I. Climate and Wine Production
Grape growing and wine production are highly dependent on climatic conditions. Most quality wine is made from cultivars from the species Vitis vinifera. This species is sensitive to winter and spring frost, which today limits cultivation to approximately 50° latitude north and 45° latitude south. In continental climates, frost issues may arise at even lower latitudes. Although grapes are highly resistant to heat and drought, the best wines are produced in temperate climates. When grapes ripen in conditions that are too warm, wines are unbalanced and lack aromatic complexity (Gladstones, Reference Gladstones1992; van Leeuwen and Seguin, Reference van Leeuwen and Seguin2006).
Wine quality results from a multitude of factors, including soil, climate, and plant material, as well as viticultural and wine-making techniques (Jackson and Lombard, Reference Jackson and Lombard1993). The effect of climate is particularly strong, and even greater than other important factors like soil and cultivar (van Leeuwen et al., Reference van Leeuwen, Friant, Choné, Tregoat, Koundouras and Dubourdieu2004). The typicity of wine produced in different wine-growing regions is very much crafted by the local climatic conditions (Gladstones, Reference Gladstones1992). For a given vineyard, wine quality and typicity vary with the climatic conditions of the year: this is the so-called vintage effect (van Leeuwen et al., Reference van Leeuwen, Tregoat, Choné, Bois, Pernet and Gaudillère2009).
For several decades, it has been observed that not only do climatic conditions vary erratically from year to year, but climate change shows a clear trend toward warmer and dryer growing conditions in most wine-producing regions around the world. According to the Intergovernmental Panel on Climate Change's (IPCC) Fifth Assessment Report, climate change over the past decades is unequivocal and will continue for the following century (IPCC, Reference Stocker, Qin, Plattner, Tignor, Allen, Boschung, Nauels, Xia, Bex and Midgley2013). In the Northern Hemisphere, the past 30 years were the warmest of the past 1,400 years. Human activities have largely contributed to this global warming. The increase in average surface temperature by the end of the twenty-first century is predicted to be likely more than 1.5 °C in all scenarios and up to 4.8 °C in the most extreme scenario (scenario 8.5; atmospheric [CO2] of approximately 1,400 ppm). The Artic regions and lands will warm up quicker than other regions and oceans. Precipitation will be affected with a larger range between dry and wet regions and dry and wet seasons. Sea level is likely to increase from 0.26 up to 1 m in the most extreme scenario. These changes will have a profound effect on wine production.
II. Impacts of Climate Change in Relation to Wine Production
A. Impact on Vine Development and Wine Quality
The effect of climate change on vine development, yield, and wine quality is already being observed in vineyards worldwide through historical data and indirect indicators such as the beginning of harvest (Quénol, Reference Quénol2014). This effect can be broken into different climate factors and accurately studied through modeling (Pieri and Lebon, Reference Pieri and Lebon2014) or real experimentation, both approaches being complementary. The impact of increased temperatures and drought has been modeled by Pieri (Reference Pieri, Brisson and Levrault2010). The impact of increased CO2 levels is mainly studied through modeling (Bindi et al., Reference Bindi, Fibbi, Gozzini, Orlandini and Miglietta1996), but experiments are also implemented in greenhouses (Martínez-Lüscher et al., Reference Martínez-Lüscher, Morales, Sánchez-Díaz, Delrot, Aguirreolea, Gomès and Pascual2015) and free-air carbon dioxide enrichment field studies (Schultz, Reference Schultz2016).
The main effect of climate change is a rise in temperature. Vine phenology is very much driven by temperatures (Parker et al., Reference Parker, Garcia de Cortázar-Atauri, Van Leeuwen and Chuine2011); hence, many studies agree on an advance in the occurrence of phenological stages (Duchêne and Schneider, Reference Duchêne and Schneider2005; Mira de Orduña, Reference Mira de Orduña2010; Pieri, Reference Pieri, Brisson and Levrault2010; van Leeuwen and Darriet, Reference van Leeuwen and Darriet2016). Maturation is expected to be advanced by 15 to 23 days by 2035 compared with 1995 in the Mediterranean basin (Ferrise et al., Reference Ferrise, Trombi, Moriondo and Bindi2016). Surprisingly, little effect is predicted in the same study on yield. The limitation of most studies on the temperature effect is that they are based on average temperatures and ignore the effect of heat spikes (Sadras and Moran, Reference Sadras and Moran2012; Sadras, Petrie, and Moran, Reference Sadras, Petrie and Moran2013).
Increased drought will negatively affect yield (Moriondo, Giannakopoulos, and Bindi, Reference Moriondo, Giannakopoulos and Bindi2011), but this effect is partly offset by increased photosynthesis and water use efficiency due to higher CO2 levels (Gambetta, Reference Gambetta2016; Giannokopoulos et al., Reference Giannakopoulos, Le Sager, Bindi, Moriondo, Kostopoulou and Goodess2009; Schultz and Stoll, Reference Schultz and Stoll2010). Plant respiration will be enhanced and will count for carbon losses at the plant level, possibly negatively affecting yield (Schultz, Reference Schultz2000). In most studies, soil nitrogen offer is not taken into account. This yield-increasing element cannot be absorbed in the organic form, which accounts for 99%+ of the soil's reserves, but needs to be broken down into its mineral form by the microbiological flora of the soil. This process is water and temperature dependent and will thus be affected by climate change (Gambetta, Reference Gambetta2016; Schultz, Reference Schultz2016).
Grapes grown in ever-warmer conditions contain increasingly more sugar, which results in wines with higher alcohol levels (Coombe, Reference Coombe1987; Duchêne and Schneider, Reference Duchêne and Schneider2005; van Leeuwen and Darriet, Reference van Leeuwen and Darriet2016). A significant temperature effect on berry acidity has also been reported, with higher temperatures inducing increased degradation of malic acid concentration (Coombe, Reference Coombe1987). The imbalance between primary and secondary metabolisms may increase, which will make the decision about harvest dates more difficult (Zamora, Reference Zamora2014). However, experimental data about the individual effect of climatic drivers on berry secondary metabolism are still scarce and difficult to collect (Mori et al., Reference Mori, Goto-Yamamoto, Kitayama and Hashizume2007). Interactions among factors like temperature and solar radiation make this research even more difficult (Spayd et al., Reference Spayd, Tarara, Mee and Ferguson2002).
B. Regional and Environmental Issues
Climate change will not occur uniformly over wine-producing regions, in particular with regard to exposure to drought. Although most attention is focused on the water balance over the growing season, rainfall and evapotranspiration in the off season also have to be considered. In a growing number of situations, winter rainfall is becoming too low to replenish the soil water reserves (Schultz, Reference Schultz2016).
The expected spatial distribution of temperature suggests that new areas will become suitable for grape growing. Nevertheless, translocation of viticulture due to climate change can provoke competition for water resources, unprotected natural areas, and habitats for biodiversity. Potential conflicts may arise in already stressed watersheds. Hence, adaptation to climate change should limit additional water development and vineyard relocalization (Hannah et al., Reference Hannah, Roehrdanz, Ikegami, Shepard, Shaw, Tabor, Zhi, Marquet and Hijmans2013; Roehrdanz and Hannah, Reference Roehrdanz and Hannah2016).
Carbon and water footprints have to be established for the wine industry. The wine industry not only is affected by climate change resulting from increased greenhouse gases, but is also a CO2 producer itself. Region-specific carbon footprints have been established in Bordeaux and Champagne production areas, and efforts have been undertaken to reduce CO2 output in these regions (Schultz, Reference Schultz2016). With regard to water, the question of the sustainability of irrigated viticulture is raised. In irrigated areas, 100 to 200 L of water is necessary to produce one bottle of wine. The vine is a highly drought-resistant species that can be dry farmed in regions receiving less than 400 mm of annual rainfall. However, yields are low in dry-farmed vineyards, and economic sustainability is a challenge in those areas that can only be addressed by reducing production costs (calculated on a per hectare basis).
C. Economic Issues
From an economic point of view, climate change is likely to produce winners and losers, winners being located at higher latitudes (Malheiro et al., Reference Malheiro, Santos, Fraga and Pinto2010). Winners from past warming may turn into losers when the warming trend continues (Ashenfelter and Storchmann, Reference Ashenfelter and Storchmann2016). Climate change will affect production costs and the relationship between quality and geographic origins. These factors are critical for the competitiveness of the wine industry not only at local and national levels, but also on an international scale.
An important body of literature is dedicated to the effect of weather on wine quality and prices. In Australia, on average, estimated optimal temperatures are lower than actual temperatures for most varieties and regions. Hence, an increase in temperature is expected to be detrimental to wine quality in that country (Oczkowski, Reference Oczkowski2016), with negative economic impact on the value chains. In Bordeaux or Mosel Valley, the warmest years until now have been correlated with higher wine quality and prices (Ashenfelter and Storchmann, Reference Ashenfelter and Storchmann2016; Jones and Storchmann, Reference Jones and Storchmann2001), but this positive correlation could be reversed in the case of increased impacts of climate change on wine quality and typicity (Fuentes Espinoza et al., Reference Fuentes Espinoza, Giraud-Héraud, Pérès, Pons, Tempère and Darriet2014).
Consequently, wine producers' incomes and assets will be redefined, as well as the hierarchies between the “terroirs” inside a given wine-producing region, or the competitiveness of each region in the world wine market (Giraud-Héraud and Pichery, Reference Giraud-Héraud and Pichery2013). The Languedoc wine region (South of France) already illustrates this spatial and economic impact (Belleti, Marescotti, and Touzard, Reference Belleti, Marescotti and Touzard2015). Over the past 30 years, the Languedoc transition from table wine to quality wine production led to the relocation of vines from the plains to the hillsides, where wines are more concentrated with higher alcohol content. Nevertheless, climate change is strongly challenging the new spatial and economic hierarchies induced by this transition. Several hillside vineyards are now affected by both lower yields and increasing variability in quality, whereas deeper soils in the plains offer new opportunities because of the greater water-holding capacity of the soil. At the same time, plots at higher altitude become increasingly fit for the production of high-quality wines because the climate is cooler.
A key question is whether consumers would accept the modification of the wine quality, which is in many European wine-producing regions strongly linked with the name of the area of origin, associated with specific soil, climate, plant material, and practices. Recently, research has been carried out on consumers' willingness to pay for origin-based wines that are already expressing the impact of climate change on their quality (Fuentes Espinoza et al., Reference Fuentes Espinoza, Giraud-Héraud, Pérès, Pons, Tempère and Darriet2014). If consumers accept the impact of climate change on wine quality, the need for radical changes in technical systems will be less important. If consumers do not accept it, then maintaining a defined wine quality will become a big challenge for producers and researchers.
In France and most other European countries, the production, exchange, and consumption of wine is heavily regulated by standards, rules, and institutions, like the AOC (Appellation d'origine contrôlée) label, which guarantees the origin and control practices, as well as the location of the vineyards. This institutional framework is challenged by climate change, generating intense debates between wine producers at regional and national levels (Belleti et al., Reference Belleti, Marescotti and Touzard2015). In many vineyards worldwide, potential indirect socio-economic impacts of climate change are also beginning to be explored. The contribution of wine to trade balance, positive externalities on tourism activities and gastronomy, and retention of employment in isolated regions could be affected (Ollat and Touzard, Reference Ollat and Touzard2014). Hence, the links between wine and climate change can become a societal issue, calling on policy makers to respond and to support adaptation measures (Delay, Piou, and Quénol, Reference Delay, Piou and Quénol2015).
III. Adaptations to Climate Change
In most studies, the predicted effect of climate change does not take into account possible adaptations by the growers (the so-called dumb farmer scenario). Hence, these studies tend to be overly alarming (van Leeuwen, Schultz et al., Reference van Leeuwen, Schultz, Garcia de Cortazar-Atauri, Duchêne, Ollat, Pieri and Bois2013). In reality, growers are already adapting to the changing climate and will continue to do so. To continue to produce high-quality wines in an environmentally and economically sustainable way, adaptation, defined as “the set of organization, localization and technical changes that societies will have to implement to limit the negative effects of climate change and to maximize the beneficial ones” is a necessity (Hallegatte, Lecocq, and de Perthuis, Reference Hallegatte, Lecocq and de Perthuis2011, p. 5). The main goal of adaptation strategies, as expressed by representatives of the French wine industry, is to maintain yield potential and wine typical quality (i.e., typicity) at a regional level (Ollat and Touzard, Reference Ollat and Touzard2014).
Short-term adaptation can be managed through viticultural (Parker et al., Reference Parker, Hofmann, van Leeuwen, McLachlan and Trought2014) and wine-making (Tilloy, Ortiz-Julien, and Dequin, Reference Tilloy, Ortiz-Julien and Dequin2014) techniques. Mid- and long-term adaptation can be addresses by modifications in plant material (later-ripening varieties and more drought-resistant rootstocks). Substitution for later-ripening varieties is easier in regions where early ripening varieties are planted. Genetic analysis of adaptation to drought is conducted on grapevine varieties and rootstocks (Parker et al., Reference Parker, Garcia de Cortázar-Atauri, Chuine, Barbeau, Bois, Boursiquot and Cahurel2013) in Montpellier and Bordeaux, respectively (Coupel-Ledru et al., Reference Coupel-Ledru, Lebon, Christophe, Doligez, Cabrera-Bosquet, Péchier, Hamard, This and Simonneau2014; Marguerit et al., Reference Marguerit, Brendel, Lebon, Van Leeuwen and Ollat2012).
Technical innovations to answer constraints and opportunities that rise from climate change are in fact the continuation of the historical process of continuous adaptation of the vine into new territories and markets (van Leeuwen, Parker, et al., Reference van Leeuwen, Parker, Destrac, de Resseguier, Garcia de Cortazar-Atauri and Chuine2013). Because of the diversity in growing conditions and wine-making processes around the world, many of these potential innovations are already used somewhere. They need to be exchanged between actors and then experimented with and adapted (Tonietto et al., Reference Tonietto, Sotes Ruiz, Zanus, Montes, Uliarte, Bruno and Climaco2014). Many oenological innovations are already available and can offset or enhance some effects of climate change. Viticultural practices potentially available to adapt to climate change have been reviewed recently (Barbeau et al., Reference Barbeau, Goulet, Neethling, Ollat, Touzard and Quénol2014).
Spatial management of the implementation of technical innovations is important. Large variations in climatic conditions exist within wine regions due to geomorphology, land use, and distance to large water bodies and urban areas (Quénol, Reference Quénol2014; Quénol and Bonnardot, Reference Quénol and Bonnardot2014). Studies of spatial temperature variability are currently implemented in different vineyards. The diversity of temperatures within a region can be similar to the variability recorded between different regions (Bois et al., Reference Bois, Wald, Pieri, Van Leeuwen, Commagnac, Chery, Christen, Gaudillère and Saur2008). The understanding of how growers deal with local climatic variability can potentially yield precious insights into possible adaptations to climate change. More broadly, simulations on the evolution of local vineyards under different collective strategies confirm that the diversity of both natural resources and human resources (wine producers' practices, knowledge, and networks) could be a solution for adaptation (Delay, Piou, and Quénol, Reference Delay, Piou and Quénol2015).
IV. Necessity for Multidisciplinary Research
Scientific approaches have to be developed to support adaptation processes in the wine industry. It is without any doubt a multidisciplinary work, which starts by building a common view among scientists from various disciplines about the possible futures and the main issues for the wine industry. Strong collaborative research needs agreements about targeted climatic scenarios in terms of intensity and timing, as well as agreements about strategic adaptation scenarios. Facing increasing socio-economic and scientific questions, at regional and national levels, the French Institut National de la Recherche Agronomique has launched a multidisciplinary research project not only to explore the impacts of climate change on viticulture and wine, but also to assess current and design future adaptation strategies. The LACCAVE (long-term adaptation to climate change in viticulture and enology) project brings together the expertise of 23 research laboratories, aiming at developing a common knowledge base on climate change issues, as well as defining and assessing adaptation strategies at local, regional, and national levels.
The first outcomes of the LACCAVE project on climate change impacts on vineyards and wines have been published (Ollat and Touzard, Reference Ollat and Touzard2014), and current studies are focusing increasingly on adaptation issues. Beyond the exchanges of information between the different disciplines, scientists decided to improve their multidisciplinary approach by launching a prospective study on the French wine industry by 2050. Four scenarios have been established and discussed with different stakeholders of the industry : a “conservative” scenario that includes only marginal changes, to assess the impact of passive adaptation; an “innovation to stay” scenario that opens all the vineyards to a wide range of technical innovations; a “nomad vineyards” scenario that highlights the opportunity for vineyard relocation under new climatic conditions; and a “liberal” scenario that tests a situation in which “everything is possible everywhere.” In all cases, the pathway to adaptation will be carried out step-by-step, and potential adaptations can by combined differently in each wine region (Viguié, Lecocq, and Touzard, Reference Viguié, Lecocq and Touzard2014). The outcomes of this foresight exercise should be considered as tools to help wine producers and their professional organizations, researchers, and public authorities to develop their own strategies. The following five first recommendations have been formulated:
– Adaptation strategies strongly depend on the level of mitigation (reduction of greenhouse gas emission) and could be reasonably implemented in all French vineyards if global warming remains below 2 °C.
– There is no unique technical solution (such as new varieties) or institutional solution (such as new insurance), but there are different combinations of multiple technical innovations, with spatial strategies and institutional changes.
– These integrated solutions may be determined through a value chain approach, including the evolution of consumers' preferences, which will be a key point of adaptation.
– These strategies of adaptation should be coordinated at local and regional levels, where climate impacts are specific and the use of resources could be optimized.
– Facing many uncertainties, the best way to adapt will rely on the improvement of regional collaboration between researchers and actors in the wine industry.
