will be too hot to grow Pinot Noir there anymore."

But how true is that idea? Is it likely that whole regions will get too hot for what they currently grow? That would change the dynamics of wine profoundly. Noah Diffenbaugh, a fellow at the Woods Institute for the Environment at Stanford University, enlisted colleagues at Utah State and Southern Oregon universities and the Oak Ridge National Laboratory to plug in conservative climate models and analyze what would happen region by region in California, Oregon and Washington if those models come true.

Diffenbaugh is the guy who scared the pants off of everyone when he predicted in a 2006 climate study that 81 percent of U.S. premium wine acreage could become unsuitable for their current varieties by the end of the 21st century. This new study narrows the focus to wines in the top 25 percent in value and limits the time frame to 30 years. The authors point out that vintners actually consider the costs and benefits of making decisions about their vineyards in this time frame.

An increase of 1.8° F in average daily temperatures over the next 30 years, about what the conservative estimates expect on average, could affect a significant percentage of current vineyards, enough to require replanting with different varieties if they want to keep growing high-quality grapes. On the other hand, adaptations could also come into play to soften the effects. New clones, vine-training systems and smart water use could make the vines and the grapes more tolerant of higher temperatures, and still produce high-quality wines.

One big issue may be the number of extra-hot days in a growing season. That would vary from region to region, the computer models say, and could be more significant than average temperatures if a vine has to withstand 50 extra-hot days per season instead of 20. In some of the models, that could happen.

Bottom line, according to the study, in some regions as much as 50 percent of the vineyard land now suitable for high-quality wine could no longer be that good, if no changes are made. At biggest risk, they note, are regions that are now considered warm, such as Napa Valley. Cooler regions, such as Santa Barbara, Willamette Valley and Columbia Valley, could see only 20 percent of current vineyards get too warm to make high-quality wine with their current grape mix.

So maybe we won't see Pinot Noir being replaced by Cabernet. But Cabernet for something else? Um, Syrah? Grenache? That could be a game changer.

On the bright side, some land currently considered unsuitable because it's too cold could get warm enough to become prime vineyard acreage. Higher elevations, the study suggests, could become more and more important.

This is not limited to the West Coast of the United States, either. Every wine region in the world will have to find ways to cope with a gradually changing climate. It's a complicated story, and it's a good thing someone is trying to figure out exactly what could happen.

Here is the full text of Climate Adaptation Wedges: A case study of premium wine in the western United States.

Follow Harvey Steiman on twitter at twitter.com/harveywine.

Ryan Pease
Paso Robles, CA —  July 13, 2011 12:31pm ET
This subject is tired. We had drought years 2007-2009 and now we have had record rains and cooler tempuratures from 2010-2011. The wines were outstanding in all of those vintages across the state whether it was super hot (08') or super cold (10'). Im not to worried about it.
Richard Gangel
San Francisco —  July 13, 2011 1:30pm ET
As one can see from the first comment that there is a lack of understanding by the public between the meaning of "climate" and "weather." There will always be differences in weather patterns from year to year, but climate refers to patterns that occur over an extended period of time. Not being a climate scientist I am unable to comment on the research that was done, but as with all science, further studies need to be made to confirm the validity of the research of Diffenbagh et al. All I can state with any certainty is that the winemakers of the next generation or two may have reason to be concerned about the future of the industry on the west coast. If the predictions are correct they will have to learn to adapt to the changes.
Harvey Steiman
San Francisco, CA —  July 13, 2011 1:36pm ET
Ryan, it's not about this year or next, but 30 years from now. If those hot years get much hotter, something will have to change to make wines that are as good.
John Albritton
Irvine, CA —  July 13, 2011 3:45pm ET
I think the key statement was "if the predictions are correct". In the 1970's people were predicting the coming ice age. In less than thirty years those same people started predicting the exact opposite. The World's climate is very complex and the modeling is very inexact and flawed, which as has been proven repeatedly. So, if you don't like the weather just wait a few minutes....
David Peters
Mission Viejo, CA —  July 13, 2011 5:42pm ET
I can't take it anymore!!! With satelite pictures, Dopler radar, & billions in NASA technology, the weather forcasters can't even come within 5 degrees of the next day's actual temps; and the scientists want us to believe they can tell what the temps will be in 50 yrs based on their 'computer models'. Give me a break. As my father used say, if you want to know the reason for anything in life just 'follow the money trail' !! The only people pushing this crap are the ones that will financially benefit from this hysteria----such as the institutions receiving gov't money, the vineyard consultants, and the companies who will be paid to rip up perfect vines and replace them with new varieties & clones. The vineyards in France have done just fine for the past 300 yrs. Look at today's futures prices for the '10 Bordeaux; I don't think the buyers are too concerned about climate change for this crop.
Lyle Kumasaka
Arlington, VA —  July 14, 2011 12:51am ET
I'm an AGW skeptic and have taken great pleasure in the recent comeuppance of the academic fraudsters at East Anglia and elsewhere, but Steiman appropriately and modestly characterized the conclusions as conditional on a set of assumptions. If we disagree with the assumptions, we can think about this as a neat-o thought experiment along the lines of "vampire vs. ninja." Personally I prefer a riper style of pinot, so a couple more degrees in the Russian River Valley wouldn't necessarily bother me, nor would more consistent vintages from marginal climates like the Mosel.
James J Sherma
hershey, PA —  July 14, 2011 10:49am ET
An important thing to consider with all of the models of climate change is that the models do NOT show weather patterns remaining the same but a degree or two warmer each day. Rather the models almost all show more variance with higher highs and lower lows resulting in a slightly higher average temperature. It's the enhanced variance in the weather that is concerning, more very hot days as Harvey mentioned but also more freakish cold snaps and heavier precipitation events offset by longer periods of little or no rain.
Jean-francois Peletier
Osnabrueck, Germany —  July 14, 2011 4:22pm ET
Most of the preceding messages are full of misunderstandings. Weather predictions are diefinitly flawed and unprecise. we know though exactly what the temperature of everyday in specific area was... because these days are now passed and we measured the temperature. That means that weather statistics tell the thruth about what is coming. And the Stats show that the planet is getting warmer. The Vintners in Bordeaux do sell their wines to astronomis prices this year... And that ist due to many news customers having no idea about how Bordeaux used to taste. The 2010s show alcohol levels of 14%... and that is definitly because of the weather in that particular year. This is not normal. I know Winegrowers in Germany planting Tempranillo with succes. Harvey Steiman is right: It's not about now or next year it's about when these "execption" years are becoming normal ones... And if you want old vines, better think about the future now.
Ivan Campos
Ottawa, Canada —  July 14, 2011 7:35pm ET
Global warming is so much more than just having hotter summers. Ontario, for instance, is also seeing more erratic rain and colder spikes during the winter.

Will Cali cabs and zins continue their happy march towards becoming Port, garnering more Classic ratings from folks hooked on their huge extraction and alcohol, while wine from the same cool climate vineyard swings from anemic green to jammy with each vintage?

Since the pollution trend doesn't seem to be going anywhere positive (cities like Beijing and Cairo are having less days of sunshine each year, given their increasing perma-smog -- you have to experience it!), seems that new hybrids will be the way of the future...
Loren Lingenfelter
Danville, CA —  July 16, 2011 1:43pm ET
Climate Change is just another myth the politicians dreamed up. I mean 1.8* seriously? Sometimes it's hot, sometimes it's cold. We have not seen the sun in northern cal in weeks and what is it mid July? What a joke Harvey.
Harvey Steiman
San Francisco, CA —  July 16, 2011 3:04pm ET
Look, I understand that the response to the idea of climate change has become highly politicized. But I can't let a comment like Loren's go by without pointing out that it was scientists, not politicians, who did the analysis of historical trends in climate and made some predictions. Reality has so far pretty much fallen in line with them. See Jean-François' and Ivan's comments.

It may be hard to believe that average temperatures are trending up over the long term when it's colder than usual for a few weeks in midsummer, but it's actually the point. Most predictions expect weather to be more wildly varied, and it has. This is looking like a particular cool vintage on the west coast, and it follows a very cold and unusually wet 2011 vintage in Australia, which had a decade of unprecedented drought before that that dried up major rivers.

From a political angle, no one is asking for government to step in and save the vintners. If the wine industry has this information, it can accept it or not, prepare for change, or not. No one is forcing them one way or the other. Any vintner is certainly free to ignore the signs and assume things will always be the same. I'm just glad someone is doing the analysis to try to work out what could be happening.
Adam Wallstein
Spokane —  July 16, 2011 7:25pm ET
The point is that the climate is changing, and doing so at a pace which will likely force some disruptive adjustments on our part, if we wish to maintain what we want and need from the planet. It's good to have pieces of information like the analysis sited in this blog in order to help everyone (vintners included) prepare, and thus minimize the turbulence we're likely to face.
You're welcome to find the responses to the science politically motivated, but the data speaks for itself. We ignore or dismiss it at our peril.
Pacific Rim Winemakers
Portland, OR —  July 18, 2011 7:49pm ET
I could use some global warming this year! We will be harvesting again in November in WA.

Seriously anyone debating that the climate is warming up is ignoring the facts.

Nicolas

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