Possibilities for adaptation
Climate change doesn’t mean the end of wine. It will require some changes but as we introduced in the previous Step, there are a number of different options for increasing the resilience of the wine industry.
Using meteorological and environmental data, combined with information about the vineyard, computer models can assist wine farmers in making decisions about: when to harvest, what varieties to plant, how much pesticide to use, and how to maximise productivity from areas within the vineyard that differ from one another. So what are the options to adapt?
Using the adaptation potential within one grape variety
One possibility is to select for individuals (or varieties) which offer potential to cope with the effects of climate change, from the existing genetic pool of the plants already cultivated within a specific region. However, this approach is limited by the potential for adaptation within a given variety.
Using varieties from warm dry climates
There are around 8000 varieties of grapes; approximately 300 of which are currently being cultivated to produce quality wines. These varieties have differing potentials for coping with heat and drought.
Creating new varieties
One possibility might be to cross two different varieties of grapes, to create a new hybrid, better adapted to heat and drought. It may be, for example, that crossing cultivated varieties of plants with wild varieties could result in new, sturdy varieties, well adapted to warmer climates and more resistant to pests and diseases.
Figure 2: New vine grapevine rootstock varieties. ©CSIRO.
Canopy and plant management
The removal of some leaves from the vine reduces the rate of transpiration and therefore the water requirement. However, removing leaves around the grapes can expose grapes to the sun before maturity. Direct exposure to sunlight can lead to the degradation of malic acid within the grape, resulting in less acid wines – an undesired side effect of warm climates. Another option for reducing the amount of water required on a vineyard, is to use plants with short trunks that facilitate water circulation.
Plant coverage and soil management on the vineyard
Cultivating plants to cover the soil around the vines offer two benefits:
As you will remember from Week 2, plant growth removes CO2 from the atmosphere thereby counteracting the greenhouse effect.
Growing plants between and around the vines can improve soil quality by improving the retention of water in the soil and through the absorption of carbon and nitrogen. Plant coverage can also help to reduce the surface temperature of the soil and the rate of evaporation. However it’s important to ensure that the plants grown as ground cover, don’t out compete the vines for water and nutrients.
Irrigation systems are already in use in many vineyards around the world, to reduce the drought stress on the plants. While irrigation can be a successful method for reducing the impact of drought on wine production, it is likely that the competition for water amongst different sectors will increase in the future. Although wine is an important agricultural product both economically and socially, the distribution of water in cases of shortage will probably be made in favour of products with a higher nutritional value. Using waste or rain water to irrigate vineyards may help reduce the need for competition with other sectors.
Modern technologies that measure and predict weather and humidity on the vineyard might improve the efficiency of irrigation. Sap flow sensors can directly measure the flow of fluids through the plant, providing information about how much water it transpires. These sensors can be part of an intelligent irrigation system that only waters the plant if needed.
Figure 3: Dripper Irrigation System, Griffith, NSW. ©CSIRO.
If restructuring a vineyard isn’t an option, relocation may need to be considered. Occupation of the soil, the presence of large bodies of water (known to warm in the winter and cool in the summer), or even proximity to urban areas, might open up possibilities to plant vineyards on new ground. On a larger scale, climate change will open up possibilities for growing grapes in completely new regions and the geographical distribution of certain grape varieties may shift. However, the exploitation of new regions also bears certain risks; small scale climatic variations like frost, for example and the establishment of a new vineyard requires a considerable investment in money, labour, and resources. Investing in setting up a vineyard in a new geographical area also bears the risk that many customers may continue to favour wines from well-known regions.
Changes in the policies for wines protected under Geographic Identity programmes
A Bordeaux wine by definition originates in the Bordeaux region in southwestern France. But what if growing wines under the regulations of geographic identity programmes, restrict the vine farmer from making any changes or growing grapes beyond its borders? Adapting policies and regulations for a specific make of wine might be crucial for ensuring its production in the future. In many vineyards, for example in the Bordeaux region, the local wine producers association realises that the ‘code of practices’ dedicated to the Geographical Indication has to evolve. They need to compromise between innovation (new varieties, new practices eg irrigation) and respect for traditional practices and the inherited wine image.
Changes in the wine itself
Since 1990, the alcohol content in French wine has risen by 2-3% per volume (vol.). On one hand this is due to higher temperature, but other factors have also led to the increase: better protection of the grapes from diseases and pests which results in later harvest and riper, sweeter grapes; more efficient yeasts; selection for sweeter grape varieties, resulting in a naturally more alcoholic wine. These factors can be altered and therefore offer potential for adaptation.
A project launched by INRA called ‘Vins de qualité à teneur réduite en alcool’ (‘Quality wines with reduced alcohol content’) investigates several crosses of varieties that show a higher resistance to fungi infections, a later ripening and therefore a lower sugar content at harvest. All of these changes result in wines made from these grapes with an alcohol content of 11-12%vol rather than 13-15%vol.
Another option for reducing the alcohol content of wine is the partial removal of alcohol by letting the wine flow past an osmotic membrane. This technical innovation allows the alcohol to be split from the water and to be reduced. In a final step, all components are mixed together again.
References and further reading:
- Ollat, N., Touzard, J.M. and van Leeuwen, C. (2016). Climate change impacts and adaptations: New challenges for the wine industry. Journal of Wine Economics, 11(01), 139-149.
- Viguié, V., Lecocq, F., & Touzard, J. M. (2014). Viticulture and adaptation to climate change. Journal International des Sciences de la Vigne et du Vin, 55-60.
© University of Reading