Tackling climate change in Bordeaux

Temperatures and unpredictable weather patterns look set to increase in Bordeaux. Elin McCoy reports on the latest research and the measures being taken to address the problem

Last June, at Bordeaux trade fair Vinexpo, Harvard University environmental scientist Professor John Holdren and a panel of winemakers discussed the impacts of climate change on wine before a large – and rapt – audience.

The charts Holdren showed painted a glum picture. In the future, higher temperatures, hotter heatwaves, torrential downpours and hailstorms, as well as more pests, he observed, will challenge the wine industry everywhere, including Bordeaux.

So far, global warming has been kind to the quality of Bordeaux’s great wines.More frequent ‘good’ years, with more sun and warmth, have meant riper grapes. ‘We no longer have vintages like 1963, 1968, and 1984, characterised by green, thin, acid-driven wines,’ says Olivier Bernard of Domaine de Chevalier.Chaptalisation – adding sugar during fermentation to boost alcohol content – is rarely necessary, another contrast with earlier times.

‘Bordeaux wines are better than they’ve ever been,’ comments Florence Cathiard of Château Smith Haut Lafitte. ‘But it shouldn’t get any warmer,’ she cautions.

Unfortunately, the Intergovernmental Panel on Climate Change predicts that average temperatures could rise between 2°C and 4°C by 2050 – the latter being the worst-case scenario. The Bordeaux winemakers I talk to regularly are keenly aware that this would drastically change the wines they make.

For many of them, the torrid 2003 vintage was a wake-up call. Allan Sichel of Maison Sichel, current president of the CIVB (Conseil Interprofessionnel du Vin de Bordeaux), explains: ‘The industry has been researching climate change for 20 years, and in 2008, we launched Bordeaux’s first carbon footprint assessment, which led to Climate Plan 2020.’

The idea behind it is to help slow climate change and figure out ways for Bordeaux wine estates to adapt and survive. But will the wines we love still taste the same?

Growing cycle

Last year, severe frosts at the end of April decimated nearly 50% of Bordeaux’s vineyards. Hard-hit estates, such as Château Corbin in St-Emilion, produced no wine at all.

Blame the devastation on the precocious growing season, one disturbing effect of climate change. The timing of every aspect of the growing cycle is important. Warmth starts it off, and in 2017 early bud-break meant the frost did maximum damage. Generally higher temperatures may make the grape vine cycle shorter, cause grapes to reach maturity sooner, or even change the composition of the grapes.

At Bordeaux University’s Institut des Sciences de la Vigne and du Vin (ISVV), Professor Kees van Leeuwen sketches out some temperature projections for key moments in a vine’s life: flowering in Bordeaux will be advanced by 15 days in 2020 to 2030, and 30 days by the end of the century. Ripeness may happen 25 to 45 days sooner. Hot days during flowering can mean wines with less finesse. If veraison (the beginning of ripening) is too early, occurring in the hottest part of the season, aromas suffer. Right now, harvest is up to two weeks earlier than it was in 1980.

In a recent prediction, winemaker and oenology consultant Dr Pascal Chatonnet bluntly stated that if harvests and growing conditions don’t change, wine will taste riper, fruitier and more syrupy in the future, and that acceleration of the ripening cycle could mean wines will lack subtlety of flavour and have less capacity to age.

Global warming is also responsible for more extreme weather events that may reduce crops. Heatwaves, extended drought, frosts, thunderstorms and hailstorms at the wrong time can wreak havoc on grapes.

New grapes?

Nearly 30 years ago Australian viticulturist and consultant Dr Richard Smart suggested that if climate change continues, Grenache might be better suited to Bordeaux than Cabernet. People called him crazy. Now winemakers worry that the region is already getting too hot for at least one of its official grapes, the early-ripening Merlot.

It’s hard to imagine Bordeaux without Merlot, but in the hottest summers its acidity drops, sugar climbs, and the wines end up as flabby fruit bombs. Agnès Destrac-Irvine, a researcher with the INRA (French National Institute for Agricultural Research), warned in 2015 that Merlot is doomed.

St-Emilion and Pomerol on the Right Bank are already feeling the impact. Baptiste Guinaudeau, owner of Château Lafleur, tells me that he is gradually replacing Merlot vines with later-ripening Cabernet Franc. That could shift the balance of the blend – and the taste.

On the Left Bank, where Merlot was planted to give later-ripening Cabernet Sauvignon some plumpness, global warming is delivering riper Cabernet. ‘That means we’re seeing higher proportions of Cabernet in the blend of Margaux and less Merlot,’ says Philippe Bascaules of Château Margaux. In 2017 it was 89%, while in 2016 that figure rose to 94%.

Another way to adapt is to turn to more exotic varieties, which would change the character of Bordeaux’s wines. At a Vignobles Ducourt vineyard in Entre-Deux-Mers, oenologist Jérémy Ducourt shows me his experimental parcel of Cal 6-04, a crossbreed of Sauvignon Blanc, Riesling and resistant varieties. ‘It has a high level of acidity, a shorter cycle of ripening, and resists mildew,’ he says. The wine, called Metissage Blanc, is fresh, crisp and bright – but hardly a substitute for Domaine de Chevalier Blanc.

Shifting to grapes outside of the permitted varieties has a political dimension as well. Ducourt had to obtain a special waiver from the Ministry of Agriculture to grow 11 experimental varieties.

In the vineyard

It’s an accepted rule in grape-growing to plant late-ripening varieties in places with hot weather. At the ISVV, van Leeuwen is also managing a research project funded by the CIVB called Vitadapt, which is studying 52 different grape varieties planted in a single plot to analyse their growing cycles and resistance to disease, and to see how they adapt to the Bordeaux climate. He explains that there is as much as six or seven weeks’ variation in harvest dates. He sees possibilities in local grape Petit Verdot, which used to have trouble ripening. Colombard, he says, might be a substitute for Sauvignon Blanc, another early-ripening variety.

In Fronsac, Paul Barre was one of the first winemakers in Bordeaux to convert his vineyards to biodynamic farming. Most weather changes he’s observed have been an increase in extremes – violent storms, no rain for months, more devastating frosts. ‘Biodynamics,’ he says, ‘gives vines the capacity to adapt better to their environment, including disease.’ He says some diseases like mildew – which used to develop slowly, so you had time to react – now spread rapidly.

Many winemakers are convinced that biodynamic farming boosts the resistance of vines, especially in hot conditions, although that doesn’t seem to be the primary reason that so many, such as Pontet-Canet, Palmer, Latour, Guiraud, Pichon Longueville Comtesse de Lalande, and others, now embrace these viticultural practices.

Research engineer Nathalie Ollat, a climate change specialist at the INRA is part of the Laccave project, a group of laboratories and teams working on long-term adaptation to climate change in viticulture and oenology. The idea is to discover how vines adapt to threats so that research can propose new growing techniques, varieties, clones – and especially rootstocks.

‘Since 2000, we’ve been working on finding new rootstocks better able to adapt to climate and drought,’ Ollat tells me in her office. The scientists are studying 55 types of rootstock to discover why some have deep roots that can extract more water during droughts and how this affects ripening date and grape composition. Timing of pruning can slow ripening.

Bordeaux can’t adapt by planting vines at higher altitudes as mountainous regions, such as Chile, are doing. But it turns out that warmer and cooler spots exist even inside an appellation. The ISVV’s van Leeuwen is also part of the European ADVICLIM project, which is tracking temperature variability in wine regions with networks of sensors. For St-Emilion and Pomerol, there are differences of 1.5˚C between the warmest and coolest spots. In the future, top bottles may come from cooler spots such as Lussac and Puisseguin.

So far it’s hard to separate out what impact climate change has had on the style of Bordeaux, because winemaking fashion has also played a significant role. Vincent Cruège, group winemaking director at Les Vignobles André Lurton, thinks that right now methods in the vineyards may be more to blame for higher sugar content and alcohol.

But it’s certain the future will usher in a wine style that is full-bodied and ripe. How acceptable will the wines be? Says Ollat of the INRA, ‘In one of our studies we found that at first taste, consumers like those full-bodied wines, but when they drink several glasses they prefer ones that are fresher and less alcoholic.’

Sustainability

Drive up the D2 north of Bordeaux, and you can’t miss the line-up of fancy new cellars designed by star architects. Incorporated into these marvels of glass and stone are investments in green construction designed to reduce greenhouse gas emissions and each estate’s carbon footprint. The goals of the CIVB’s Climate Plan 2020 to reduce use of fossil fuels, water and emissions by 20% by 2020 also include increasing renewable energy use by 20%. Châteaux are taking all of this very seriously. They want to do more than adapt their winemaking to rising temperatures – they want to help slow global warming by saving energy.

At Château Brane-Cantenac, Henri Lurton set up an integrated environmental management system in 2012 to reduce the impact of winemaking on the environment by recycling and using stakes, vine trunks, and stems to help produce electricity. Meanwhile, the massive renovations at Château Montrose have vastly reduced its environmental footprint through the use of 3,000m² of solar panels, geothermal energy, and wind power to generate just about all the energy the estate consumes.

But no château has done more to further the idea of sustainability in Bordeaux than Château Smith Haut Lafitte in Pessac-Léognan, which was invited by the secretariat of the United Nations Framework Convention on Climate Change to make a presentation at COP21, the 2015 Paris Climate Conference.

The vineyards at Smith Haut Lafitte are biodynamic and the estate collects rainwater – and even recycles grape seeds into expensive cosmetic creams. The eco-friendly underground ‘stealth cellar’ for its second wines has no need for electric cooling systems and photovoltaic panels generate energy.

Most intriguing however, is the system to capture the carbon dioxide released in fermentation and recycle it into eco-friendly baking soda via a device on each fermentation vat. So far they obtain about eight tonnes a year, some of which is used at their Les Sources des Caudalie spa and restaurants. ‘We’re aiming for 20 tonnes,’ says owner Daniel Cathiard.

Will all this be enough? Scientists are optimistic that Bordeaux’s major vineyards will still be there in 2050, thanks to adaptation and innovation. But eventually wine lovers will have to get used to different tastes in the glass.

Elin McCoy is an award-winning journalist and author who writes for Bloomberg News

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