An overview of climate change impacts on European viticulture

Abstract

The importance of viticulture and of the winemaking socioeconomic sector in Europe is largely acknowledged. The most famous winemaking regions in Europe commonly present very specific environmental characteristics, where climate often plays a central role. Furthermore, given the strong influence of the atmospheric factors on this crop, climate change can significantly affect yield and wine quality under future conditions. Trends recorded in the recent past on many viticultural regions in Europe hint at an already pronounced increase in the growing‐season mean temperatures. Furthermore, climate‐change projections give evidence for significant changes in both the growing‐season temperatures and precipitations in the next decades. Although grapevines have several survival strategies, the mounting evidence for significant climate change in the upcoming decades urges adaptation and mitigation measures to be taken by the whole winemaking sector. Short‐term adaptation measures can be considered as a first protection strategy and should be focused at specific threats, mostly changes in crop‐management practices (e.g., irrigation, sunscreens for leaf protection). At long term, however, a wide range of adaptation measures should be considered (e.g., varietal and land allocation changes). An overview of the current scientific knowledge, mostly concerning the European viticulture, the potential climate change impacts, and feasible adaptation measures is provided herein.

Viticulture Worldwide

Both viticulture and winemaking are important practices that represent a key economic activity in many regions worldwide. In the most recent report of the International Organization of Vine and Wine (OIV ), it is estimated that the world's vineyards reached a total area of 7.59 Mha in 2011, despite its decrease in the last few years (Fig. A). This trend is clearly associated with the decrease of the vineyard area over Europe. Although Europe has lost some of its dominance to Asia, USA, and some southern hemisphere areas (Argentina, Australia, Chile, South Africa), Europe still encompasses the largest vineyard area in the world (38%; Fig. A). Based on the same report, global wine production stood at 265 Mhl in 2011 (Fig. B), while wine consumption reached 244 Mhl. In spite of the downward trend in vine surface area, grape production underwent an upward trend over the last few years (Fig. B). The world's top wine‐producing countries (Table ) are France, Italy, and Spain, while it is worth noticing that China, Chile, and New Zealand recorded the largest increases in production over the last years.

Top 16 wine‐producing countries in 2011 (with respective growth rate from 2007). Total vineyard area in 2011 is also shown (with respective growth rate from 2007). Table is sorted by a descending order based on wine production (OIV )

Country	Wine production (Mhl)/growth rate	Vine area (mha)/growth rate
France	49.6	9%	807	−7%
Italy	41.6	−10%	776	−6%
Spain	34.3	−1%	1032	−4%
USA	18.7	−6%	405	2%
Argentina	15.5	3%	218	−4%
China	13.2	6%	560	4%
Australia	11.0	14%	174	0%
Chile	10.6	29%	202	3%
South Africa	9.3	−1%	131	−12%
Portugal	5.9	−2%	240	−3%
Romania	4.7	−11%	204	0%
Brazil	3.5	−1%	92	0%
Greece	2.6	−26%	111	−6%
Hungary	2.4	−24%	65	−13%
New Zealand	2.4	59%	37	21%
Bulgaria	1.3	−29%	73	−22%

(A) Total vine surface area and percentage of this area in Europe, Asia, USA + southern hemisphere regions, and others, from 2000 to 2011. (B) Total grape production, wine production, and wine consumption for 2000–2011. Adapted from OIV ().

Figure  depicts the current viticultural regions of the world, including some world‐renowned winemaking regions, such as Bordeaux, Burgundy, California, Cape/South Africa, Champagne, La Mancha, La Rioja, Mendoza, Mosel, Porto/Douro, South Australia, Tuscany, among others. The current viticultural regions are usually within areas with Recognized Appellation of Origin (RAO; Resolution OIV/ECO 2/92) or Designation of Origin (DO; European Community 479/2008 Art. 34 1a), which ensures the typicity of wines. In Europe, more specifically, these famous winemaking regions are traditionally distinguishable by their prevailing environmental characteristics, such as climate, soils, and grown varieties. While most of the regions in southern Europe have typical Mediterranean climates, with long, warm, and dry summers, central and northern Europe are often characterized by more continental and/or humid climates, with mild and rainy summers (Kottek et al. ; Peel et al. ). According to Carbonneau (), the microclimatic and mesoclimatic characteristics of a given viticultural region are key factors in understanding its varietal suitability and wine types. These climatic aspects have been valorized and properly taken into account in all ancestral wine regions, where vine growers have gradually adapted to best suit their regional/local environmental conditions (Jones ).

World distribution of the viticultural regions (darker areas).

Soil and cultural practices are also important controlling factors in the development of viticulture. It is widely known that certain winegrape varieties produce the best results in soils with specific characteristics. Soil chemistry and structure may indeed influence wine grape composition (Mackenzie and Christy ). Moreover, management practices such as crop load, girdling, pinching, pruning, rootstock and scion, thinning, and topping may also influence wine grape growth and quality (Winkler ). Regarding the enological practices, Unwin () stated that they have remained nearly unchanged until recent decades, when some technological breakthroughs have been carried out. As such, climate, soil, and management practices form a highly complex and interactive system called Terroir (Magalhães ). According to the OIV (Resolution OIV/VITI 333/2010), “Terroir is a concept which refers to an area in which collective knowledge of the interactions between the identifiable physical and biological environment and applied vitivinicultural practices develops, providing distinctive characteristics for the products originating from this area. Terroir includes specific soil, topography, climate, landscape characteristics and biodiversity features.” This system significantly affects vine development and berry composition and has been accepted as a central aspect in determining wine quality and typicity (van Leeuwen et al. ).

Nowadays, viticulture faces new challenges and threats, some of the most important being related to climate change. Therefore, a discussion on the interconnections between vine physiology and climate is presented in Vine Physiology and Climate Influences. The climate change projections and their impacts on viticulture are presented in Climate Change Projections in Agriculture and Climate Change Impacts on Viticulture. Adaptation and Mitigation Measures is devoted to the adaptation and mitigation strategies. Finally, Conclusion outlines the main outcomes.

Vine Physiology and Climate Influences

The vine undergoes morphological and physiological changes resulting from different stages of its vegetative and reproductive cycles (Fig. ). The duration of each phenological stage differs according to each grapevine variety, which is generally tied to the thermal conditions of each region (Mandelli et al. ). The prediction of stage evolution is of utmost importance in planning viticultural activities and winemaking decisions (Lopes et al. ). Jones () showed that the length of the growing season, for each variety, is directly related to the growing‐season mean temperature (Fig. ). Additionally, Webb et al. () concluded that the length of the growing season could also be linked to soil moisture, air temperature, and crop‐management practices. In fact, climate strongly influences the development of this crop, by requiring suitable temperatures, radiation intensities/duration, and water availability during its growth cycle, which ultimately influence yield and wine quality (Magalhães ; Makra et al. ).

Vegetative and reproductive cycles and vine phenological stages. Adapted from Eichorn and Lorenz () and Magalhães ().

Maturity groupings based on the growing‐season mean temperature, for a set of grapevine varieties. Adapted from Jones ().

Air temperature is considered the most important factor in the overall growth and productivity of winegrapes (Jones and Alves ). In effect, grapevine physiology and fruit metabolism/composition are highly influenced by the mean temperature along the growing season (Coombe ). Even though this crop has a good adaptation to environmental stresses, enduring extremely low temperatures in short time periods during winter (Hidalgo ), negative temperatures during spring may severely damage the developing buds and leaves/shoots (Branas ). This crop is also very sensitive to late frost and hail events (e.g., Spellman ). However, winter chill is an important aspect in its growth development, as cold promotes bud dormancy (Kliewer and Soleiman ), initiating carbohydrate reserves for the following year (Bates et al. ; Field et al. ). In the same way, a 10°C basal temperature is required for the vine to break this dormancy and initiate its growing cycle (Amerine and Winkler ; Winkler ). Extreme heat or heat weaves may also permanently affect vine physiology and yield attributes (Kliewer ; Mullins et al. ), although some varieties may be more tolerant than others (Schaffer and Andersen ; Moutinho‐Pereira et al. ). Grapevines growing under severe heat stress experience a significant decline in productivity, due to stomatal and mesophyll limitations in photosynthesis (Moutinho‐Pereira et al. ), as well as injures under other physiological processes (Berry and Bjorkman ). Some studies argue that cool night temperatures in the period preceding the harvest (maturation/ripening), combined with high diurnal temperatures, stimulate the synthesis of anthocyanins and other phenolic compounds, being thus beneficial for high‐quality wines (Kliewer and Torres ; Mori et al. ).

Annual precipitation and its seasonality are also critical factors influencing viticulture, as water stress can lead to a wide range of effects, yet largely dependent on the stage of development (Austin and Bondari ). For instance, proper soil moisture during budburst and shoot/inflorescence development is of foremost importance for vine growth development (Hardie and Martin ; Paranychianakis et al. ). Water stress at this stage may also cause small shoot growth, poor flower cluster and berry set development (Hardie and Considine ). On the contrary, excessive humidity during these early stages overstimulates the vegetative growth, which leads to denser canopies and a higher likelihood of disease problems in leaves and in inflorescences. From flowering to berry ripening, severe water stress results in low leaf area, limiting photosynthesis, flower abortion, and cluster abscission (During ). During this development stage, moderately dry and stable atmospheric conditions are considered favorable for high‐quality wines (Jones and Davis ; Nemani et al. ; Ramos et al. ). Furthermore, slower leaf canopy development may lead to higher transpiration efficiency (Porter and Semenov ). During ripening, excessive humidity is unfavorable to maturation (Tonietto ), due to the promotion of sugar dilution (Reynolds and Naylor ). On the contrary, moderate dryness, at this stage, seems to enhance quality (Storchi et al. ).

Solar radiation is also a key factor affecting viticulture. Adequate radiant energy is required, especially during ripening (Manica and Pommer ). During maturation, sugar and phenolic contents are favored by the occurrence of sunny days (Riou et al. ). Regions with less sunlight tend to surmount this limitation by adjusting training systems, optimizing solar exposure and canopy density. With more exposed leaves and grape clusters, stomatal conductance and photosynthesis are favored, but at the same time increasing water demands (Archer and Strauss ) and boosting other problems, namely sunburns in leaves and clusters. In opposition, less exposed grape clusters result in lower berry temperatures, but at the expense of reducing sugar and anthocyanin concentrations (Sparks and Larsen ; Smart et al. ). High canopy density can also reduce bud fertility (Morgan et al. ), which is important for the subsequent years.

To better characterize the relationship between winegrapes and climate, several bioclimatic indices have been developed. Using the growing degree sums for a basal temperature of 10°C (degree days), Amerine and Winkler () developed one of the earliest indices (Winkler Index). Still using this concept, the Huglin Index (Huglin ) was developed to also account for maximum temperatures during the growing season and include a radiation component. The Cool Night Index (Tonietto ; Tonietto and Carbonneau ), which accounts for minimum temperatures preceding the harvest, is also often used as a bioclimatic index. The Dryness Index (Riou et al. ; Tonietto and Carbonneau ) was developed to estimate potential soil water availability. More recently, Malheiro et al. () developed a composite index based on the limiting thresholds of three bioclimatic indices, allowing a more comprehensive viticultural zoning and the assessment of the suitability of a given region to grapevine growth and wine production.

In most Mediterranean‐like climatic regions, vineyards are subject to high radiation levels interacting with high temperatures and strong atmospheric and soil water deficits, which largely constrain grapevine productivity. Frequently, leaves display permanent photoinhibition and chlorosis, followed by necrosis, exposing the grape clusters, thus leading to low intrinsic water‐use efficiency (WUE; Moutinho‐Pereira et al. ). Hence, low vigor tends to be associated with reduced berry weight, sugar content, and yield. Other berry organoleptic properties such as color, flavor, and aroma components are inhibited by excessive solar radiance and severe dryness too. This results in unbalanced wines, with high alcoholic content and excessively low acidity (Jones ). In this context, the Mediterranean viticulture and winemaking may be significantly challenged by climate change (Jones ).

Climate Change Projections in Agriculture

Climate change is an inevitable challenge that society will have to cope with in the upcoming decades. During the 20th century, most of Europe endured changes in numerous climatic factors with great regional heterogeneity (International Panel on Climate Change [IPCC] ). Significant changes in temperatures were found during the 20th century (Santos and Leite ), including increases of 2.3–5.3°C in northern Europe and 2.2–5.1°C in southern Europe (Christensen et al. ). Moreover, decreases/increases in the annual precipitations over southern/northern Europe (Christensen et al. ) are also expected under higher anthropogenic greenhouse gas (GHG) forcing in the future. These changes were shown to occur not only in the normal values but also in the rate of occurrence of extremes (Hanson et al. ). In fact, changes in the frequency of temperature and precipitation extremes, in Europe, were related to certain atmospheric features, such as the North Atlantic Oscillation (NAO; Santos and Corte‐Real ).

The first climate theories considered climate as the mean state of the weather conditions over a long period (Hann ). The modern perspective of climatic analysis may be perceived as a system‐analytic approach (Peixoto and Oort ; von Storch and Flöser ), where climate dynamics is a result of the combined interactions among the different components of the global climate system (atmosphere, hydrosphere, biosphere, cryosphere, and lithosphere). Due to the complexity and high nonlinearity of the climate system (Fig. A), the isolation of the forcing factors underlying climate variability is indeed a rather difficult task. In fact, the differentiation of the human‐induced climate change from the natural climate change is only possible when the physical processes in the climate system are fully understood. These processes can be described by balance equations, and their numerical integration allows climate simulation.

(A) Schematic view of the components of the climate system, their processes, and interactions. (B) Multimodel averages and assessed ranges for surface warming. Solid lines are multimodel global averages of surface warming (relative to 1980–1999) for the scenarios A2, A1B, and B1, shown as continuations of the 20th‐century simulations. Shading denotes the ±1 standard deviation range of individual model annual averages. The orange line is for the experiment where concentrations were held constant at year 2000 values. The gray bars at right indicate the best estimate (solid line within each bar) and the likely range assessed for the six special report on emissions marker scenarios. The assessment of the best estimate and likely ranges in the gray bars includes the atmosphere‐ocean coupled general circulation models (AOGCMs) in the left part of the figure, as well as results from a hierarchy of independent models and observational constraints. (A) Adapted from Le Treut et al. (), (B) Adapted from (IPCC ).

The study of climate change impacts on environmental systems usually employs data from atmospheric models. Due to different aspects of climate variability in paleontological and present‐day conditions, different approaches of climate modeling are carried out, induced by varying CO₂ concentrations. The IPCC developed different climate projections, referring to different future scenarios of divergent CO₂‐emission pathways (Fig. B), such as the A2, A1B, and B1 (Nakićenović et al. ). These scenarios aim at objectively representing likely pathways of human development until the end of the 21st century, covering a feasible level of uncertainty (Nakićenović et al. ). The IPCC 4th Assessment Report (4AR) provides evidence on the general agreement among observations from different measurement techniques, all documenting a clear upward trend in the global mean surface temperature in recent decades (Trenberth et al. ). Besides the significant changes detected in the means, the frequencies of occurrence and strength of some extremes have also increased, including precipitation (droughts and heavy rain events) and temperature (heat waves, hot days/nights) extremes (Trenberth et al. ; Andrade et al. ). Furthermore, the trends observed in the recent past can only be reproduced by climate modeling when anthropogenic forcing is taken into account (Hegerl et al. ).

For future decades, ensemble projections reveal that global climate change tends to be mostly consistent with the trends already recorded during the 20th century, although their magnitude is highly dependent on the emission scenario (Meehl et al. ). The global mean surface temperature is expected to increase at about 0.2°C per decade, reaching values between 1°C and 6°C at the end of the 21st century for the full range of special report on emissions scenarios (SRES; Fig. B). These values imply remarkably different impacts on the Earth's system, as the environmental and socioeconomic systems present nonlinear responses to a certain change in temperature, besides their limited ability to adapt to new external conditions. Moreover, the regional impacts may be stronger/weaker than the global mean signal, which highlights the need for regional assessment studies using regional dynamical downscaling (Christensen et al. ). Finally, it is worth mentioning that all these projections still encompass high uncertainties (Fraga et al. ), not only due to model limitations and to emission scenario uncertainties, but also due to uncertainties inherent to the climate‐carbon cycle (Denman et al. ; Meehl et al. ). A new generation of emission scenarios (Moss et al. ) will enable the analysis of the interactions within this cycle in more detail.

The projected changes in atmospheric parameters are of key importance for agricultural practices. Regarding perennial crops (such as vineyards), under future climate change, Lobell et al. () state that actual yield changes will reflect the combined influence of climatic factors and the potentially positive effects of management, technology, and increased atmospheric CO₂ contents. For estimating impacts of climate on agricultural systems it is needed, in addition to the first‐order impact of changed climate parameters on physiological and yield indicators, knowledge about the second‐order effect of CO₂ influence on primary plant production. Furthermore, understanding the interactions of elevated CO₂ concentrations with changes in climatic parameters, including extremes, soil water availability, pests, diseases, and physiological interactions remain a key aspect for assessing climate change impacts on agriculture (Tubiello and Fischer ).

Although a global assessment of climate change impacts on agriculture highlight negative impacts due to more frequent extreme weather events (Porter and Semenov ), increased irrigation demands (Doll ), and increased risk of pests and diseases (Alig et al. ), this should not occur evenly throughout the European continent. Olesen and Bindi () stated two different climate change consequences for European agriculture. For northern Europe, positive effects can be expected from the introduction of new crop species/varieties, higher crop production, and new suitable agricultural areas, but also experiencing disadvantages through the greater need for plant protection and increased risk of nutrient leaching. In southern Europe, on the other hand, water scarcity and extreme climate conditions may cause lower yields, higher yield variability, and a reduction in suitable areas for traditional crops. Moreover, Moriondo and Bindi () found that the Mediterranean crops may have earlier development stages and may experience a reduction in the length of growing season under future climates.

As such, the development of future climate projections based on feasible future socioeconomic storylines is of great value, as they provide objective information that can be used in developing suitable adaptation/mitigation managements to minimize climate change impacts on environment and on human activities.

Climate Change Impacts on Viticulture

Climate change can potentially influence vine yield and quality (Kenny and Harrison ; Jones ). Temperature trends of the recent past, focusing on viticultural regions, show that the growing‐season mean temperatures have increased globally by about 1.3°C in 1950–1999 and by 1.7°C from 1950 to 2004 in Europe (Jones et al. ,b). For some European viticultural regions, in Italy, Germany, and France, studies already reported shortenings of the growing season and earlier phenological events (Chuine et al. ; Jones et al. ; Dalla Marta et al. ; Bock et al. ; Daux et al. ). Similar changes were also reported in some Australian viticultural regions (Webb et al. ; Sadras and Petrie ). Furthermore, advances in the phenological events resulting in ripening during a warmer period can have negative impacts on wine quality (Webb et al. ). Vrsic and Vodovnik () showed that higher temperatures during the growing season in North East Slovenia promoted a significant decrease in the total acidity content of early‐ripening varieties.

Climate change projections for the 21st century are expected to have important impacts on viticulture, as changes in the temperature and precipitation patterns (Meehl et al. ) may significantly modify the current viticultural zoning in Europe (Malheiro et al. ). Recent climate change studies by Fraga et al. () for Portugal, Neumann and Matzarakis () for Germany, and Duchene and Schneider () for Alsace, France, hint at an increase in the growing‐season temperature. Santos et al. (), using a multimodel ensemble for the Douro Valley (Portugal), demonstrated that springtime warming may lead to earlier budburst under a future warmer climate, which may affect wine quality. Additionally, future projections for this same region, suggest higher grapevine yields (Santos et al. ) and wine productions (Gouveia et al. ), but also suggest increased risks of pests and diseases. Orduna () argues that winemaking regions under extremely hot temperatures may lead to a significant increase in the risk of organoleptic degradation and wine spoilage. Under a future warmer climate, higher temperatures may inhibit the formation of anthocyanin (Buttrose et al. ), thus reducing grape color (Downey et al. ) and increasing volatilization of aroma compounds (Bureau et al. ). Future changes in minimum temperatures during ripening in the Iberian Peninsula were also reported (Fraga et al. ; Malheiro et al. ), suggesting a decrease in wine quality.

In the future scenarios, a decrease in the suitability of the current winemaking regions in southern Europe might also be expected (Jones et al. ; Stock et al. ; Fraga et al. ). Southern European winegrapes are also expected to face adverse conditions due to severe dryness (Santos et al. ; Malheiro et al. ). In fact, these regions may become excessively dry for high‐quality winemaking (Kenny and Harrison ), or even unsuitable for grapevine growth without sufficient irrigation (Koundouras et al. ). Malheiro et al. () stated that regions like Alentejo, Andalucía, Mancha, Sicily, Puglia, and Campania will suffer from water deficits. Santos et al. () also showed increased summer dryness in southern Europe. As an illustration, Alonso and O'Neill () highlighted the negative impacts of climate change in the Spanish viticulture, which may result in increased water demand due to irrigation. Camps and Ramos () found a decrease in winegrape yield for northeastern Spain that can be attributed to water deficits. Ruml et al. (), in a study for Serbia, identified changes that may require additional vineyard irrigation. In addition to a lowering of wine quality, expected in the future for some southern European winemaking regions, changes in the interannual variability and extremes may increase the irregularity of the yields (Schultz ; Jones et al. ), with detrimental effects on the whole winemaking sector.

In contrast to southern Europe, future warmer climates may be beneficial for many regions in central and western Europe, such as Alsace, Champagne, Bordeaux, Bourgogne, Loire Valley, Mosel, and Rheingau (Stock et al. ; Malheiro et al. ; Neethling et al. ). Despite the projected increases in precipitation, which can be favorable to pests and diseases (e.g., downy mildew), the warming will enable the growth of a wider range of varieties (Malheiro et al. ). As an example, Eitzinger et al. () project a doubling of the potential winegrape‐growing areas in Austria by the 2050s. Hungarian southern wine regions are also expected to expand according to Gaal et al. (). Furthermore, the projected warming in central and northern European regions (e.g., Mosel) will result in prolonged frost‐free periods and growing seasons (Bertin ), which will favor wine quality (Ashenfelter and Storchmann ).

The enhanced concentrations of CO₂ in the future, per se, are expected to have positive impacts on the grapevine development cycle and yield attributes (Bindi et al. ; Goncalves et al. ; Moutinho‐Pereira et al. ). Higher CO₂ will promote a decrease in plant transpiration, which will tend to overcompensate for the increased soil evaporation (Rabbinge et al. ), resulting in a reduced evapotranspiration in the future climate (Wramneby et al. ). This indirect effect of CO₂ increase will be combined with the direct effect of an increase in carbon compound accumulation (Drake et al. ), which may thus provide a positive response to climate change.

Adaptation and Mitigation Measures

While mitigation refers to measures that require human intervention, usually over long temporal periods, in reducing the sources or enhancing the sinks of GHG (IPCC ), adaptation can be either a human or a natural response to the actual or expected climate change effects (IPCC ). Although the complex interrelationship between adaptation and mitigation measures are noteworthy, mitigation measures are mainly determined by international agreements and national public policies, while adaptation measures involve local entities and private actions (Klein et al. ).

Mitigation measures are crucial, as long‐term stabilization of CO₂ concentrations may reduce damage to yield and quality (Easterling et al. ). Fischer et al. () found that mitigation strategies, resulting in lower GHG concentrations, may reduce agricultural water requirements by about 40% when compared with unmitigated climate. As for agricultural mitigation measures, tillage systems are of key importance, as they may slightly compensate for GHG emissions (Ugalde et al. ). No‐till systems and minimum tillage (MIT) are considered the best for this purpose, as no disturbance of the soil surface promotes carbon retention/sequestration (Kroodsma and Field ). In regions with very steep slope (e.g., Douro Valley), no‐till systems may also significantly contribute to reduce soil erosion.

Short‐term adaptation measures may be considered as the first protection strategy against climate change and should be focused at specific threats, aiming at optimizing production. These measures mostly imply changes in management practices (e.g., irrigation, sunscreens for leaf protection), while changes in the enological practices, through technological advances (Lobell et al. ), may also have positive effects on wine quality. Long‐term adaptation measures mainly include varietal and land‐allocation changes, as some regions may become excessively warm and dry, while others consistently show high winemaking suitability (Malheiro et al. ). Changes to cooler sites, to higher altitudes, or coastal areas may also prove beneficial for future vineyards (changes in the vineyard microclimatic and mesoclimatic conditions). These regions may, however, struggle against an increasing risk of pests and diseases, requiring more intense plant protection. In this case, biological control agents should be preferably used, thus reducing the environmental impacts (Butt and Copping ).

Adequate and timely planning of the adaptation measures need to be adopted by the winemaking sector. The readiness to implement adaptation measures is highly correlated with the degree of changes planned, independent of climate change (Battaglini et al. ). A deeper insight into some adaptation measures is discussed in the subsections that follow.

Varietal and rootstock decisions

The optimum climate for a given variety produces consistent yields, balanced fruit composition, and acceptable vintage variation (Jones ). A key factor in adapting to climate change may include the growing of varieties with different thermal requirements and higher summer stress resistance. Currently, despite the large number (thousands) of existing varieties, the global wine market is dominated by only a few of them (e.g., Airén, Cabernet‐Sauvignon, Chardonnay, Merlot, Pinot Noir, Tempranillo, Touriga Nacional, Riesling), owing to current trading practices (This et al. ).

In the future, some northern European regions may benefit from a wide range of varieties for winegrape growth (Stock et al. ), while southern Europe will need to adapt to varieties more suitable to warmer and dryer climates. Jones () gives clues to some varieties more adapted to warmer climates, such as Cabernet Franc, Cabernet‐Sauvignon, Malbec, Merlot, Syrah, and Tempranillo (Fig. ). White et al. () proposes that grapevine breeding programs should now focus on the development of heat‐resistant varieties. Still with respect to this issue, Duchene et al. () developed a framework for genetic breeding of new varieties more adapted to future climatic conditions while maintaining some key aspects of existing varieties. Furthermore, owing to the large number of existing grapevine varieties, the maintenance of the natural biodiversity is essential for the better adaptation to climate change (Tello et al. ).

Rootstock is another factor that may affect yield, quality, and other vine physiological parameters (Hedberg et al. ; Pavlousek ). Its effects under warm and dry climates should be taken into account, as rootstocks show complex interaction with soil water availability (Romero et al. ). Several studies have been undertaken to assess rootstock effects under different water conditions (Ozden et al. ; Pavlousek ; Harbertson and Keller ). As an example, Koundouras et al. () used the Cabernet‐Sauvignon variety in Greece and compared the effect of two different rootstocks, concluding that the 1103P is better for winegrape growth under semiarid conditions, while S04 is preferable where no water limitation exists. As such, accessing the more adapted rootstock for each case can improve WUE, thus improving yield and quality.

Irrigation management

Regions under conditions of higher water scarcity will need to improve grapevine WUE (Flexas et al. ), thus lowering water usage for irrigation purposes (Chaves et al. ). Deficit irrigation strategies (e.g., regulated deficit irrigation – RDI; partial root drying – PRD; sustained deficit irrigation – SDI) can be used to improve WUE, allowing an optimal grape maturity and wine quality. Different deficit irrigation techniques are usually achieved by assessing soil (water potential and moisture) and physiological parameters (leaf or stem water potential, relative transpiration using sap flow techniques, trunk growth variations, canopy temperature, and chlorophyll fluorescence) as water status indicators (Pellegrino et al. ; Cifre et al. ; Sousa et al. ; Centeno et al. ). Romero et al. (), using RDI by applying 60% crop evapotranspiration (ETc.) water for irrigation during the growing season, found significant increases in WUE on Monastrell grapevines. Junquera et al. () found that irrigating at 45% of the reference evapotranspiration (ET₀) shows the best results for Cabernet‐Sauvignon. Conversely, a recent study by Basile et al. () reported that RDI may also affect wine sensory attributes.

Partial root drying is another deficit irrigation strategy that has been adapted for viticulture to improve WUE (Chaves et al. ; Romero and Martinez‐Cutillas ). In this system, half of the plant root system is slowly dehydrating, whereas the other half is irrigated, decreasing water usage by 50%. Using this technique, Santos et al. () reported no reduction in yield for the Castelão grapevines. Improvements in quality were also reported using this irrigation strategy on other varieties, resulting from increased anthocyanin concentration (Poni et al. ; Bindon et al. ; Du et al. ).

Chalmers et al. () implemented a SDI strategy by applying a lower volume of water at each irrigation event. These authors state that this may increase soil water tension by not replenishing the entire root zone. In this study, wine anthocyanin and other phenolic compounds (for Cabernet‐Sauvignon and Shiraz) showed significant increases using this irrigation strategy.

Along the previous lines, it can be stated that sustainable water management (together with available water) may be a profitable economic strategy for the grape grower (Garcia et al. ), providing a compromise solution between environmental costs and plant water requirements, which is highly pertinent under increasingly dryer and water‐demanding southern European climates (Bruinsma ).

Tillage treatments

Different tillage treatments can also affect yield and quality (Bahar and Yasasin ). These treatments may differ in both the start and duration of the tillage process. In the no‐till or conventional tillage (CVT), natural vegetation is usually allowed to grow spontaneously. In a MIT treatment, periodic tillage is applied from the fruit set to veraison. In the conservative tillage (CST), some vegetation is always allowed to grow, although periodic tillage is made from the beginning of the growing season to the end of veraison. While most of these treatments have been used to stimulate plant competition, aiming to increase vine performance and wine quality (Bahar and Yasasin ), they may be required to account for future climate change too.

Monteiro and Lopes () found that although intensive soil tillage increases soil moisture during spring, cover cropping increases upper‐layer soil moisture from veraison to harvest, indicating lower soil evaporation caused by the cover cropping. Moreover, Xi et al. () reported that a cover crop increased total phenols in berry and wine, thereby improving wine quality. Judit et al. (), for the Tokaj region (Hungary), reported that covering the soil with straw mulch had a positive effect on the soil water content, while using a cover crop implied higher water demand. Celette et al. () demonstrated that the use of cover cropping is increasing throughout European vineyards except in the Mediterranean regions, due to the possibility of competition for water resources. These authors stated that cover crops can modify grapevine root systems in order to explore other soil zones, increasing water intake. Also, the use of a cover crop allows better wintertime soil water renewal.

Vineyard microclimate

In order to account for the joint effect of increased temperature, water stress, and high solar radiation under future climates, adjustments in the traditionally settled training systems can also be applied by optimizing canopy management (Pieri and Gaudillere ). Row orientation should also be considered (if feasible), as it is one of the main factors influencing solar radiation interception (Intrieri et al. ; Grifoni et al. ). The use of shading nets, often used to protect agricultural crops from excessive solar radiation, can be applied to viticulture (Shahak et al. ). In fact, covering the vines with a shading material can help reducing heat stress at the cost of reduced vine biomass (Greer et al. ). Furthermore, the use of mineral, chemically inert sunscreens for leaf protection against sunburns may prove to be an important alternative (Pelaez et al. ; Glenn et al. ).

Conclusions

Climate change is expected to bring new challenges to the European viticultural sector (Malheiro et al. ). Although grapevines have several survival strategies (e.g., deep root system, efficient stomatal control), viticulture is strongly dependent on climate. Hence, the mounting evidence for significant climate change in the upcoming decades urges adaptation measures to be taken. A lowering in the suitability of some important winemaking regions was indeed reported (Hall and Jones ). Therefore, appropriate measures need to be adopted by the viticultural sector to face climate change impacts, mainly by developing suitable adaptation and mitigation strategies at regional scales (Metzger et al. ). Winegrape growers are becoming progressively more aware of this problem (Battaglini et al. ), as strategic planning will provide them a competitive advantage over competitors. Nevertheless, to effectively cope with the projected changes, short‐ and long‐term strategies deserve much greater attention in future research (Metzger and Rounsevell ).

Even though the full extent of the contribution of the adaptive strategies in reducing climate change impacts is still unclear (Lobell et al. ), adaptation strategies to climate change can be highly beneficial for the agricultural sector (Tubiello and Fischer ). As an illustration, Reidsma et al. () concluded that adaptation measures can largely reduce the impacts of climate change and climate variability on crop yields. A selection of alternative crop species, grapevine cultivars, rootstocks, and changes in the management practices are among the measures already being taken by European viticulturists to adapt to climate change (Olesen et al. ).

Acknowledgments

This study was carried out under the project: ClimVineSafe – Short‐term climate change mitigation strategies for Mediterranean vineyards (Fundação para a Ciência e Tecnologia – FCT, contract PTDC/AGR‐ALI/110 877/2009). This work is supported by European Union Funds (FEDER/COMPETE – Operational Competitiveness Programme) and by national funds (FCT – Portuguese Foundation for Science and Technology) under the project FCOMP‐01‐0124‐FEDER‐022 692.

Conflict of Interest

None declared.