Dormant buds of temperate woody perennial plants must attain cold hardiness to survive winters and timely lose it in spring to break bud while avoiding damage from low temperatures and late frosts. Therefore, we asked: Can a cold hardiness model be used to predict budbreak? Here, we used a previously published cold hardiness model to predict bud cold hardiness of three grapevine (Vitis spp.) varieties ('Cabernet-Sauvignon', 'Riesling', and 'Concord') from historical temperature records of eight locations in North America and Europe. Based on those predictions and thresholds of cold hardiness at budbreak from literature, budbreak date was extracted. Despite being untrained on budbreak data, the model resulted in good predictions (RMSE = 7.3d, n = 329), further improved based on expected delays from estimated cold damage (RMSE = 7.2d). Both increasing and decreasing freeze damage risk trends were predicted with increasing temperature, depending on the range of mean dormant season temperature (MDST; 1 Nov-30 Apr) in each location. Spring phenology predictions in relation to MDST also showed warming to advance (MDST < 10°C) or delay (MDST > 10°C) budbreak. Cold hardiness dynamics represent a key advancement in spring phenological modeling that provides information on low-temperature damage potential for the entire dormant season alongside improved predictions of budbreak timing.

Advancements in low-cost, connected temperature sensors have made local-scale climate zoning within vineyards more accessible for both the research community and the wine industry. However, the optimal sensor density and interpolation methods for capturing high-resolution thermal variability remain poorly defined. The following study evaluates the impact of network density on interpolation accuracy within an 800-ha wine-growing area in Burgundy (France), using 112 temperature sensors positioned at the grape-cluster level (60 cm) which were deployed from March 2023 to September 2024. To ensure methodological consistency within the high-density (1m x 1m) planting system, sensors were specifically installed in missing-vine spots. Seven interpolation techniques – spanning linear regressions, machine-learning ensembles (Random Forest) and hybrid geostatistical methods (Regression-Kriging) – were compared to determine their accuracy in mapping daily Tmin and Tmax. This evaluation followed a two-step sensitivity analysis: an initial baseline was established using the total sensor population, followed by a reduction in sensor density generated through terrain-informed stratified sampling. Results reveal a critical density threshold: below 5 sensors/km2 (N < 40), modelling efficiency (EFF) drops below 0.4 for over 50% of the study period, rendering the zoning unreliable. While Random Forest shows relative robustness at lower densities (5 -10 sensors/km2), Regression-Kriging (LMK) significantly outperforms all methods at high densities (14 sensors/km2), achieving a mean RMSE of 0.4°C for Tmin and 0.56°C for Tmax. Notably, Tmax interpolation was consistently less efficient (EFF = 0.264) than Tmin (EFF = 0.660). This disparity suggests that in high-density viticultural systems, maximum temperatures at the cluster level are driven by micro-scale energy fluxes and aerodynamic decoupling that override topographical signals. These findings provide a practical framework for optimizing sensor networks, suggesting that while 40 – 60 sensors (5 – 7.5 sensors/km2) are sufficient for mapping indices related to minimum temperatures (e.g. number of frost days), higher densities or additional surface-level covariates might be required to accurately map indices sensitive to maximum temperatures and thermal accumulation (e.g. average temperature during the growing season and heat stress indices). By quantifying how interpolation errors propagate into these agroclimatic indicators, this study provides essential guidance for the implementation of high-resolution climate zoning in viticultural terroirs.

Changing climate conditions raise questions about the evolution of perennial grapevine varieties, which are grown in various places around the world, where complex interplay between environmental factors, genetics and viticultural practices can contribute to unexpected adaptability. Based on experimental measurements of water status (δ13C) and untargeted metabolomics of up to 256 grape juices from 13 wine regions in Europe and Argentina, over 3 successive vintages, we assessed the adaptability to climate change of ‘Pinot noir’ and ‘Chardonnay’ grapevines. Both varieties appeared to be able to withstand a wide range of water deficits, some of which may be associated with climatic conditions similar to a + 2 °C warming scenario in Burgundy. Multivariate models revealed hundreds of water-status-related mesocarp metabolites, with ‘Chardonnay’ showing a consistent dynamic response across the water status range, whereas many ‘Pinot noir’ markers faded under severe water deficit, suggesting this grape variety is less resilient to changing climatic conditions.

Temperate woody perennial plants form buds during late summer that contain leaves and flowers that emerge in the following growth season. To survive winter, dormant buds must attain cold hardiness, and timely lose it in spring to break bud while avoiding damage from low temperatures and late frosts. Here, we use an untrained process-based model to predict bud cold hardiness of three grapevine varieties ( V. vinifera 'Cabernet-Sauvignon' and 'Riesling', and V. hybrid 'Concord') from historical temperature records of eight different locations in North America and Europe (n = 329). Based on those predictions, and thresholds of cold hardiness at budbreak from literature, timing of budbreak was extracted. Despite being untrained to the data, the RMSE of budbreak predictions was 7.3 days (Bias=−0.83). Based on cold hardiness estimations and air temperature records, low temperature damage was quantified and validated through newspapers and extension records. In years × location where damage was predicted, corrections to budbreak based on delays expected resulted in improvements of predictions (RMSE=7.2d, Bias=0.58). Predictions of instances of freeze damage risk demonstrate genotypic adaptation to different environments. At the species level, increasing or decreasing trends in freeze damage risk are predicted, depending on the range of mean dormant season temperature (MDST; 1 Nov - 30 Apr) present in each location. Sensitivity analysis of predicted time to budbreak based on MDST shows a general advancement of phenology at −5.8d/°C. However, in much warmer locations, delays can be expected as temperatures continue to increase (+1.9d/°C for MDST>10°C). Through cold hardiness dynamics, the estimation of chilling accumulation appears as an important source of error for predictions of spring phenology across environments. Cold dynamics represents an advancement in phenological modeling that provides information for the entirety of the dormant season, as well as budbreak. ### Competing Interest Statement The authors have declared no competing interest.

The impact of climate variability on wine grape yield is assessed using ecoclimatic indices tailored to the crop's specific life cycle stages during the whole growing season and specific key phenological periods. These periods are selected through a validated phenological development model that accounts for various grape varieties. The risk of crop losses due to the main cryptogamic vine diseases is also considered. This study actively involves winegrowers as yield data are provided by two Italian wine consortia, situated in Lombardia and Toscana (Italy), respectively. It considers the unique characteristics of each study region, operating at a local scale with a focus on specific grape varieties. The ecoclimatic indices are correlated with grape yield data using single and multiple regression analyses. The contribution of each ecoclimatic index to the yield formation process is evaluated and the portion of total yield variability explained by these predictors, both individually and in linear combination, is quantified. The results obtained explained 25-50 % of yield variance and identified key ecoclimatic indices based on the region and the case considered. Recognizing the scarcity of existing literature on grapevine yield modelling, this paper presents a novel set of ecoclimatic indices, meticulously derived from the latest insights into climate's impact on grapevine development. Furthermore, the innovative methodology outlined here is designed also for application in future climate projections, enabling a comprehensive investigation of climate change and its potential ramifications on grape yield.

With climate change, the risk of water deficits in vineyards is tending to increase, potentially affecting yield and grape quality potential. In this study, the Lebon et al. (2003) soil water balance model was applied to assess the impact of training systems, soil water holding capacity (SWHC), and soil management practices on vine water status in the Cognac production area from 1962 to 2021. This research quantifies if and how water deficits can be effectively managed by modifying vine training systems and soil management practices in a wine-producing region using simulation tools. Such tools can guide research and provide actionable levers for wine producers to adapt their production system to climate change.

Viticulture is a key business for Italy, significantly contributing to the country's economy and cultural heritage. Italy is the largest world wine producer, with an estimated wine production of 41.0 mhL (2024 World Wine Production - OIV First Estimates). The relationship between climate variability and wine grape yield is a critical area of research, particularly considering ongoing climate change.This study evaluates this relationship by employing ecoclimatic indices computed on key phenological periods that are crucial for grape development and specifically tailored to the life cycle of grapevines throughout the entire growing season. These periods have been identified using a validated phenological development model that accounts for various grape varieties. In addition to examining the effects of climate variability, this research also considers the risks posed by major cryptogamic diseases that can lead to significant crop losses.To ensure the validity and relevance of the findings, the study actively engages with growers and obtains yield data from two prominent Italian wine consortia based in Lombardy and Tuscany. This localised approach allows the specific climatic and agronomic characteristics of each region to be considered, as well as the different grape varieties grown there.The methodology developed correlates the ecoclimatic indices with the collected grape yield data through both single and multiple regression analyses, quantifying the proportion of total yield variability that can be explained by these predictors, both individually and in combination. The findings indicate that the ecoclimatic indices account for approximately 25% to 50% of the variance in grape yield.By presenting a novel set of ecoclimatic indices derived from contemporary knowledge of climate impacts on grapevine development, this study contributes to filling a gap in the current research framework.

This study investigates the impact of vine training systems on water deficits in the Cognac region (France), through the application of a vine water balance model, taking into account different soil water holding capacities (SWHC) and soil management strategies, including grass cover. Using climate data from the SAFRAN gridded database, over 2 million simulations were performed for the period 1962 to 2021 to quantify the response of grapevine water status under varying training systems and environmental conditions. Indices based on simulated relative stomatal conductance were developed to characterise the intensity of grapevine water deficit during the critical flowering-to-maturity period. Results show a significant trend of increasing water deficit between 1962 and 2021, particularly in the north-western part of the region, affecting 23 % of the Cognac production area. Sensitivity analysis of the water balance model indicates that SWHC is the predominant factor influencing grapevine water status, explaining nearly 80 % of the variance in water deficit days. The simulations further suggest that adjustments in canopy width and grass cover have a significant effect on the duration and severity of water deficit. The methodology developed in this research allows quantifying the relative importance of major drivers of vine water deficits: SWHC, training system parameters and vineyard floor management, under different climatic conditions. It can be used as a basis for providing easy-to-implement vineyard management strategies to mitigate the effects of climate change in viticulture. It was applied to the Cognac region, but the workflow developed is applicable to any grape-growing region in the world.

A useful resource for understanding and describing worldwide climatic patterns is the Köppen-Geiger (KG) climate classification system. The classification of climates suited for viticulture has been crucial to the wine sector, given the importance of climate in cultivating grapes for wine production. Wine production has come to be associated with Mediterranean climates due to the combination of the KG climate classification system and the geographic location of Europe's old-world wine areas. These climate types can also be found in the fynbos of South Africa, the Mallee of southern Australia, the matorral of Chile and Argentina, the chaparral and coastal valleys of western North America, and in the Mediterranean basin of Europe. But today, wine is produced in many different sorts of climates. Overall, a region's climate has a significant impact on wine production since it decides whether particular grape types can be grown there, greatly influencing the type of wine that can be produced and affecting the wine's quality.This study examines the KG classification system's application to the most recent CMIP6 experiments. Using an ensemble of 14 global climate models and the WorldClim dataset, a baseline for the historical period 1970–2000 was established. Climate variability in winemaking regions is assessed using future estimates from 2041 to 2060, based on several scenarios of human radiative forcing (SSP2-4.5 and SSP5-8.5). The findings represent the most thorough record of past climate classifications for most wine regions globally, as well as prospective future changes to these categories.Globally, temperate and arid zones (climate types C and B, respectively) are expected to undergo a substantial transition from a warm summer temperature to a hot summer climate. High temperatures can have a major impact on the grape development process. They may cause early ripening, alter the aromatic components in the grape berry, and perhaps change the acidity balance. Wine producers must modify their vineyard management practices in response to climate shifts and employ appropriate countermeasures to mitigate the negative effects of abiotic pressures on grape quality and vineyard health. These adaptation tactics could involve relocating to other microclimatic zones, adopting irrigation techniques, modifying canopy and soil management, or utilizing different variety-clone-rootstock combinations. Wine producers need to consider regional climate change projections to ensure the long-term sustainability of the environment and the socioeconomic landscape. This will help them make more informed decisions about vineyard management practices, and ultimately strengthen the wine industry's resilience and adaptability to the ongoing effects of climate change.Acknowledgments: Research funded by National Funds by FCT under the project UIDB/04033/2020 and LA/P/0126/2020. Vine & Wine Portugal – Driving Sustainable Growth Through Smart Innovation, PRR e pelos Fundos Europeus Next Generation EU, no âmbito das Agendas Mobilizadoras para a Reindustrialização, Projeto n.º C644866286-011.

A valuable tool for comprehending and characterizing climate patterns on a global scale is the Köppen–Geiger climate classification system. When it comes to wine production, the climate of a region plays an essential role in determining whether specific grape varieties can be cultivated, largely determining the style of wine that can be made, and influencing the consistency of overall wine quality. In this study, the application of the Köppen–Geiger classification system to the latest Coupled Model Intercomparison Project (CMIP6) experiments has been explored. To establish a baseline for the historical period (1970–2000), the WorldClim dataset was used alongside a selection of an ensemble of 14 Global Climate Models. The evaluation of climate variability across winemaking regions is conducted by considering future climate projections from 2041 to 2060, which are based on different anthropogenic radiative forcing scenarios (Shared Socioeconomic Pathways, SSP2–4.5, and SSP5–8.5). The results are the most comprehensive documentation of both the historical climate classifications for most wine regions worldwide and the potential changes in these classifications in the future. General changes in climate types are projected to occur largely in a significant shift from a warm summer climate to a hot summer climate in temperate and dry zones worldwide (climate types C and B, respectively). This shift poses challenges for grape cultivation and wine production. The grape development process can be significantly affected by high temperatures, which could result in early ripening and changes in the grape berry’s aromatic compounds. As regions transition and experience different climates, wine producers are required to adapt their vineyard management strategies by implementing suitable measures that can effectively counter the detrimental impacts of abiotic stresses on grape quality and vineyard health. These adaptation measures may include changes in canopy and soil management, using different variety-clone-rootstock combinations, adopting irrigation methods, or shifting into other microclimatic zones, among other effective techniques. To ensure long-term sustainability, wine producers must consider the climatic change projections that are specific to their region, allowing them to make more informed decisions about vineyard management practices, reducing risks, and ultimately making the wine industry more resilient and adaptive to the ongoing effects of climate change.

The composition of the juice from grape berries is at the basis of the definition of technological ripeness before harvest, historically evaluated from global sugar and acid contents. If many studies have contributed to the identification of other primary and secondary metabolites in whole berries, deepening knowledge about the chemical composition of the sole flesh of grape berries (i.e., without considering skins and seeds) at harvest is of primary interest when studying the enological potential of widespread grape varieties producing high-added-value wines. Here, we used non-targeted DI-FT-ICR-MS and RP-UHPLC-Q-ToF-MS analyses to explore the extent of metabolite coverage of up to 290 grape juices from four Vitis vinifera grape varieties, namely Chardonnay, Pinot noir, Meunier, and Aligoté, sampled at harvest from 91 vineyards in Europe and Argentina, over three successive vintages. SPE pretreatment of samples led to the identification of more than 4500 detected C,H,O,N,S-containing elemental compositions, likely associated with tens of thousands of distinct metabolites. We further revealed that a major part of this chemical diversity appears to be common to the different juices, as exemplified by Pinot noir and Chardonnay samples. However, it was possible to build significant models for the discrimination of Chardonnay from Pinot noir grape juices, and of Chardonnay from Aligoté grape juices, regardless of the geographical origin or the vintage. Therefore, this metabolomic approach opens access to a remarkable holistic molecular description of the instantaneous composition of such a biological matrix, which is the result of complex interplays among environmental, biochemical, and vine growing practices.

1 Biogéosciences UMR 6282 CNRS uB, Université Bourgogne-Franche-Comté, 6 Boulevard Gabriel, 21000 Dijon, France 2 IUVV, Université Bourgogne-Franche-Comté, 2 rue Claude Ladrey, 21000 Dijon, France 3 EGFV, Univ. Bordeaux, Bordeaux Sciences Agro, INRAE, ISVV, 33882 Villenave d’Ornon, France With milder winters, earlier budburst could lead to increased frost damage in the 21st century, despite global warming. However, the projection of future frost risk is currently subject to uncertainty. We look here at the data to be considered when assessing the risk of spring frost damage and the limitations of spring frost simulation, based on simulation work carried out in the Chablis wine region (Burgundy, France). Uncertain changes to spring frost risks in vineyards in the 21st century

Assessment of vine water status is needed to understand the effect of environmental factors and management practices on dry-farmed and irrigated vineyards. Among plant-based indicators, carbon isotope discrimination (δ13C) is easily accessible, reliable, and inexpensive. As it provides a post-hoc assessment of vine water status during the berry ripening period, it can be useful for assessing the results of vineyard management practices during the season, and to map water status in the vineyard to aid in future precision management. Possible applications and limitations of this technique for practical vineyard management are discussed in this article.

One of the main challenges of growing grapevines in a warmer climate is that grape sugar accumulation gets faster and soluble solids content at harvest exceeds the target chosen by grape growers, specifically for wine production, where alcohol level is a key component of wine quality. When grapevines are cultivated on a trellis with vertical shoot positioning (VSP), leaf removal on the upper part of the canopy after veraison makes it possible to delay and limit sugar quantity in grapes. The impacts of this technique have been assessed in Burgundy (France), during vintages 2020 and 2021, on Vitis vinifera 'Pinot noir' planted in 2015. Three treatments have been compared with respect to a control: a severe leaf removal (2/3 of the upper foliage eliminated) applied before veraison (25 days approximately before mid-veraison), a light leaf-removal (1/3 of the upper foliage eliminated) applied before veraison and a severe leaf-removal applied 5 to 10 days after mid-veraison (late veraison treatment). Analyses on mature grapes show a significant decrease in the sugar content when a severe leaf removal was performed during vintage 2021. The water status of the vines during the ripening period of the grapes, assessed using delta C-13 (carbon isotopic discrimination) was significantly different between the treatments. The severe leaf removal significantly reduced grapevine water deficit, especially if it is applied before veraison. These results suggest that the leaf removal of the upper part of the canopy may be a relevant technique to adapt grapevine cultivation according to the heat and dryness of the current vegetative season.

Climate change is a major challenge for the French wine industry. Climatic conditions in French vineyards have already changed and will continue to evolve impacting viticulture.This study aims to analyse the evolution of agro- and eco-climatic indices based on phenology simulation of French wine-growing regions. This evolution was analysed on a recent-past period (1962–1991 to 1992–2021) using SAFRAN climate data and on a future projected period (1985–2014 to 2041–2070) with two SSP trajectories (SSP2-4.5 and SSP5-8.5). A set of 19 CMIP6 climate models downscaled at 8 km grid resolution over France coupled with three phenological and a water balance model were used. Phenological model parameters and training system characteristics were adapted to each region to match as much as possible current practices.Temperatures during the growing season have increased by +1 °C to +2.1 °C since the second half of the 20th century and could rise to +3.7 °C in regions around the Mediterranean by 2070. The inter-model variance concerning the precipitation is high, a significant change (decrease) in precipitation during the grapevine growing season is observed only for the regions of western France (Oceanic climate) over the period 2040–2071 with the SSP5 trajectory. All simulated phenological stages have shifted toward earlier dates. Their occurrence should be even earlier by 2070 with an average advance of up to 22 days for the mid-veraison of Pinot noir in eastern France. The theoretical maturity date (sugar content) should also be advanced from 19 to 30 days depending on the considered region and SSP. Thermal conditions closer to the photosynthetic optimum should promote onset by the early second half of the 21st century. The increase in both the number of hot days and grapevine water deficit during the period of fruit development should impact grape production in quality and quantity in all wine-growing regions. Spring frost projections show no significant change in risk for the second half of the 21st century, compared to current conditions.

Avec des hivers plus doux, une plus grande précocité du débourrement de la vigne pourrait conduire à un accroissement des dégâts de gel au cours du 21ème siècle, en dépit du réchauffement climatique. Toutefois la projection du risque de gelées dans le futur souffre actuellement d’incertitudes. Nous revenons ici sur les éléments à considérer quand on souhaite évaluer le risque de dégâts de gel de printemps et les limites de l’exercice de simulation de ce dernier, en s’appuyant sur des travaux de simulations menées dans la région viticole de Chablis (Bourgogne, France).

This study aims to compare the δ13C isotopic signal between bulk wood and α-cellulose in wood samples from the main trunk of Vitis vinifera L. to verify whether α-cellulose extraction is necessary for ecophysiological studies in this species. A pool of samples from different cultivars and provenances was analysed. The wood samples were obtained from cross sections of the main trunk of the plants, from where the annual growth rings were anatomically recognised, dated to the year of formation, and then separated. Each ring comprised both early- and latewood portions. For each sample, a part was saved as bulk wood and another part was destined for α-cellulose extraction. The δ13C isotopic signal in both types of samples was performed on a Vario Micro Cube elemental analyser coupled to a continuous flow mode to an isotope ratio mass spectrometer. A least squares regression was used to verify the correlation between the two variables. The results showed that the correlation coefficient of the isotopic signal for both types of samples was 0.86, and the slope of the regression line was not significantly different from one. Those results indicated that it is acceptable to use bulk wood instead of α-cellulose for δ13C isotopic studies in Vitis vinifera. This study is the first to compare isotopic δ13C signals between bulk wood and α-cellulose in grapevines. Therefore, this study constitutes a starting point to explore dendrochemical techniques based on the analysis of the δ13C content in Vitis vinifera wood, with the aim of deepening the ecophysiological knowledge of the grapevine in relation to water economy strategies and the links with climate variability and change.

Evaluating the potential climatic suitability for premium wine production is crucial for adaptation planning in Europe. While new wine regions may emerge out of the traditional boundaries, most of the present-day renowned winemaking regions may be threatened by climate change. Here, we analyse the future evolution of the geography of wine production over Europe, through the definition of a novel climatic suitability indicator, which is calculated over the projected grapevine phenological phases to account for their possible contractions under global warming. Our approach consists in coupling six different de-biased downscaled climate projections under two different scenarios of global warming with four phenological models for different grapevine varieties. The resulting suitability indicator is based on fuzzy logic and is calculated over three main components measuring (i) the timing of the fruit physiological maturity, (ii) the risk of water stress and (iii) the risk of pests and diseases. The results demonstrate that the level of global warming largely determines the distribution of future wine regions. For a global temperature increase limited to 2°C above the pre-industrial level, the suitable areas over the traditional regions are reduced by about 4%/°C rise, while for higher levels of global warming, the rate of this loss increases up to 17%/°C. This is compensated by a gradual emergence of new wine regions out of the traditional boundaries. Moreover, we show that reallocating better-suited grapevine varieties to warmer conditions may be a viable adaptation measure to cope with the projected suitability loss over the traditional regions. However, the effectiveness of this strategy appears to decrease as the level of global warming increases. Overall, these findings suggest the existence of a safe limit below 2°C of global warming for the European winemaking sector, while adaptation might become far more challenging beyond this threshold.

Italy is a world leader for viticulture and wine business with an export valued 7 billion of euros in 2021, and wine being the second most exported product within the national agri-food sector. However, these figures might be threatened by climate change and winegrowers call for more reliable local information on future impacts of climate change on viticulture. The study aims to understand the impact of climate on wine production in Italy using grape productivity data and bioclimatic indices. Using temperature and precipitation observations from the E-OBS gridded dataset, a set of bioclimatic indices recommended by the International Organisation of Vine and Wine guidelines is calculated and correlated with grape productivity data at the regional scale (Nomenclature of territorial units for statistics, NUTS, level 2) over the last 39 years (1980-2019). The study investigates how both long-term change and natural variability of the bioclimatic indices impacted on grape productivity. Both single and multi-regression approaches are applied to assess the portion of grape productivity variability explained by the selected indices. When the single-regression approach is applied, the correlations between bioclimatic indices and grape productivity explain up to the 45 % of total production variability, however they are statistically significant only in few regions. Conversely, the multi-regression approach improves the proportion of variance explained and gives statistically significative results in region where the single regression is not statically significant. The multi-regressive approach shows the added value of considering the interplay of different bioclimatic indices in explaining the overall variability of productivity. The possibility of using bioclimatic indicators as a proxy for grape productivity provides a simple tool that grape growers, wine consortia and policy makers can use to adapt to future climate.