Dual pressures of climate change and wildfire hazard on wine-growing potential in California

This study presents an integrated analysis to assess climate change impacts on wine grape cultivation in California by jointly considering spatial suitability, wine quality, and wildfire weather. Species distribution modeling based on MaxEnt algorithm (AUC > 0.93) indicates substantial declines in climatic viticulture suitability across major regions such as Napa and Sonoma, alongside notable increases in northern and coastal areas under high emission scenario in future climate. While many regions show concurrent increases in suitability and extreme fire-weather days, areas such as Mendocino and Monterey exhibit increasing suitability coupled with decreasing extreme fire-weather days, identifying them as comparatively favorable expansion zones. Wine quality projections using a Random Forest classification model (F1 score > 0.94) show that responses to fire-weather conditions differ by variety. In Sonoma, Chardonnay tends to achieve higher quality in years without extreme fire weather but declines in high fire-danger years, whereas Pinot Noir shows the opposite tendency. These contrasting responses suggest that varietal selection will be critical for adaptation under increasing wildfire danger. Overall, the results highlight the importance of integrating disturbance regimes into climate impact assessments for sustainable viticulture.