The impact of climate change on grapevine phenology and the influence of altitude: a regional study

Simulations of the effect of climate change on the phenology of grapevines indicate shorter growing seasons, earlier occurrences of phases and shorter phase duration in the future. The impact varies depending on the geolocalization of the studied region and its microclimate. The objective of this study is to further understand the impact of climate change on grapevine phenology by studying the role of varieties and microclimates through a regional assessment carried out in two future periods of time (2021–2050 and 2071–2099). The influence of altitude on phenological stages was studied on five different phenophases for five grapevine varieties in the province of Trento (Italian Alps). The model predicts a significant advance for all phenological stages (advanced harvest up to four weeks), which could affect the quality and suitability of the region for the selected varieties. In particular, the model indicates shorter phenophases and a shorter time between bud break and harvest, from one to three weeks. Furthermore, projected phenological changes are not homogeneous in the region under study: more pronounced effects of the temperature increase are expected at higher altitudes. Indeed, phenological advance is more pronounced for varieties grown at higher altitudes. On the contrary, phase duration and growing season length are more affected on the varieties grown at lower altitudes. A lower spread of harvest timing is expected in altitudinal transects, up to 3 days for every 100 m. We can conclude that adaptation strategies such as change of varieties, harvest management and wine making technologies will be necessary to cope with the effect of climate change