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Hot topic – Global Warming

BEVERLEY BLANNING MW looks at how winemakers are coping with climate change, and wonders if it means an end to our classic wine styles

Consider this: Bordeaux may already have had its best vintages for Cabernet.’ This blunt analysis, from Australia’s flying ‘vine doctor’ Richard Smart, probably gave more pause for thought than any of the swirling maps, emotive speeches or lists of data presented at the second Climate Change and Wine Conference, held earlier this year in Barcelona. Warming to his theme, Smart added: ‘Maybe we’ll think of future vintages as “postclassic”, and therefore worth less.’ If anything more was needed to fuelthe spiralling prices of 2005 Bordeaux, there it was. But the larger question is this: if climate change really does mean Bordeaux’s days as a fine wine region are numbered, does the same fate await the rest of Europe’s great vineyards?

The Europeans show more optimism about the future than winemakers Down Under. When Bordeaux-based international consultant Michel Rolland spoke at the Barcelona event, his tone was more relaxed than Smart’s: ‘Climate change is not changing our lives day to day,’ he said, ‘We’re making wines in the same way. We have more sugar because we want more sugar; we have more silky tannins because of what we are doing in the winery.’ It sounds rather glib, but Rolland does have a point. So far, climate change has favoured production of the style of wines the world loves, and for which Rolland is acclaimed. Why would he – or we – be complaining? Well, for a start, fashions are turning away from the more full-bodied, riper styles that are high in alcohol, and there is a surge of rosé and flavour-light whites, such as Pinot Grigio. Is it even going to

be possible in the future to produce crisp, lightweight, yet high-quality wines in

the cool European climates of today? According to Hans Schultz of the Geisenheim Research Centre in Germany, higher temperatures have already changed some styles of wine. ‘The wines from classic, cool-climate grape

regions used to be thin and low in alcohol,’ he says, ‘but now, ripening is

much more consistent.’

A growing problem

Perhaps we have been slow to pick up on the relatively gradual effects of climate change because improvements in vineyard management and winemaking knowledge have taken place alongside better vintages. All of these factors cater for today’s demand for ripe wines that are approachable earlier. Schultz’s view is backed by numbers from France, showing, for example, that the average alcohol level in Alsace Riesling has risen by 2% in the past 30 years (and let’s not forget, these are wines that are also getting sweeter). According to Smart, viticulture is the ‘canary in the coalmine’ for agriculture. ‘The effects [of climate change] will be seen earlier, and be more dramatic,’ he says. Harvest dates are getting earlier in many regions of Europe, yet grapes are riper when they are picked. The harvest in Châteauneuf-du-Pape, for example, is a month earlier than in 1945. Bernard Seguin, of INRA, the French agricultural research institute, reports that for every 1˚C increase in temperature in France, it is necessary to go 200km north. If the prediction that temperatures rise by 2ºC

in Europe within 50 years is accurate, growing conditions are probably going

to change sooner than we think. The ways in which warming will affect grape growing are, in many respects, well understood. Higher levels of carbon dioxide will increase photosynthesis and vegetative cycles will shorten. Raised temperatures will lead to more evaporation and transpiration, which could, in turn, lead to vines with water stress if rainfall levels drop. If winters are mild, advanced vine growth in the spring will lead to greater risk of frost or poor fruit set in some regions, possibly creating new risks. With the growing season being earlier, the crucial ripening period of véraison will fall in the warmer month of July, instead of August. This will affect the flavour and aromatic profile of fine wines. At high temperatures, the aroma potential of grapes falls away sharply.

Years of practice

Smart notes that the reputations of the classic regions of Europe were created by hundreds of years of a climate that was more or less stable. The well-known

relationship between varieties and climate, and the consequent strictly delineated boundaries that mark the world’s historic wine-growing regions were formed by centuries of accumulated knowledge and tradition. The Old World has always had a headstart in wine: there has always been the experience of previous generations to draw on, so fewer mistakes to make. But the current evidence suggests that the pace of change for today’s generation in

Europe will be so fast that they will be the ones to shape the future. Moreover,

they may well be looking to the experiences of those in the warmer climates of the New World to know what the future holds for them in Europe. The Geisenheim’s Hans Schultz and Greg Jones of Southern Oregon University studied climate trends in 27 of the world’s major wine regions (see

maps, above and over). They found that between 1950 and 2000, the average increase in temperature during the vine’s growing season was 1.3°C. Looking at the European regions only, the increase was significantly higher, at 1.7°C. Andthis is before the heatwave of 2003 and steady rise in average temperatures since. ‘It’s not just the rise in temperature that will be the challenge in Europe,’ says Schultz. ‘For most regions, it’s the variability that will be the problem.’ The

same study showed increased variability in climate in 18 of the 27 regions. Schultz and Jones predict these patterns are set tocontinue. Mosel winegrower Ernst Loosen is all to aware of the issues: ‘We used to have vintages that were not as ripe, but we knew what we were dealing with. Now, it’s a new problem every year. I want to keep making the same style of wine, but we have different

problems now.’ He cites the heatwave of 2003 and the botrytis rot problems of

2006. ‘We must learn how to handle these kinds of vintages,’ he says. Changes in temperature will, says Schultz, cause ‘massive fluctuations’ in

rainfall, a scenario that could threaten the continued viability of some of Europe’s

best vine-growing areas. Shortages of water are a relatively new problem in Europe, and one that producers are ill-equipped to deal with. Quite apart from the legal and ideological constraints that have prevented irrigation in the past, there is simply no infrastructure at present in Europe for this type of water management. ‘The New World idea of planning a vineyard around water availability is a conceptthat is absent in traditional wine growing regions,’ Schultz points out. Vineyards on steep slopes, such as those of the

Mosel Valley and the Douro, will suffer most, he predicts, both from the

impracticality of setting up irrigation systems and from extremes of precipitation. Heavy rainfall will increase erosion and degrade the organic matter

in the soil. This is more problematic the steeper the slope, and will affect how the soil retains water and the quality of wine.

Adopt, adapt, improve

But it’s not all doom and gloom for the vineyards. Those that can adapt to the

changing conditions will be best placed to continue to make fine wine, even if it is not necessarily the same wine, in the same place they make it today. Schultz comments that so far in Europe, we have only really understood the lower limits of temperature for viticulture, and have never explored the upper limits. What is

needed is more understanding of how existing vine varieties can adapt and still

make quality wine in the areas where they are planted today. One hopes for

speedier (or more relaxed) legislation to allow winemakers more flexibility.

For the most part, the French, at least, seem bullish about their situation. On a

recent week-long trip to the Côte d’Or, nobody was talking about anything more

sinister than the most recent Burgundy vintage in the glass before them. And the

Bordelais are relentlessly optimistic. Bruno Prats, winemaker and former

owner of Cos d’Estournel, says: ‘Yes, there are problems, but we do have solutions. Bordeaux has lots of options: there’s Syrah and Carmenère, and Malbec could replace Merlot.’ Smart has some words of comfort, too: ‘It’s not all bad news. Warm areas like Bordeaux can bring back old varieties, and hot areas have 20 years to breed something new.’ Even so, it looks like his money is still on Tasmania.

Written by Beverley Blanning

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