Grape expectations

Global warming has blessed cool-weather wine regions with record vintages. But while savoring their gold-medal wines, viticulturists are looking to the future -- and it isn't pretty.

By Ann Bauer

Read more: Wine, Alcohol, Global Warming, Climate Change, Life, Eat and Drink, Food and Travel

Aug. 28, 2007 | Harry Peterson-Nedry, owner and winemaker at Chehalem Winery in Oregon's northern Willamette Valley, has been having a string of spectacular years. His grapes are ripening like never before: They're juicy and rich with just the right proportion of acid. And since the late 1990s, growing has only gotten easier. With the exception of 2005 -- the coolest year of the past decade -- his crops have avoided frost damage. Winemaking used to be a fickle, backbreaking business; but lately, he's hardly had to work at it at all!

Summers full of sunshiny days and warm temperatures have meant a longer growing season and more opportunities for diversification; whereas the valley used to be appropriate only for cool-weather grapes like pinot noir and Riesling, now Peterson-Nedry is suddenly able to harvest richer, sweeter varietals, such as Syrah, Tempranillo and Grenache. The blending possibilities are endless. And Chehalem's wines improve with every new release, earning higher Wine Spectator points with every passing year. Business is booming.

But Peterson-Nedry is not pleased.

"Sure, this is a great thing for us in the short term," he says. "We've had 10 years of above-average vintages thanks to global warming. And a lot of winemakers in this region are just sitting back, fat, dumb and happy. But we're all fools if we think we can stop this freight train. Sooner or later, it's going to run us over."

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The effects of weather on winemaking go way back.

Vineyards throughout the British Isles and northern Europe were wiped out during the so-called Little Ice Age -- a cyclic period of cooling that began in the 13th century but was most evident during the years from 1650 to 1850 -- and never really recovered, that is, until now. We've traveled nearly full circle: returning to the winemaking climates of the Crusaders' era. But, this time, scientists say it's unlikely another ice age will come to reset the sequence.

Today, however, the problem isn't a natural expanding and contracting of the world's glacial sheets. Rather, it's consistent, excessive heat, likely due to global warming: Temperatures in the world's most famous modern winemaking regions (namely California and southern France) have, on average, risen 2 degrees Celsius over the past 50 years.

Receding glaciers, rising sea levels, deadly heat waves, disease, drought, famine and floods: The potential devastations of manmade climate change are manifold. But one of the things that makes it possible for the world to remain complacent -- burning through record amounts of ($3 per gallon) gasoline and sipping Evian from disposable plastic bottles -- is that the effects tend to be gradual, long-range, difficult to categorize and prove. By the time they're here, it will be too late to do anything.

Not so in the winemaking business.

Viticulture may be the canary in the coal mine of our planet's agricultural system. Grapevines are extremely fickle, and successful vineyards require a very delicate calibration of temperature, growing season, rain and light. Different varietals need different amounts, of course: Zinfandel grapes thrive on heat and direct sun, whereas the notoriously temperamental pinot noir starts to lose its delicate flavor and aroma when exposed to temperatures above 35 degrees Celsius for even a short period of time. By watching the way global warming is affecting vintners, scientists are able to track a so-called environmental envelope for wine -- one that is migrating from the approximate center of the earth (California, southern France, Italy, Australia, Chile and Spain) toward the polar extremes.

"There's a combination of temperature, moisture, slope, latitude and soil quality that goes into the total envelope for wine," says Noah Diffenbaugh, a climate scientist and professor of earth and atmospheric science at Purdue University. "Temperature is only part of the equation, but we do know that one result of excess greenhouse gas concentrations is the frequency of severely hot days. And these will have a very negative effect on most grapevines."

The situation in the Southern Hemisphere is pretty dire: Movement of the wine envelope from Australia and South America toward the pole means the appropriate climate for viticulture will soon be located mostly over water. But in the case of the Northern Hemisphere, where there's more land mass, there's been a definite "upward" trend from the fine wine regions of the past -- namely California and the Mediterranean basin -- toward Oregon, Washington, upstate New York and Ontario, northern France, and Germany.

"In the short term, speaking about global warming from a purely objective point of view, there will be losers, but there will also be winners," says Greg Jones, a professor in the environmental studies department at Southern Oregon University and one of the nation's leading experts in climactic issues affecting wine. "Right now, the warmer winemaking regions nearer the equator are becoming challenged. But if you're on the polar side in either the Northern or Southern Hemisphere, you're a winner. For instance, the wine industries in Britain, Denmark and Tasmania are all growing. And in a lot of cases -- such as the Pacific Northwest and northern Europe -- we're just seeing better ripening climates overall."

Next page: Winemakers are living on a bubble that's due to burst