Raise a Glass of Scottish Wine to Global Climate Changes

Thanks to climate change, Christopher Trotter will make history later this year by pairing a Scottish white wine with the local spoots.

The razor clams harvested from the nearby shores of the North Sea will go down nicely with the first bottles from Trotter’s vineyard north of Edinburgh. The 2014 vintage will be special for Scotland, where Highlanders have distilled whisky and brewed ale for centuries.

“Scotland has probably been more of a beer-drinking nation than anything else,” said Trotter, a chef and food writer. Wine hasn’t been part of the culture, he said, “until now.”

Trotter might as well pour a splash on the ground in memory of a vanishing world. Climate change, which scientists say is caused by heat-trapping gas accumulating in the atmosphere, is transforming dinner tables and scrambling traditions in the $270 billion global wine industry. In Europe, warmer seasons are chasing Italian and Spanish vintners up hillsides, making a winner of Germany, encouraging growers in Poland and spreading the cultivation of wine grapes to latitudes friendlier to belly-warming whiskies and ales. And it’s raising the alcohol content, and altering the flavors, of famous wines in France.

Vitis vinifera, the common grape vine, is a finicky crop. Vineyards flourish where average annual temperatures range from 10 to 20 degrees Celsius (50 to 68 degrees Fahrenheit). Too much dry weather, hail or too much rain can downgrade or wreck a vintage.

Fine Wine

“Wine is very responsive to climatic factors,” said Karl Storchmann, a professor of economics at New York University and managing editor of the Journal of Wine Economics. “This is especially true for fine wine, when weather-induced vintage-to-vintage price variations can exceed 1,000 percent.”

Over centuries, growers in the top producing countries -- France, Italy and Spain -- selected grape varieties that now account for 75 percent of the world’s wine plantings, according to a database prepared by the University of Adelaide in Australia.

As much as 73 percent of today’s major wine-growing regions will no longer be optimal by 2050, according to a study last year by Lee Hannah, a senior scientist at Arlington, Virginia-based Conservation International. With grape varieties in Europe selected for local conditions over more than a millennium, warming may leave the natives outside their comfort zone, according to research by Gregory Jones, a research climatologist at Southern Oregon University in Ashland.

More Sugar

Already, global warming is boosting sugar levels in grapes. That means more alcohol in wine. In the Bordeaux region of southwestern France, where viticulture dates to Roman times, alcohol levels have risen to between 13 percent and 14 percent from 11 percent 15 years ago, Christian Seely, the managing director of wine-estate owner AXA Millesimes, wrote in a September presentation for a symposium on reducing alcohol levels.

While more alcohol partly results from wine-makers’ choice to let grapes ripen longer for bolder flavors, the growers are only able to do so because of a warming climate, said Jones, who’s published dozens of studies on wine and climate.

“A warmer climate is taking hold little by little,” said Olivier Bernard, owner of the Domaine de Chevalier estate in Bordeaux’s Pessac Leognan area since 1983. “We’re harvesting grapes in Bordeaux now that are indisputably riper than 20 years ago.”

Optimal Climate

What Bordeaux harvests will look like 20 years from now concerns Antonio Busalacchi, a climate scientist at the University of Maryland in College Park who is also an advanced sommelier. Bordeaux is the largest wine-growing area in France, producing about 543 million bottles last year, according to government estimates. It’s also the best-known region for oenophiles in the U.K., Germany and China and in the U.S. ranks behind only Napa Valley and Sonoma County in name recognition, according to surveys by Wine Intelligence Ltd., a London-based marketing and research firm.

For now, climate conditions in the region are optimal, with warmer temperatures allowing growers to coax their Cabernet Sauvignon grapes to full ripeness, Busalacchi said. Future Bordeaux may differ from the wine that made the region famous, with aromas such as blackcurrant and cigar box shifting to spicy and peppery, he said.

“The Bordeaux you’re drinking today will not be the Bordeaux you’re drinking 20 years from now,” Busalacchi said.

The Burgundy region, in east-central France, has reached a peak where “upside potential is tapped,” he said.

Earlier Harvest

One reason is that more alcohol means fewer of the acids and tannins that contribute to a wine’s character, such as the freshness of dry Riesling or the complexity of aged Bordeaux, and which also help extend a bottle’s shelf life.

Burgundy harvest dates going back to the 14th century have been used to reconstruct past climate. A 1-degree Celsius rise in average growing-season temperatures means growers harvest about 10 days earlier, according to studies building on research by French historian Emmanuel Le Roy Ladurie.

Today, Burgundy growing seasons are on average 1.4 degrees warmer than in the 1970s, and harvest begins about two weeks earlier, according to Benjamin Bois, a climate researcher at the University of Burgundy in Dijon.

Upper Limit

Seasonal temperatures now average about 17 degrees Celsius, which may be the upper limit to produce quality wine from the Pinot Noir reds and Chardonnay whites that are Burgundy’s signature grapes. Further warming may push the wines to the cooked-fruit end of the taste spectrum, according to research by Jones at Southern Oregon University.

In Fife, in eastern Scotland, where farming is dominated by pasture and barley fields, last summer was hotter than anything Trotter said he remembered since childhood. At a weather station about 13 miles north of Trotter’s vineyard, monthly high temperatures averaged 21.4 degrees Celsius last July, the second-highest on record.

For his inaugural Scottish vintage, Trotter said he planted 75 percent Solaris grapes, an early-budding variety developed in Germany in 1975, with the remainder Siegerrebe and Rondo. He said he chose them for their easy ripening rather than for their ability to produce great wines. It’s still too cold for Sauvignon Blanc, he said.

Trotter said he just pruned the vines back to 45 centimeters (18 inches) after “incredibly vigorous” growth last year. He said he’s considering spreading seashells under the vines to retain daytime warmth, a trick he says was inspired by French growers who use limestone to the same effect.

Heat Wave

He’s planted 200 vines as a first step, and this year’s production may not be more than a dozen bottles, Trotter said. If it works, he said he’ll look for investors and plant his entire 2.4 hectare (6 acre) field.

The 30-year period through 2012 was likely the warmest in 1,400 years, according to the Intergovernmental Panel on Climate Change, meeting through March 29 in Yokohama, Japan.

For a taste of the future, climatologists look to 2003, when a heat wave in Europe prompted Burgundy’s earliest harvest in more than 650 years and shriveled berries in the vineyards of Bordeaux.

The conditions of 2003 may represent an average year by the end of the century, according to Bois. A hotter climate may reduce the acidity that plays a role in storage potential and the night-time cooling that maintains a broad palette of aromas in the wine, he said.

Rhine Valley

On the upside, global warming may be a boon for areas like Germany’s Rhine Valley, and growers are pushing the cold limit in Poland, Jones said. Podkarpacie, Poland’s biggest wine-producing province, had fewer than 40 wineries a decade ago; it now has more than 100, according to a local industry association.

The most recent edition of the 400-page World Atlas of Wine reported “considerable” expansion of the world wine map toward the poles, said Jancis Robinson, a U.K. wine critic who is the co-author of the atlas.

The 12th-century geographer Al-Idrisi described vineyards around Ghent in modern-day Belgium, Utrecht in the Netherlands, in Bremen in what is now Germany as well as around Krakow in Poland. Vineyards were planted in southern England from the 10th to the 13th century, before disappearing during the cooling period known as the Little Ice Age.

Mueller Thurgau

In Germany, the most northerly major wine producer, warming means the risk of later varieties not ripening has all but disappeared, according to the country’s Wine Institute.

Mueller Thurgau, a white wine grape that ripens at temperatures about 1 degree Celsius lower than the bottom limit for other varieties, covered 26 percent of Germany’s vineyards in 1980. Today the grape, maligned by some critics as a source of low-quality wines, covers half that area while Pinot Noir raised its share to 11 percent from 3.8 percent.

As efforts to mitigate climate change have fallen short of goals, development groups such as Oxfam have urged farmers to adapt. The world is “woefully unprepared” for the threat to food security from drought and flooding brought on by a warming climate, the Oxford, England-based Oxfam said yesterday. There are plenty of practices wine growers can adopt, according to Busalacchi. Vintners may prune to leave more foliage or raise grapes away from the ground, irrigate to blunt the effect of heat waves, plant different varieties or change vineyard orientation.

North Face

“There are games you can play with exposure and altitude, even in a place like Burgundy,” Busalacchi said.

Greek wine farmers are planting on north-facing slopes, he said. And Miguel Torres SA, Spain’s largest family-owned wine-maker, has planted vines 1 kilometer (0.6 mile) above sea level in the foothills of the Pyrenees, four times higher than its main winery in southern Catalonia, according to company President Miguel A. Torres.

“Assuming a farmer who is static and doesn’t adjust, economists call this ‘dumb-farmer scenario,’ yields and quality will fall as temperatures exceed the optimum,” Storchmann said.

Weather extremes, some caused by climate change, threaten viticulture. A European Union study published in January predicted droughts will intensify in southern Europe, with minimum stream flows in Spain, Portugal and southern France and Italy falling by as much as 40 percent.

Bordeaux, Burgundy and the Loire Valley’s Vouvray suffered unusually intense and widespread summer hailstorms last year, denuding entire plots of grapes. Between 1989 and 2009, the intensity of hailstorms in France increased by 70 percent even as the frequency didn’t rise significantly, according to the country’s National Association to Suppress Atmospheric Plagues.

Warmer Regions

A 2012 heat wave and drought across southern Europe reduced the harvest in Italy, France and Spain by a combined 12 percent, based on data from the International Organisation for Vine & Wine in Paris.

Vines shut down above 35 degrees Celsius, a temperature that is likely to become more frequent in warmer growing regions later this century.

For now, it’s the deer that eat the rose bushes that pose a bigger threat to his vines north of Edinburgh than winter cold, Trotter said.

As for getting enough heat to ripen the grapes for delicious wine, Trotter said, “We’re quietly confident.”