# A Review of the Potential Climate Change Impacts and Adaptation Options for European Viticulture
## 4 Potential Climate Change Impacts
### Climate Change Projections and Impacts on Grapevines  
Climate change projections for the 21 st century, based on global and regional climate models, are in general agreement with the observed trends over the past decades [96], leading to important impacts on viticulture. In some regions, climate change is supposed to be beneficial for viticulture, for instance due to higher fruit maturity and opening new areas for cultivation, whereas the impact might be detrimental in other regions by challenging the ability for adequate grape cultivation and wine production [12]. Alterations in the spatial patterns and temporal regimes of temperature and precipitation [97] may significantly modify current viticultural bioclimatic zones in Europe [98]. Climate change studies for Italy [99; 100; 101; 102], France [82; 103; 104], Spain [105], Portugal [106; 30; 107], Germany [37; 108; 107], Greece [109], and Luxembourg [80; 110; 111], among others, hint at an increase in the growing season mean temperature. In future scenarios, the current winemaking regions in southern Europe may undergo a decline in their viticultural suitability [112; 113; 114; 115], mainly due to severe dryness [112]. These regions may indeed become excessively dry for high-quality winemaking [85] and, in some most extreme cases, will require intensive irrigation [112; 116]. Regions such as Andalucia, La Mancha (Spain), Alentejo (Portugal), Sicily, Puglia, and Campania (Italy) will very likely suffer from severe water deficits [98]. It was also shown that increased summer dryness in southern Europe will lead to yield reduction, mostly due to the synergistic effect of warming and drying [98]. For some southern European winemaking regions, increased inter-annual variability and more frequent extremes are expected to intensify the irregularity of yields, with harmful impacts on the whole winemaking sector. Winemaking regions under extremely high temperatures may experience an increase in the risk of organoleptic degradation [94], excessively high alcohol contents [117], an acceleration in the degradation of organic acids [84], and an inhibition in the synthesis of anthocyanin [118], thus affecting grape colour and aroma [119; 120; 121; 122]. In particular, the fruitiness, aroma [84], acidity, and relatively low alcohol content, characteristics of white wines in (former) cool climate wine regions, is expected to be negatively affected by high ripening temperatures [80]. Moreover, such high ripening temperatures are supposed to lead to higher concentrations of some specific phenols and an as stringent wine taste [123]. Projected future increases in minimum temperatures during ripening, for example on the Iberian Peninsula [98], may also result in a decrease in wine quality. Higher respiratory rates at night associated with higher temperatures will consume more sugar, which is a key precursor for the biosynthesis of vital flavour compounds. Future warmer climates may also have positive impacts for several traditional wine regions in Western and Central Europe, such as Burgundy, Champagne, Alsace, Loire Valley, Rheingau, and Mosel [95; 114], as well as for potential new areas north- and eastwards of these traditional regions, although there are still many uncertainties owed to the complex interplay of different factors. As an example, a doubling of the areas suitable for viticulture in Austria by 2050s was projected on the basis of temperature evolution [124]. Hungarian southern winemaking regions are also expected to expand [125]. Furthermore, the expected warming in Central and Northern Europe will lead to longer growing seasons and frost-free periods [126], which will reduce fall frost damage and favour potential wine quality [127]. The impact of climate change on spring frost risk has been discussed controversially in the scientific literature in recent years. Generally, spring frost occurs when budburst precedes the date of the last frost event in the spring of a given year. Under future climate conditions, both events are projected to occur earlier.