Future scenarios for wine production in the Douro (Portugal)

Abstract

Wine production is known to be largely dependent on favorable environmental conditions. The Douro Valley in Portugal is known for its world-famous wines, such as Port Wine. Establishing relationships between atmospheric elements and viticultural parameters is of great importance for the region in order to provide a measure of yield predictability. Furthermore, future human-driven climate change is projected to have significant effects on the winemaking sector worldwide. A long wine production series for the Douro, from 1932 to 2010, shows that high precipitation and cool temperatures during early development stages (February-March) and high temperatures during berry development (May) are commonly favorable to high production. Additionally, the modeled probabilities of three production classes (low, normal and high) are assessed. These statistical approaches are useful tools for seasonal forecasting, given monthly temperatures and precipitation 3-4 months prior to harvest. For future projections, an ensemble of 16 climate model experiments, under the SRES A1B climate change scenario, is used. Production is projected to rise by about 10% until the end of the 21st century, while the occurrence of high production years is expected to increase from 25% to over 60%. Nonetheless, further model research will be needed to include other aspects that may influence future wine production. Particularly, the increase in heat and hydric stresses, combined with changes in ripening conditions, could significantly limit the estimated production increase.