Late frost damage risk for viticulture under future climate conditions: a case study for the Luxembourgish winegrowing region

Background and Aims: Late frosts are a significant risk to grape production in frost-prone viticultural regions. Increasing air temperature because of climate change is likely to advance grape budburst and last frost events in spring. So far, it is unclear whether one trend will be more pronounced than the other, and hence, whether the risk of late frost damage will increase or decrease. The aim of this work was to investigate the future frost risk in the Luxembourgish winegrowing region by assessing the effect of simulated future climate conditions on the timing of budburst and last frost date. Methods and Results: Late frost risk was assessed by combining: (i) a phenological model for budburst of the grapevine (DORMPHOT); and (ii) ensemble-based projections of future air temperature. Analyses indicated that increasing spring temperature will advance the timing of budburst and the date of the last frost. This advancement, however, will be more pronounced for last frost events than for budburst. Conclusions: Modelled projections showed that the frequency of spring frost damage in the Luxembourgish winegrowing region will decrease, without completely excluding them for the near (2021-2050) or the far future (2069-2098). Significance of the Study: The application of a combination of a phenological model for grape budburst and ensemble-based projections of future air temperature enables the assessment of the future late frost risk in a frost-prone viticulture region.