Projected changes of grapevine phenology in Belgian and South African vineyards under climate change scenarios

Abstract

The concept of ‘terroir’ describes the interplay of the environmental factors that affect the grapevine. This includes but is not limited to climate, soil composition, vineyard management, topography, and geology. Climate is considered one of the most important factors and is receiving increased attention, as climate change has a considerable impact on grapevines. Temperature is the main driver of grapevine phenology, and its increase can affect grape growth by shifting phenological stages. Significant advancements of phenological stages have been recorded over recent decades and are predicted to continue in the future, changing the suitability of certain varieties for specific regions. In this study, we analysed the relationship between grapevine phenology variability and weather conditions in vineyards in two regions of interest, namely Belgium and South Africa, and predicted the potential changes under climate change. Dates of budbreak, flowering, veraison and maturity were evaluated for Chardonnay and Pinot noir, and projections were made for 2050 and 2070 under two climate change scenarios: SSP1-2.6 and SSP5-8.5. The onset of veraison in the Belgian vineyard was predicted to be on average up to 27 days earlier by 2070 under the worst case scenario, while harvest in the South African vineyard will on average be 35 days earlier under the same scenario by 2070 according to our results. The ripening period will also shift to a warmer period of summer, which can potentially change grape composition and ultimately also wine quality. Our findings have the potential to provide winegrowers with a more detailed understanding of grapevine responses to climate change, enabling them to anticipate on this by changing their vineyard management or changing rootstocks and/or varieties.