Land use options for Viticulture in Portugal in light of bioclimatic shifts

<p>Climate and land are closely intertwined through multiple interface processes. On one hand, land endows means for agriculture practices and agroforestry systems thus contributing to the food and materials supply; on the other, climate change may lead to significant impacts in land use and efficient water availability and management. Therefore, the study of these interactions and the impact of the bioclimatic shifts, since land use, plays a relevant role in the climatic system is highly relevant.</p><p>Towards this aim, in this study, 1‒km observational gridded datasets are used to assess changes in the Köppen–Geiger and Worldwide Bioclimatic (WBCS) Classification Systems in mainland Portugal. As such, two past periods were analyzed: 1950–1979 and 1990–2019. A compound bioclimatic-shift exposure index (BSEI) is defined to identify the most exposed regions to recent climatic changes. The temporal evolution of land cover with vineyards between 1990 and 2018, as well as correlations with areas with bioclimatic shifts, are then analyzed.</p><p>Results show significant climatic changes between the two periods with an increase of 18.1% in the Warm Mediterranean with hot summer (CSa) climate in Portugal. This increase was followed by a 17.8% decrease in the Warm Mediterranean with warm summer (CSb) climate. Furthermore, the WBCS Temperate areas also reveal a decrease of 5.11%. Arid and semi-arid ombrotypes areas increased, whilst humid to sub-humid ombrotypes decreased. Thermotypic horizons depict a shift towards warmer classes. BSEI highlights the most significant shifts in northwestern Portugal.</p><p>Overall results show that vineyards have been displaced towards regions that are either the coolest/humid, in the northwest, or the warmest/driest, in the south. Since vineyards in southern Portugal are commonly irrigated, options for the intensification of these crops in this region may threaten the already scarce water resources and challenge the future sustainability of this sector. As similar problems can be found in other regions with Mediterranean-type climates, the main findings of this study can be easily extrapolated to other wine producer countries worldwide.</p><p><strong>Acknowledgement:</strong> This work was supported by National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020.</p><p><strong>Keywords:</strong> Köppen-Geiger Climate Classification, Worldwide Bioclimatic Classification System (WBCS), Vineyards, Portugal.</p>