Berger on Wine: Climate change may shift vineyard planting

Pinot noir grapes are removed at a vineyard near Forestville, where they were shriveled by a heat wave. (JOHN BURGESS / The Press Democrat)


A decade ago I wrote an April Fool’s Day wine column about an optimistic winemaker in Sweden who had planted cabernet sauvignon, anticipating that climate change would put him ahead of the curve.

At the time, the idea was considered radical; Sweden was too cool to grow wine grapes. Not anymore.

In fact, a hybrid grape called Rondo now is growing in Sweden, England, and Germany, and going into red wines in all three regions. Part of the reason Rondo works in such previously wine-barren regions is that all three areas are seeing warmer average temperatures.

An article published earlier this month in the New Zealand Herald addressed how climate change Down Under will impact one of New Zealand’s most important wine regions – Central Otago.

Long known as a superb cool location for pinot noir and riesling, New Zealand’s south island area Central Otago has already begun seeing the effects of increasing temperatures – so much so that the area may soon be warm enough to warrant planting other grape varieties.

“Wine enthusiasts may well be able to buy Central Otago-grown syrah and merlot in the next few decades,” the Herald article said, quoting former Central Otago Winegrowers President James Dicey.

Temperature changes, including additional heat spells and higher peak temperatures, require changes in farming techniques such as better irrigation systems and new techniques to maintain vine character, Dicey said.

Glenn McGourty, UC Cooperative Extension Farm Advisor for Mendocino and Lake counties, just returned from a technical conference in Argentina where the topic was water — or a lack thereof as a result of drought, scant spring runoff and other difficult conditions for wine growers.

Part of the problem for many southern hemisphere wineries will be the shortage of water, he said.

“Specifically, their snowpack (in Argentina) was not as big as in past years, and many areas are very arid,” McGourty said. “Water is scarce.”

“We face this same situation in most areas of the Central Coast — they are in dire straits in Santa Barbara, San Luis Obispo, and Monterey counties. You can see how dry everything is by looking at the fires down there right now.”

He said that following the October fires in Napa and Sonoma, “the North Coast got ample rainfall, but before all that we had some incredibly hot weeks, even in places where you wouldn’t expect it, like San Francisco.”

McGourty noted that during the recently concluded harvest, the four North Coast counties had several days in a row of 100 degree temperatures. Really, they were heat storms that lasted for a period of time, and that can change the composition of the fruit.

“(Heat) can create sunburn, it increases the pH and the sugar. And yes, winemakers can deal with some of these things in the winery, but it’s not their favorite way to go.”

He said the resulting wines may be satisfactory, but occasionally such conditions will produce characteristics that are atypical: “It’s contrary to our handcrafted image of wines made from exquisitely grown fruit. If you’re a pinot noir grower and all of a sudden the temperatures rise to 100 degrees for several days in a row, well, that’s not the kind of wine you want to make. It’s not what you signed up for.”

Such high temperatures “cause acids to metabolize and, to a degree, the higher alcohol we are seeing is due more to dehydration,” which he said can cause many red wines to smell oddly atypical.

McGourty pointed out that California’s Department of Food and Agriculture strongly supports the Healthy Soils Initiative, a collaboration of various departments and agencies to insure that farmers are properly equipped with the right scientific data to deal with climate change issues.

One key issue is fixing carbon in the soil, a vital aspect of modern farming, he said.

In wine regions of California, farming changes are being made to deal with local climate-change problems that will affect the industry. McGourty said similar changes can be anticipated throughout the wine world.

One thing many California growers now are saying privately is that some wines may change in style.

Look at how radically different most red wines are today from what they were just 25 years ago when lower alcohol wines (12 to 13 percent) were easy to find. Today most fine red wines have alcohol levels at 14 percent or more.

Encouraged by some vocal advocates of high-alcohol wines, consumers learned to like the new higher-alcohol style of wine, notably red wines. But if average temperatures continue to rise, grape sugars will accelerate and red wine alcohol levels of 16 and 17 percent will be commonplace.

Because of this possibility, many winemakers are seeking grape clones as well as yeast strains that deliver lower alcohols.

In labs around the world, research is underway to develop yeasts and grape clones as well as fermentation techniques that deliver mainstream flavors at lower alcohols.

Any wine changes brought on by increased vineyard temperatures could make for new and interesting aromas and flavors. But global climate change will present all wine lovers — from winemakers to collectors, from restaurant and retail personnel to casual drinkers — with a number of dilemmas, some of which will change the way we think about wine.

It also may result in us seeing Swedish cabernets or Irish sauvignon blancs sooner than we realize.