When wine has a thirst for research. © FOTOLIA, Fotolia

When wine has a thirst for research

Climate change: which wines for tomorrow?

What are the effects of climate change on vines and wines?  How can winegrowers adapt to this change?  Which scenarios can be applied to French winegrowing regions in 2050? In March 2012, INRA initiated a multidisciplinary project federating 23 research units around these high priority issues.  Named Laccave (Long term impacts and Adaptations to Climate Change in Viticulture and Enology), this programme aims to examine the principal effects of climate change on vines and wines and to explore different innovations and strategies for adaptation.

Updated on 11/21/2013
Published on 11/21/2013

3 weeks ahead in 30 years

Data collected by INRA over the past thirty years have proved that combined with changes to certain cultivation methods, global warming has already pushed forwards the entire growing cycle of vines, from flowering to harvest.  Today, grapes are harvested between two and three weeks earlier than they were thirty years ago!  The berries are sweeter and less acid, which produces wines containing more alcohol and less acidity.  In the longer term, climate change may also have an impact on yields, the varieties grown, diseases and pests.  In southern France, the principal consequences may be a reduction in yields and wines that are more concentrated, including in alcohol.  In northern areas, grapes will ripen better, causing modifications to the aromatic profiles of wines.  New regions may also start producing wine, such as Brittany or south-eastern counties in the UK.

Vines and vineyards in the future

In each winegrowing region, actors are mobilising their efforts and envisaging levers for possible adaptations, which include selecting later varieties or those producing less sweet grapes, using yeasts that limit the transformation of sugar, managing future planting schemes based on simulations of climate change, modifying the regulations, etc.  Numerous ideas are under study in the context of the Laccave project; here are a few examples:

◗ Analysis of economic strategies
What are the economic conditions for the adaptation of producers and consumers to global warming?  At INRA and the Institute of Vine and Wine Sciences in Bordeaux, economists and oenologists are analysing the heterogeneity of consumer tastes and willingness to pay for wines produced under specific conditions of late harvesting and the overmaturation of grapes.  In 2013, they initiated a study that notably involves some thirty tasting experts and a hundred regular consumers.  Its results will supplement other work being carried out at INRA on how consumers perceive a lower alcohol content in wines.

◗ Facilities that are unique in the world
Measuring the heterogeneity of berries at harvest on a grille (for random sampling). © INRA, Yves Cadot
Measuring the heterogeneity of berries at harvest on a grille (for random sampling) © INRA, Yves Cadot
In the context of potential changes to the varieties grown in the Bordeaux region, an experimental plot grouping some fifty varieties has been set up on INRA's experimental farm, with the support of professionals from the Bordeaux vine and wine industry.  Planted in June 2009, this plot - named Vitadapt - is unique in the world: 52 varieties, all grafted on the same rootstock, were selected and will be monitored each year for at least thirty years.  Numerous measurements are being performed and include vine phenology and grape ripening parameters.  This plot is now coming into production (first harvest in 2011) and micro-vinifications are planned in the years to come in order to characterise the winemaking qualities of the varieties planted.  This work will supplement other INRA research on the vine developmental cycle and varieties producing grapes with a lower sugar content.

◗ Loire Valley: studying the climate at a mini-scale
One of the major French wine-producing regions, the Loire Valley, experiences quite marked climatic nuances that partly explain the diversity of the wines produced.  By experimenting on pilot sites (Coteaux du Layon and Saumur Champigny), INRA researchers have shown that this diversity also exists at the scale of wine-growing terroirs or appellations.  Furthermore, they have analysed the evolution of the composition of grapes from the six varieties most widely grown in the Loire Valley.  Their results have revealed a widespread rise in temperature and in the bioclimatic indices1 affecting vines during the past 60 years.  Thus the perspective of climate change may involve a major variability in grape quality and changes to the typicality of wines.  However, this work has also indicated margins for adaptation in the short or medium term that will ensure maintenance of the quality and typicality of the wines produced at present.

◗ The spectre of drought: agronomy and precision irrigation
By acting on the opportunities for, and intensity of, irrigation, it is possible to produce wines with markedly different qualities.  INRA researchers are developing tools to evaluate the water requirements of different varieties and to manage precision irrigation.  The challenge is to ensure the efficient  use of water, with particular emphasis on preserving this resource.  To achieve this, studies are also ongoing on the use of alternative water sources, such as the collection of winter rainfall or the use of water from water treatment plants.

1 These bioclimatic indices calculate the climatic factors which influence grape quality; they take into account for example the daily average temperatures above 10°C, cool night temperatures, sugar content, soil properties, etc.