High resolution climatic zoning of the Portuguese viticultural regions

Viticulture and winemaking represent a key sector for the Portuguese economy. As grapevines are strongly governed by atmospheric factors, climate change may impose a major threat to this crop. In this study, the current-past (1950-2000) and future (2041-2070) climatic conditions in Portugal are analyzed using a number of bioclimatic indices, including a new categorized index (CatI). A two-step method of spatial downscaling is applied in order to attain a very high spatial resolution (near 1 km) over Portuguese mainland. Future projections are established using an ensemble of 13 regional climate models, under the IPCC A1B-SRES emission scenario. Results show that CatI integrates the most important bioclimatic characteristics of a given region, and allows the direct comparison between them. Outcomes for the recent-past are in clear agreement with the current geographical distribution of this crop and of the established winemaking regions. Conversely, under future scenarios, projections point to a lower bioclimatic diversity, due to the expected warming and drying throughout the country. This will likely lead to changes in grapevine suitability and wine characteristics of each viticultural region, which may result in additional challenges for the winemaking sector. As such, suitable adaptation measures need to be developed in order to mitigate climate change impacts on the Portuguese viticulture.