How are winegrowers adapting to cope with global warming?

If a few years ago some winegrowers were still doubtful about global warming, today the whole profession has become aware of the phenomenon and climate change is now on everyone's mind. Vineyards and agriculture in general are in the front line. Forced to adapt, winegrowers are laying the foundations for new working strategies.

Global warming in the vineyards

Climate change, global warming, adaptation... all these terms are used in reports, congresses, working groups and conferences, and the entire industry, from winegrowers to institutions, is now aware of the problem. It is impossible to ignore it after the extreme weather events of the last few years which have destroyed several harvests and significantly modified the intrinsic characteristics of the wines. Early harvests, high alcoholic degrees, a notable decrease in acidity, floods, storms, hail, spring frosts and droughts have marked the last three vintages.

Reducing excess heat on the grape berries

When temperatures are too high, ripening is blocked. Winegrowers are therefore working more and more at the vineyard level to lower the temperature of the grapes. In the south of France, winegrowers are reducing or even eliminating leaf removal in order to protect the grapes from the sun thanks to the foliage. In Burgundy, where humidity is high, winegrowers prefer to raise the height of the trimming (an operation that consists of cutting theends of the vines).

Because "warmer weatherdoes not mean good weather", underlines Ludivine Griveau, manager of the Hospices de Beaunes in Burgundy, during an interview for BurgundyToday. In fact, Burgundy has to deal with higher temperatures while maintaining a high level of humidity, thereby increasing pest pressure.

Fighting against periods of drought

The availability of water will be the major challenge in the years to come, a brutal consequence of climate change. Rainy periods are more powerful and less well distributed over the year. They often cause damage and are insufficient in the face of summer droughts. Winegrowers are reappropriating cultivation techniques that help drain the soil better, limit erosion and replenish the water table.

Grass cover in the vineyard is a subject that is increasingly studied in research centres and practised by winegrowers. Grass cover helps to reinforce biodiversity, protect the soil and maintain a certain amount of humidity in the vines. In the Languedoc region, where the drought is very severe in the summer, weeding the inter-rows avoids the competition of the grass on the vine for water.

Towards irrigation of vineyards?

The question of de facto irrigation is being raised more and more in the vineyards. Will it one day become essential to continue producing quality wines? Or will water constraints render this solution obsolete before it is even discussed? Looking beyond our borders, it is clear that while irrigation has helped the development of vines in the provinces of Mendoza (Argentina) and California (United States), it has not solved the wine problem.It does not solve the problem of global warming in these regions, nor does it provide answers to the lack of water.

Adaptation through the choice of grape varieties

Well aware of this contradiction, the IFV (Institut Français de la Vigne et du Vin) is focusing its research on varietal improvement and rootstock selection in order to offer winegrowers varieties with better water resistance. Winegrowers have not waited for the results of this research to consider the varietal adaptation of their plots, favouring more water-efficient varieties that can adapt to rising temperatures.

Limiting the alcoholic degrees of the wines

The latest vintages show that alcoholic degrees are rising, acidity is falling and it is not easy for oenologists to maintain good balance. A glance at the catalogues of oenological products confirms this trend. Yeasts that limit alcohol production and/or increase acidity in wines are increasingly being proposed as a solution to winemakers. Winemakers are also playing with the length of maceration to balance the wines, modifying the oenological processes slightly but quite easily, as Ludivine Griveau explains: "Aslightly longermacerationbefore it ferments into red, to get the maximum amount of aromas [...] Afterwards, a shorter alcoholic fermentation, the alcohol coming out more slowly, silkier extracted tannins".

Global warming: a boon for northern vineyards?

It's a saying that we sometimes hear: vineyards are moving north, a boon for some regions at the expense of southerners. Professor Monika Christmann, director of the University of Geisenheim in Germany, reports that global warming, initially positive for German vineyards, is "now proving to be too much". Moreover, "whilesummers are increasingly favourable for wines, they are also increasingly chaotic and winegrowers have to deal with climatic accidents".