In light of the strong relationships between climate and viticulture many researchers have investigated the impacts of climate change on viticulture on a global scale.
3.1 Global climate trends and impacts of climate change on viticulture
3.1.1 The status of global wine sector
All wine growing regions are divided into the so-called “Old world winegrape regions” (i.e. France, Italy, Spain, Portugal, Greece, Austria, Hungary and Germany) and “New world winegrape regions” (i.e. United States, Australia, South Africa, Chile, Argentina and New Zealand). Among them, France, Italy and Spain produce almost half of the wine produced on a global scale.
3.1.2 Climatic conditions and trends
An early study in the coasts of California reported an assymetric warming with higher trends in temperature during night and spring. Another study in the Australian winegrape areas resulted that average air temperature during the growing season (October to April in the Southern Hemisphere) increased at a higher rate regarding the inland regions compared to the more coastal ones.
In Europe, similar studies have been conducted and the results suggested warmer and drier conditions in the majority of the winegrape regions namely France, Spain, Italy, Germany and Portugal.
3.1.3 Phenology and future viticulture suitability
These warmer conditions have been proved to be responsible for earlier phenological events.
During the last decades, the majority of wine growing regions showed significant warming trends resulting in significantly earlier occurrence of budburst, flowering, véraison and harvest. For example an early study on the Bordeaux region showed that two of the most important varieties (cultivars Merlot and Cabernet Sauvignon) trended earlier leading to shorter phenological intervals. Moreover, warmer conditions in the Iberian Peninsula strongly related with earlier phenology in the study regions. Such results led scientists to explorefuture suitability of the traditional winegrape regions to the upcoming climate changes. A relevant study modelled the suitability of the most important winegrape regions in USA using different climatic variables and resulted that the number of suitable wine producing regions could be significantly decreased by the end of the century. In Europe, a study focused on viticultural zoning using ensemble projections for two future periods concluded that it is likely for some regions to explore the possibility of selecting alternative winegrape varieties more resilient to warmer conditions while others to relocate at higher altitudes.
3.2 Climate trends and the impacts of climate change on viticulture in Greece
3.2.1 The status of Greek wine sector
Greece is one of the oldest wine producing regions of the world. According to the latest report of the International Organization of Vine and Wine (OIV) today the area cultivated with wine grapes covers approximately 110 000 ha, 1/3 of which are under geographical indication, where 200 indigenous varieties are cultivated. Among them 4 cultivars (Savatiano, Roditis, Agiorgitiko and Xinomavro) represents approximately 1/3 of the total wine production.
3.3.1 Climatic conditions and trends
Greece is one of the warmest winegrape regions in Europe. Based on a previous study most of Greece’s wine producing areas are currently classified as hot and very hot according to the GST index with some cooler areas situated in higher altitudes. Moreover, during the last 30 years in the main winegrape areas of Greece there is a significant warming trend especially regarding night time temperatures in the majority of the studied regions. This warming trend resulted in an increase in the total number of days with maximum temperature above 30oC and total number of days with minimum temperature above 20oC.
3.3.2 Phenology and future viticulture suitability
A study that focused on investigating the relationships between harvest dates and climate for eight indigenous winegrape varieties showed thatin 5 out of 8 locations harvest commenced significantly earlier mostly driven by maximum air temperature during the growing season.
Another study examined the potential shifts in regional classifications using the above mentioned bioclimatic indices for the current period and two future periods (2021-2050 and 2061-2090).Overall, the resultssuggested that the majority of the regions will be facing warmer and drier condition in the future.
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