The research director at CNRS, Herve Quenol, works on the issue of climate change in vineyards. This Thursday, February 6, he gives a conference at the Bio pole, in Colmar.
Herve Quenol, you are a specialist in climatic consequences on wine and a scientific expert on the Wine-growing environment and climate change commission of the International Organization of Vine and Wine. What are the implications of climate change on the vineyards?
In general, there is an increase in temperatures, which influences the growth of the vines and the wines’ characteristics. That is glaring around the world. In some regions, the effect is negative, especially in the south of France, in Europe, where there are too much sugar and alcohol levels. Conversely, for northern Europe, it is quite positive because everything that was lacking in temperature to achieve good maturity is starting to have it. The regions of the north are experiencing more favorable conditions.
Are there any vineyards that are doing well?
In the Alsace, Champagne, Val de Loire, and Bordeaux vineyards, the maturities are much better than 30 years ago. The negative points are the devastating frost episodes for the vegetation, which wakes up earlier, 15 days on average, during previous events.
The quest for freshness and significant tartaric acidity is the workhorse of many vineyards that produce white wines in particular. And we know that temperatures affect acidity levels.
Absolutely. Compared to the grape varieties, the type of wine we are looking for, the impacts are undesirable. The question of acidity arises above all in the future. We can wonder about the kind of grape varieties to favor in the future, what sort of rootstock to set up, what cultural practice to develop to preserve the quality of the wines.
When tasting certain white wines from the South, one can sometimes be surprised by the level of tartaric acidity. Have you already noticed the implementation of wine-making strategies on the part of producers?
You mention Porquerolles, an island vineyard with a local climate. We are starting to work on these islands to see how this example could limit the adverse effects of climate change. Here we consider the local variability of the climate by integrating characteristics such as altitude, proximity to the sea, etc. How the winegrower adapts to regional climate variability, depending on the aspects of his viticulture, is the subject of my work.
The winegrower has already adapted to the spatial variability of the climate.
How exactly are winegrowers adapting?
That is notably the basis of the European LIFE-Adviclim project. We use different scenarios simulating climatic changes and temperatures to adapt according to the characteristics of our vineyards. Our work consists of defining the current climate of the vineyard by installing sensors and a network of weather stations, depending on local factors such as slopes, types of soil. We thus collect the temperature differences observed in the coldest and hottest sectors. In some areas with rugged topography, there are temperature differences of several degrees. The winegrower has already adapted to the spatial variability of the climate. He plants grape varieties that are less sensitive to cold in the colder parts, and vice versa. In our studies, the winegrower is involved upstream, within the framework of participatory workshops. The ambition is to move towards a reasoned adaptation of practices, rather than towards abrupt change.
Are the French vineyards and the corresponding PDOs armed?
That is a complicated question. There is an experimental project in Bordeaux. Fifty-two different grape varieties plant to observe their potential. What type of grape variety could adapt to future change? As a result of this project, which has been running for ten years, several grape varieties have been added to the list of grape varieties authorized by the INAO on an experimental basis. The awareness is real but is it going fast enough? I don’t know. Within the framework of the European Adviclim project, the wine sector of Geisenheim is a pilot. Tests were carried out on this site by collecting data at the bottom of the slopes, mid-slope, at the slope’s top. That is a question that goes far beyond the scope of French PDOs.
I am not convinced that viticulture is a priority if we had to consider irrigation systems.
irrigation is a debate that is becoming particularly important in the very early stages.
This question is central, but it poses a big problem, not only for the world viticulture. The only exceptions that exist in France are in wine-growing areas where there is precisely the least water. Imagine eventually across the country, if droughts multiply, that irrigation is allowed for viticulture. Here is a source of conflict. I work a lot in Argentina in the Mendoza region. There, viticulture is not possible without irrigation. Logically, the water should go primarily to the population. The conflicts are enormous between all economic sectors. On this issue, we must be vigilant because water will become a significant issue. I am not convinced that viticulture is a priority if we had to consider irrigation systems.
The limits of the culture of the vine go up. We are witnessing the planting of vines in improbable geographical areas at higher altitudes. Are we moving towards a change in the mapping of PDOs?
There is undoubtedly the issue of the climate but also a craze for viticulture. For example, we are working on new vineyards in Brittany. Here is an exploration for the moment—the first commercial vineyard projects plant. The thermal conditions in Brittany are those observed in Anger 40 years ago. We can see very well that there is a rise in the north’s limits: Denmark, Sweden, England. There is a craze for vines in Patagonia, New Zealand, etc. The conditions are much better, and the quality of the wines has become excellent.
Regarding the high altitude vineyards, they have potential shortly, much better than today. Take the example of northern Argentina, in the Cafayate region. The vines thrive at an altitude of over 2700 m and produce excellent wines. In France, if you go up the vineyards a few hundred meters, you can very well find much better conditions.
Do the ancients clear the historical lands in danger?
The characteristics of wines have always evolved. Even if the climate changes, the behavior of the winegrower and the consumer also changes.
Today, to find climate skeptics in the vineyard, it is much more difficult.
You do not hold alarmist speeches.
There is a relatively broad range of adaptation tools. That is what we are trying to show: that there are possibilities for adaptation. The climate is changing very quickly. However, we must be aware that climate changes are rapid and significant. I started my observations in 2006, and many winegrowers argued that there was no climate change. Today, to find climate skeptics in the vineyard, it is much more difficult. They are indeed on the front line.
Do you think that the world’s vineyards are at a turning point in their history?
There is an awareness of the profession. Work with researchers opens up a vast range of adaptation tools in the short, medium, and long term. I am thinking in particular of the national Laccave 2.21 program coordinated by INRA. There are many initiatives: a return to old grape varieties, a desire to adopt in connection with research, etc. I am not pessimistic if I consider the research programs implemented and all these winegrowers developing their cultivation and oenological practices.