The The use of GFV and GSR temperature-based models in emerging wine regions to help decision-making regarding choices in grape varieties and wine styles. Application to Brittany (France)

Abstract

Viticulture and wine production are facing climate change. While it can be a challenge in some regions, it is an opportunity for others. The aim of this study is to develop a methodology to assess climatic characteristics and potential for viticulture of new areas, through spatial analyses of data from temperature-based grapevine models (the Grapevine Flowering Veraison model -GFV and the Grapevine Sugar Ripeness model -GSR) during current and future periods. A deadline for veraison was set on the 1st of September for dry wine and on the 15th of September for sparkling wine. Different sugar levels were targeted for the production of different wine styles (170 g·L-1 for sparkling wine, 190 g·L-1 and 200 g·L-1 dry white and red wines, respectively) on the 15th of October. The methodology was applied over the region of Brittany (France) to assess the potential to produce different wine styles from 6 grapevine varieties (‘Sauvignon blanc’, ‘Chardonnay’, ‘Chenin’, ‘Pinot noir’, ‘Cabernet franc’ and ‘Cabernet-Sauvignon’). Observed data from the Météo-France weather stations network and an 8-km gridded climate model data from the 2014 EUROCORDEX simulation set (CNRM-CM5/RCA4 climate model) were used over the past (1950-2020) and future periods (2031-2060 and 2071-2100) under two GHG emission scenarios (RCP 4.5 and 8.5). Climatic conditions of this region seem to be increasingly suitable in the future depending on climate scenario, time period projections and targeted types of wine. The methodology can be applied to any emerging winegrowing region with the ability to adjust variety choices, time lines and sugar levels thresholds as desired to meet the needs of a specific region.