Future exposure of Portuguese viticulture to weather extremes

Grape berries and their yields can be strongly affected by the complex connections and interactions between the grapevines and the conditions of the local environment. In areas of known wine production, the yield and quality are usually improved by considering the climate, planting the best grape variety, and using specific agricultural techniques. Thus, sustainability in the winemaking sector worldwide is under pressure due to ongoing climate change, requiring adaptation at multiple levels. Portuguese vineyards will experience increasingly dry and warm conditions due to climate change, with varying degrees of intensity and frequency of weather extremes. Nevertheless, the potential effects of these extraordinary occasions and their effects on viticulture in the future are not well known. In this research, we calculated seventeen climate extreme indices for the Portuguese wine denomination of origin regions/subregions in the historical period (1981–2010) and future periods (2041–2070 and 2071–2100), under the Representative Concentration Pathway 8.5, and based on a five-member ensemble of Regional Climate Model-Global Climate Model chain simulations. Moreover, a principal component analysis was performed for both precipitation and temperature extremes independent of each other. All of Portugal's wine regions experienced an increase in temperature extremes, predominantly in the westernmost regions. When it comes to the precipitation extremes, they show a decrease in the future and a general decline in precipitation but still are a major risk in the northeastern regions. In contrast, the dry extremes, likely bringing on severe droughts, will become much stronger. Finally, it was then possible to recognize which wine regions will be the most vulnerable to extreme weather conditions in the future. This information is essential for enabling smarter choices in the sector, including for long-term planning, climate change adaptation and risk reduction.

Acknowledgments: Soil recover for a healthy food and quality of life (SoilRec4+Health). Projeto cofinanciado pelo Fundo Europeu de Desenvolvimento Regional (FEDER) através do Programa Operacional Regional do Norte (NORTE-01-0145-FEDER-000083).