Agroclimatic zoning of wine denominations of origin in Portugal: current and future conditions

Weather and climatic conditions have a strong implication on wine production and quality. High-Resolution agroclimatic zoning over 50 protected denominations of origin (DOs) in Portugal is carried out using two agroclimatic indices commonly applied in viticultural zoning (dryness and Huglin indices). For this purpose, a high-resolution dataset of climate data over Portugal and for 1981–2015 (baseline) is used. Furthermore, climate change projections are assessed based on two anthropogenic forcing scenarios (RCP4.5 and RCP8.5), retrieved from a 5-member climate model ensemble over two future periods (medium-range: 2041–2070, and long-range: 2071–2100). An optimized compound index was isolated from a principal component analysis applied to the time mean spatial patterns of the two selected indices, for baseline and over vineyard cover areas in each region only. The spatial variability of Portuguese DOs is highlighted. For the future periods, and regardless of the scenario, significant changes in the agroclimatic conditions are projected for most of the DOs. In future scenarios, strong upward trends in the growing-season mean temperatures, along with an overall strengthening of dryness are projected. This is particularly noteworthy in south-eastern Portugal and north-eastern Portugal along the upper Douro Valley. Hence, as Portuguese DOs are projected to become much drier than currently, irrigation or the selection of new varieties are likely adaptation measures to maintain the viability and sustainability of regional viticulture in future decades. New research methods and decision support tools should be applied to assist stakeholders in developing more climate change-resilient viticulture. The Clim4Vitis project (Climate change impact mitigation for European viticulture: knowledge transfer for an integrated approach, WIDESPREAD-05-2017 Twinning, European Union’s Horizon 2020 research and innovation programme, under grant agreement nº 810176) has been very active in promoting capacity building activities and knowledge transfer to the European winemaking sector.